Assembly type mixed foundation pit supporting system

Abstract

The invention relates to the field of constructional engineering, and discloses an assembly type mixed foundation pit supporting system. According to the system, I-shaped, T-shaped and cross-shaped reinforced concrete beam sections are used as a framework of an inner support and are matched with a steel structure auxiliary support to form an inner support system, the three reinforced concrete beam sections are connected only through axial nodes, a plurality of steel latticed columns are arranged in the middle of the inner support system, and a jack is arranged between the inner support system and a top beam or a waist beam; the invention further provides a construction method of the assembly type mixed foundation pit supporting system. The construction period is short, and the inner supporting system is flexible and diverse in plane arrangement structure and can be used for various occasions; the basic parts are manufactured in advance and can be recycled for multiple times, and the whole-life carbon emission and the cost are lower.

Description

Technical Field

[0001] The invention belongs to the field of construction engineering, and in particular relates to an assembled mixed foundation pit support system. 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 and build a stable and reliable support system to ensure the overall stability of the foundation pit.

[0003] Internal support is a structural system used to support the enclosure structure during the construction of buildings, underground projects, etc. to ensure construction safety and structural stability. It is mainly divided into steel support, concrete support and combined internal support. Steel structure support is not suitable for occasions with large stress, because large-section components are required to control deformation, which will lead to excessive costs; although cast-in-place concrete support is suitable for occasions with large stress and deformation control, it has a long construction period and is inconvenient to dismantle.

[0004] In order to overcome the shortcomings of cast-in-place reinforced concrete internal supports, the Chinese patent announcement number: CN118793069A discloses an assembled reinforced concrete foundation pit support system and construction method. The internal supports provided by this patent are completely made of prefabricated concrete components. Although the components used are easy to dismantle and reuse, all main supports and auxiliary supports, regardless of the size of the force, use reinforced concrete components. The auxiliary supports with smaller forces use overly heavy reinforced concrete components, which are not convenient for transportation and installation. Moreover, the cross-shaped assembly nodes in the system will affect the overall stability of the support in the foundation pit.

[0005] In order to overcome the above problems, it is necessary to develop a new type of prefabricated hybrid foundation pit support system for use in foundation pits, which not only fully utilizes the respective advantages of steel support and concrete support, but also avoids the use of cross-shaped reinforced concrete beam segment assembly nodes, so as to achieve the effect of reuse, shorten construction period and reduce costs. Summary of the invention

[0006] The purpose of the present invention is to provide an assembled mixed foundation pit support system, which uses reinforced concrete supports at locations with greater stress and steel structure supports at locations with less stress, giving full play to the respective advantages of steel structure supports and concrete supports, and allowing all reinforced concrete beam sections to be connected using only axial nodes, thereby achieving the effect of repeated use, shortening construction period, and reducing costs.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an assembled hybrid foundation pit support system, including an internal support system and a crown beam, wherein the internal support system has three types: one includes an I-shaped beam section, a T-shaped beam section, a cross-shaped beam section, a steel structure auxiliary support, a steel lattice column, a cap, a tray and a jack; another includes an I-shaped beam section, a cross-shaped beam section, a steel structure auxiliary support, a steel lattice column, a cap, a tray and a jack; and yet another includes an I-shaped beam section, a cross-shaped beam section, a steel structure auxiliary support, a steel lattice column, a cap, a tray and a jack; The I-shaped beam section, T-shaped beam section and cross-shaped beam section are prefabricated steel-concrete beam sections, all of which are composed of reinforced concrete and beam sleeves; the I-shaped beam section, T-shaped beam section and cross-shaped beam section are all standard parts; each end of the I-shaped beam section, T-shaped beam section and cross-shaped beam section has a transverse screw hole, a vertical screw hole and a positioning hole, the end sections of the I-shaped beam section, T-shaped beam section and cross-shaped beam section have the same cross-sectional dimensions and the arrangement of the transverse screw holes of the three ends is the same, and the arrangement of the vertical screw holes and positioning holes of the three ends is also the same; The crown beam is provided with a corbel, and a cap is provided on the corbel; the caps are arranged in pairs, and one of each pair of caps is provided with a jack; The joint of the end faces of the I-shaped beam section, T-shaped beam section and cross-shaped beam section is called an axial node; the structure of the axial node is as follows: the two end faces are tightly fitted, a positioning I-beam is inserted into the positioning hole, and a connecting steel plate is provided in each span above and below the axial node; the connecting steel plate has a steel plate connecting hole; the steel plate connecting holes are respectively matched with the vertical screw holes on the two end faces butted at the axial node, and vertical tension screws are inserted into the coaxial steel plate connecting hole and the vertical screw hole, and the two ends are fastened with nuts; The I-shaped beam segments, T-shaped beam segments, and cross-shaped beam segments are spliced ​​into several rows of main supports through axial nodes, and both ends of each row of main supports are placed on the pedestal; The steel structure auxiliary support includes an end plate and a frame; the end plate is provided with an end plate connection hole; the steel structure auxiliary support is respectively connected to the side surfaces of two adjacent rows of main supports through the end plates, or one end plate is fixed to the side surface of the main support, and the other end is fixed to the crown beam; Each row of main supports is placed on trays of a plurality of steel lattice columns, and the positions of the trays are staggered with the axial nodes.

[0008] Furthermore, the beam sleeve of the I-shaped beam section is welded by four angle steels, four side steel plates, two upper steel plates, and two lower steel plates; The beam sleeve of the T-shaped beam section is welded by ten angle steels, six side steel plates, three upper steel plates and three lower steel plates; The beam sleeve of the cross-shaped beam section is welded by sixteen angle steels, eight side steel plates, four upper steel plates, and four lower steel plates to form a cross-shaped beam sleeve; The upper steel plate is provided with an upper steel plate hole, the lower steel plate is provided with a lower steel plate hole, and the side steel plate is provided with a side steel plate hole; the upper steel plate and the lower steel plate have the same size, and the arrangement and aperture of the upper steel plate holes are the same as those of the lower steel plate holes.

[0009] Furthermore, the vertical screw hole and the transverse screw hole are through holes; the positioning hole is a blind hole; the vertical screw hole, the transverse screw hole and the positioning hole do not intersect with each other.

[0010] Furthermore, the bone components are I-beams, round steel pipes, rectangular steel pipes, and H-shaped steels; the end plates are steel plates with end plate connecting holes thereon, and the end plate connecting holes are adapted to the transverse screw holes at the axial nodes.

[0011] Furthermore, there are three ways to connect one side of the axial node of the main support with the auxiliary support of the steel structure. The first way is: one side of the axial node is connected to an auxiliary support of the steel structure, and the end plate is connected to the axial node across the seam, that is, the end plate connection holes of the end plate are respectively connected to the transverse screw holes on the side surfaces of the ends 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 side steel plate connection holes, the span seam is respectively adapted to the two rows of transverse screw holes on the sides of the two steel-concrete beam sections at the axial node, and is also adapted to the end plate connection holes on the end plates of the two steel structure auxiliary supports, and the transverse tension screws are passed through the coaxial end plate connection holes, the side steel plate connection holes and the transverse screw holes, and then tightened with nuts at both ends; The third type is: there is no auxiliary support connection on one side of the axial node, and the side connecting steel plate is installed on this side of the axial node, and the transverse tension screw is passed through the side steel plate connecting hole and the transverse screw hole, and then fixed with a nut.

