A prefabricated foundation pit steel support structure and construction method thereof

Abstract

The present invention belongs to the field of underground engineering technology, and specifically relates to an assembled foundation pit steel support structure and a construction method thereof, including a crown beam, a prefabricated steel support, a temporary locator, and a vertical construction error adjuster for adjusting the vertical construction error of the prefabricated steel support; the prefabricated steel support is composed of two end segments and a plurality of intermediate segments arranged between the two end segments, which are sequentially spliced ​​through connecting joints; the end of the end segment is cast with end concrete, and the end of the end segment and the end concrete are partially extended into the crown beam, and the end concrete and the crown beam are integrally cast and formed; one end of the vertical construction error adjuster is connected to the enclosure structure, and the other end is connected to the end segment through a temporary locator. The present invention can not only realize the rigid connection between the prefabricated steel support segments and between the prefabricated steel support and the crown beam, thereby ensuring the integrity and safety of the foundation pit, but also accurately adjust the vertical construction error through the vertical construction error adjuster to achieve precise construction.

Description

Technical Field

[0001] The invention belongs to the technical field of underground engineering, and in particular relates to an assembled foundation pit steel support structure and a construction method thereof. Background Art

[0002] At present, the first support in the support system of deep foundation pits in China mostly adopts cast-in-place concrete support to improve the stability of the entire foundation pit and to cope with the tensile force that may occur in the first support. If the first support is a steel support, the steel support cannot form a rigid connection with the crown beam, and cannot withstand the tensile force, and local failure will affect the whole system. Although the first concrete support is safe, it has also become a pain point for the construction unit. It is time-consuming and laborious to chisel out the concrete support later, and it does not conform to the concept of green and environmental protection of modern buildings.

[0003] In order to solve the above problems, many types of prefabricated supports have been developed, but none of them have effectively reached the construction depth, and some cannot achieve the same effect as concrete supports, and cannot guarantee the integrity and stability of the foundation pit retaining structure. Therefore, it is necessary to develop a new type of feasible assembled foundation pit steel support structure and its construction method. Summary of the invention

[0004] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide an assembled foundation pit steel support structure and a construction method thereof, which can not only ensure the integrity and safety of the foundation pit, but also realize precise construction.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is an assembled foundation pit steel support structure, including a crown beam, a prefabricated steel support, a temporary positioner and a vertical construction error adjuster for adjusting the vertical construction error of the prefabricated steel support; the prefabricated steel support is composed of two end segments and a plurality of intermediate segments arranged between the two end segments, which are spliced ​​in sequence through connecting joints; the ends of the end segments are cast with end concrete, the ends of the end segments and the end concrete both partially extend into the crown beam, and the end concrete is cast integrally with the crown beam; one end of the vertical construction error adjuster is connected to the retaining structure, and the other end is connected to the end segment through a temporary positioner.

[0006] Furthermore, the vertical construction error adjuster includes a positioning I-beam, a positioning I-beam connecting plate, a T-shaped connecting plate and two push-pull mechanisms arranged on both sides of the prefabricated steel support; one end of each of the push-pull mechanisms is connected to the enclosure structure, and the other end is connected to a parallel plate of a T-shaped connecting plate; the upper flange plate of the positioning I-beam is fixed to the bottom of the end segment through the temporary positioner, and the positions on both sides of the prefabricated steel support on the lower flange plate of the positioning I-beam are respectively connected with positioning I-beam connecting plates; the vertical plate of the T-shaped connecting plate and the positioning I-beam connecting plate are both provided with oblong holes, and the two are fixed by high-strength friction bolts passing through the oblong holes on the vertical plate of the T-shaped connecting plate and the positioning I-beam connecting plate.

[0007] Furthermore, the push-pull mechanism includes a length-adjustable pressure rod and a length-adjustable pull rod; one end of the length-adjustable pull rod and one end of the length-adjustable pressure rod are respectively connected to the enclosure structure through a hinged support, the other end of the length-adjustable pull rod is connected to the length-adjustable pressure rod, and the other end of the length-adjustable pressure rod is connected to the parallel plate of the T-shaped connecting plate.

[0008] Furthermore, the temporary locator includes a pressure plate, a temporary positioning bolt, an adjusting nut and a balancing pad; one end of the pressure plate presses the bottom of the end segment on the upper flange plate of the positioning I-beam, and the other end is pressed on the upper flange plate of the positioning I-beam through a balancing pad; the temporary positioning bolt passes through the pressure plate and the upper flange plate of the positioning I-beam and is fixed by an adjusting nut.

[0009] Furthermore, the hinged support includes a fixed steel plate and an ear plate, the ear plate is fixed to the fixed steel plate, and the fixed steel plate is connected to the enclosure structure through expansion bolts; one end of the length-adjustable pull rod or one end of the length-adjustable pressure rod is hinged to the ear plate.

[0010] Furthermore, the end segment and the middle segment are both double H-shaped steel structures, formed by welding two H-shaped steels side by side along their length direction.

