Assembly type reinforced concrete-steel structure foundation pit supporting system convenient to disassemble and construction technology

Abstract

The invention relates to the field of constructional engineering, and discloses an assembly type reinforced concrete-steel structure foundation pit supporting system convenient to disassemble and a construction technology, and the assembly type reinforced concrete-steel structure foundation pit supporting system comprises a top beam, a waist beam, a supporting pile and an inner supporting system; the inner supporting system is formed by assembling a standard steel-concrete beam section main support and a steel member auxiliary support in cooperation with a jack adjusting system. The invention further provides a new system on-site assembly construction process, namely detailed steps of assembly construction from the uppermost layer to the lower layer step by step. The fabricated structure integrates the advantages of two fabricated structures, is suitable for foundation pit supporting with large stress and strict deformation control, and has the advantages of being high in construction speed, short in construction period, low in construction cost, convenient to dismantle and capable of completely recycling most of inner supporting components compared with a traditional cast-in-place steel-concrete foundation pit supporting system.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to an easily dismantled assembled steel-concrete-steel structure foundation pit support system and a construction process. Background Art

[0002] In foundation pit engineering projects, foundation pit support plays a vital role. Its main function is to effectively support the surrounding soil, thereby ensuring the overall stability of the foundation pit and avoiding excessive deformation of the surrounding soil.

[0003] In situations where the ground stress is large, cast-in-place reinforced concrete internal support is the best choice. It has the advantages of flexible design, good integrity, high pressure resistance and high reliability. However, it also has the disadvantages of long construction period, difficult demolition, short service life and low recycling value of the main material.

[0004] In order to overcome the shortcomings of cast-in-place reinforced concrete internal supports, the Chinese patent announcement number: CN118793069A discloses an easily dismantled assembled reinforced concrete foundation pit support system and construction method. The internal supports provided by the patent are completely made of prefabricated concrete components. Although they are easy to dismantle and reuse, all parts of the internal supports are made of prefabricated concrete components regardless of the stress, resulting in a large deadweight of the internal supports, which is inconvenient to transport and install, and the cost is also high.

[0005] In order to overcome the above problems, a new type of prefabricated steel-concrete-steel structure foundation pit support system needs to be developed for foundation pits with large ground stress. This system should give full play to the advantages of prefabricated steel-concrete beam sections, such as easy dismantling and installation, reusability, and shortened construction period. Prefabricated reinforced concrete supports are used in the direction of large stress, and steel structure auxiliary supports are used in the direction of small stress. This can not only obtain a reliable support system with good integrity, but also reduce the overall weight of the support in the foundation pit, so that all parts of the support in the foundation pit can be recycled, reducing the cost and construction period of the support in the foundation pit. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides an easy-to-dismantle assembled steel-concrete-steel structure foundation pit support system and construction process, which not only takes advantage of the assembled support beams that are easy to dismantle and install, can be reused, and shorten the construction period, but also solves the problems in the prior art that the foundation pit support system cannot be used in conjunction with steel support components, the internal support has a large dead weight, is inconvenient to construct and has a high cost.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an easily dismantled assembled steel-concrete-steel structure foundation pit support system, comprising a crown beam, a waist beam, support piles and an internal support system, wherein the internal support system is composed of a plurality of main supports composed of a plurality of prefabricated steel-concrete beam sections, a plurality of steel structure auxiliary supports, a plurality of steel lattice columns and an adjustment system; the steel-concrete beam sections are standard parts of the same structure and size; The crown beam and waist beam are provided with a plurality of corbels, each of which is provided with a cap; Each of the main supports is formed by axially connecting a plurality of steel-concrete beam sections, and the connection point between two steel-concrete beam sections is an axial node; a plurality of steel structure auxiliary supports are connected between adjacent main supports, and the connection method is that the two ends of the steel structure auxiliary supports are connected to one side of the two axial nodes of the adjacent main supports; one side of the axial node of some main supports close to the foundation pit wall is connected to a steel structure auxiliary support, and the other end of the steel structure auxiliary support is connected to the side of the crown beam or the waist beam, and the steel structure auxiliary support here is a steel structure eight-shaped beam; The main support described above forms a row of main supports or two main supports are connected to form a row of main supports through an adjustment system, and both ends of each row of main supports are placed on the bearing platform; The main support is installed on the steel lattice column, and the contact position between the main support and the steel lattice column is staggered with the axial node.

[0008] Furthermore, the surface of the steel-concrete beam section is provided with a beam sleeve, and a rectangular concrete is arranged inside, and a cable hole is arranged in the rectangular reinforced concrete; longitudinal rebar holes, vertical screw holes, and transverse screw holes are arranged at both ends of the steel-concrete beam section, and the longitudinal rebar holes, vertical screw holes, transverse screw holes, and cable holes do not intersect with each other.

[0009] Furthermore, the structure of the axial node is as follows: the end surfaces of the two steel-concrete beam sections are tightly fitted, and connecting steel plates are provided in each span of the upper and lower surfaces of the fitting part, and No. 6 holes are opened on the connecting steel plates, and the longitudinal rebar holes on the end surfaces of the two steel-concrete beam sections are aligned one by one and round steels are inserted.

[0010] Furthermore, a cable adjuster is provided below the axial node, and the cable adjuster is composed of an adjuster base plate, an adjusting screw, an adjuster support rod, a web, a left-handed nut, a fixing piece, a right-handed nut, and a pin shaft; a No. 2 hole is provided on the adjusting base plate; two fixing pieces are welded on the web and the adjusting base plate; each fixing piece has two pin shafts, and two adjuster support rods are connected to the two pin shafts, and the other ends of the two adjuster support rods are respectively connected to a right-handed nut and a left-handed nut through the pin shafts; a handle is provided at the end of the adjusting screw, and a There are two groups of positive and negative threads, each group of positive and negative threads includes a right-hand thread and a left-hand thread; each group of positive and negative threads is equipped with a right-hand nut and a left-hand nut; the vertical screw hole at the axial node, the No. 6 hole on the two connecting steel plates and the No. 2 hole on the inclined cable adjuster are coaxial, and vertical tension screws are passed through, and nuts are provided at both ends of the vertical tension screws; the inclined cable is inserted into the inclined cable hole, and the inclined cable extends from the inclined cable hole of one steel-concrete beam section and extends from the inclined cable hole of another adjacent steel-concrete beam section; the two ends of the inclined cable are fixed with anchor heads, and the middle part is placed on the web of the inclined cable adjuster.

[0011] Furthermore, the steel structure auxiliary support is formed by welding frame members and end plates; the frame members are I-beams, steel pipes or H-shaped steels; the end plates are steel plates, on which No. 1 holes for connection are provided, and the No. 1 holes have the same diameter and spacing as the transverse screw holes.

[0012] Furthermore, after the No. 1 hole of one end plate of the steel structure S-beam is aligned one by one with the transverse screw hole at the axial node position on the steel-concrete beam section close to the foundation pit wall, a transverse tension screw is inserted, and the two ends of the transverse tension screw are fixed with nuts; the other end plate of the steel structure S-beam is fixed to the crown beam or waist beam with bolts.

[0013] Further, there are three ways to connect one side of the axial node with the steel structure auxiliary support. The first one is: one side of the axial node is connected to a steel structure auxiliary support, and the end plate is connected to the axial node across the seam, that is, the No. 1 hole of the end plate is respectively connected to the transverse screw hole on one side of the end of the two steel-concrete beam sections connected at the axial node, and fixed with transverse tension screws and nuts; The second type is: one side of the axial node is connected to two steel structure auxiliary supports, a side connection steel plate is arranged on one side of the axial node, the side connection steel plate has four rows of No. 5 holes, the span seams correspond one-to-one with the two rows of transverse screw holes on the sides of the two steel-concrete beam sections at the axial node, and also correspond one-to-one with the No. 1 holes on the end plates of the two steel structure auxiliary supports, and after the transverse tension screws pass through the coaxial No. 1 holes, No. 5 holes and transverse screw holes, both ends are tightened with nuts; The third type is: there is no auxiliary support connection on one side of the axial node, the axial node is installed on this side with a connecting steel plate, and the transverse tension screw is passed through the No. 5 hole and the transverse screw hole, and the two ends of the transverse tension screw are fixed with nuts.

[0014] Furthermore, the adjustment system is divided into a mid-beam adjustment system and a beam end adjustment system; the mid-beam adjustment system includes a force-retaining steel structure and a jack placed on the force-retaining steel structure, and the beam end adjustment system includes a force-retaining head, a gasket and a jack arranged on the pedestal; the force-retaining steel structure is composed of part A, part B, steel sheets, insert rings and insert plates; part A is composed of two long steel plates and a steel partition plate vertically welded between the two long steel plates, wherein a connecting plate is welded on one side of a long steel plate, and the connecting plate has a number three hole; a force-retaining box is welded on one side of the other long steel plate, and the force-retaining box is formed by welding steel plates; part B is composed of two long steel plates and a steel partition plate vertically welded between the two long steel plates, wherein a connecting plate is welded on one side of a long steel plate, and the connecting plate has a number four hole, and a jack is welded on one side of the other long steel plate Top support and protruding steel plate, the jack support is formed by welding a semicircular steel plate on a long steel plate; the height of the long steel plate and several steel partitions is the same as the cross-sectional height of the steel-concrete beam section; the connecting plate is a group of two, and the spacing between the two connecting plates is the same as the cross-sectional width of the steel-concrete beam section; the plug ring is welded on the side of the force box at both ends of part A and the side of the two end heads of part B; the arrangement and aperture of the No. 3 hole and the No. 4 hole are the same as the transverse screw holes of the steel-concrete beam section, and the width of the steel sheet is the same as the width of the force box; the force box of part A is placed on the protruding steel plate of part B, and the connection between part A and part B is achieved by inserting the plug plate into the plug ring; the connection between the force steel structure and the main support is achieved by making the No. 4 hole on the connecting plate correspond one by one to the transverse screw hole of the main support end, inserting the transverse tension screw and tightening it with a nut.

[0015] Furthermore, there are two types of the pedestals, one of which is composed of embedded steel plates, embedded steel bars, a pedestal bottom plate, and pedestal side plates; the other of which is composed of embedded steel plates, embedded steel bars, a pedestal bottom plate, a pedestal side plates, a jack wooden support, a force-retaining head, and a gasket; the force-retaining head is formed by welding an I-beam and a steel plate, the steel plate size of the force-retaining head is the same as the cross-sectional size of the steel-concrete beam section, the embedded steel plates are all arranged at the corbels, and embedded steel bars are welded to one side of the embedded steel plates.

[0016] Furthermore, a pallet is provided on the steel lattice column, and the main support is placed on the pallet. One side of the steel-concrete beam section in the main support is close to the lattice column. One end of a clamp is welded on the pallet, and the clamp embraces the main support. The other end is welded to the steel lattice column to fix the main support.

[0017] Furthermore, L-shaped pre-buried holes and I-shaped pre-buried holes for wire saw cutting are preset every 3-5 m in the crown beam and waist beam respectively; The L-shaped embedded hole is formed by embedding an L-shaped PVC tube in the crown beam. The L-shaped PVC tube has two openings at both ends, one end is opened on the upper surface of the crown beam, and the other end is opened on the side of the crown beam. The embedded position of the L-shaped PVC tube is staggered with the position of the corbel. The I-shaped embedded hole is formed by embedding an I-shaped PVC pipe in the waist beam. Both ends of the I-shaped PVC pipe are open, one end is located on the top surface of the waist beam, and the other end is located on the bottom surface of the waist beam. The I-shaped PVC pipe is embedded on one side of the waist beam close to the supporting pile, and the embedded position of the I-shaped PVC pipe is staggered with the position of the corbel.

[0018] Furthermore, the construction process of the prefabricated steel-concrete-steel structure foundation pit support system that is easy to dismantle includes the following construction steps: 1) Construction of multiple support piles, column piles and steel lattice columns; 2) Roughen the pile heads of the supporting piles, tie the steel cage of the crown beam, embed the L-shaped PVC pipe, weld the embedded steel bars to the embedded steel plates, and after welding, tie the embedded steel bars to the steel cage of the crown beam, and tie the remaining steel bars at the corbel; 3) Carry out formwork for the crown beam and its upper corbel, and pour concrete after formwork completion. When pouring concrete, ensure that the positions of the embedded steel bars and embedded steel plates do not shift. After the concrete curing is completed, carry out subsequent construction; 4) Excavate to the bottom elevation of the first inner support beam, and excavate 1 m more at the steel lattice columns and corbels; 5) Weld the tray on the steel lattice column and weld the cap on the embedded steel plate; 6) The main supports are constructed row by row. The steel-concrete beam sections are hoisted into the foundation pit for assembly, and assembled from one end of a row of main supports to the other end. When connecting adjacent steel-concrete beam sections, round steel is first inserted into the longitudinal reinforcement holes. After the end faces of the two steel-concrete beam sections are closely attached, the connecting steel plates are installed and fixed with vertical tension screws and nuts. The main supports are placed on the pallet, with one side of the steel-concrete beam section in the main supports close to the lattice column, and both ends of each row of main supports are placed on the cap. 7) Install the auxiliary support of the steel structure. For the installation of the auxiliary support between the main supports, use transverse tension screws and nuts to connect the auxiliary support with the adjacent main support; for the installation of the steel structure S-shaped beam, use transverse tension screws and nuts to connect the steel structure S-shaped beam with the axial node of the main support near the foundation pit wall at one end, and fix the other end to the crown beam with bolts; fill the installation gap between the steel structure auxiliary support and the side of the axial node with steel bars; 8) Install the mid-beam adjustment system, install the steel structure in the middle of the main support, fix Part A and Part B to the main supports on both sides through the connecting plates with transverse tension screws and nuts, then place the force box of Part B on the protruding steel plate of Part A, and connect Part A and Part B by inserting the insert plate into the insert ring; finally, install the jack on the jack support; 9) Install the beam end adjustment system, install the force head on the cap and place the jack wooden support, install the jack on the jack wooden support, and make the longitudinal axis of the jack's plunger coincide with the longitudinal axis of the main support; 10) The jacks are pressurized at the same time, the jacks on the beam adjustment system extend the A part of the force-retaining steel structure, and the jacks on the beam end adjustment system extend the force-retaining head; a number of steel sheets are inserted into the gap between the force-retaining box and the B part of the force-retaining steel structure, and a number of gaskets are inserted into the gap between the force-retaining head and the embedded steel plate, so that the end faces of all axial nodes of each main support are closely fitted; welding clamps; 11) Depressurize the jack so that the plunger of the jack is out of contact and remove the jack; 12) Excavate to the bottom elevation of the second inner support beam, and excavate 1 m more at the steel lattice columns and corbels; 13) Roughen the supporting pile body, tie the steel cage of the waist beam, embed the I-shaped PVC pipe, weld the embedded steel bars to the embedded steel plate, and after welding, use steel wire to tie the embedded steel bars to the steel cage of the waist beam, and tie the remaining steel bars at the corbel; 14) Carry out formwork for the waist beam and its upper corbel, and pour concrete after formwork completion. When pouring concrete, ensure that the positions of the embedded steel bars and embedded steel plates do not shift. After the concrete curing is completed, carry out subsequent construction; 15) Weld the tray on the steel lattice column and weld the cap on the embedded steel plate; 16) The steel-concrete beam segments are hoisted into the foundation pit for assembly; the assembly method is the same as step 6); 17) Install the auxiliary steel support. For the installation of the auxiliary support between the main supports, use transverse tension screws and nuts to connect the auxiliary support with the adjacent main support. For the installation of the steel structure S-shaped beam, use transverse tension screws and nuts to connect the steel structure S-shaped beam with the axial node of the main support near the foundation pit wall at one end, and fix the other end to the waist beam with bolts. Fill the installation gap between the steel structure auxiliary support and the side of the axial node with steel bars; 18) Install the mid-beam adjustment system and the end-beam adjustment system in the same way as step 8) and step 9) respectively; 19) The jacks apply pressure at the same time, insert several steel sheets into the gap between the force box and the B part of the force steel structure, and insert several gaskets into the gap between the force head and the embedded steel plate; weld the clamps; 20) Depressurize the jack so that the plunger of the jack is out of contact and remove the jack; 21) Repeat the steps from 12) to 20) until the construction of the remaining internal supports below the second internal support is completed; 22) After completing the installation of the last support, pour the foundation slab.