[0012] Furthermore, the pedestal for placing the jack is composed of an embedded steel plate, a pedestal bottom plate, a pedestal side plate, a force-retaining head, a jack wooden support and a steel sheet; the pedestal without a jack is composed of an embedded steel plate, a pedestal bottom plate and a pedestal side plate; embedded steel bars are welded to one side of the embedded steel plate, and the embedded steel bars are tied to the steel cage of the crown beam; the force-retaining head is formed by welding a steel plate and an I-beam, and the size of the steel plate is the same as the cross-sectional size of the end of the steel-concrete beam section.

[0013] Furthermore, one end of a hoop is welded on the pallet, and the hoop embraces the main support, and the other end is welded to the steel lattice column to fix the main support.

[0014] Furthermore, the jack is placed on the jack wooden support of the foundation; and the gap between the force-retaining head and the embedded steel plate is filled with steel sheets.

[0015] Compared with the prior art, the technical solution of this application has the following beneficial effects: 1. The present invention provides an assembled hybrid foundation pit support system, which adopts I-shaped beam sections, T-shaped beam sections, cross-shaped beam sections, and steel structure auxiliary supports as the main supporting components for 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.

[0016] 2. The present invention provides an assembled mixed foundation pit support system. In an internal support, assembled concrete components are used in the parts with greater stress, and steel structure components are used in the parts with less stress. This not only brings out the respective advantages of steel structure components and concrete components, but also reduces the cost and facilitates construction.

[0017] 3. The present invention provides an assembled mixed foundation pit support system. I-shaped beam sections, T-shaped beam sections, and cross-shaped beam sections are all standard parts, which can achieve standardization of steel-concrete beam sections and part of steel structure auxiliary supports in a certain foundation pit or a larger range, reduce the production cost of steel-concrete beam sections and steel structure auxiliary supports, and reduce the cost of foundation pit support. Moreover, the use of the components provided by the present invention avoids the problem of a large number of cross-shaped assembly nodes in the internal support system in the existing patent (publication number CN 118793069 A) technology; the present invention only has axial nodes, which significantly improves the stability of the internal support system.

[0018] 4. The present invention provides an assembled hybrid foundation pit support system, in which the I-shaped beam segments, T-shaped beam segments, cross-shaped beam segments, and steel structure auxiliary supports in the foundation pit are connected by tension screw anchoring, so that the I-shaped beam segments, T-shaped beam segments, cross-shaped beam segments, steel structure auxiliary supports and other components 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.

[0019] 5. The present invention provides an assembled hybrid foundation pit support system, in which 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 forces on the internal support beams similar, avoid the phenomenon of excessive local stress and large deformation, and make the support system in the foundation pit safer, more reliable and controllable.

[0020] 6. The present invention provides an assembled hybrid foundation pit support system. By casting a section of corbel on the crown beam or waist beam, the situation where 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. The steel-concrete beam section can be used in various regular or irregular foundation pit shapes, expanding the application scope of the assembled hybrid foundation pit support system and facilitating the recycling of various supporting components in the foundation pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the plan layout of the assembled mixed foundation pit support system containing three types of beam sections; Figure 2 It is a schematic diagram of the plan layout of the assembled mixed foundation pit support system including I-shaped beam sections and T-shaped beam sections; Figure 3 It is a schematic diagram of the plan layout of the assembled mixed foundation pit support system containing I-shaped beam sections and cross-shaped beam sections; Figure 4 It is a schematic diagram of the overall structure of the I-beam segment; Figure 5 It is a schematic diagram of the overall structure of the T-beam section; Figure 6 It is a schematic diagram of the overall structure of the cross-shaped beam segment; Figure 7 It is a schematic diagram of the structure where the cross beam section is installed on the pallet; Figure 8 It is a schematic diagram of the structure of the T-beam section installed on the pallet; Fig. 9 It is a schematic diagram of the structure where the I-beam section is installed on the pallet; Fig.10 It is a schematic diagram of a side of an axial node obliquely connecting two steel structure auxiliary supports; Fig.11 It is a schematic diagram of a steel structure auxiliary support structure vertically connected to one side of the axial node; Fig.12 It is a schematic diagram of a steel structure auxiliary support structure in which the two sides of the axial node are obliquely connected to each other; Fig.13 This is a partial schematic diagram of the steel structure auxiliary support installed at the crown beam; Fig.14 This is a schematic diagram of the pedestal where the jack is placed on the edge of the support; Fig.15 This is a schematic diagram of the pedestal where the jack is placed on the edge of the angle brace; Fig.16 This is a schematic diagram of the pedestal where no jack is placed on the edge of the support; Fig.17 This is a schematic diagram of the pedestal where no jack is placed on the edge of the angle brace; Fig.18It is a schematic diagram of the cap on which the jack is placed; Fig.19 This is a schematic diagram of the foundation without jacks; Fig. 20 It is a schematic diagram of the beam sleeve structure of the I-shaped beam section; Fig.21 It is a schematic diagram of the beam sleeve structure of the T-shaped beam section; Fig. 22 It is a schematic diagram of the beam sleeve structure of the cross-shaped beam segment; Fig.23 It is a schematic diagram of the structure of connecting steel plates and side connecting steel plates.

[0022] In the figure: 1, I-shaped beam section; 2, T-shaped beam section; 3, cross-shaped beam section; 4, steel structure auxiliary support; 401, end plate; 401-1, end plate connection hole; 402, frame; 5, crown beam; 6. Steel lattice column; 7. Pallet; 8. Corbel; 9. Cap; 901. Embedded steel plate; 902. Cap bottom plate; 903. Cap side plate; 904. Jack wooden support; 905. Bolster head; 906. Steel sheet; 10. Jack; 11. Connecting steel plate; 1101. Steel plate connecting hole; 12. Side connecting steel plate; 1201. Side steel plate connecting hole; 13. Vertical tension screw; 14. Nut; 15. Positioning I-beam; 16. Horizontal tension screw; 17. Hoop; 18. Angle steel; 19. Upper steel plate; 1901. Upper steel plate hole; 20. Lower steel plate; 2001. Lower steel plate hole; 21. Side steel plate; 2101. Side steel plate hole; 22. Vertical screw hole; 23. Horizontal screw hole; 24. Positioning hole. DETAILED DESCRIPTION

[0023] 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.