[0019] Furthermore, after the construction of the internal support system is completed, angle steels are welded at the four corners where the connecting steel plate is connected to the side connecting steel plate or at the four corners where the connecting steel plate is connected to the end plate of the auxiliary support.

[0020] Furthermore, an alternative step to the step 6) is: construct the main supports row by row, hoist the steel-concrete beam sections into the foundation pit for assembly, and assemble from one end of a row of main supports to the other end; when connecting adjacent steel-concrete beam sections, first insert round steel into the longitudinal reinforcement holes, and after the end surfaces of the steel-concrete beam sections are tightly attached, install the connecting steel plates and the inclined cable adjusters, first fix the connecting steel plates and the inclined cable adjusters with vertical tension screws and nuts, then pass the inclined cables through the inclined cable holes, fix the ends of the inclined cables with anchor heads, and when the inclined cables pass over the axial nodes, they are placed on the webs of the inclined cable adjusters.

[0021] Compared with the prior art, the technical solution of this application has the following beneficial effects: 1. The present invention provides an assembled steel-concrete-steel structure foundation pit support system which is easy to dismantle. The steel-concrete beam section and the steel structure auxiliary support are used as the main supporting components of the support inside the foundation pit, eliminating the processes of steel bar binding, concrete pouring and maintenance of the cast-in-place steel bar support inside the foundation pit, greatly shortening the construction period of the support inside the foundation pit, greatly saving time and labor costs, and reducing the cost of foundation pit support.

[0022] 2. The present invention provides an easy-to-dismantle assembled steel-concrete-steel structure foundation pit support system. Reinforced concrete is used for support in locations or directions with greater stress, and steel structure support is used in locations or directions with less stress. This not only gives full play to the advantages of the two materials and structures, but also greatly reduces the weight of the internal support system, making it easier to hoist, transport and install, and also saving costs. The assembled steel-concrete-steel structure foundation pit support system provided by the present invention can provide various forms of planar support structures that can adapt to a variety of application sites.

[0023] 3. The present invention provides an assembled steel-concrete-steel structure foundation pit support system that is easy to dismantle. The structure and specifications of the steel-concrete beam sections in the foundation pit are exactly the same, thereby achieving standardization of the foundation pit support beam sections over a larger range, greatly reducing the production cost of the steel-concrete beam sections, making it easier to reuse and reducing the cost of foundation pit support.

[0024] 4. The present invention provides an assembled steel-concrete-steel structure foundation pit support system which is easy to dismantle. The steel-concrete beam sections, steel structure auxiliary supports and other components in the foundation pit are connected by means of tension screw anchoring, etc., so that the steel-concrete beam sections in the foundation pit can be completely recovered and can be reused many times, which greatly reduces the cost of a single foundation pit support.

[0025] 5. The present invention provides a connection method for assembled steel-concrete foundation pit support beam sections that can be matched with steel supports. Common tools such as steel plates, round steels, tension screws, and nuts are used to fix the steel-concrete beam sections and the steel structure auxiliary supports. The node connections are reliable, the support system has high rigidity, and the integrity of the entire system is good, which greatly reduces the cost of connection construction. In addition, the steel plates, round steels, tension screws, nuts and other tools used for connection can all be recycled for multiple times, which greatly reduces the cost of single use and speeds up the construction speed of the support in the foundation pit.

[0026] 6. The present invention provides an assembled steel-concrete-steel structure foundation pit support system that is easy to dismantle. Cable adjusters and cables are installed at the axial node positions of the steel-concrete beam sections. The cable adjusters and cables cooperate to reduce the negative bending moment at the nodes, thereby enhancing the safety and stability of the internal support system.

[0027] 7. The present invention provides an easily dismantled assembled steel-concrete-steel structure foundation pit support system. By casting a section of corbel on the crown beam or waist beam, the situation that the standard size of the steel-concrete beam section is not suitable for the size of the foundation pit is avoided, and the purpose of flexible use of the steel-concrete beam section is achieved, so that the steel-concrete beam section can be used in various regular or irregular foundation pit shapes, which greatly facilitates the application scope of the dismantled assembled steel-concrete-steel structure foundation pit support system and facilitates the recycling of various supporting components in the foundation pit.

[0028] 8. The present invention provides an easy-to-dismantle assembled steel-concrete-steel structure foundation pit support system, adopts a full-life design concept, and pre-buries holes for rope saw cutting in the crown beam and waist beam of the foundation pit. During the cutting and dismantling process of the crown beam and waist beam of the foundation pit, drilling is avoided, which speeds up the dismantling of the crown beam and waist beam of the foundation pit, saves dismantling costs, reduces carbon emissions, and implements the concept of green development.

[0029] 9. The present invention provides an assembled steel-concrete-steel structure foundation pit support system which is easy to dismantle. Jacks are arranged at multiple locations. The installation positions of the jacks leave splicing gaps for the steel-concrete beam sections, which is convenient for the assembly and construction of the supports in the foundation pit. After the construction is completed, the jacks can be completely recovered and reused many times. If necessary, the jacks can be put back to adjust the internal force of the foundation pit. The simultaneous adjustment of multiple jacks can make the internal support beams bear similar forces, avoid the phenomenon of excessive local stress and large deformation, and make the support system in the foundation pit safer, more reliable and controllable.

[0030] 10. The present invention provides an easy-to-dismantle assembled steel-concrete-steel structure foundation pit support system. It is easy to dismantle, produces little noise and causes little air pollution during dismantling. It is a perfect application of green demolition in the field of foundation pit support and another breakthrough of circular economy in the field of construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the first support plane layout of the prefabricated steel-concrete-steel structure foundation pit support system that is easy to dismantle.

[0032] Figure 2 It is a schematic diagram of the non-first support plane layout of the prefabricated steel-concrete-steel structure foundation pit support system that is easy to dismantle.

[0033] Figure 3 It is a schematic diagram of the overall structure of the steel-concrete beam section.

[0034] Figure 4 It is a schematic diagram of the overall structure of a steel structure S-beam whose frame is an I-beam.

[0035] Figure 5 It is a schematic diagram of the overall structure of a steel structure support with steel pipes as the frame.

[0036] Figure 6 It is a schematic diagram of the overall structure of the Baoli steel structure.

[0037] Figure 7 This is a schematic diagram of the application of Baoli steel structure.

[0038] Figure 8 It is a schematic diagram of the vertical arrangement and connection between the steel-concrete beam section and the steel structure auxiliary support whose frame is steel pipe.

[0039] Fig. 9 It is a schematic diagram of connecting steel plates and side connecting steel plates.

[0040] Fig.10 It is a schematic diagram of the overall structure of the inclined cable tendon adjuster.

[0041] Fig.11 It is a structural schematic diagram of steel-concrete beam sections installed on lattice columns.

[0042] Fig.12 It is a schematic diagram of the edge of the angle brace of the first support of the prefabricated steel-concrete-steel structure foundation pit support system.

[0043] Fig.13 It is a schematic diagram of the bracing edge of the first support of the prefabricated steel-concrete-steel structure foundation pit support system.

[0044] Fig.14 It is a schematic diagram of the steel bars in the cross section of the pedestal where the crown beam supports the base.

[0045] Fig.15This is a schematic diagram of the steel bars in the cross section at the base position of the crown beam angle brace.

[0046] Fig.16 It is a schematic diagram of the steel bars in the cross section of the pedestal position where the waist beam is axially supported.

[0047] Fig.17 This is a schematic diagram of placing jacks on the pedestal at the crown beam angle brace position.

[0048] Fig.18 It is a schematic diagram of the steel-concrete beam section and the steel structure auxiliary support whose frame is a steel pipe, which is vertically arranged and connected and then welded with angle steel.

[0049] Fig.19 It is a schematic diagram of the oblique connection between the steel-concrete beam section and the steel structure auxiliary support whose frame is I-beam.

[0050] Fig. 20 It is a schematic diagram of the oblique arrangement and connection between the steel-concrete beam section and the steel structure auxiliary support whose frame is steel pipe.

[0051] Fig.21 It is a schematic diagram of the internal support plane layout of Example 1.

[0052] Fig. 22 It is a schematic diagram of the internal support plane layout of Example 2.

[0053] Fig.23 It is a schematic diagram of the internal support plane layout of Example 3.

[0054] In the figure: 1. Steel-concrete beam section; 101. Beam sleeve; 102. Rectangular reinforced concrete; 103. Longitudinal reinforcing bar hole; 104. Vertical screw hole; 105. Horizontal screw hole; 106. Cable hole; 2. Steel structure auxiliary support; 201. Frame; 202. End plate; 202-1. No. 1 hole; 3. Support pile; 4. Jack; 5. Retaining steel structure; 501. Part A; 501-1. No. 3 hole; 501-2. Retaining Force box; 502, part B; 502-1, hole No. 4; 502-2, jack support; 502-3, protruding steel plate; 503, steel sheet; 504, plug ring; 505, plug plate; 6, round steel; 7, vertical tension screw; 8, horizontal tension screw; 9, inclined cable; 10, nut; 11, side connecting steel plate; 1101, hole No. 5; 12, connecting steel plate; 1201, hole No. 6; 13, inclined cable tendon adjuster; 1 301, bottom plate of regulator; 1301-1, No. 2 hole; 1302, adjusting screw; 1302-1, right-hand thread; 1302-2, left-hand thread; 1302-3, handle; 1303, support rod of regulator; 1304, web bar; 1305, left-hand nut; 1306, fastener; 1307, right-hand nut; 1308, pin; 14, bearing platform; 1401, embedded steel plate; 1402, embedded steel ribs; 1403, pedestal bottom plate; 1404, pedestal side plate; 1405, jack wooden support; 1406, force head; 1407, gasket; 15, pallet; 16, steel lattice column; 17, crown beam; 1701, L-shaped embedded hole; 18, waist beam; 1801, I-shaped embedded hole; 19, corbel; 20, clamp; 21, bolt; 22, L-shaped PVC pipe; 23, I-shaped PVC pipe; 24, angle steel; 25, anchor head. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The steel-concrete beam section 1 is fully called an assembled foundation pit support beam section that can be matched with a steel support.

[0057] See also Figure 1-18 The easily dismantled assembled steel-concrete-steel structure foundation pit support system in this embodiment includes a crown beam 17, a waist beam 18, a support pile 3 and an internal support system. The internal support system is composed of a plurality of main supports composed of a plurality of prefabricated steel-concrete beam sections 1, a plurality of steel structure auxiliary supports 2, a plurality of steel lattice columns 16 and an adjustment system; the steel-concrete beam sections 1 are standard parts with the same structure and size; A plurality of corbels 19 are provided on the crown beam 17 and the waist beam 18, and a cap 14 is provided on each of the corbels 19; Each main support is formed by axially connecting a plurality of steel-concrete beam sections 1, and the connection point between two steel-concrete beam sections 1 is an axial node; a plurality of steel structure auxiliary supports 2 are connected between adjacent main supports, and the connection method is that the two ends of the steel structure auxiliary supports 2 are connected to one side of the two axial nodes of the adjacent main supports; one side of the axial node of some main supports close to the foundation pit wall is connected to a steel structure auxiliary support 2, and the other end of this steel structure auxiliary support 2 is connected to the side of the crown beam 17 or the waist beam 18, and the steel structure auxiliary support 2 here is a steel structure eight-shaped beam; One main support constitutes a row of main supports or two main supports are connected to form a row of main supports through an adjustment system, and both ends of each row of main supports are placed on the cap 14; The main support is installed on the steel lattice column 16, and the contact position between the main support and the steel lattice column 16 is staggered from the axial node.

[0058] Preferably, the surface of the steel-concrete beam section 1 is provided with a beam sleeve 101, and a rectangular concrete 102 is arranged inside, and a cable hole 106 is arranged in the rectangular reinforced concrete 102; longitudinal rebar holes 103, vertical screw holes 104, and transverse screw holes 105 are arranged at both ends of the steel-concrete beam section 1, and the longitudinal rebar holes 103, vertical screw holes 104, transverse screw holes 105, and cable holes 106 do not intersect with each other.

[0059] Preferably, the structure of the axial node is: the end surfaces of the two steel-concrete beam sections 1 are tightly fitted, and connecting steel plates 12 are provided on the upper and lower surfaces of the fitting part, and No. 6 holes 1201 are opened on the connecting steel plates 12. The longitudinal reinforcing bar holes 103 on the end surfaces of the two steel-concrete beam sections 1 are aligned one by one and round steels 6 are inserted.

[0060] Preferably, a cable adjuster 13 is provided below the axial node, and the cable adjuster 13 is composed of an adjuster base plate 1301, an adjusting screw 1302, an adjuster support rod 1303, a web 1304, a left-handed nut 1305, a fixing piece 1306, a right-handed nut 1307, and a pin 1308; a No. 2 hole 1301-1 is provided on the adjusting base plate 1301; two fixing pieces 1306 are welded on the web 1304 and the adjusting base plate 1301; each fixing piece 1306 has two pins 1308, and two adjuster support rods 1303 are connected to the two pins 1308, and the other ends of the two adjuster support rods 1303 are respectively connected to the right-handed nut 1307 and the left-handed nut 1305 through the pins 1308; a handle 1301 is provided at the end of the adjusting screw 1302 02-3, two groups of positive and negative threads are arranged on the adjusting screw 1302, and each group of positive and negative threads includes a right-handed thread 1302-1 and a left-handed thread 1302-2; each group of positive and negative threads is equipped with a right-handed nut 1307 and a left-handed nut 1305; the vertical screw hole 104 at the axial node, the No. 6 hole 1201 on the two connecting steel plates 12 and the No. 2 hole 1301-1 on the inclined cable adjuster 13 are coaxial, and are penetrated by the vertical tension screw 7, and the two ends of the vertical tension screw 7 are provided with nuts 10; the inclined cable 9 is inserted into the inclined cable hole 106, and the inclined cable 9 extends from the inclined cable hole 106 of one steel-concrete beam section 1, and extends from the inclined cable hole 106 of another adjacent steel-concrete beam section 1; the two ends of the inclined cable 9 are fixed with anchor heads 25, and the middle part is placed on the web 1304 of the inclined cable adjuster 13.

[0061] Preferably, the steel structure auxiliary support 2 is formed by welding a frame 201 and an end plate 202; the frame 201 is an I-beam or a steel pipe or an H-beam; the end plate 202 is a steel plate, on which a No. 1 hole (202-1) for connection is provided, and the No. 1 hole 202-1 has the same diameter and spacing as the transverse screw hole 105.

[0062] Preferably, the No. 1 hole 202-1 of one end plate 202 of the steel structure S-beam is aligned one by one with the transverse screw hole 105 at the axial node position on the steel-concrete beam section 1 close to the foundation pit wall, and a transverse tension screw 8 is inserted therein, and both ends of the transverse tension screw 8 are fixed with nuts 10; the other end plate 202 of the steel structure S-beam is fixed to the crown beam 17 or the waist beam 18 with bolts 21.

[0063] Preferably, there are three ways to connect one side of the axial node with the steel structure auxiliary support 2. The first way is: one side of the axial node is connected to a steel structure auxiliary support 2, and the end plate 202 is connected to the axial node across the seam, that is, the No. 1 hole 202-1 of the end plate 202 is respectively connected to the transverse screw hole 105 on one side of the end of the two steel-concrete beam sections 1 connected at the axial node, and is fixed with a transverse tension screw 8 and a nut 10; The second type is: one side of the axial node is connected to two steel structure auxiliary supports 2, a side connection steel plate 11 is arranged on one side of the axial node, and the side connection steel plate 11 has four rows of No. 5 holes 1101, and the spans correspond to the two rows of transverse screw holes 105 on the sides of the two steel-concrete beam sections 1 at the axial node, and also correspond to the No. 1 holes 202-1 on the end plates 202 of the two steel structure auxiliary supports 2. After the transverse tension screw 8 passes through the coaxial No. 1 hole 202-1, No. 5 hole 1101 and transverse screw hole 105, both ends are tightened with nuts 10; The third type is: there is no auxiliary support connection on one side of the axial node, the axial node is installed on this side with a connecting steel plate 11, and the transverse tension screw 8 is passed through the No. 5 hole 1101 and the transverse screw hole 105, and the two ends of the transverse tension screw 8 are fixed with nuts 10.

[0064] Preferably, the adjustment system is divided into a mid-beam adjustment system and a beam end adjustment system; the mid-beam adjustment system includes a force-retaining steel structure 5 and a jack 4 placed on the force-retaining steel structure 5, and the beam end adjustment system includes a force-retaining head 1406, a gasket 1407 and a jack 4 arranged on a cap 14; the force-retaining steel structure 5 is composed of a part A 501, a part B 502, a steel sheet 503, an insert ring 504, and an insert plate 505; the part A 501 is composed of two long steel plates and a steel partition plate vertically welded between the two long steel plates , wherein a connecting plate is welded on one side of a long steel plate, and a No. 3 hole 501-1 is formed on the connecting plate; a force box 501-2 is welded on one side of another long steel plate, and the force box 501-2 is formed by welding steel plates; part B 502 is composed of two long steel plates and a steel partition plate vertically welded between the two long steel plates, wherein a connecting plate is welded on one side of one long steel plate, and a No. 4 hole 502-1 is formed on the connecting plate; a jack support 502-2 and a protruding steel plate 502-3 are welded on one side of another long steel plate, The jack support 502-2 is formed by welding a semicircular steel plate to a long steel plate; the height of the long steel plate and several steel partitions is the same as the cross-sectional height of the steel-concrete beam section 1; the connecting plates are in a group of two, and the distance between the two connecting plates is the same as the cross-sectional width of the steel-concrete beam section 1; the insert ring 504 is welded to the side of the force box 501-2 at both ends of the A part 501 and the side of the two ends of the B part 502; the arrangement of the third hole 501-1 and the fourth hole 502-1 and the transverse screw hole 105 of the steel-concrete beam section 1 and the hole The diameters are the same, and the width of the steel sheet 503 is the same as that of the force box 501-2; the force box 501-2 of part A is placed on the protruding steel plate 502-3 of part B 502, and the connection between part A 501 and part B 502 is achieved by inserting the plug plate 505 into the plug ring 504; the connection between the force-retaining steel structure 5 and the main support is achieved by making the fourth hole 502-1 on the connecting plate correspond one by one to the transverse screw hole 105 at the end of the main support, inserting the transverse tension screw 8 and tightening it with the nut 10.

[0065] Preferably, there are two types of caps 14, one type of cap 14 is composed of embedded steel plates 1401, embedded steel bars 1402, cap bottom plates 1403, and cap side plates 1404; the other type of cap 14 is composed of embedded steel plates 1401, embedded steel bars 1402, cap bottom plates 1403, cap side plates 1404, jack wooden supports 1405, force-retaining heads 1406, and gaskets 1407; the force-retaining heads 1406 are formed by welding I-beams and steel plates, the steel plate size of the force-retaining heads 1406 is the same as the cross-sectional size of the steel-concrete beam section 1, the embedded steel plates 1401 are all arranged at the corbels 19, and embedded steel bars 1402 are welded to one side of the embedded steel plates 1401.

[0066] Preferably, a pallet 15 is provided on the steel lattice column 16, and the main support is placed on the pallet 15. One side of the steel-concrete beam section 1 in the main support is close to the lattice column 16. One end of a clamp 20 is welded on the pallet 15. The clamp 20 embraces the main support and the other end is welded to the steel lattice column 16 to fix the main support.

[0067] Preferably, L-shaped pre-buried holes 1701 and I-shaped pre-buried holes 1801 for wire saw cutting are preset every 3-5 m in the crown beam 17 and the waist beam 18; The L-shaped embedded hole 1701 is formed by embedding an L-shaped PVC tube 22 in the crown beam 17. The L-shaped PVC tube 22 has two openings at both ends, one end is opened on the upper surface of the crown beam 17, and the other end is opened on the side of the crown beam 17. The embedded position of the L-shaped PVC tube 22 is staggered with the position of the corbel 19. The I-shaped embedded hole 1801 is formed by embedding an I-shaped PVC pipe 23 in the waist beam 18. Both ends of the I-shaped PVC pipe 23 are open, one end is located on the top surface of the waist beam 18, and the other end is located on the bottom surface of the waist beam 18. The I-shaped PVC pipe 23 is embedded on one side of the waist beam 18 close to the supporting pile 3, and the embedded position of the I-shaped PVC pipe 23 is staggered with the position of the corbel 19.

[0068] Preferably, the construction process of the assembled steel-concrete-steel structure foundation pit support system that is easy to dismantle includes the following construction steps: 1) Construction of multiple support piles 3, column piles and steel lattice columns 16; 2) The pile head of the support pile 3 is roughened, the steel cage of the crown beam 17 is tied, the L-shaped PVC pipe 22 is embedded, and the embedded steel bars 1402 are welded to the embedded steel plate 1401. After the welding is completed, the embedded steel bars 1402 are tied to the steel cage of the crown beam 17, and the remaining steel bars at the corbel 19 are tied; 3) Formwork the crown beam 17 and the upper corbel 19, and pour concrete after the formwork is completed. When pouring concrete, ensure that the positions of the embedded steel bars 1402 and the embedded steel plates 1401 do not shift. After the concrete curing is completed, proceed with the subsequent construction; 4) Excavate to the bottom elevation of the first inner support beam, and excavate 1 m more at the steel lattice column 16 and the corbel 19; 5) Weld the tray 15 on the steel lattice column 16, and weld the cap 14 on the embedded steel plate 1401; 6) The main supports are constructed row by row, and the steel-concrete beam segments 1 are hoisted into the foundation pit for assembly, and assembled from one end of a row of main supports to the other end; when connecting adjacent steel-concrete beam segments 1, first insert the round steel bars 6 into the longitudinal reinforcement holes 103, and after the end faces of the two steel-concrete beam segments 1 are closely attached, install the connecting steel plates 12 and fix them with vertical tension screws 8 and nuts 10; the main supports are placed on the pallet 15, and one side of the steel-concrete beam segment 1 in the main supports is closely attached to the lattice column 16, and both ends of each row of main supports are placed on the cap 14; 7) Install the steel structure auxiliary support 2. For the installation of the auxiliary support between the main supports, use the transverse tension screw 8 and the nut 10 to connect the auxiliary support with the adjacent main support; for the installation of the steel structure S-shaped beam, use the transverse tension screw 8 and the nut 10 to connect the steel structure S-shaped beam with the axial node of the main support near the foundation pit wall at one end, and fix the other end to the crown beam 17 with the bolt 21; fill the installation gap between the steel structure auxiliary support 2 and the side of the axial node with steel bars; 8) Install the beam adjustment system, install the steel structure 5 in the middle of the main support, fix the A part 501 and the B part 502 to the main supports on both sides through the connecting plates with the transverse tension screws 8 and nuts 10, then place the B part's force box 501-2 on the protruding steel plate 502-3 of the A part 501, and insert the insert plate 505 into the insert ring 504 to achieve the connection between the A part 501 and the B part 502; finally, install the jack 4 on the jack support 502-2; 9) Install the beam end adjustment system, install the force head 1406 on the cap 14 and place the jack wooden support 1405, install the jack 4 on the jack wooden support 1405, and make the longitudinal axis of the plunger of the jack 4 coincide with the longitudinal axis of the main support; 10) The jacks 4 apply pressure at the same time, the jacks 4 on the beam adjustment system extend the A part 501 of the force-retaining steel structure 5, and the jacks 4 on the beam end adjustment system extend the force-retaining head 1406; a number of steel sheets 503 are inserted into the gap between the force-retaining box 501-2 and the B part 502 of the A part 501 of the force-retaining steel structure 5, and a number of gaskets 1407 are inserted into the gap between the force-retaining head 1406 and the embedded steel plate 1401, so that the end faces of all axial nodes of each main support are closely fitted; welding the clamps 20; 11) Jack 4 is depressurized, causing the plunger of Jack 4 to disengage, and Jack 4 is removed; 12) Excavate to the bottom elevation of the second inner support beam, and excavate 1 m more at the steel lattice column 16 and the corbel 19; 13) Roughen the pile body of the support pile 3, tie the steel cage of the waist beam 18, embed the I-shaped PVC pipe 23, weld the embedded steel bars 1402 to the embedded steel plate 1401, and after welding, use steel wire to tie the embedded steel bars 1402 to the steel cage of the waist beam 18, and tie the remaining steel bars at the corbel 19; 14) Formwork the waist beam 18 and its upper corbel 19, and pour concrete after the formwork is completed. When pouring concrete, ensure that the positions of the embedded steel bars 1402 and the embedded steel plates 1401 do not shift. After the concrete curing is completed, proceed with the subsequent construction; 15) Welding the tray 15 on the steel lattice column 16, and welding the cap 14 on the embedded steel plate 1401; 16) The steel-concrete beam segment 1 is hoisted into the foundation pit for assembly; the assembly method is the same as step 6); 17) Install the steel structure auxiliary support 2. For the installation of the auxiliary support between the main supports, use the transverse tension screw 8 and the nut 10 to connect the auxiliary support with the adjacent main support; for the installation of the steel structure S-shaped beam, use the transverse tension screw 8 and the nut 10 to connect the steel structure S-shaped beam with the axial node of the main support near the foundation pit wall at one end, and fix the other end to the waist beam 18 with the bolt 21; fill the installation gap between the steel structure auxiliary support and the side of the axial node with steel bars; 18) Install the mid-beam adjustment system and the end-beam adjustment system in the same way as step 8) and step 9) respectively; 19) The jack 4 applies pressure at the same time, inserts a number of steel sheets 503 into the gap between the force box 501-2 and the B part 502 of the A part 501 of the force steel structure 5, and inserts a number of gaskets 1407 into the gap between the force head 1406 and the embedded steel plate 1401; welds the clamp 20; 20) Jack 4 is depressurized, causing the plunger of Jack 4 to disengage, and Jack 4 is removed; 21) Repeat the steps from 12) to 20) until the construction of the remaining internal supports below the second internal support is completed; 22) After completing the installation of the last support, pour the foundation slab.

[0069] Preferably, after the construction of the internal support system is completed, angle steels 24 are welded at the four corners where the connecting steel plate 12 is connected to the side connecting steel plate 11 or at the four corners where the connecting steel plate 12 is connected to the end plate of the auxiliary support.

[0070] Preferably, an alternative step of step 6) is: construct the main supports row by row, hoist the steel-concrete beam sections 1 into the foundation pit for assembly, and assemble from one end of a row of main supports to the other end; when connecting adjacent steel-concrete beam sections 1, first insert the round steel 6 into the longitudinal reinforcement hole 103, and after the end surfaces of the steel-concrete beam sections 1 are tightly attached, install the connecting steel plate 12 and the inclined cable adjuster 13, first use the vertical tension screws 8 and nuts 10 to fix the connecting steel plate 12 and the inclined cable adjuster 13, and then the inclined cable 9 passes through the inclined cable hole 106, and the end of the inclined cable 9 is fixed with an anchor head 25. When the inclined cable 9 passes the axial node, it is placed on the web 1304 of the inclined cable adjuster 13.

[0071] Example 1 For a certain foundation pit, the general excavation depth is 14.75-16.20 m, the perimeter of the foundation pit is about 586 m, and the basement excavation area is about 20,537 m2.

[0072] Design three foundation pit internal supports. The main supports of the three supports use steel-concrete beam sections. The internal support plane layout is as follows: Fig.21 As shown; each internal support includes four corner braces arranged at the four corners of the foundation pit and one brace arranged in the middle of the foundation pit. The cross-section design of the crown beam 17 is 1000 mm high and 1200 mm wide, the L-shaped PVC pipe 22 has an outer diameter of 40 mm, and one is set every 3-5 m; the waist beam 18 has a size of 1000 mm×1000 mm, the I-shaped PVC pipe 23 has an outer diameter of 40 mm, and one is set every 3-5 m; the column piles are bored cast-in-place piles ⌀800 mm, a total of 117 piles, and the concrete strength of the pile body is C30; 62 brackets are set on the crown beam 17 and waist beam 18, and the cross-section size of the bracket is 1020 mm×1000 mm.

[0073] There are two types of caps on the corbels; there are 28 caps for placing jacks, whose embedded steel plates 1401 are 20 mm thick, 1000 mm high and 1020 mm wide, and the embedded steel bars 1402 are HRB400 with a diameter of 10 mm. There are 16 steel plates welded on each side of the left and right sides, and the thickness of the cap bottom plate 1403 is 20 mm, the width is 1020 mm and the length is 1300 mm. The thickness of the cap side plate 1404 is 20 mm, the diameter of the semicircular groove of the jack wooden support 1405 is 600 mm, and the length is 100 mm. The force head 1406 uses a steel plate with a thickness of 20 mm, a width of 1000 mm and a height of 1000 mm. Two stacked 50a I-beams are welded on each side, and the size after stacking is 1000 mm high and 160 mm wide; there are 34 caps without jacks, whose embedded steel plates 1401 are 20 mm thick, 1000 mm high and 1000 mm wide. mm, width 1020 mm, embedded steel bars 1402 are HRB400 with a diameter of 10 mm, one row is welded on each side of the steel plate, for a total of 16 steel bars, the pedestal bottom plate 1403 is 20 mm thick, 1020 mm wide and 500 mm long, the pedestal side plate 1404 is 20 mm thick.

[0074] The cross-sectional dimensions of the steel lattice column 16 are 460 mm × 460 mm. The tie material of the steel lattice column 16 is long angle steel, the long angle steel is L140 × L14, the tie plate thickness is 10 mm, the height is 400 mm, the width is 460 mm, and the tie plate spacing is 600 mm.

[0075] Pallet 15 is 20 mm thick, 860 mm wide and 1860 mm long. A right-angle triangular steel plate is welded under the pallet. One side of the steel plate is welded to the pallet and the other side is welded to the lattice column. The thickness of the steel plate is 20 mm.

[0076] The adjustment system includes 1 mid-beam adjustment system and 28 beam end adjustment systems, using a total of 32 jacks, and 500-ton hydraulic jacks 4 are selected; the mid-beam adjustment system includes a force-retaining steel structure and 4 jacks, and the 6 main supports are connected into 3 rows of main supports through the adjustment system.