[0024] like Figure 1-23 As shown; the assembled mixed foundation pit support system includes an internal support system and a crown beam 5, and there are three types of internal support systems: one includes an I-shaped beam section 1, a T-shaped beam section 2, a cross-shaped beam section 3, a steel structure auxiliary support 4, a steel lattice column 6, a cap 9, a tray 7 and a jack 10; another includes an I-shaped beam section 1, a cross-shaped beam section 3, a steel structure auxiliary support 4, a steel lattice column 6, a cap 9, a tray 7 and a jack 10; and yet another includes an I-shaped beam section 1, a cross-shaped beam section 3, a steel structure auxiliary support 4, a steel lattice column 6, a cap 9, a tray 7 and a jack 10; The I-shaped beam section 1, the T-shaped beam section 2, and the cross-shaped beam section 3 are prefabricated steel-concrete beam sections, all of which are composed of reinforced concrete and beam sleeves; the I-shaped beam section 1, the T-shaped beam section 2, and the cross-shaped beam section 3 are all standard parts; each end of the I-shaped beam section 1, the T-shaped beam section 2, and the cross-shaped beam section 3 has a transverse screw hole 23, a vertical screw hole 22, and a positioning hole 24, and the cross-shaped beam section 1, the T-shaped beam section 2, and the cross-shaped beam section 3 have the same cross-sectional dimensions of the ends and the same arrangement of the transverse screw holes 23 of the three ends, and the same arrangement of the vertical screw holes 22 and the positioning holes 24 of the three ends; A corbel 8 is provided on the crown beam 5, and a cap 9 is provided on the corbel 8; the caps 9 are arranged in pairs, and one of each pair of caps is provided with a jack 10; The joint of the end faces of the I-shaped beam section 1, the T-shaped beam section 2, and the cross-shaped beam section 3 is called an axial node; the structure of the axial node is as follows: the two end faces are tightly fitted, a positioning I-beam 15 is inserted into the positioning hole 24, and a connecting steel plate 11 is provided in each span above and below the axial node; the connecting steel plate 11 has a steel plate connecting hole 1101; the steel plate connecting hole 1101 is respectively matched with the vertical screw holes 22 on the two end faces butted at the axial node, and the vertical tension screws 13 are inserted into the coaxial steel plate connecting hole 1101 and the vertical screw hole 22, and the two ends are fastened with nuts 14; The I-shaped beam segment 1, the T-shaped beam segment 2, and the cross-shaped beam segment 3 are spliced ​​into several rows of main supports through axial nodes, and both ends of each row of main supports are placed on the cap 9; The steel structure auxiliary support 4 includes an end plate 401 and a frame 402; the end plate 401 has an end plate connection hole 401-1; the steel structure auxiliary support 4 is connected to the side surfaces of two adjacent rows of main supports through the end plates 401, or one end plate 401 is fixed to the side surface of the main support, and the other end is fixed to the crown beam 5; Each row of main supports is placed on trays 7 of a number of steel lattice columns 6, and the positions of the trays 7 are staggered with the axial nodes.

[0025] Preferably, the beam sleeve of the I-shaped beam section 1 is welded by four angle steels 18, four side steel plates 21, two upper steel plates 19, and two lower steel plates 20; The beam sleeve of the T-shaped beam section 2 is welded by ten angle steels 18, six side steel plates 21, three upper steel plates 19, and three lower steel plates 20; The beam sleeve of the cross-shaped beam section 3 is welded by sixteen angle steels 18, eight side steel plates 21, four upper steel plates 19, and four lower steel plates 20 to form a cross-shaped beam sleeve; The upper steel plate 19 is provided with an upper steel plate hole 1901, the lower steel plate 20 is provided with a lower steel plate hole 2001, and the side steel plate 21 is provided with a side steel plate hole 2101; the upper steel plate 19 and the lower steel plate 20 have the same size, and the upper steel plate hole 1901 and the lower steel plate hole 2001 have the same arrangement and aperture.

[0026] Preferably, the vertical screw hole 22 and the transverse screw hole 23 are through holes; the positioning hole 24 is a blind hole; the vertical screw hole 22, the transverse screw hole 23 and the positioning hole 24 do not intersect with each other.

[0027] Preferably, the frame member 402 is an I-beam, a round steel pipe, a rectangular steel pipe, or an H-shaped steel; the end plate 401 is a steel plate having an end plate connecting hole 401 - 1 thereon, and the end plate connecting hole 401 - 1 is adapted to the transverse screw hole 23 at the axial node.

[0028] Preferably, there are three ways to connect one side of the axial node of the main support with the steel structure auxiliary support 4. The first way is: one side of the axial node is connected to a steel structure auxiliary support 4, and the end plate 401 is connected to the axial node across the seam, that is, the end plate connection hole 401-1 of the end plate 401 is respectively connected to the transverse screw hole 23 on the side surface of the two steel-concrete beam sections connected at the axial node, and is fixed with a transverse tension screw 16 and a nut 14; The second type is: one side of the axial node is connected to two steel structure auxiliary supports 4, a side connection steel plate 12 is provided on one side of the axial node, the side connection steel plate 12 has four rows of side steel plate connection holes 1201, the span seam is respectively adapted to the two rows of transverse screw holes 23 on the sides of the two steel-concrete beam sections at the axial node, and is also adapted to the end plate connection holes 401-1 on the end plates 401 of the two steel structure auxiliary supports 4, and the transverse tension screws 16 pass through the coaxial end plate connection holes 401-1, the side steel plate connection holes 1201 and the transverse screw holes 23, and then the two ends are tightened with nuts 14; The third type is: there is no auxiliary support connection on one side of the axial node, and the side connecting steel plate 12 is installed on this side of the axial node, and the transverse tension screw 16 is passed through the side steel plate connecting hole 1201 and the transverse screw hole 23, and then fixed with the nut 14.

[0029] Preferably, the pedestal 9 on which the jack 10 is placed is composed of an embedded steel plate 901, a pedestal bottom plate 902, a pedestal side plate 903, a force-retaining head 905, a jack wooden support 904 and a steel sheet 906; the pedestal on which the jack 10 is not placed is composed of an embedded steel plate 901, a pedestal bottom plate 902, and a pedestal side plate 903; embedded steel bars are welded on one side of the embedded steel plate 901, and the embedded steel bars are tied to the steel cage of the crown beam 5; the force-retaining head 905 is formed by welding a steel plate and an I-beam, and the size of the steel plate is the same as the cross-sectional size of the end of the steel-concrete beam section.

[0030] Preferably, one end of a hoop 17 is welded to the tray 7, the hoop 17 embraces the main support, and the other end is welded to the steel lattice column 6 to fix the main support.

[0031] Preferably, the jack 10 is placed on the jack wooden support 904 of the base 9; and the gap between the force head 905 and the embedded steel plate 901 is filled with a steel sheet 906.

[0032] Example 1 A foundation pit with a general excavation depth of 6.75-7.20 m, a foundation pit perimeter of 276 m, and a basement excavation area of ​​about 4370 m2 is designed. The foundation pit support is designed as two rows of seven columns of braces. Figure 1 (The directions in the figure are north at the top, south at the bottom, west on the left and east on the right, the same below); the designed length of the I-shaped beam section is 5m; the flange beam of the T-shaped beam section is 5m long, and the web beam is 2.3m long (the T-shaped beam section is formed by a short beam and a long beam connected in the middle, the long beam is called the flange beam, and the short beam is called the web beam, the same below); the main beam of the cross-shaped beam section is 5m long, and the cross beam is also 5m long (the cross-shaped beam section is formed by two beams intersecting in the middle, the two beams are perpendicular to each other, one of the beams is the main beam, and the other beam perpendicular to it is the cross beam, the same below).