[0077] The mid-beam adjustment system includes a force-retaining steel structure 5 and a jack 4 placed on the force-retaining steel structure 5; the beam end adjustment system includes a force-retaining head 1406, a gasket 1407 and a jack 4 placed on the base 14 arranged at one end of the main support, the gasket 1407 is 10 mm thick, and the gasket is 1000 mm high and 1000 mm wide. The force-retaining steel structure 5 is composed of a part A 501, a part B 502, a steel sheet 503, an insert ring 504, and an insert plate 505; the part A 501 is formed by welding two long steel plates with a length of 11000 mm, a height of 1000 mm, a thickness of 20 mm, and a steel partition with a length of 1000 mm, a height of 1000 mm, and a thickness of 20 mm, and the two long steel plates are welded and connected by a steel partition perpendicular to the long steel plates; wherein, a connecting plate with a length of 500 mm, a height of 1000 mm, and a thickness of 20 mm is welded on one side of a long steel plate, and the connecting plate has two rows of six No. 3 holes 501-1, and the No. 3 holes 501-1 are adapted to the transverse screw holes 105; a force-retaining box 501-2 is welded on one side of the other long steel plate, and the force-retaining box 501-2 is formed by welding a steel plate with a height of 1000 mm, and a thickness of 20 mm; the part B 502 is formed by welding two long steel plates with a length of 11000 mm, a height of 1000 mm, and a thickness of 20 The invention relates to a method for manufacturing a jack support 502-2 for a steel plate 501 having a length of 500 mm, a width of 1000 mm and a thickness of 20 mm. The two steel plates are connected by welding via a steel partition perpendicular to the long steel plates. A connecting plate 502-1 having a length of 500 mm, a height of 1000 mm and a thickness of 20 mm is welded on one side of one long steel plate. The connecting plate has two rows of six No. 4 holes 502-1. The No. 4 holes 502-1 are matched with the transverse screw holes 105. A jack support 502-2 and a protruding steel plate 502-3 having a length of 500 mm, a width of 1000 mm and a thickness of 20 mm are welded on one side of the other long steel plate. The jack support 502-2 is formed by welding a 20 mm thick semicircular steel plate on the long steel plate. The insert rings 504 are welded on the side surfaces of the two end heads of the A part 501 and the B part 502, with a total of 12. The insert rings 504 are inserted with the insert plates 505 having a cross-sectional size of 100 mm×20 mm.

[0078] Each row of main supports in the axial bracing is composed of 12 steel-concrete beam segments 1 axially connected, and the four corner supports are 7 rows each. The 7 rows of main supports are composed of 2, 4, 6, 8, 10, 12, and 14 steel-concrete beam segments 1 respectively; both ends of each row of main supports are placed on the pedestal 14.

[0079] A steel plate with a thickness of 20 mm and a width of 100 mm is selected for welding to form a hoop 20 , which fixes the main support on the pallet 15 , with one end welded to the pallet 15 and the other end welded to the steel lattice column 16 .

[0080] In each inner support, there are 184 steel structure auxiliary supports 2 connecting the adjacent main supports, and there are 4 steel structure S-beams.

[0081] The steel structure auxiliary support 2 used for connecting adjacent main supports is formed by welding a frame 201 and an end plate 202; the frame 201 is an H-shaped steel, and the model of the H-shaped steel is H500×500; the end plate 202 is a steel plate, and the end plate is 1000 mm high and 1000 mm wide, and is provided with two rows of No. 1 holes 202-1 for connection, the aperture of the No. 1 hole 202-1 is 30 mm, and the row spacing of the two rows of No. 1 holes 202-1 is 720 mm, which is compatible with the transverse screw hole 105.

[0082] The steel structure auxiliary support 2 used for the steel structure S-beam is formed by welding a frame 201 and an end plate 202; the frame 201 is an H-shaped steel, and the model of the H-shaped steel is H600 mm×600 mm; the end plate 202 is a steel plate, on which two rows of No. 1 holes 202-1 for connection are arranged, the hole diameter of the No. 1 hole 202-1 is 30 mm, the row spacing between the two rows of No. 1 holes 202-1 is 720 mm, and the No. 1 hole 202-1 is compatible with the transverse screw hole 105.

[0083] The cross-sectional width of the steel-concrete beam section 1 is 1000 mm, the cross-sectional height is 1000 mm, and the length is 5 m. The end of the steel-concrete beam section 1 is provided with two rows of six vertical screw holes 104 (three holes in each row), two columns of six transverse screw holes 105 (three holes in each column), and two columns of four longitudinal reinforcing bar holes 103 (two holes in each column). In the middle of the rectangular reinforced concrete 102, symmetrically to the middle section of the steel-concrete beam section 1, two rows of six inclined cable holes 106 (three holes in each row) are arranged. (At a certain end position of the steel-concrete beam section 1, when the line connecting the hole centers of the multiple vertical screw holes 104 on the same plane is parallel to the end surface of the steel-concrete beam section, these holes constitute a row of vertical screw holes 105; when the line connecting the hole centers of the multiple transverse screw holes 105 on the same plane is parallel to the end surface of the steel-concrete beam section 1, these holes constitute a row of transverse screw holes 105; when the line connecting the hole centers of the multiple longitudinal reinforcing bar holes 103 on the same plane is parallel to the side surface of the steel-concrete beam section 1, these holes constitute a row of longitudinal reinforcing bar holes 103; when the line connecting the hole centers of the multiple inclined cable holes 106 on the same plane is perpendicular to the side surface of the steel-concrete beam section 1, these holes constitute a row of inclined cable holes 106, the same below) The hole plane layout of the vertical screw hole 104 is a rectangular hole layout with a hole diameter of 30 mm, a row spacing of 200 mm, a hole spacing of 300 mm, a distance from the outermost row of holes to the end face of 250 mm, and a distance from the outermost hole in each row of holes to the adjacent end side of 200 mm.

[0084] The hole plane layout of the transverse screw holes 105 is a rectangular hole layout with a hole diameter of 30 mm, a row spacing of 240 mm, a hole spacing of 300 mm, a distance of 120 mm from the outermost row of holes to the end face of the steel-concrete beam section 1, and a distance of 200 mm from the uppermost hole in each row of transverse screw holes 105 to the upper surface.

[0085] The hole opening plane layout of the longitudinal reinforcement holes 103 is a rectangular hole layout, with a hole diameter of 40 mm, a hole depth of 500 mm, a row spacing of 400 mm, a hole spacing of 400 mm, a distance from the top hole to the upper surface of 300 mm, and a distance from the left hole to the left side of the steel-concrete beam section 1 of 300 mm.

[0086] The hole diameter of the cable-stayed hole 106 is 30 mm, the inclination angle is 45°, the hole openings are arranged in a rectangular pattern on the upper surface of the steel-concrete beam segment 1, the hole spacing is 300 mm, the row spacing is 1000 mm, and the distance from the hole openings of each row of holes on the upper surface of the steel-concrete beam segment 1 to the end face of the adjacent steel-concrete beam segment 1 is 2000 mm, and the distance from the outermost holes of each row to the side face of the adjacent steel-concrete beam segment 1 is 200 mm.

[0087] A steel plate with a size of 800 mm×500 mm×10 mm is selected as the upper and bottom steel plates of the beam sleeve 101. The diameter, row spacing and hole spacing of the holes on it are the same as those of the vertical screw holes 104, and the edge of the steel plate with a length of 500 mm is welded to the angle steel. A steel plate with a size of 800 mm×500 mm×10 mm is selected as the side steel plate of the beam sleeve 101. The diameter, row spacing and hole spacing of the holes on it are the same as those of the transverse reinforcement holes 105, and the edge of the steel plate with a length of 500 mm is welded to the angle steel. An angle steel with a model of L100×10 and a length of 5 m is selected as the angle steel of the beam sleeve 101.

[0088] The structure of the axial node is as follows: the end faces of the two steel-concrete beam sections 1 are closely fitted, and a connecting steel plate 12 with a length of 1000 mm, a width of 1000 mm and a thickness of 20 mm is provided on each span of the upper and lower surfaces of the fitting, and four rows of twelve No. 6 holes 1201 are opened on the connecting steel plate 12, and the hole diameter of the No. 6 hole 1201 is 30 mm and is adapted to the vertical screw hole 104, and the longitudinal dowel holes 103 on the end faces of the two steel-concrete beam sections 1 are aligned one by one and inserted with round steel bars 6; The diameter of the round steel 6 is 34 mm; the thickness of the connecting steel plate 12 is 20 mm, the width is 1000 mm, and the length is 1000 mm; the diameter of the horizontal tension screw 8 is 24 mm; and the diameter of the vertical tension screw 7 is 24 mm.

[0089] The inclined cable adjuster 13 is composed of an adjuster base plate 1301, an adjusting screw 1302, an adjuster support rod 1303, a web 1304, a left-handed nut 1305, a fastener 1306, a right-handed nut 1307, and a pin 1308; the adjuster base plate 1301 of the inclined cable adjuster 13 is 1000 mm long, 1000 mm wide, and 20 mm thick. There are two rows of six No. 2 holes 1301-1 on the adjuster base plate 1301. The aperture of the No. 2 hole 1301-1 is 30 mm and is compatible with the vertical screw hole 104. Two fasteners 1306 are welded on the web 1304 and the adjusting base plate 1301. The web 1304 is 20 thick. mm, each fixing member 1306 has two pins 1308, two adjuster support rods 1303 are connected to the two pins 1308, the diameter of the adjuster support rods 1303 is 30 mm, the other ends of the two adjuster support rods 1303 are respectively connected to a right-handed nut 1307 and a left-handed nut 1305 through the pins 1308, the end of the adjusting screw 1302 is provided with a handle 1302-3, the diameter of the adjusting screw 1302 is 40 mm, and two groups of positive and negative threads are arranged on the adjusting screw 1302, each group of positive and negative threads includes a right-handed thread 1302-1 and a left-handed thread 1302-2; each group of positive and negative threads is equipped with a right-handed nut 1307 and a left-handed nut 1305.

[0090] The No. 1 hole 202-1 of one end plate 202 of the steel structure S-beam is aligned one by one with the transverse screw hole 105 at the axial node position on the steel-concrete beam section 1 close to the foundation pit wall, and a transverse tension screw 8 is inserted therein, and both ends of the transverse tension screw 8 are fixed with nuts 10; the other end plate 202 of the steel structure S-beam is fixed to the crown beam 17 or the waist beam 18 with bolts 21.

[0091] One side of the axial node is connected to a steel structure auxiliary support 2, and the end plate 202 is connected to the axial node across the seam, that is, the No. 1 hole 202-1 of the end plate 202 is respectively connected to the transverse screw hole 105 on one side of the end of the two steel-concrete beam sections 1 connected at the axial node, and is fixed with a transverse tension screw 8 and a nut 10.

[0092] There is no auxiliary support connection on one side of the axial node. The side connecting steel plate 11 is installed on this side of the axial node, and the transverse tension screw 8 passes through the No. 5 hole 1101 and the transverse screw hole 105, and is fixed with a nut 10. The side connecting steel plate 11 is 1000 mm high, 1000 mm wide and 20 mm thick. There are four rows of twelve No. 5 holes 1101 on it, and the row spacing is 240 mm. The diameter of the No. 5 hole 1101 is 30 mm, which is compatible with the transverse screw hole 105.