[0033] The cross-sectional dimensions of the end faces of the three types of steel-concrete beam sections are all 700mm wide and 800mm high. There are two rows of six vertical screw holes (three holes in each row), two columns of six transverse screw holes (three holes in each column), and one positioning hole at the end. (At the end, when the line connecting the center points of the holes of multiple vertical screw holes on the same plane is parallel to the end face, these holes constitute a row of vertical screw holes; when the line connecting the center points of the holes of multiple transverse screw holes on the same plane is parallel to the end face, these holes constitute a row of transverse screw holes, the same below.) The hole plane layout of the vertical screw holes is a rectangular hole layout with a hole diameter of 30mm, a row spacing of 140mm, a hole spacing of 250mm, a distance of 120mm from the outermost row of holes to the end face, and a distance of 100mm from the outermost hole in each row of holes to the adjacent end side.

[0034] Steel plates of 600mm×350mm×8mm are selected as the upper and lower steel plates. The hole diameter, row spacing and hole spacing of the upper steel plates are the same as those of the vertical screw holes. The edges of the steel plates with a length of 350mm are welded to the beam sleeve angle steel 204.

[0035] The hole plane layout of the transverse screw holes is a rectangular hole layout with a hole diameter of 30mm, a row spacing of 150mm, a hole spacing of 250mm, a distance of 75mm from the outermost row of holes to the end face, and a distance of 150mm from the uppermost hole in each row of transverse screw holes to the upper surface.

[0036] 700mm×350mm×8mm is selected as the side steel plate. The hole diameter, row spacing and hole spacing are the same as the transverse screw holes. The edge of the steel plate with a length of 350mm is welded to the angle steel.

[0037] The locating hole is a square hole, there is one of them, the size is 40mm×40mm, the axis of the locating hole coincides with the axis of the end of the steel-concrete beam section, and the depth of the locating hole is 60mm.

[0038] Select 600mm×350mm×8mm steel plates as the upper and lower steel plates. The hole diameter, row spacing and hole spacing of the upper holes are the same as the vertical screw holes. The edge of the steel plate with a length of 350mm is welded to the beam sleeve angle steel 204. Select 700mm×350mm×8mm as the side steel plate. The hole diameter, row spacing and hole spacing of the upper holes are the same as the horizontal screw holes. The edge of the steel plate with a length of 350mm is welded to the angle steel. The angle steel model is L50×5, and there are two types of angle steels: 5m long and 2.15m long.

[0039] The I-shaped beam section's beam sleeve is welded from four 5m-long angle steels, two upper steel plates, two lower steel plates and four side steel plates. The T-shaped beam section's beam sleeve is welded from two 5m-long angle steels, eight 2.15m-long angle steels, three upper steel plates, three lower steel plates and six side steel plates. The cross-shaped beam section's beam sleeve is welded from sixteen 2.15m-long angle steels, four upper steel plates, four lower steel plates and eight side steel plates.

[0040] 1. Construction of support piles, column piles and steel lattice columns. Support piles are bored cast-in-place piles ⌀1000mm, with a pile spacing of 1300mm. The concrete strength of the pile body is C30. They are matched with ⌀1000mm mixing piles to form a bite-type water stop. Column piles are bored cast-in-place piles ⌀800mm, with a pile body concrete strength of C30. The cross-sectional size of the steel lattice column is 460 mm×460 mm. The long angle steel of the steel lattice column is L140×L14. The thickness of the gusset plate is 10 mm, the height is 400 mm, and the width is 460 mm. The spacing between the gusset plates is 600 mm. The verticality deviation of the steel lattice column is less than 1 / 300. 2. The pile heads of the supporting piles are roughened. The cross-section of the crown beam is designed to be 1000 mm high and 1000 mm wide. The steel cage of the crown beam is tied. The embedded steel plate is 20 mm thick, 800 mm high and 720 mm wide. The embedded steel bars are HRB400 with a diameter of 10 mm. The embedded steel bars are welded on the embedded steel plates. One row is welded on each side of the steel plate, for a total of 14 bars. The weld length between each embedded steel bar and the embedded steel plate 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 and embedded steel plates are tied to the steel cage of the crown beam according to the design requirements. The position accuracy error during tying is less than 3 mm. After the embedded steel bars and embedded steel plates are set, the remaining steel bars at the tying position of the embedded steel plates are tied according to the design requirements. 3. The cross-sectional size of the corbel is designed to be 720 mm × 800 mm. The formwork of the crown beam and its upper corbel is supported. After the formwork is supported, concrete is poured. When pouring concrete, ensure that the position of the embedded steel plate and embedded steel bars does not shift. After pouring, the concrete is cured. 4. Excavate to the bottom elevation of the inner support, and excavate 1m more at the base and tray; 5. Weld the pallet on the steel lattice column. The pallet panel is 20 mm thick, 860 mm wide and 1860 mm long. It is welded and reinforced with isosceles right-angle triangle steel plates. 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 cap on the embedded steel plate. Weld the cap on the embedded steel plate at the position of the corbel. The base plate of the cap without jack is 20 mm thick, 720 mm wide and 500 mm long. The side plate of the cap is 20 mm thick. Spot welding is performed first and then full welding. The welding error is less than 2 mm. Weld the cap with jack. The base plate 1403 is 20 mm thick, 720 mm wide and 1300 mm long. The side plate of the cap is 20 mm thick. The semicircular groove of the jack wooden support is 600 mm in diameter and 100 mm in length. Spot welding is performed first and then full welding. The welding accuracy is less than 2 mm. Place the force head. The force head uses a thickness of 20 mm, a width of 700 mm and a height of 800 mm. mm steel plate, two 40a I-beams are welded on each side, the size after stacking is 800 mm high and 142 mm wide, and the force-retaining head is welded to form a force-retaining head, which is placed on the pedestal with the jack; 6. I-shaped beam segments, T-shaped beam segments, and cross-shaped beam segments are hoisted into the foundation pit for assembly. From the west to the east, first assemble each row of main supports in the north-south direction. After the main supports in the north-south direction are assembled, assemble each row of main supports in the east-west direction. In the same row of main supports, start assembling from the pedestal position where no jack is placed. When two steel-concrete beam sections are spliced, first insert a positioning I-beam into the positioning hole at the end of the spliced ​​steel-concrete beam section to be spliced, align the ends of the two steel-concrete beam sections to be spliced ​​by a crane, align the positioning hole at one end of the steel-concrete beam section to be spliced ​​with the positioning I-beam and insert it, so that the end surfaces of the two steel-concrete beam sections are tightly fitted, and then place the connecting steel plate above the axial node, align the steel plate connecting hole on the connecting steel plate with the vertical screw hole, and then insert the vertical tension screw. At this time, there is a nut at one end of the vertical tension screw, and then set a connecting steel plate below the axial node, align the steel plate connecting hole on the connecting steel plate with the vertical tension screw, so that the connecting steel plate set below the axial node is close to the lower surface of the axial node, and then tighten the vertical tension screw with the nut, so that the connecting steel plate is close to the upper and lower surfaces of the axial node.

[0041] If the gap between the two steel-concrete beam sections does not meet the conditions for inserting the positioning I-beam, the I-beam will not be inserted into the positioning hole.

[0042] 7. Use a 500-ton hydraulic jack and place it on the jack wooden support. The jack extends the force head, which is displaced. Insert a steel sheet with a size of 800mm×142mm into the gap between the force head and the embedded steel plate to fill the gap. 8. Drill bolt holes on the crown beam, with twelve bolt holes in four rows, arranged in the same way as the end plate connection holes on the end plate of the steel structure auxiliary support; 9. Install the steel structure auxiliary support. The end plate of the steel structure auxiliary support is a steel plate with a height of 800mm, a width of 700mm and a thickness of 10mm. There are end plate connection holes on the end plate with a diameter of 30mm. The arrangement is the same as the transverse screw hole at the axial node. The frame is H-shaped steel. The models of H-shaped steel are H600×600, H800×800 and H1000×1000. Use a crane to lift the prefabricated steel structure auxiliary support into the foundation pit. There are two ways to connect one side of the axial node to the steel structure auxiliary support.

[0043] The first is that 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 end plate connection holes of the end plate are respectively connected to the transverse screw holes on one side of the ends of the two steel-concrete beam sections connected at the axial node, and are fixed with transverse tension screws and nuts; The second type is: there is no auxiliary support connection on one side of the axial node, and the side connecting steel plate is installed on this side of the axial node, and the transverse tension screws are passed through the side steel plate connecting holes and the transverse screw holes, and the two ends of the transverse tension screws are fixed with nuts.

[0044] The connection method between the steel structure auxiliary support and the crown beam is that the end plate connection holes are aligned one by one with the bolt holes set on the crown beam, and the bolts pass through the end plate connection holes and extend into the bolt holes to fix the end plate on the crown beam, thereby realizing the connection between the steel structure auxiliary support and the crown beam.

[0045] 10. Weld the hoop. Use a steel plate with a thickness of 20mm and a width of 100mm to weld it into a hoop. The hoop fixes the main support on the pallet. One end of the hoop is welded to the pallet and the other end is welded to the steel lattice column.

[0046] 11. Excavate to the bottom of the foundation pit and pour the foundation slab.

[0047] Example 2 A foundation pit with a depth of 5.6-6.8 m, a perimeter of about 289 m, and an area of ​​about 5030 m2 is designed. The support inside the foundation pit is designed as north-south bracing + four corner braces. Figure 2 The designed length of the I-beam section is 5m; the flange beam of the T-beam section is 5m long and the web beam is 2.3m long.

[0048] The cross-sectional dimensions of the end faces of the two types of steel-concrete beam sections are both 700mm in width and 800mm in height. There are two rows of six vertical screw holes (three holes in each row), two columns of six horizontal screw holes (three holes in each column), and one positioning hole at the end.

[0049] The hole plane layout of the vertical screw holes is a rectangular hole layout with a hole diameter of 30mm, a row spacing of 140mm, a hole spacing of 250mm, a distance of 120mm from the outermost row of holes to the end face, and a distance of 100mm from the outermost hole in each row of holes to the adjacent end side.

[0050] Steel plates of 600mm×350mm×8mm are selected as the upper and lower steel plates. The hole diameter, row spacing and hole spacing of the upper steel plates are the same as those of the vertical screw holes. The edges of the steel plates with a length of 350mm are welded to the beam sleeve angle steel 204.

[0051] The hole plane layout of the transverse screw holes is a rectangular hole layout with a hole diameter of 30mm, a row spacing of 150mm, a hole spacing of 250mm, a distance of 75mm from the outermost row of holes to the end face, and a distance of 150mm from the uppermost hole in each row of transverse screw holes to the upper surface.

[0052] 700mm×350mm×8mm is selected as the side steel plate. The hole diameter, row spacing and hole spacing are the same as the transverse screw holes. The edge of the steel plate with a length of 350mm is welded to the angle steel.

[0053] The locating hole is a square hole, there is one of them, the size is 40mm×40mm, the axis of the locating hole coincides with the axis of the end of the steel-concrete beam section, and the depth of the locating hole is 60mm.

[0054] Select 600mm×350mm×8mm steel plates as the upper and lower steel plates. The hole diameter, row spacing and hole spacing of the upper holes are the same as the vertical screw holes. The edge of the steel plate with a length of 350mm is welded to the beam sleeve angle steel 204. Select 700mm×350mm×8mm as the side steel plate. The hole diameter, row spacing and hole spacing of the upper holes are the same as the horizontal screw holes. The edge of the steel plate with a length of 350mm is welded to the angle steel. The angle steel model is L50×5, and there are two types of angle steels: 5m long and 2.15m long.

[0055] The I-beam section's beam sleeve is welded from four 5m-long angle steels, two upper steel plates, two lower steel plates and four side steel plates. The T-beam section's beam sleeve is welded from two 5m-long angle steels, eight 2.15m-long angle steels, three upper steel plates, three lower steel plates and six side steel plates.

[0056] 1. Construction of support piles, column piles and steel lattice columns. Support piles are bored cast-in-place piles ⌀1000mm, with a pile spacing of 1300mm. The concrete strength of the pile body is C30. They are matched with ⌀1000mm mixing piles to form a bite-type water stop. Column piles are bored cast-in-place piles ⌀800mm, with a pile body concrete strength of C30. The cross-sectional size of the steel lattice column is 460 mm×460 mm. The long angle steel of the steel lattice column is L140×L14. The thickness of the gusset plate is 10 mm, the height is 400 mm, and the width is 460 mm. The spacing between the gusset plates is 600 mm. The verticality deviation of the steel lattice column is less than 1 / 300. 2. The pile heads of the supporting piles are roughened. The cross-section of the crown beam is designed to be 1000 mm high and 1000 mm wide. The steel cage of the crown beam is tied. The embedded steel plate is 20 mm thick, 800 mm high and 720 mm wide. The embedded steel bars are HRB400 with a diameter of 10 mm. The embedded steel bars are welded on the embedded steel plates. One row is welded on each side of the steel plate, for a total of 14 bars. The weld length between each embedded steel bar and the embedded steel plate 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 and embedded steel plates are tied to the steel cage of the crown beam according to the design requirements. The position accuracy error during tying is less than 3 mm. After the embedded steel bars and embedded steel plates are set, the remaining steel bars at the tying position of the embedded steel plates are tied according to the design requirements. 3. The cross-sectional size of the corbel is designed to be 720 mm × 800 mm. The formwork of the crown beam and its upper corbel is supported. After the formwork is supported, concrete is poured. When pouring concrete, ensure that the position of the embedded steel plate and embedded steel bars does not shift. After pouring, the concrete is cured. 4. Excavate to the bottom elevation of the inner support, and excavate 1m more at the base and tray; 5. Weld the pallet on the steel lattice column. The pallet panel is 20 mm thick, 860 mm wide and 1860 mm long. It is welded and reinforced with isosceles right-angle triangle steel plates. 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 cap on the embedded steel plate. Weld the cap on the embedded steel plate at the position of the corbel. The base plate of the cap without jack is 20 mm thick, 720 mm wide and 500 mm long. The side plate of the cap is 20 mm thick. Spot welding is performed first and then full welding. The welding error is less than 2 mm. Weld the cap with jack. The base plate 1403 is 20 mm thick, 720 mm wide and 1300 mm long. The side plate of the cap is 20 mm thick. The semicircular groove of the jack wooden support is 600 mm in diameter and 100 mm in length. Spot welding is performed first and then full welding. The welding accuracy is less than 2 mm. Place the force head. The force head uses a thickness of 20 mm, a width of 700 mm and a height of 800 mm. mm steel plate, two 40a I-beams are welded on each side, the size after stacking is 800 mm high and 142 mm wide, and the force-retaining head is welded to form a force-retaining head, which is placed on the pedestal with the jack; 6. The I-shaped beam sections and T-shaped beam sections are hoisted into the foundation pit for assembly. First, the main supports in the north-south direction are assembled, and then the angle supports are installed. Within the same row of main supports, the assembly starts from the pedestal position where the jacks are not placed.