[0093] 1. Construction of support piles 3, column piles and steel lattice columns 16. Support piles 3 are bored cast-in-place piles ⌀1000 mm, with a pile spacing of 1300 mm. The concrete strength of the pile body is C30. They are matched with ⌀1000 mm mixing piles to form a bite-type water stop. The column piles are bored cast-in-place piles ⌀800, with a pile body concrete strength of C30. The cross-sectional size of steel lattice columns 16 is 460 mm×460 mm. The long angle steel of steel lattice columns 16 is L140×L14. The thickness of the gusset plate is 10 mm, the height is 400 mm, and the width is 460 mm. The gusset plate spacing is 600 mm. The construction verticality deviation of steel lattice columns 16 is less than 1 / 300. 2. After the pile head of the supporting pile 3 is roughened, the cross-section design height of the crown beam 17 is 1000 mm and the width is 1200 mm. The steel cage of the crown beam 17 is tied. At the same time, the L-shaped PVC pipe 22 is tied to the steel cage of the crown beam 17. The outer diameter of the L-shaped PVC pipe 22 is 40 mm. One is set every 3-5 m and staggered with the corbel 19 of the crown beam 17. The L-shaped PVC pipe 22 is sealed with gypsum. The embedded steel bar 1402 is welded on the embedded steel plate 1401. The embedded steel plate 1401 is 20 mm thick, 1000 mm high and 1020 mm wide. The embedded steel bar 1402 is HRB400 with a diameter of 10 mm. One row is welded on each side of the steel plate, with a total of 16 welds. The length of the weld between each embedded steel bar 1402 and the embedded steel plate 1401 is 50 mm, and the welding position accuracy is less than 2 mm, vertical accuracy is less than H / 1000, the welded embedded steel bars 1402 and embedded steel plates 1401 are tied at the designed positions according to the design requirements, and the position accuracy error during tying is less than 3 mm. The rest of the steel bars at the tying position of the embedded steel plate 1401 are tied according to the design requirements; 3. Carry out formwork work on the crown beam 17 and the upper corbel 19. The cross-sectional size of the corbel is designed to be 1020 mm × 1000 mm. After the formwork is completed, pour concrete. When pouring concrete, ensure that the positions of the embedded steel plate 1401, the embedded steel bar 1402, and the L-shaped PVC pipe 22 do not shift. After pouring, maintain the concrete; 4. Excavate to the bottom elevation of the first supporting beam, and excavate 1 m more at the base 14 and tray 15; 5. Weld the first supporting tray 15 on the steel lattice column 16. The tray 15 is 20 mm thick, 860 mm wide and 1860 mm long. It is welded and reinforced with isosceles right triangle steel plates. Spot welding is performed first and then full welding is performed during welding. The welding error is less than 2 mm. Weld the cap 14 on the embedded steel plate 1401 at the position of the corbel 19. The cap bottom plate 1403 of the cap without jack is 20 mm thick, 1020 mm wide and 500 mm long. The cap side plate 1404 is 20 mm thick. Spot welding is performed first and then full welding is performed during welding. The welding error is less than 2 mm. Weld the cap 14 with jack. The cap bottom plate 1403 is 20 mm thick, 1020 mm wide and 1300 mm long. The cap side plate 1404 is 20 mm thick. The semicircular groove of the jack wooden support 1405 is 600 mm in diameter and 100 mm in length. Spot welding is performed first and then full welding is performed. The welding accuracy is less than 2 mm; place the force head 1406, which is made of a steel plate with a thickness of 20 mm, a width of 1000 mm, and a height of 1000 mm. Two stacked 50a I-beams are welded on each side. The size after stacking is 1000 mm in height and 160 mm in width. The force head 1406 is formed by welding. The force head 1406 is placed on the base 14 of the angle support; 6. The crane hoists the steel-concrete beam section 1 into the foundation pit for assembly. A 34 mm diameter round steel bar 6 is inserted into the longitudinal reinforcement hole 103. The two connecting steel plates 12 are 20 mm thick, 1000 mm wide and 1000 mm long. There are two rows of six holes on the adjuster bottom plate 1301 of the inclined cable adjuster 13, and the hole diameter is 30 mm. The connecting steel plate 12 and the inclined cable adjuster bottom plate 1301 are fixed at the node position with a 24 mm diameter vertical tension screw 7 and a nut 10. The inclined cable 9 is inserted into the inclined cable hole 106, and the inclined cable 9 is prestressed and fixed with an anchor head 25. The inclined cable 9 below the axial node is carried on the inclined cable adjuster 13; the two ends of the main support assembled by the steel-concrete beam section 1 are placed on the pedestal 14, and the middle part of the steel-concrete beam section 1 is placed on the tray 15 welded to the steel lattice column 16, and the position accuracy error is less than 3 mm; 7. The steel structure auxiliary support in the foundation pit uses H-shaped steel as the frame 201, and the steel structure auxiliary support 2 used for connecting the main supports is arranged vertically with the main support; the steel structure auxiliary support 2 is installed, and the crane hoists the steel structure auxiliary support 2 into the foundation pit; the steel structure auxiliary support 2 used for connecting the main supports is fixed to the steel-concrete beam section 1 using a 24 mm diameter transverse tension screw 8 and a nut 10; one end of the steel structure S-shaped beam is fixed to the assembled steel-concrete beam section 1 using a transverse tension screw 8 and a nut, and the other end is fixed to the crown beam 17 with bolts, and the installation error of the steel structure auxiliary support is less than 2 mm; the side connecting steel plate 11 is installed on the side of the axial node where the steel structure auxiliary support 2 is not installed; 8. Install the retaining steel structure 5 in the middle of the axial brace. The three rows of axial braces share the retaining steel structure 5. The retaining steel structure 5 is formed by welding a 20 mm thick steel plate. The A part 501 is fixed to the steel-concrete beam section 1 through the No. 3 hole 501-1, and the B part 502 is fixed to the steel-concrete beam section 1 through the No. 4 hole 502-1. They are fixed with 24 mm transverse tension screws 8 and nuts 10. 9. Place the jack 4 on the jack support 502-2 of the Baoli steel structure 5; place the jack 4 on the jack wooden support 1405 of the pedestal 14 at both ends of the angle support, and the longitudinal axis of the plunger of the jack 4 coincides with the longitudinal axis of the main support; 10. All jacks 4 of the first support are pressurized at the same time. The jacks 4 on the beam adjustment system extend the A part 501 and the B part 502 of the force-retaining steel structure 5, and the jacks 4 on the beam end adjustment system extend the force-retaining head 1406. The steel sheet 503 is inserted between the gap between the force-retaining box 501-2 and the B part 502 of the A part 501 of the force-retaining steel structure 5, and the gasket 1407 is inserted into the gap between the force-retaining head 1406 and the embedded steel plate 1401. The end faces of all axial nodes of each main support are tightly fitted. The hoop 20 is welded. The angle steel 24 is welded at the node. 11. After the pressure of jack 4 is reduced, remove jack 4; 12. Excavate to the second support bottom elevation, and excavate 1 m more at the base 14 and tray 15; 13. The pile body of the support pile 3 is roughened, and the steel cage of the waist beam 18 is tied. The size of the waist beam 18 is designed to be 1000 mm×1000 mm. The I-shaped PVC pipe 23 is tied to the steel cage with steel wire, and one is set every 3-5 m. The hole of the I-shaped PVC pipe 23 is sealed with gypsum. The outer diameter of the I-shaped PVC pipe 23 is 40 mm. The embedded steel bar 1402 is welded on the embedded steel plate 1401. The embedded steel plate 1401 is 20 mm thick, 1000 mm high, and 1020 mm wide. The embedded steel bar 1402 uses HRB400 with a diameter of 10 mm. One row is welded on each side of the steel plate, for a total of 16 bars. The length of the weld between each embedded steel bar 1402 and the embedded steel plate 1401 is 50 mm, the welding position accuracy is less than 2mm, the vertical accuracy is less than H / 1000, the welded embedded steel bars 1402 and embedded steel plates 1401 are tied at the designed positions according to the design requirements, and the position accuracy error during tying is less than 3 mm. The rest of the steel bars at the tying position of the embedded steel plate 1401 are tied according to the design requirements; 14. Carry out formwork work on the waist beam 18 and the upper corbel 19. The cross-sectional size of the corbel 19 is 1020 mm × 1000 mm. After the formwork is completed, pour concrete. When pouring concrete, ensure that the positions of the embedded steel plate 1401, the embedded steel bar 1402, and the I-shaped PVC pipe 23 do not shift. After pouring, maintain the concrete; 15. Weld the second supporting tray 15 on the steel lattice column 16. The tray 15 is 20 mm thick, 860 mm wide and 1860 mm long. It is welded and reinforced with isosceles right triangle steel plates. Spot welding is performed first and then full welding is performed during welding. The welding error is less than 2 mm. Weld the cap 14 on the embedded steel plate 1401 at the position of the corbel 19. The base plate 1403 of the cap without the jack 4 is 20 mm thick, 1020 mm wide and 500 mm long. The base side plate 1404 is 20 mm thick. Spot welding is performed first and then full welding is performed during welding. The welding error is less than 2 mm. Weld the cap 14 with the jack. The base plate 1403 is 20 mm thick, 1020 mm wide and 1300 mm long. The base side plate 1404 is 20 mm thick. The semicircular groove of the jack wooden support 1405 is 600 mm in diameter and 100 mm in length. Spot welding is performed first and then full welding is performed. The welding accuracy is less than 2 mm; place the force head 1406, which is made of a steel plate with a thickness of 20 mm, a width of 1000 mm, and a height of 1000 mm. Two stacked 50a I-beams are welded on each side. The size after stacking is 1000 mm in height and 160 mm in width. The force head 1406 is formed by welding. The force head 1406 is placed on the base 14 of the angle support; 16. Use a crane to hoist the steel-concrete beam segment 1 into the foundation pit and assemble it in the foundation pit. Insert a 34 mm diameter round steel bar 6 into the longitudinal reinforcement hole 103. The two connecting steel plates 12 are 20 mm thick, 1000 mm wide and 1000 mm long. The connecting steel plates 12 and the inclined cable adjuster 13 are fixed at the node position with a 30 mm diameter vertical tension screw 7 and a nut 10. Insert the inclined cable 9 into the inclined cable hole 106. Apply prestress to the inclined cable 9 and fix it with an anchor head 25. The inclined cable 9 is placed on the inclined cable adjuster 13. The two ends of the main support assembled by the steel-concrete beam segment 1 are placed on the pedestal 14. The middle part of the steel-concrete beam segment 1 is placed on the tray 15 welded to the steel lattice column 16. The position accuracy error is less than 3 mm. 17. Install the steel structure auxiliary support 2 of the second inner support; the steel structure auxiliary support of the second support is the same as the first one; install the side connection steel plate 11 on the side of the node where the auxiliary support is not installed; 18. Install the force-retaining steel structure 5 at the middle position of the axial brace. The force-retaining steel structure 5 is formed by welding a 20 mm thick steel plate. The A portion 501 is fixed to the steel-concrete beam segment 1 through the No. 3 hole 501-1, and the B portion 502 is fixed to the steel-concrete beam segment 1 through the No. 4 hole 502-1. They are fixed with a 24 mm diameter transverse tension screw 8 and a nut 10. 19. Place the jack 4 on the jack support 502-2 of the steel structure 5, and place the jack 4 on the jack wooden support 1405 of the pedestal 14 at both ends of the angle support; 20. All jacks 4 of the second support are pressurized at the same time. The jacks 4 on the beam adjustment system extend the A part 501 and the B part 502 of the force-retaining steel 5 structure, and the jacks 4 on the beam end adjustment system extend the force-retaining head 1406. A steel sheet 503 is inserted between the gap between the force-retaining box 501-2 of the A part 501 and the B part 502 of the force-retaining steel structure 5, and a gasket 1407 is inserted into the gap between the force-retaining head 1406 and the embedded steel plate 1401. The end faces of all axial nodes of each main support are closely fitted. 21. After the pressure of jack 4 is reduced, remove jack 4; 22. Repeat the steps 12)-21) to complete the construction of the third internal support; 23. After completing the installation of the third support, excavate to the bottom of the foundation pit and pour the foundation slab.

[0094] Example 2 For a certain foundation pit, the general excavation depth is 24.75-25.20 m, the perimeter of the foundation pit is 374 m, and the basement excavation area is approximately 8687 m2.

[0095] Design five foundation pit internal supports. The main supports of the five supports are steel-concrete beam sections. The internal support plane layout is as follows: Fig. 22 As shown; each internal support includes 4 corner braces arranged at the four corners of the foundation pit. The cross-section design height of the crown beam 17 is 1200 mm and the width is 1400 mm. The L-shaped PVC pipe 22 has an outer diameter of 40 mm and is set every 3-5 m. The size of the waist beam 18 is 1000 mm×1000 mm, and the outer diameter of the I-shaped PVC pipe 23 is 40 mm, and it is set every 3-5 m. The column piles are bored cast-in-place piles ⌀800 mm, with a total of 36 piles, and the concrete strength of the pile body is C30; 40 brackets are set on the crown beam 17 and the waist beam 18, and the cross-section size of the brackets is 1020 mm×1000mm.

[0096] There are two types of caps on the corbels; there are 20 caps for placing jacks, and the embedded steel plate 1401 is 20mm thick, 1000mm high and 1020mm wide. The embedded steel bars 1402 are HRB400 with a diameter of 10mm. One row of steel plates are welded on the left and right sides, with a total of 16 welded. The base plate 1403 is 20mm thick, 1020mm wide and 1300mm long. The side plate 1404 is 20mm thick. The semicircular groove of the jack wooden support 1405 is 600mm in diameter and 100mm in length. The force head 1406 uses a steel plate with a thickness of 20mm, a width of 1000mm and a height of 1000mm. Two stacked 50a I-beams are welded on each side. The size after stacking is 1000mm high and 160mm wide. There are 20 caps without jacks, and the embedded steel plates 1401 are 20mm thick, 1000mm high and 1000mm wide. mm, width 1020 mm, embedded steel bars 1402 are HRB400 with a diameter of 10 mm, one row is welded on each side of the steel plate, for a total of 16 steel bars, the pedestal bottom plate 1403 is 20 mm thick, 1020 mm wide and 500 mm long, the pedestal side plate 1404 is 20 mm thick.

[0097] The cross-sectional dimensions of the steel lattice column 16 are 460 mm × 460 mm. The tie material of the steel lattice column 16 is long angle steel, the long angle steel is L140 × L14, the tie plate thickness is 10 mm, the height is 400 mm, the width is 460 mm, and the tie plate spacing is 600 mm.

[0098] Pallet 15 is 20 mm thick, 860 mm wide and 1860 mm long. A right-angle triangular steel plate is welded under the pallet. One side of the steel plate is welded to the pallet and the other side is welded to the lattice column. The thickness of the steel plate is 20 mm.

[0099] The adjustment system includes 20 beam end adjustment systems, using a total of 20 jacks, and 500-ton hydraulic jacks 4 are selected; There are 5 rows of four corner supports each, and the 7 rows of main supports are composed of 2, 4, 6, 8, and 10 steel-concrete beam segments 1 respectively; both ends of each row of main supports are placed on the pedestal 14.

[0100] A steel plate with a thickness of 20 mm and a width of 100 mm is selected for welding to form a hoop 20 , which fixes the main support on the pallet 15 , with one end welded to the pallet 15 and the other end welded to the steel lattice column 16 .

[0101] In each inner support, 80 steel structure auxiliary supports 2 are connected between adjacent main supports.

[0102] The steel structure auxiliary support 2 used for connecting adjacent main supports is formed by welding a frame 201 and an end plate 202; the frame 201 is an I-beam with a waist height of 600 mm and a leg width of 200 mm; the end plate 202 is a steel plate with a height of 1000 mm and a width of 500 mm, on which two rows of No. 1 holes 202-1 for connection are arranged, the aperture of the No. 1 hole 202-1 is 30 mm, the row spacing between the two rows of No. 1 holes 202-1 is 240 mm, and the No. 1 hole 202-1 is compatible with the transverse screw hole 105.

[0103] The cross-sectional width of the steel-concrete beam section 1 is 1000 mm, the cross-sectional height is 1000 mm, and the length is 5 m. The end of the steel-concrete beam section 1 is provided with two rows of six vertical screw holes 104 (three holes in each row), two columns of six transverse screw holes 105 (three holes in each column), and two columns of four longitudinal reinforcing bar holes 103 (two holes in each column). In the middle of the rectangular reinforced concrete 102, symmetrically to the middle section of the steel-concrete beam section 1, two rows of six inclined cable holes 106 (three holes in each row) are arranged.

[0104] The hole plane layout of the vertical screw hole 104 is a rectangular hole layout with a hole diameter of 30 mm, a row spacing of 200 mm, a hole spacing of 300 mm, a distance from the outermost row of holes to the end face of 250 mm, and a distance from the outermost hole in each row of holes to the adjacent end side of 200 mm.

[0105] The hole plane layout of the transverse screw holes 105 is a rectangular hole layout with a hole diameter of 30 mm, a row spacing of 240 mm, a hole spacing of 300 mm, a distance of 120 mm from the outermost row of holes to the end face of the steel-concrete beam section 1, and a distance of 200 mm from the uppermost hole in each row of transverse screw holes 105 to the upper surface.

[0106] The hole opening plane layout of the longitudinal reinforcement holes 103 is a rectangular hole layout, with a hole diameter of 40 mm, a hole depth of 500 mm, a row spacing of 400 mm, a hole spacing of 400 mm, a distance from the top hole to the upper surface of 300 mm, and a distance from the left hole to the left side of the steel-concrete beam section 1 of 300 mm.

[0107] The hole diameter of the cable-stayed hole 106 is 30 mm, the inclination angle is 45°, the hole openings are arranged in a rectangular pattern on the upper surface of the steel-concrete beam segment 1, the hole spacing is 300 mm, the row spacing is 1000 mm, and the distance from the hole openings of each row of holes on the upper surface of the steel-concrete beam segment 1 to the end face of the adjacent steel-concrete beam segment 1 is 2000 mm, and the distance from the outermost holes of each row to the side face of the adjacent steel-concrete beam segment 1 is 200 mm.

[0108] A steel plate with a size of 800 mm×500 mm×10 mm is selected as the upper and bottom steel plates of the beam sleeve 101. The diameter, row spacing and hole spacing of the holes on it are the same as those of the vertical screw holes 104, and the edge of the steel plate with a length of 500 mm is welded to the angle steel. A steel plate with a size of 800 mm×500 mm×10 mm is selected as the side steel plate of the beam sleeve 101. The diameter, row spacing and hole spacing of the holes on it are the same as those of the transverse reinforcement holes 105, and the edge of the steel plate with a length of 500 mm is welded to the angle steel. An angle steel with a model of L100×10 and a length of 5 m is selected as the angle steel of the beam sleeve 101.

[0109] The structure of the axial node is as follows: the end faces of the two steel-concrete beam sections 1 are closely fitted, and a connecting steel plate 12 with a length of 1000 mm, a width of 1000 mm and a thickness of 20 mm is provided on each span of the upper and lower surfaces of the fitting, and four rows of twelve No. 6 holes 1201 are opened on the connecting steel plate 12, and the hole diameter of the No. 6 hole 1201 is 30 mm and is adapted to the vertical screw hole 104, and the longitudinal dowel holes 103 on the end faces of the two steel-concrete beam sections 1 are aligned one by one and inserted with round steel bars 6; The diameter of the round steel 6 is 34 mm; the thickness of the connecting steel plate 12 is 20 mm, the width is 1000 mm, and the length is 1000 mm; the diameter of the horizontal tension screw 8 is 24 mm; and the diameter of the vertical tension screw 7 is 24 mm.

[0110] One side of the axial node is connected to a steel structure auxiliary support 2, and the end plate 202 is connected to the axial node across the seam, that is, the No. 1 hole 202-1 of the end plate 202 is respectively connected to the transverse screw hole 105 on one side of the end of the two steel-concrete beam sections 1 connected at the axial node, and is fixed with a transverse tension screw 8 and a nut 10.

[0111] One side of the axial node is connected to two steel structure auxiliary supports 2. A side connection steel plate 11 is provided on one side of the axial node. The side connection steel plate 11 is 1000 mm high, 1000 mm wide, and 20 mm thick. There are four rows of twelve No. 5 holes 1101 on it, and the row spacing is 240 mm. The diameter of the No. 5 holes 1101 is 30 mm. The spans correspond to the two rows of transverse screw holes 105 on the sides of the two steel-concrete beam sections 1 at the axial node, and also correspond to the No. 1 holes 202-1 on the end plates 202 of the two steel structure auxiliary supports 2. After the transverse tension screw 8 passes through the coaxial No. 1 hole 202-1, No. 5 hole 1101 and transverse screw hole 105, both ends are tightened with nuts 10; There is no auxiliary support connection on one side of the axial node. The side connecting steel plate 11 is installed on this side of the axial node, and the transverse tension screw 8 passes through the No. 5 hole 1101 and the transverse screw hole 105, and is fixed with a nut 10. The side connecting steel plate 11 is 1000 mm high, 1000 mm wide and 20 mm thick. There are four rows of twelve No. 5 holes 1101 on it, and the row spacing is 240 mm. The diameter of the No. 5 hole 1101 is 30 mm, which is compatible with the transverse screw hole 105.

[0112] 1. Construction of support piles 3, column piles and steel lattice columns 16. Support piles 3 are bored cast-in-place piles ⌀1000 mm, with a pile spacing of 1300 mm. The concrete strength of the pile body is C30. They are matched with ⌀1000 mm mixing piles to form a bite-type water stop. The column piles are bored cast-in-place piles ⌀800 mm, with a pile body concrete strength of C30. The cross-sectional size of steel lattice columns 16 is 460 mm×460 mm. The long angle steel of steel lattice columns 16 is L140×L14. The thickness of the gusset plate is 10 mm, the height is 400 mm, and the width is 460 mm. The gusset plate spacing is 600 mm. The construction verticality deviation of steel lattice columns 16 is less than 1 / 300. 2. After all the piles are constructed, the heads of the supporting piles 3 are roughened. The cross-section design height of the crown beam 17 is 1200 mm and the width is 1400 mm. The steel cage of the crown beam 17 is tied. While the steel cage of the crown beam 17 is tied, the L-shaped PVC pipe 22 is tied to the steel cage of the crown beam 17. The outer diameter of the L-shaped PVC pipe 22 is 40 mm. One is set every 3-5 m and staggered with the corbel 19 of the crown beam 17. The L-shaped PVC pipe 22 is sealed with gypsum. The embedded steel bars 1402 are welded on the embedded steel plate 1401. The embedded steel plate 1401 is 20 mm thick, 1000 mm high and 1020 mm wide. The embedded steel bars 1402 are HRB400 with a diameter of 10 mm. One row is welded on each side of the steel plate, for a total of 16 bars. The length of the weld between each embedded steel bar 1402 and the embedded steel plate 1401 is 50 mm, and the welding position accuracy is less than 2 mm, vertical accuracy is less than H / 1000, the welded embedded steel bars 1402 and embedded steel plates 1401 are tied at the designed positions according to the design requirements, and the position accuracy error during tying is less than 3 mm. The rest of the steel bars at the tying position of the embedded steel plate 1401 are tied according to the design requirements; 3. Carry out formwork work on the crown beam 17 and the upper corbel 19. The cross-sectional size of the corbel 19 is designed to be 1020 mm × 1000 mm. After the formwork is completed, pour concrete. When pouring concrete, ensure that the positions of the embedded steel plate 1401, the embedded steel bar 1402, and the L-shaped PVC pipe 22 do not shift. After pouring, maintain the concrete; 4. Excavate to the bottom elevation of the first supporting beam, and excavate 1 m more at the base 14 and tray 15; 5. The first supporting tray 15 is welded on the steel lattice column 16. The tray 15 is 20 mm thick, 860 mm wide and 1860 mm long. It is welded and reinforced with isosceles right triangle steel plates. The thickness of the steel plate is 20 mm. Spot welding is performed first and then full welding is performed during welding. The welding error is less than 2 mm. The cap 14 is welded on the embedded steel plate 1401 at the position of the corbel 19. The base plate 1403 of the cap without jack is 20 mm thick, 1020 mm wide and 500 mm long. The side plate 1404 of the cap is 20 mm thick. Spot welding is performed first and then full welding is performed during welding. The welding error is less than 2 mm. The cap 14 with jack is welded. The base plate 1403 is 20 mm thick, 1020 mm wide and 1300 mm long. The side plate 1404 of the cap is 20 mm thick. The semicircular groove of the jack wooden support 1405 has a diameter of 600 mm and a length of 100 mm. Spot welding is performed first and then full welding is performed. The welding accuracy is less than 2 mm; place a force head 1406, which is made of a steel plate with a thickness of 20 mm, a width of 1000 mm, and a height of 1000 mm. Two 50a I-beams are welded on each side. The size after stacking is 1000 mm in height and 160 mm in width. The force head 1406 is formed by welding. The force head 1406 is placed on the base 14 with a jack. 6. Use a crane to move the steel-concrete beam segment 1 into the foundation pit for assembly. Insert a 34 mm diameter round steel bar 6 into the longitudinal reinforcement hole 103. The two connecting steel plates 12 are 20 mm thick, 1000 mm wide and 1000 mm long. The connecting steel plates 12 are fixed at the node position with a 24 mm diameter vertical tension screw 7 and a nut 10. The assembled steel-concrete beam segment 1 is placed on the pedestal 14 and the tray 15, and the position accuracy error is less than 3 mm. 7. Install the steel structure auxiliary support 2. The steel structure auxiliary support 2 includes an I-beam auxiliary support 2 with an I-beam as a frame member 201 arranged obliquely. The I-beam waist is 600 mm high and the leg width is 200 mm. The end plate 202 is a steel plate. The end plate is 1000 mm high and 500 mm wide. Two rows of No. 1 holes 202-1 for connection are set on it. The hole diameter of the No. 1 hole 202-1 is 22 mm, and the row spacing between the two rows of No. 1 holes 202-1 is 240 mm. The crane hoists the steel structure auxiliary support 2 into the foundation pit, and uses a 24 mm diameter transverse tension screw 8 and a nut 10 to fix the steel structure auxiliary support and the assembled steel-concrete beam section 1. The installation error of the I-beam auxiliary support 2 is less than 2 mm. The side connecting steel plate is installed on the side of the axial node where the auxiliary support is not installed. 8. The jack wooden support 1405 of the bearing platform 14 is used to place the jack 4; 9. All jacks 4 of the first support are pressurized at the same time, and the gasket 1407 is inserted into the gap between the I-beam of the force-retaining head 1406 and the embedded steel plate 1401; and the clamp 20 is welded; 10. After the pressure of jack 4 is reduced, remove jack 4; 11. Excavate to the second support bottom elevation, and excavate 1 m more at the base 14 and tray 15; 12. The pile body of the support pile 3 is roughened, and the steel cage of the waist beam 18 is tied. The cross-sectional size of the waist beam 18 is designed to be 1200 mm×1000 mm. The I-shaped PVC pipe 23 is tied to the steel cage with steel wire. The hole of the I-shaped PVC pipe 23 is sealed with gypsum. The outer diameter of the I-shaped PVC pipe 23 is 40 mm. The embedded steel bars 1402 are welded on the embedded steel plate 1401. The embedded steel plate 1401 is 20 mm thick, 1000 mm high, and 1020 mm wide. The embedded steel bars 1402 are HRB400 with a diameter of 10 mm. One row is welded on each side of the steel plate, for a total of 16 bars. The length of the weld between each embedded steel bar 1402 and the embedded steel plate 1401 is 50 mm. The welding position accuracy is less than 2 mm, and the vertical accuracy is less than H / 1000. The welded embedded steel bars 1402 and embedded steel plates 1401 are tied at the designed position according to the design requirements. The position accuracy error during tying is less than 3 mm, complete the binding of the remaining steel bars at the binding position of the embedded steel plate 1401 according to the design requirements; 13. Carry out formwork work on the waist beam 18 and the upper corbel 19. The cross-sectional size of the corbel 19 is 1020 mm × 1000 mm. After the formwork is completed, pour concrete. When pouring concrete, ensure that the positions of the embedded steel plate 1401, the embedded steel bar 1402, and the I-shaped PVC pipe 23 do not shift. After pouring, maintain the concrete; 14. Weld the second supporting tray 15 on the steel lattice column 16. The tray 15 is 20 mm thick, 860 mm wide and 1860 mm long. It is welded and reinforced with a right-angle triangle steel plate. The thickness of the steel plate is 20 mm. Spot welding is performed first and then full welding. The welding error is less than 2 mm. Weld the pedestal 14 on the embedded steel plate 1401 at the position of the corbel 19. The pedestal bottom plate 1403 of the pedestal without a jack is 20 mm thick, 1020 mm wide and 500 mm long. The pedestal side plate 1404 is 20 mm thick. Spot welding is performed first and then full welding. The welding error is less than 2 mm. Weld the pedestal 14 with a jack. The pedestal bottom plate 1403 is 20 mm thick, 1020 mm wide and 1300 mm long. The pedestal side plate 1404 is 20 mm thick. The semicircular groove of the jack wooden support 1405 has a diameter of 600 mm and a length of 100 mm. Spot welding is performed first and then full welding. The welding accuracy is less than 2 mm; place a force head 1406, which is made of a steel plate with a thickness of 20 mm, a width of 1000 mm, and a height of 1000 mm. Two stacked 50a I-beams are welded on each side. The stacked size is 1000 mm high and 160 mm wide. The force head 1406 is formed by welding. The force head 1406 is placed on the base 14 with a jack. 15. Install the steel-concrete beam section 1 of the second support. Use a crane to lift the steel-concrete beam section 1 into the foundation pit and assemble it in the foundation pit. Insert the round steel bar 6 with a diameter of 34 mm into the longitudinal reinforcement hole 103. The two connecting steel plates 12 are 20 mm thick, 1000 mm wide and 1000 mm long. The connecting steel plates 12 are fixed at the axial nodes with vertical tension screws 7 and nuts. The steel-concrete beam section 1 is placed on the pedestal 14 and the tray 15, and the position accuracy error is less than 3 mm. 16. Install steel structure auxiliary support for the second support. The steel structure auxiliary support of the second support is arranged obliquely with the main support. The installation error of the steel structure auxiliary support is less than 2 mm. Install the side connecting steel plate on the side of the axial node where the steel structure auxiliary support is not installed. 17. Place the jack 4 on the jack wooden support 1405 of the second supporting platform 14; 18. All jacks 4 of the second support are pressurized at the same time, and the gasket 1407 is inserted into the gap between the I-beam of the force-retaining head 1406 and the embedded steel plate 1401; and the clamp 20 is welded; 19. After the pressure of jack 4 is reduced, remove jack 4; 20. Repeat the steps 11-19 to complete the construction of the third, fourth and fifth internal supports; 21. Excavate to the bottom of the foundation pit and pour the foundation slab.

[0113] Example 3 For a certain foundation pit, the general excavation depth is 5.5-6.3 m, the perimeter of the foundation pit is about 539 m, and the basement excavation area is about 14,693 m2.

[0114] Design an internal support for the foundation pit. The main support uses a steel-concrete beam segment 1. The internal support plane layout is as follows: Fig.23 As shown; the internal support includes four pairs of braces. The cross-section design of the crown beam 17 is 1000 mm high and 1000 mm wide. The L-shaped PVC pipe 22 has an outer diameter of 40 mm and is set every 3-5 m. The column piles are bored cast-in-place piles ⌀800 mm, with a total of 70 piles, and the concrete strength of the pile body is C30. There are 20 brackets on the crown beam 17 and the waist beam 18, and the cross-section size of the bracket is 1020 mm×1000 mm.

[0115] There are caps on each corbel; there are 20 caps, with embedded steel plates 1401 of 20 mm thickness, 1000 mm height and 1020 mm width. The embedded steel bars 1402 are HRB400 with a diameter of 10 mm. There are 16 steel bars welded in a row on each side of the steel plate. The cap bottom plate 1403 is 20 mm thick, 1020 mm wide and 500 mm long. The cap side plates 1404 are 20 mm thick.

[0116] The cross-sectional dimensions of the steel lattice column 16 are 460 mm × 460 mm. The tie material of the steel lattice column 16 is long angle steel, the long angle steel is L140 × L14, the tie plate thickness is 10 mm, the height is 400 mm, the width is 460 mm, and the tie plate spacing is 600 mm.

[0117] Pallet 15 is 20 mm thick, 860 mm wide and 1860 mm long. A right-angle triangular steel plate is welded under the pallet. One side of the steel plate is welded to the pallet and the other side is welded to the lattice column. The thickness of the steel plate is 20 mm.

[0118] The adjustment system includes 4 mid-beam adjustment systems, using a total of 12 jacks, and 4 500-ton hydraulic jacks are selected; the mid-beam adjustment system includes a retaining steel structure 5 and jacks. The 20 main supports are connected into 10 rows of main supports through 4 adjustment systems. From west to east, they are three rows of main supports sharing the retaining steel structure 5, two rows of main supports sharing the retaining steel structure 5, two rows of main supports sharing the retaining steel structure 5, and three rows of main supports sharing the retaining steel structure 5.

[0119] The mid-beam adjustment system includes a force-retaining steel structure 5 and a jack 4 placed on the force-retaining steel structure 5; the beam end adjustment system includes a force-retaining head 1406, a gasket 1407 and a jack 4 placed on the base 14 arranged at one end of the main support, the gasket 1407 is 10 mm thick, and the gasket is 1000 mm high and 1000 mm wide. The force-retaining steel structure 5 is composed of a part A 501, a part B 502, a steel sheet 503, an insert ring 504, and an insert plate 505; the part A 501 is formed by welding two long steel plates with a length of 11000 mm, a height of 1000 mm, a thickness of 20 mm, and a steel partition with a length of 1000 mm, a height of 1000 mm, and a thickness of 20 mm, and the two long steel plates are welded and connected by a steel partition perpendicular to the long steel plates; wherein, a connecting plate with a length of 500 mm, a height of 1000 mm, and a thickness of 20 mm is welded on one side of a long steel plate, and the connecting plate has two rows of six No. 3 holes 501-1, and the No. 3 holes 501-1 are adapted to the transverse screw holes 105; a force-retaining box 501-2 is welded on one side of the other long steel plate, and the force-retaining box 501-2 is formed by welding a steel plate with a height of 1000 mm, and a thickness of 20 mm; the part B 502 is formed by welding two long steel plates with a length of 11000 mm, a height of 1000 mm, and a thickness of 20 The invention relates to a method for manufacturing a jack support 502-2 for a steel plate 501 having a length of 500 mm, a width of 1000 mm and a thickness of 20 mm. The two steel plates are connected by welding via a steel partition perpendicular to the long steel plates. A connecting plate 502-1 having a length of 500 mm, a height of 1000 mm and a thickness of 20 mm is welded on one side of one long steel plate. The connecting plate has two rows of six No. 4 holes 502-1. The No. 4 holes 502-1 are matched with the transverse screw holes 105. A jack support 502-2 and a protruding steel plate 502-3 having a length of 500 mm, a width of 1000 mm and a thickness of 20 mm are welded on one side of the other long steel plate. The jack support 502-2 is formed by welding a 20 mm thick semicircular steel plate on the long steel plate. The insert rings 504 are welded on the side surfaces of the two end heads of the A part 501 and the B part 502, with a total of 12. The insert rings 504 are inserted with the insert plates 505 having a cross-sectional size of 100 mm×20 mm.