[0057] When two steel-concrete beam sections are spliced, first insert a positioning I-beam into the positioning hole at the end of the spliced ​​steel-concrete beam section to be spliced, align the ends of the two steel-concrete beam sections to be spliced ​​by a crane, align the positioning hole at one end of the steel-concrete beam section to be spliced ​​with the positioning I-beam and insert it, so that the end surfaces of the two steel-concrete beam sections are tightly fitted, and then place the connecting steel plate above the axial node, align the steel plate connecting hole on the connecting steel plate with the vertical screw hole, and then insert the vertical tension screw. At this time, there is a nut at one end of the vertical tension screw, and then set a connecting steel plate below the axial node, align the steel plate connecting hole on the connecting steel plate with the vertical tension screw, so that the connecting steel plate set below the axial node is close to the lower surface of the axial node, and then tighten the vertical tension screw with the nut, so that the connecting steel plate is close to the upper and lower surfaces of the axial node.

[0058] If the gap between the two steel-concrete beam sections does not meet the conditions for inserting the positioning I-beam, the I-beam will not be inserted into the positioning hole.

[0059] 7. Use a 500-ton hydraulic jack and place it on the jack wooden support. The jack extends the force head, which is displaced. Insert a steel sheet with a size of 800mm×142mm into the gap between the force head and the embedded steel plate to fill the gap. 8. Drill bolt holes on the crown beam, with twelve bolt holes in four rows, arranged in the same way as the end plate connection holes on the end plate of the steel structure auxiliary support; 9. Install the steel structure auxiliary support. The end plate of the steel structure auxiliary support is a steel plate. The steel plate is 800mm high, 700mm wide and 10mm thick. There are end plate connecting holes on the end plate. The hole diameter of the end plate connecting hole is 30mm. The arrangement is the same as the transverse screw hole at the axial node. The frame is H-shaped steel. The models of H-shaped steel are H1000×1000 and H600×600.

[0060] Use a crane to lift the prefabricated steel structure auxiliary support into the foundation pit. There are three ways to connect one side of the axial node with the steel structure auxiliary support.

[0061] The first is that 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 end plate connection holes of the end plate are respectively connected to the transverse screw holes on one side of the ends of the two steel-concrete beam sections connected at the axial node, and are 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 a side steel plate connection hole, the span seam corresponds to the two rows of transverse screw holes on the sides of the two steel-concrete beam sections at the axial node, and also corresponds to the end plate connection holes on the end plates of the two steel structure auxiliary supports. After the transverse tension screw passes through the coaxial side steel plate connection hole, the end plate connection hole and the transverse screw hole, both ends are tightened with nuts; The third type is: there is no auxiliary support connection on one side of the axial node, and the side connecting steel plate is installed on this side of the axial node, and the transverse tension screws are passed through the side steel plate connecting holes and the transverse screw holes, and the two ends of the transverse tension screws are fixed with nuts.

[0062] The connection method between the steel structure auxiliary support and the crown beam is that the end plate connection holes are aligned one by one with the bolt holes set on the crown beam, and the bolts pass through the end plate connection holes and extend into the bolt holes to fix the end plate on the crown beam, thereby realizing the connection between the steel structure auxiliary support and the crown beam.

[0063] 10. Weld the hoop. Use a steel plate with a thickness of 20mm and a width of 100mm to weld it into a hoop. The hoop fixes the main support on the pallet. One end of the hoop is welded to the pallet and the other end is welded to the steel lattice column.

[0064] 11. Excavate to the bottom of the foundation pit and pour the foundation slab.

[0065] Example 3 A foundation pit with an excavation depth of 5.5-6.3 m, a perimeter of 312 m, and an excavation area of ​​6084 m2 is supported by underground continuous wall + internal support. Design an internal support for the foundation pit. The internal support for the foundation pit is designed as a pair of supports + four corner supports. Figure 3 The designed length of the I-shaped beam section is 5m; the main beam length of the cross-shaped beam section is 5m, and the cross beam length is also 5m.

[0066] The cross-sectional dimensions of the end faces of the two types of steel-concrete beam sections are both 700mm in width and 800mm in height. There are two rows of six vertical screw holes (three holes in each row), two columns of six horizontal screw holes (three holes in each column), and one positioning hole at the end.

[0067] The hole plane layout of the vertical screw holes is a rectangular hole layout with a hole diameter of 30mm, a row spacing of 140mm, a hole spacing of 250mm, a distance of 120mm from the outermost row of holes to the end face, and a distance of 100mm from the outermost hole in each row of holes to the adjacent end side.

[0068] Steel plates of 600mm×350mm×8mm are selected as the upper and lower steel plates. The hole diameter, row spacing and hole spacing of the upper steel plates are the same as those of the vertical screw holes. The edges of the steel plates with a length of 350mm are welded to the beam sleeve angle steel 204.

[0069] The hole plane layout of the transverse screw holes is a rectangular hole layout with a hole diameter of 30mm, a row spacing of 150mm, a hole spacing of 250mm, a distance of 75mm from the outermost row of holes to the end face, and a distance of 150mm from the uppermost hole in each row of transverse screw holes to the upper surface.

[0070] 700mm×350mm×8mm is selected as the side steel plate. The hole diameter, row spacing and hole spacing are the same as the transverse screw holes. The edge of the steel plate with a length of 350mm is welded to the angle steel.

[0071] The locating hole is a square hole, there is one of them, the size is 40mm×40mm, the axis of the locating hole coincides with the axis of the end of the steel-concrete beam section, and the depth of the locating hole is 60mm.