[0120] Each row of main supports in the axial bracing is formed by axially connecting 14 steel-concrete beam segments 1, and both ends of each row of main supports are placed on the cap 14.

[0121] A steel plate with a thickness of 20 mm and a width of 100 mm is selected for welding to form a hoop 20 , which fixes the main support on the pallet 15 . One end of the hoop 20 is welded to the pallet 15 , and the other end is welded to the steel lattice column 16 .

[0122] In each inner support, there are 72 steel structure auxiliary supports 2 connecting the adjacent main supports, and there are 16 steel structure S-beams.

[0123] The steel structure auxiliary support 2 used for connecting adjacent main supports is formed by welding a frame 201 and an end plate 202; the frame 201 is a circular steel tube with a diameter of 500 mm and a wall thickness of 20 mm; the end plate 202 is a steel plate, on which two rows of No. 1 holes 202-1 for connection are provided, the aperture of the No. 1 hole 202-1 is 30 mm, the row spacing between the two rows of No. 1 holes 202-1 is 720 mm, and the No. 1 hole 202-1 is compatible with the transverse screw hole 105.

[0124] The steel structure auxiliary support 2 used for the steel structure S-beam is formed by welding a frame 201 and an end plate 202; the frame 201 is an H-shaped steel, and the model of the H-shaped steel is H600 mm×600 mm; the end plate 202 is a steel plate, on which two rows of No. 1 holes 202-1 for connection are arranged, the hole diameter of the No. 1 hole 202-1 is 30 mm, and the row spacing between the two rows of No. 1 holes 202-1 is 720 mm.

[0125] The cross-sectional width of the steel-concrete beam section 1 is 1000 mm, the cross-sectional height is 1000 mm, and the length is 5 m. The end of the steel-concrete beam section 1 is provided with two rows of six vertical screw holes 104 (three holes in each row), two columns of six transverse screw holes 105 (three holes in each column), and two columns of four longitudinal reinforcing bar holes 103 (two holes in each column). In the middle of the rectangular reinforced concrete 102, symmetrically to the middle section of the steel-concrete beam section 1, two rows of six inclined cable holes 106 (three holes in each row) are arranged.

[0126] The hole plane layout of the vertical screw hole 104 is a rectangular hole layout with a hole diameter of 30 mm, a row spacing of 200 mm, a hole spacing of 300 mm, a distance from the outermost row of holes to the end face of 250 mm, and a distance from the outermost hole in each row of holes to the adjacent end side of 200 mm.

[0127] The hole plane layout of the transverse screw holes 105 is a rectangular hole layout with a hole diameter of 30 mm, a row spacing of 240 mm, a hole spacing of 300 mm, a distance of 120 mm from the outermost row of holes to the end face of the steel-concrete beam section 1, and a distance of 200 mm from the uppermost hole in each row of transverse screw holes 105 to the upper surface.

[0128] The hole opening plane layout of the longitudinal reinforcement holes 103 is a rectangular hole layout, with a hole diameter of 40 mm, a hole depth of 500 mm, a row spacing of 400 mm, a hole spacing of 400 mm, a distance from the top hole to the upper surface of 300 mm, and a distance from the left hole to the left side of the steel-concrete beam section 1 of 300 mm.

[0129] The hole diameter of the cable-stayed hole 106 is 30 mm, the inclination angle is 45°, the hole openings are arranged in a rectangular pattern on the upper surface of the steel-concrete beam segment 1, the hole spacing is 300 mm, the row spacing is 1000 mm, and the distance from the hole openings of each row of holes on the upper surface of the steel-concrete beam segment 1 to the end face of the adjacent steel-concrete beam segment 1 is 2000 mm, and the distance from the outermost holes of each row to the side face of the adjacent steel-concrete beam segment 1 is 200 mm.

[0130] A steel plate with a size of 800 mm×500 mm×10 mm is selected as the upper and bottom steel plates of the beam sleeve 101. The diameter, row spacing and hole spacing of the holes on it are the same as those of the vertical screw holes 104, and the edge of the steel plate with a length of 500 mm is welded to the angle steel. A steel plate with a size of 800 mm×500 mm×10 mm is selected as the side steel plate of the beam sleeve 101. The diameter, row spacing and hole spacing of the holes on it are the same as those of the transverse reinforcement holes 105, and the edge of the steel plate with a length of 500 mm is welded to the angle steel. An angle steel with a model of L100×10 and a length of 5 m is selected as the angle steel of the beam sleeve 101.

[0131] The structure of the axial node is as follows: the end faces of the two steel-concrete beam sections 1 are closely fitted, and a connecting steel plate 12 with a length of 1000 mm, a width of 1000 mm and a thickness of 20 mm is provided on each span of the upper and lower surfaces of the fitting, and four rows of twelve No. 6 holes 1201 are opened on the connecting steel plate 12, and the hole diameter of the No. 6 hole 1201 is 30 mm, and the hole diameter of the No. 6 hole 1201 is 30 mm, which is compatible with the vertical screw hole 104, and the longitudinal dowel holes 103 on the end faces of the two steel-concrete beam sections 1 are aligned one by one and inserted with round steel 6; The diameter of the round steel 6 is 34 mm; the thickness of the connecting steel plate 12 is 20 mm, the width is 1000 mm, and the length is 1000 mm; the diameter of the horizontal tension screw 8 is 24 mm; and the diameter of the vertical tension screw 7 is 24 mm.

[0132] The inclined cable adjuster 13 is composed of an adjuster base plate 1301, an adjusting screw 1302, an adjuster support rod 1303, a web 1304, a left-handed nut 1305, a fastener 1306, a right-handed nut 1307, and a pin 1308; the adjuster base plate 1301 of the inclined cable adjuster 13 is 1000 mm long, 1000 mm wide, and 20 mm thick. There are two rows of six No. 2 holes 1301-1 on the adjuster base plate 1301. The aperture of the No. 2 hole 1301-1 is 30 mm and is compatible with the vertical screw hole 104. Two fasteners 1306 are welded on the web 1304 and the adjusting base plate 1301. The web 1304 is 20 thick. mm, each fixing member 1306 has two pins 1308, two adjuster support rods 1303 are connected to the two pins 1308, the diameter of the adjuster support rods 1303 is 30 mm, the other ends of the two adjuster support rods 1303 are respectively connected to a right-handed nut 1307 and a left-handed nut 1305 through the pins 1308, the end of the adjusting screw 1302 is provided with a handle 1302-3, the diameter of the adjusting screw 1302 is 40 mm, and two groups of positive and negative threads are arranged on the adjusting screw 1302, each group of positive and negative threads includes a right-handed thread 1302-1 and a left-handed thread 1302-2; each group of positive and negative threads is equipped with a right-handed nut 1307 and a left-handed nut 1305.

[0133] The No. 1 hole 202-1 of one end plate 202 of the steel structure S-beam is aligned one by one with the transverse screw hole 105 at the axial node position on the steel-concrete beam section 1 close to the foundation pit wall, and a transverse tension screw 8 is inserted therein, and both ends of the transverse tension screw 8 are fixed with nuts 10; the other end plate 202 of the steel structure S-beam is fixed to the crown beam 17 or the waist beam 18 with bolts 21.

[0134] One side of the axial node is connected to a steel structure auxiliary support 2, and the end plate 202 is connected to the axial node across the seam, that is, the No. 1 hole 202-1 of the end plate 202 is respectively connected to the transverse screw hole 105 on one side of the end of the two steel-concrete beam sections 1 connected at the axial node, and is fixed with a transverse tension screw 8 and a nut 10.

[0135] There is no auxiliary support connection on one side of the axial node. The side connecting steel plate 11 is installed on this side of the axial node, and the transverse tension screw 8 passes through the No. 5 hole 1101 and the transverse screw hole 105, and is fixed with a nut 10. The side connecting steel plate 11 is 1000 mm high, 1000 mm wide and 20 mm thick. There are four rows of twelve No. 5 holes 1101 on it, and the row spacing is 240 mm. The diameter of the No. 5 hole 1101 is 30 mm, which is compatible with the transverse screw hole 105.

[0136] 1. Construction of underground continuous wall, thickness 800 mm, concrete strength C30, column piles use bored cast-in-place piles ⌀800, pile body concrete strength C30, steel lattice column 16 section size 460 mm × 460 mm, steel lattice column 16 long angle steel use L140 × L14, gusset plate thickness 10 mm width 400 mm, gusset plate spacing 600 mm, steel lattice column 16 construction verticality deviation less than 1 / 300; 2. The cross-section design height of crown beam 17 is 1000 mm and width is 1000 mm. The steel cage of crown beam 17 is tied. At the same time, L-shaped PVC pipe 22 is tied to the steel cage of crown beam 17. The outer diameter of L-shaped PVC pipe 22 is 40 mm. One pipe is set every 3-5 m and staggered with the corbel of crown beam 17. The hole of L-shaped PVC pipe 22 is sealed with gypsum. Pre-embedded steel bar 1402 is welded on the embedded steel plate 1401. The embedded steel plate 1401 is 20 mm thick, 1000 mm high and 1020 mm wide. The embedded steel bar 1402 is HRB400 with a diameter of 10 mm. One row is welded on each side of the steel plate, for a total of 16 steel bars. The length of the weld between each embedded steel bar 1402 and embedded steel plate 1401 is 50 mm, and the welding position accuracy is less than 2 mm, vertical accuracy is less than H / 1000, the welded embedded steel bars 1402 and embedded steel plates 1401 are tied at the designed positions according to the design requirements, and the position accuracy error during tying is less than 3mm. The rest of the steel bars at the tying position of the embedded steel plate 1401 are tied according to the design requirements; 3. Carry out formwork work on the crown beam 17 and the upper corbel 19. The cross-sectional size of the corbel 19 is designed to be 1020 mm × 1000 mm. After the formwork is completed, pour concrete. When pouring concrete, ensure that the positions of the embedded steel plate 1401, the embedded steel bar 1402, and the L-shaped PVC pipe 22 do not shift. After pouring, maintain the concrete; 4. Excavate to the bottom elevation of the first supporting beam, and excavate 1 m more at the base 14 and tray 15; 5. The first supporting tray 15 is welded on the steel lattice column 16. The tray 15 is 20 mm thick, 860 mm wide and 1860 mm long. It is welded and reinforced with a right-angle triangle steel plate. The thickness of the steel plate is 20 mm. Spot welding is performed first and then full welding. The welding error is less than 2 mm. The cap 14 is welded on the embedded steel plate 1401 at the position of the corbel 19. The axially supported cap bottom plate 1403 is 20 mm thick, 1020 mm wide and 500 mm long. The cap side plate 1404 is 20 mm thick. Spot welding is performed first and then full welding. The welding error is less than 2 mm. 6. The crane moves the steel-concrete beam segment 1 into the foundation pit for assembly. A 34 mm diameter round steel bar 6 is inserted into the longitudinal reinforcement hole 103. The two connecting steel plates 12 are 20 mm thick, 1000 mm wide and 1000 mm long. The axial node is the connecting steel plate 12 and the inclined cable adjuster 13. The vertical tension screw rod 7 and nut 10 with a diameter of 20 mm are fixed at the node position. The inclined cable 9 is inserted into the inclined cable hole 106. The inclined cable 9 is prestressed and fixed with an anchor head 25. The inclined cable 9 is placed on the inclined cable adjuster 13. The assembled steel-concrete beam segment 1 is placed on the pedestal 14 and the tray 15. The installation accuracy error is less than 3 mm. 7. The steel structure auxiliary support 2 used for connecting the main supports in the foundation pit uses steel pipes as the frame 201. The steel structure auxiliary support 2 used for connecting the main supports is arranged vertically with the main support. The steel structure S-shaped beam uses H-shaped steel as the auxiliary support frame 201. The steel structure auxiliary support is installed; the crane hoists the steel structure auxiliary support used for connecting the main supports into the foundation pit, and uses 20 mm diameter transverse tension screws 8 and nuts 10 to fix the steel structure auxiliary support 2 to the steel-concrete beam section 1; one end of the steel structure S-shaped beam is fixed to the assembled steel-concrete beam section 1 using transverse tension screws 8 and nuts 10, and the other end is fixed to the crown beam 17 with bolts 10. The installation error of the steel structure auxiliary support is less than 2 mm; the side connecting steel plate is installed on the side of the node where the steel structure auxiliary support 2 is not installed; 8. Install the force-retaining steel structure 5 at the middle position of the axial brace. The force-retaining steel structure 5 is formed by welding a 20 mm thick steel plate. The A part 501 is fixed to the steel-concrete beam section 1 through the No. 3 hole 501-1, and the B part 502 is fixed to the steel-concrete beam section 1 through the No. 4 hole 502-1. They are fixed with a 24 mm diameter transverse tension screw 8 and a nut 10; 9. Place the jack 4 on the jack support 502-2 of the Baoli steel structure 5; 10. All jacks 4 of the first support are pressurized at the same time, and the jacks 4 extend the A part 501 and the B part 502 of the force-retaining steel structure 5, and the steel sheet 503 is inserted between the gap between the force-retaining box 501-2 of the A part 501 and the B part 502 of the force-retaining steel structure 5; the hoop 20 is welded; and the angle steel 24 is welded at the node; 11. After the pressure of jack 4 is reduced, remove jack 4; 12. Excavate to the bottom of the foundation pit and pour the foundation slab.

[0137] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0138] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An easily dismantled assembled steel-concrete-steel structure foundation pit support system, comprising a crown beam (17), a waist beam (18), support piles (3) and an internal support system, characterized in that: The internal support system is composed of a plurality of main supports formed by a plurality of prefabricated steel-concrete beam sections (1), a plurality of steel structure auxiliary supports (2), a plurality of steel lattice columns (16), and an adjustment system; the steel-concrete beam sections (1) are standard parts with the same structure and size; The crown beam (17) and the waist beam (18) are provided with a plurality of corbels (19), and each of the corbels (19) is provided with a support platform (14); Each main support is formed by axially connecting a plurality of steel-concrete beam sections (1), wherein the connection point between two steel-concrete beam sections (1) is an axial node; a plurality of steel structure auxiliary supports (2) are connected between adjacent main supports, wherein the two ends of the steel structure auxiliary supports (2) are connected to one side of two axial nodes of adjacent main supports; one side of the axial node of some main supports close to the foundation pit wall is connected to a steel structure auxiliary support (2), wherein the other end of the steel structure auxiliary support (2) is connected to the side of a crown beam (17) or a waist beam (18), wherein the steel structure auxiliary support (2) is a steel structure eight-shaped beam; The main support described above forms a row of main supports or two main supports are connected to form a row of main supports through an adjustment system, and both ends of each row of main supports are placed on a bearing platform (14); The main support is installed on the steel lattice column (16), and the contact position between the main support and the steel lattice column (16) is staggered from the axial node.

2. The easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 1, characterized in that: The surface of the steel-concrete beam section (1) is provided with a beam sleeve (101), and a rectangular concrete (102) is arranged inside. A cable hole (106) is arranged inside the rectangular reinforced concrete (102); longitudinal reinforcing bar holes (103), vertical screw holes (104), and transverse screw holes (105) are arranged at both ends of the steel-concrete beam section (1), and the longitudinal reinforcing bar holes (103), vertical screw holes (104), transverse screw holes (105), and cable holes (106) do not intersect with each other.