[0072] Select 600mm×350mm×8mm steel plates as the upper and lower steel plates. The hole diameter, row spacing and hole spacing of the upper holes are the same as the vertical screw holes. The edge of the steel plate with a length of 350mm is welded to the beam sleeve angle steel 204. Select 700mm×350mm×8mm as the side steel plate. The hole diameter, row spacing and hole spacing of the upper holes are the same as the horizontal screw holes. The edge of the steel plate with a length of 350mm is welded to the angle steel. The angle steel model is L50×5, and there are two types of angle steels: 5m long and 2.15m long.

[0073] The I-shaped beam section's beam sleeve is welded from four 5m-long angle steels, two upper steel plates, two lower steel plates and four side steel plates. The cross-shaped beam section's beam sleeve is welded from sixteen 2.15m-long angle steels, four upper steel plates, four lower steel plates and eight side steel plates.

[0074] 1. Construction of support piles, column piles and steel lattice columns. Support piles are bored cast-in-place piles ⌀1000mm, with a pile spacing of 1300mm. The concrete strength of the pile body is C30. They are matched with ⌀1000mm mixing piles to form a bite-type water stop. Column piles are bored cast-in-place piles ⌀800mm, with a pile body concrete strength of C30. The cross-sectional size of the steel lattice column is 460 mm×460 mm. The long angle steel of the steel lattice column is L140×L14. The thickness of the gusset plate is 10 mm, the height is 400 mm, and the width is 460 mm. The spacing between the gusset plates is 600 mm. The verticality deviation of the steel lattice column is less than 1 / 300. 2. The pile heads of the supporting piles are roughened. The cross-section of the crown beam is designed to be 1000 mm high and 1000 mm wide. The steel cage of the crown beam is tied. The embedded steel plate is 20 mm thick, 800 mm high and 720 mm wide. The embedded steel bars are HRB400 with a diameter of 10 mm. The embedded steel bars are welded on the embedded steel plates. One row is welded on each side of the steel plate, for a total of 14 bars. The weld length between each embedded steel bar and the embedded steel plate 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 and embedded steel plates are tied to the steel cage of the crown beam according to the design requirements. The position accuracy error during tying is less than 3 mm. After the embedded steel bars and embedded steel plates are set, the remaining steel bars at the tying position of the embedded steel plates are tied according to the design requirements. 3. The cross-sectional size of the corbel is designed to be 720 mm × 800 mm. The formwork of the crown beam and its upper corbel is supported. After the formwork is supported, concrete is poured. When pouring concrete, ensure that the position of the embedded steel plate and embedded steel bars does not shift. After pouring, the concrete is cured. 4. Excavate to the bottom elevation of the inner support, and excavate 1m more at the base and tray; 5. Weld the pallet on the steel lattice column. The pallet panel is 20 mm thick, 860 mm wide and 1860 mm long. It is welded and reinforced with isosceles right-angle triangle steel plates. 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 cap on the embedded steel plate. Weld the cap on the embedded steel plate at the position of the corbel. The base plate of the cap without jack is 20 mm thick, 720 mm wide and 500 mm long. The side plate of the cap is 20 mm thick. Spot welding is performed first and then full welding. The welding error is less than 2 mm. Weld the cap with jack. The base plate 1403 is 20 mm thick, 720 mm wide and 1300 mm long. The side plate of the cap is 20 mm thick. The semicircular groove of the jack wooden support is 600 mm in diameter and 100 mm in length. Spot welding is performed first and then full welding. The welding accuracy is less than 2 mm. Place the force head. The force head uses a thickness of 20 mm, a width of 700 mm and a height of 800 mm. mm steel plate, two 40a I-beams are welded on each side, the size after stacking is 800 mm high and 142 mm wide, and the force-retaining head is welded to form a force-retaining head, which is placed on the pedestal with the jack; 6. The I-shaped beam sections and cross-shaped beam sections are hoisted into the foundation pit for assembly. First, from the south to the north, each row of main supports in the east-west direction are spliced; then from the west to the east, the main supports in the north-south direction are spliced; finally, the angle supports are installed; within the same row of main supports, the splicing starts from the pedestal position where the jack is not placed.

[0075] When two steel-concrete beam sections are spliced, first insert a positioning I-beam into the positioning hole at the end of the spliced ​​steel-concrete beam section to be spliced, align the ends of the two steel-concrete beam sections to be spliced ​​by a crane, align the positioning hole at one end of the steel-concrete beam section to be spliced ​​with the positioning I-beam and insert it, so that the end surfaces of the two steel-concrete beam sections are tightly fitted, and then place the connecting steel plate above the axial node, align the steel plate connecting hole on the connecting steel plate with the vertical screw hole, and then insert the vertical tension screw. At this time, there is a nut at one end of the vertical tension screw, and then set a connecting steel plate below the axial node, align the steel plate connecting hole on the connecting steel plate with the vertical tension screw, so that the connecting steel plate set below the axial node is close to the lower surface of the axial node, and then tighten the vertical tension screw with the nut, so that the connecting steel plate is close to the upper and lower surfaces of the axial node.

[0076] If the gap between the two steel-concrete beam sections does not meet the conditions for inserting the positioning I-beam, the I-beam will not be inserted into the positioning hole.

[0077] 7. Use a 500-ton hydraulic jack and place it on the jack wooden support. The jack extends the force head, which is displaced. Insert a steel sheet with a size of 800mm×142mm into the gap between the force head and the embedded steel plate to fill the gap. 8. Drill bolt holes on the crown beam, with twelve bolt holes in four rows, arranged in the same way as the end plate connection holes on the end plate of the steel structure auxiliary support; 9. Install the steel structure auxiliary support. The end plate of the steel structure auxiliary support is a steel plate. The steel plate is 800mm high, 700mm wide and 10mm thick. There are end plate connecting holes on the end plate. The hole diameter of the end plate connecting hole is 30mm. The arrangement is the same as the transverse screw hole at the axial node. The frame is H-shaped steel. The models of H-shaped steel are H800×800 and H600×600.

[0078] Use a crane to lift the prefabricated steel structure auxiliary support into the foundation pit. There are two ways to connect one side of the axial node to the steel structure auxiliary support.

[0079] The first is that 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 end plate connection holes of the end plate are respectively connected to the transverse screw holes on one side of the ends of the two steel-concrete beam sections connected at the axial node, and are fixed with transverse tension screws and nuts; The second type is: there is no auxiliary support connection on one side of the axial node, and the side connecting steel plate is installed on this side of the axial node, and the transverse tension screws are passed through the side steel plate connecting holes and the transverse screw holes, and the two ends of the transverse tension screws are fixed with nuts.

[0080] The connection method between the steel structure auxiliary support and the crown beam is that the end plate connection holes are aligned one by one with the bolt holes set on the crown beam, and the bolts pass through the end plate connection holes and extend into the bolt holes to fix the end plate on the crown beam, thereby realizing the connection between the steel structure auxiliary support and the crown beam.

[0081] 10. Weld the hoop. Use a steel plate with a thickness of 20mm and a width of 100mm to weld it into a hoop. The hoop fixes the main support on the pallet. One end of the hoop is welded to the pallet and the other end is welded to the steel lattice column.

[0082] 11. Excavate to the bottom of the foundation pit and pour the foundation slab.

[0083] 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 assembled hybrid foundation pit support system, comprising an inner support system and a crown beam (5), characterized in that: There are three types of internal support systems: one type comprises an I-shaped beam section (1), a T-shaped beam section (2), a cross-shaped beam section (3), a steel structure auxiliary support (4), a steel lattice column (6), a cap (9), a tray (7) and a jack (10); another type comprises an I-shaped beam section (1), a cross-shaped beam section (3), a steel structure auxiliary support (4), a steel lattice column (6), a cap (9), a tray (7) and a jack (10); and yet another type comprises an I-shaped beam section (1), a cross-shaped beam section (3), a steel structure auxiliary support (4), a steel lattice column (6), a cap (9), a tray (7) and a jack (10); The I-shaped beam section (1), T-shaped beam section (2), and cross-shaped beam section (3) are prefabricated steel-concrete beam sections, all of which are composed of reinforced concrete and beam sleeves; each end of the I-shaped beam section (1), T-shaped beam section (2), and cross-shaped beam section (3) has a transverse screw hole (23), a vertical screw hole (22), and a positioning hole (24); the cross-sectional dimensions of the ends of the I-shaped beam section (1), T-shaped beam section (2), and cross-shaped beam section (3) are the same, and the arrangement of the transverse screw holes (23) at the ends of the three is the same, and the arrangement of the vertical screw holes (22) and the positioning holes (24) at the ends of the three are also the same; The crown beam (5) is provided with a corbel (8), and a support (9) is provided on the corbel (8); the support (9) is arranged in pairs, and one of each pair of support (9) is provided with a jack (10); The joint point of the end faces of the I-shaped beam section (1), the T-shaped beam section (2), and the cross-shaped beam section (3) is called an axial node; the structure of the axial node is as follows: the two end faces are tightly fitted, a positioning I-beam (15) is inserted into the positioning hole (24), and a connecting steel plate (11) is provided in each span above and below the axial node; the connecting steel plate (11) has a steel plate connecting hole (1101); the steel plate connecting hole (1101) is respectively matched with the vertical screw holes (22) on the two end faces connected at the axial node, and vertical tension screws (13) are inserted into the coaxial steel plate connecting hole (1101) and the vertical screw hole (22), and the two ends are fastened with nuts (14); The I-shaped beam segment (1), T-shaped beam segment (2), and cross-shaped beam segment (3) are spliced ​​into a plurality of rows of main supports through axial nodes, and both ends of each row of main supports are placed on a cap (9); The steel structure auxiliary support (4) comprises an end plate (401) and a frame member (402); the end plate (401) is provided with an end plate connection hole (401-1); the steel structure auxiliary support (4) is respectively connected to the side surfaces of two adjacent rows of main supports through the end plates (401), or one end plate (401) is fixed to the side surface of the main support, and the other end is fixed to the crown beam (5); Each row of main supports is placed on trays (7) of a plurality of steel lattice columns (6), and the positions of the trays (7) are staggered from the axial nodes.

2. The assembled mixed foundation pit support system according to claim 1 is characterized in that: The beam sleeve of the I-shaped beam section (1) is welded from four angle steels (18), four side steel plates (21), two upper steel plates (19), and two lower steel plates (20); The beam sleeve of the T-shaped beam section (2) is welded from ten angle steels (18), six side steel plates (21), three upper steel plates (19), and three lower steel plates (20); The beam sleeve of the cross-shaped beam section (3) is welded from sixteen angle steels (18), eight side steel plates (21), four upper steel plates (19), and four lower steel plates (20) to form a cross-shaped beam sleeve; The upper steel plate (19) is provided with an upper steel plate hole (1901), the lower steel plate (20) is provided with a lower steel plate hole (2001), and the side steel plate (21) is provided with a side steel plate hole (2101); the upper steel plate (19) and the lower steel plate (20) have the same size, and the upper steel plate hole (1901) and the lower steel plate hole (2001) have the same arrangement and aperture.

3. The assembled mixed foundation pit support system according to claim 1 is characterized in that: The vertical screw hole (22) and the transverse screw hole (23) are through holes; the positioning hole (24) is a blind hole; the vertical screw hole (22), the transverse screw hole (23) and the positioning hole (24) do not intersect with each other.

4. The assembled hybrid foundation pit support system according to claim 1 is characterized in that: The frame (402) is an I-beam, a round steel pipe, a rectangular steel pipe, or an H-shaped steel; the end plate (401) is a steel plate having an end plate connection hole (401-1) thereon, the end plate connection hole (401-1) being compatible with the transverse screw hole (23) at the axial node.

5. The assembled mixed foundation pit support system according to claim 1 is characterized in that: There are three ways to connect one side of the axial node of the main support with the steel structure auxiliary support (4). The first way is: one side of the axial node is connected to a steel structure auxiliary support (4), and the end plate (401) is connected to the axial node across the seam, that is, the end plate connection hole (401-1) of the end plate (401) is respectively connected to the transverse screw hole (23) on the side surface of the end of the two steel-concrete beam sections connected at the axial node, and fixed with a transverse tension screw (16) and a nut (14); The second type is: one side of the axial node is connected to two steel structure auxiliary supports (4), a side connection steel plate (12) is provided on one side of the axial node, the side connection steel plate (12) has four rows of side steel plate connection holes (1201), the span seam is respectively matched with two rows of transverse screw holes (23) on the sides of the two steel-concrete beam sections at the axial node, and is also matched with the end plate connection holes (401-1) on the end plates (401) of the two steel structure auxiliary supports (4), and after the transverse tension screws (16) pass through the coaxial end plate connection holes (401-1), the side steel plate connection holes (1201) and the transverse screw holes (23), the two ends are tightened with nuts (14); The third type is: there is no auxiliary support connection on one side of the axial node, and the side connecting steel plate (12) is installed on this side of the axial node, and the transverse tension screw (16) passes through the side steel plate connection hole (1201) and the transverse screw hole (23), and is fixed with a nut (14).

6. The assembled mixed foundation pit support system according to claim 1 is characterized in that: The cap (9) on which the jack (10) is placed is composed of a pre-embedded steel plate (901), a cap bottom plate (902), a cap side plate (903), a force-retaining head (905), a jack wooden support (904) and a steel sheet (906); the cap without the jack (10) is composed of a pre-embedded steel plate (901), a cap bottom plate (902) and a cap side plate (903); one side of the pre-embedded steel plate (901) is welded with pre-embedded steel bars, which are tied to the steel cage of the crown beam (5); the force-retaining head (905) is formed by welding a steel plate and an I-beam, and the size of the steel plate is the same as the cross-sectional size of the end of the steel-concrete beam section.

7. The assembled hybrid foundation pit support system according to claim 1 is characterized in that: One end of a hoop (17) is welded to the tray (7), the hoop (17) embraces the main support, and the other end is welded to the steel lattice column (6) to fix the main support.

8. The assembled hybrid foundation pit support system according to claim 1 is characterized in that: The jack (10) is placed on the jack wooden support (904) of the bearing platform (9); and the gap between the force-retaining head (905) and the embedded steel plate (901) is filled with a steel sheet (906).

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