3. The easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 2, characterized in that: The structure of the axial node is as follows: the end surfaces of the two steel-concrete beam sections (1) are tightly fitted, and connecting steel plates (12) are provided on the upper and lower surfaces of the fitting location, and a No. 6 hole (1201) is opened on the connecting steel plate (12). The longitudinal reinforcement holes (103) on the end surfaces of the two steel-concrete beam sections (1) are aligned one by one and round steel bars (6) are inserted therein.

4. The easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 3, characterized in that: A cable adjuster (13) is provided below the axial node, and the cable adjuster (13) is composed of an adjuster base plate (1301), an adjusting screw rod (1302), an adjuster support rod (1303), a web rod (1304), a left-handed nut (1305), a fixing member (1306), a right-handed nut (1307), and a pin (1308); a second hole (1301-1) is provided on the adjusting base plate (1301); the web rod (13 04) and the adjusting base plate (1301), respectively, two fixing members (1306) are welded thereon; each of the fixing members (1306) has two pins (1308), the two pins (1308) are connected to two adjusting device support rods (1303), and the other ends of the two adjusting device support rods (1303) are respectively connected to a right-handed nut (1307) and a left-handed nut (1305) through the pins (1308); the end of the adjusting screw (1302) has a handle (1302-3), the adjusting screw (1302) is provided with two groups of positive and negative threads, each group of positive and negative threads includes a right-handed thread (1302-1) and a left-handed thread (1302-2); each group of positive and negative threads is equipped with a right-handed nut (1307) and a left-handed nut (1305); the vertical screw hole (104) at the axial node, the sixth hole (1201) on the two connecting steel plates (12) and the second hole (1301) on the inclined cable adjuster (13) -1) are coaxial and penetrated by a vertical tension screw rod (7), and nuts (10) are provided at both ends of the vertical tension screw rod (7); a cable (9) is inserted into the cable hole (106), and the cable (9) extends from the cable hole (106) of one steel-concrete beam section (1) and extends from the cable hole (106) of another adjacent steel-concrete beam section (1); both ends of the cable (9) are fixed by anchor heads (25), and the middle part is placed on the web (1304) of the cable adjuster (13).

5. The easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 2, characterized in that: The steel structure auxiliary support (2) is formed by welding a frame (201) and an end plate (202); the frame (201) is an I-beam, a steel pipe or an H-beam; the end plate (202) is a steel plate, on which a No. 1 hole (202-1) for connection is provided, and the No. 1 hole (202-1) has the same diameter and spacing as the transverse screw hole (105).

6. The easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 5, characterized in that: A No. 1 hole (202-1) of one end plate (202) of the steel structure S-shaped beam is aligned one by one with the transverse screw hole (105) at the axial node position on the steel-concrete beam section (1) close to the foundation pit wall, and a transverse tension screw (8) is inserted therein, and both ends of the transverse tension screw (8) are fixed with nuts (10); the other end plate (202) of the steel structure S-shaped beam is fixed to the crown beam (17) or the waist beam (18) with bolts (21).

7. The easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 6, characterized in that: There are three ways to connect one side of the axial node with the steel structure auxiliary support (2), the first of which is: one side of the axial node is connected to a steel structure auxiliary support (2), and the end plate (202) is connected to the axial node across the seam, that is, the No. 1 hole (202-1) of the end plate (202) is respectively connected to the transverse screw hole (105) on one side of the end of the two steel-concrete beam sections (1) connected at the axial node, and fixed with a transverse tension screw (8) and a nut (10); The second type is as follows: one side of the axial node is connected to two steel structure auxiliary supports (2), a side connection steel plate (11) is provided on one side of the axial node, the side connection steel plate (11) has four rows of No. 5 holes (1101), the span seams correspond one-to-one with the two rows of transverse screw holes (105) on the sides of the two steel-concrete beam sections (1) at the axial node, and also correspond one-to-one with the No. 1 holes (202-1) on the end plates (202) of the two steel structure auxiliary supports (2), and after the transverse tension screws (8) pass through the coaxial No. 1 holes (202-1), No. 5 holes (1101) and transverse screw holes (105), the two ends are tightened with nuts (10); The third type is as follows: there is no auxiliary support connection on one side of the axial node, the side connecting steel plate (11) is installed on this side of the axial node, and after the transverse tension screw (8) passes through the fifth hole (1101) and the transverse screw hole (105), the two ends of the transverse tension screw (8) are fixed with nuts (10).

8. The easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 1, characterized in that: The adjustment system is divided into a mid-beam adjustment system and a beam end adjustment system; the mid-beam adjustment system comprises a force-retaining steel structure (5) and a jack (4) placed on the force-retaining steel structure (5); the beam end adjustment system comprises a force-retaining head (1406), a gasket (1407) and a jack (4) arranged on a cap (14); the force-retaining steel structure (5) comprises a part A (501), a part B (502), a steel sheet (503), an insert ring (504), and an insert plate (505); the part A (501) comprises two long steel plates and a steel partition plate vertically welded between the two long steel plates The invention is composed of a connecting plate welded to one side of a long steel plate, and the connecting plate has a No. 3 hole (501-1); a force box (501-2) is welded to one side of another long steel plate, and the force box (501-2) is formed by welding steel plates; the B part (502) is composed of two long steel plates and a steel partition plate vertically welded between the two long steel plates, wherein a connecting plate is welded to one side of one long steel plate, and the connecting plate has a No. 4 hole (502-1); a jack support (502-2) and a protruding steel plate (502-3) are welded to one side of another long steel plate, and the jack The jack support (502-2) is formed by welding a semicircular steel plate to a long steel plate; the height of the long steel plate and the plurality of steel partitions is the same as the cross-sectional height of the steel-concrete beam section (1); the connecting plates are in groups of two, and the spacing between the two connecting plates is the same as the cross-sectional width of the steel-concrete beam section (1); the insert ring (504) is welded to the side surfaces of the force-retaining box (501-2) at both ends of the A part (501) and the side surfaces of both ends of the B part (502); the arrangement of the No. 3 hole (501-1) and the No. 4 hole (502-1) and the transverse screw hole (105) of the steel-concrete beam section (1) and the hole The diameters of the steel sheets (503) are the same, and the width of the steel sheet (503) is the same as the width of the force box (501-2); the force box (501-2) of part A is placed on the protruding steel plate (502-3) of part B (502), and the connection between part A (501) and part B (502) is achieved by inserting the insert plate (505) into the insert ring (504); the connection between the force-retaining steel structure (5) and the main support is achieved by making the fourth hole (502-1) on the connecting plate correspond to the transverse screw hole (105) at the end of the main support one by one, inserting the transverse tension screw (8) and tightening it with a nut (10).

9. The easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 1, characterized in that: There are two types of the cap (14), one type of cap (14) is composed of a pre-embedded steel plate (1401), pre-embedded steel bars (1402), a cap bottom plate (1403), and a cap side plate (1404); the other type of cap (14) is composed of a pre-embedded steel plate (1401), pre-embedded steel bars (1402), a cap bottom plate (1403), a cap side plate (1404), a jack wooden support (1405), a force-retaining head (1406), and a gasket (1407); the force-retaining head (1406) is formed by welding an I-beam and a steel plate, the steel plate size of the force-retaining head (1406) is the same as the cross-sectional size of the steel-concrete beam section (1), the pre-embedded steel plates (1401) are all arranged at the corbels (19), and one side of the pre-embedded steel plates (1401) is welded with pre-embedded steel bars (1402).

10. The easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 1, characterized in that: A tray (15) is provided on the steel lattice column (16), the main support is placed on the tray (15), one side of the steel-concrete beam section (1) in the main support is closely attached to the lattice column (16), one end of a hoop (20) is welded to the tray (15), the hoop (20) surrounds the main support, and the other end is welded to the steel lattice column (16), thereby fixing the main support.

11. The easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 1, characterized in that: The crown beam (17) and the waist beam (18) are respectively provided with L-shaped embedded holes (1701) and I-shaped embedded holes (1801) for rope saw cutting at intervals of 3-5 m. The L-shaped embedded hole (1701) is formed by embedding an L-shaped PVC tube (22) in the crown beam (17). The L-shaped PVC tube (22) is open at both ends, one end is open on the upper surface of the crown beam (17), and the other end is open on the side of the crown beam (17). The embedded position of the L-shaped PVC tube (22) is staggered with the position of the corbel (19). The I-shaped embedded hole (1801) is formed by embedding an I-shaped PVC pipe (23) in the waist beam (18); the I-shaped PVC pipe (23) has openings at both ends, one end of the opening is located on the top surface of the waist beam (18), and the other end of the opening is located on the bottom surface of the waist beam (18); the I-shaped PVC pipe (23) is embedded on one side of the waist beam (18) close to the supporting pile (3); and the embedded position of the I-shaped PVC pipe (23) is staggered with the position of the corbel (19).

12. The construction process of the easily dismantled assembled steel-concrete-steel structure foundation pit support system as claimed in claims 1 to 11, characterized in that: The construction steps include: 1) constructing a plurality of support piles (3), column piles and steel lattice columns (16); 2) The pile head of the support pile (3) is roughened, the steel cage of the crown beam (17) is tied, the L-shaped PVC pipe (22) is embedded, and the embedded steel bars (1402) are welded to the embedded steel plate (1401). After the welding is completed, the embedded steel bars (1402) are tied to the steel cage of the crown beam (17), and the remaining steel bars at the corbel (19) are tied; 3) Forming the crown beam (17) and its upper corbel (19), pouring concrete after the formwork is completed, ensuring that the positions of the embedded steel bars (1402) and the embedded steel plates (1401) do not deviate during the pouring of concrete, and after the concrete curing is completed, proceed with subsequent construction; 4) Excavate to the bottom elevation of the first inner support beam, and excavate 1 m more at the steel lattice column (16) and the corbel (19); 5) Welding the tray (15) to the steel lattice column (16), and welding the cap (14) to the embedded steel plate (1401); 6) The main supports are constructed row by row, and the steel-concrete beam segments (1) are hoisted into the foundation pit for assembly, and are assembled from one end of a row of main supports to the other end; when connecting adjacent steel-concrete beam segments (1), first insert the round steel (6) into the longitudinal reinforcement hole (103), and after the end surfaces of the two steel-concrete beam segments (1) are closely attached, install the connecting steel plate (12) and fix it with vertical tension screws (8) and nuts (10); the main supports are placed on the pallet (15), one side of the steel-concrete beam segment (1) in the main supports is closely attached to the lattice column (16), and both ends of each row of main supports are placed on the cap (14); 7) Install the steel structure auxiliary support (2). For the installation of the auxiliary support between the main supports, use transverse tension screws (8) and nuts (10) to connect the auxiliary support with the adjacent main support. For the installation of the steel structure cross-beam, use transverse tension screws (8) and nuts (10) to connect the steel structure cross-beam with the axial node of the main support near the foundation pit wall at one end, and fix the other end to the crown beam (17) with bolts (21). Fill the installation gap between the steel structure auxiliary support (2) and the side of the axial node with steel bars. 8) Install the mid-beam adjustment system, install the retaining steel structure (5) in the middle of the main support, and fix the A part (501) and the B part (502) to the main supports on both sides through the connecting plates by using the transverse tension screws (8) and nuts (10). Then, place the retaining box (501-2) of the B part on the protruding steel plate (502-3) of the A part (501), and insert the insert plate (505) into the insert ring (504) to realize the connection between the A part (501) and the B part (502); finally, install the jack (4) on the jack support (502-2); 9) Install the beam end adjustment system, install the force head (1406) on the cap (14) and place the jack wooden support (1405), install the jack (4) on the jack wooden support (1405), and make the longitudinal axis of the plunger of the jack (4) coincide with the longitudinal axis of the main support; 10) The jacks (4) are pressurized simultaneously, the jacks (4) on the beam adjustment system extend the A part (501) of the force-retaining steel structure (5), and the jacks (4) on the beam end adjustment system extend the force-retaining head (1406); a plurality of steel sheets (503) are inserted into the gap between the force-retaining box (501-2) and the B part (502) of the A part (501) of the force-retaining steel structure (5), and a plurality of gaskets (1407) are inserted into the gap between the force-retaining head (1406) and the embedded steel plate (1401), so that the end faces of all axial nodes of each main support are closely fitted; and the clamps (20) are welded; 11) The pressure of the jack (4) is reduced, so that the plunger of the jack (4) is out of contact, and the jack (4) is removed; 12) Excavate to the bottom elevation of the second inner support beam, and excavate 1 m more at the steel lattice column (16) and the corbel (19); 13) The pile body of the support pile (3) is roughened, the steel cage of the waist beam (18) is tied, the I-shaped PVC pipe (23) is embedded, and the embedded steel bars (1402) are welded to the embedded steel plate (1401). After welding, the embedded steel bars (1402) are tied to the steel cage of the waist beam (18) with steel wire, and the remaining steel bars at the corbel (19) are tied; 14) Forming the waist beam (18) and its upper corbel (19), pouring concrete after the formwork is completed, ensuring that the positions of the embedded steel bars (1402) and the embedded steel plates (1401) do not shift during the concrete pouring, and after the concrete curing is completed, proceed with the subsequent construction; 15) Welding the tray (15) on the steel lattice column (16), and welding the cap (14) on the embedded steel plate (1401); 16) The steel-concrete beam segment (1) is hoisted into the foundation pit for assembly; the assembly method is the same as step 6); 17) Install the steel structure auxiliary support (2). For the installation of the auxiliary support between the main supports, use transverse tension screws (8) and nuts (10) to connect the auxiliary support with the adjacent main support. For the installation of the steel structure cross-beam, use transverse tension screws (8) and nuts (10) to connect the steel structure cross-beam with the axial node of the main support near the foundation pit wall at one end, and fix the other end to the waist beam (18) with bolts (21). Fill the installation gap between the steel structure auxiliary support and the side of the axial node with steel bars. 18) Install the mid-beam adjustment system and the end-beam adjustment system in the same way as step 8) and step 9) respectively; 19) The jack (4) applies pressure simultaneously, inserts a plurality of steel sheets (503) into the gap between the force box (501-2) and the B portion (502) of the A portion (501) of the force steel structure (5), and inserts a plurality of gaskets (1407) into the gap between the force head (1406) and the embedded steel plate (1401); and welds the clamp (20); 20) The pressure of the jack (4) is reduced, so that the plunger of the jack (4) is out of contact, and the jack (4) is removed; 21) Repeat the steps from 12) to 20) until the construction of the remaining internal supports below the second internal support is completed; 22) After completing the installation of the last support, pour the foundation slab.

13. The construction process of the easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 12, characterized in that: After the construction of the internal support system is completed, angle steels (24) are welded to the four corners where the connecting steel plate (12) is connected to the side connecting steel plate (11) or the four corners where the connecting steel plate (12) is connected to the end plate of the auxiliary support.

14. The construction process of the easily dismantled assembled steel-concrete-steel structure foundation pit support system according to claim 13, characterized in that: An alternative step to the step 6) is as follows: constructing the main supports row by row, hoisting the steel-concrete beam sections (1) into the foundation pit for assembly, and assembling from one end of a row of main supports to the other end; when connecting adjacent steel-concrete beam sections (1), first insert the round steel (6) into the longitudinal reinforcement hole (103), and after the end surfaces of the steel-concrete beam sections (1) are tightly attached, install the connecting steel plate (12) and the inclined cable adjuster (13), first fix the connecting steel plate (12) and the inclined cable adjuster (13) with the vertical tension screw rod (8) and the nut (10), and then pass the inclined cable (9) through the inclined cable hole (106), and fix the end of the inclined cable (9) with the anchor head (25), and when the inclined cable (9) passes over the axial node, it rests on the web (1304) of the inclined cable adjuster (13).

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