[0011] Furthermore, the connection joint includes a flange outer connecting steel plate, a flange inner connecting steel plate and a web connecting steel plate; the outer side and the inner side of the H-shaped steel flange plate at the joint of the two sections are respectively provided with the flange outer connecting steel plate and the flange inner connecting steel plate, and the flange outer connecting steel plate, the flange inner connecting steel plate and the H-shaped steel flange plates of the two sections are connected by high-strength bolts; web connecting steel plates are provided on both sides of the H-shaped steel web at the joint of the two sections, and the web connecting steel plates on both sides are connected to the H-shaped steel webs of the two sections by high-strength bolts.

[0012] The present invention also provides a construction method for the above-mentioned assembled foundation pit steel support structure, comprising the following steps:

[0013] S1. The end segments and middle segments of prefabricated steel supports are manufactured in the factory and transported to the construction site;

[0014] S2. According to the width of the foundation pit, several intermediate segments are assembled in sequence through connecting joints;

[0015] S3, installing a vertical construction error adjuster, and connecting one end of the vertical construction error adjuster to the enclosure structure;

[0016] S4, splicing the end segments at the ends of the middle segments at both ends through connecting joints to form a prefabricated steel support;

[0017] S5. Before the construction of the crown beam, the prefabricated steel support is hoisted by a gantry crane and placed in a designated position, so that the two end segments of the prefabricated steel support are respectively supported on the enclosure structures on both sides, and the end segments of the prefabricated steel support are also supported on the other end of the vertical construction error adjuster, and the vertical construction error of the prefabricated steel support is adjusted by the vertical construction error adjuster; after the error adjustment is completed, the other end of the vertical construction error adjuster and the end segment are connected by a temporary positioner;

[0018] S6. Cast the end concrete and the crown beam at the end of the end segment into one piece.

[0019] Furthermore, the specific method of installing the vertical construction error adjuster in step S3 is:

[0020] Drive expansion bolts into the enclosure structure, fix the fixed steel plate to the enclosure structure through the expansion bolts, and weld lugs on the fixed steel plate;

[0021] One end of the length-adjustable pressure rod and one end of the length-adjustable pull rod are respectively hinged to the corresponding ear plates, the other end of the length-adjustable pull rod is connected to the length-adjustable pressure rod, and the other end of the length-adjustable pressure rod is connected to the horizontal plate of a T-shaped connecting plate;

[0022] A positioning I-shaped steel connecting plate is welded on the positioning I-shaped steel, and the two are fixed by high-strength friction bolts passing through the vertical plate of the T-shaped connecting plate and the oblong holes on the positioning I-shaped steel connecting plate.

[0023] Furthermore, in step S5, the vertical construction error of the prefabricated steel support is adjusted by means of an adjustable length pressure rod and an adjustable length pull rod. After the error adjustment is completed, the bottom of the end segment is pressed against the upper flange plate of the positioning I-beam through one end of the pressure plate of the temporary positioner, and the other end of the pressure plate is pressed against the upper flange plate of the positioning I-beam through a balancing pad; then a temporary positioning bolt is used to pass through the pressure plate and the upper flange plate of the positioning I-beam and fixed through an adjusting nut.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The prefabricated steel support of the present invention is rigidly connected between segments and between the end segment and the crown beam to ensure the integrity and safety of the foundation pit;

[0026] (2) The present invention accurately adjusts the vertical construction error through the vertical construction error adjuster, and positions the prefabricated steel support through the temporary positioner, so as to achieve accurate construction and convenient construction;

[0027] (3) The segments of the prefabricated steel support of the present invention and the temporary positioner and the vertical construction error adjuster are all connected by bolts, which are easy to install and disassemble, so as to facilitate recycling;

[0028] (4) The prefabricated steel support of the present invention has guaranteed rigidity. It adopts the form of double H-shaped steel + gusset plate. The support section can withstand a large axial force and has good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A diagram of the construction process of the assembled foundation pit steel support structure provided by an embodiment of the present invention;

[0031] Figure 2 A top view of the assembled foundation pit steel support structure provided by an embodiment of the present invention;

[0032] Figure 3 A side view of an assembled foundation pit steel support structure provided by an embodiment of the present invention;

[0033] Figure 4 A cross-sectional view of a double H-shaped steel structure of an intermediate segment and an end segment provided in an embodiment of the present invention;

[0034] Figure 5 A top view of a connection node on a prefabricated steel support provided by an embodiment of the present invention;

[0035] Figure 6 A cross-sectional view of a connection node on a prefabricated steel support provided by an embodiment of the present invention;

[0036] Figure 7 A schematic diagram of the structure of the flange outer connecting steel plate of the connecting joint provided in an embodiment of the present invention;

[0037] Figure 8 A schematic diagram of the structure of the web connecting steel plates of the connection joint provided in an embodiment of the present invention;

[0038] Fig. 9 A schematic diagram of the structure of the connecting steel plate in the flange of the connecting joint provided by an embodiment of the present invention;

[0039] Fig.10 A side view of a vertical construction error adjuster provided by an embodiment of the present invention;

[0040] Fig.11 A top view of a terminal segment provided by an embodiment of the present invention;

[0041] Fig.12 A top view of a positioning I-shaped steel provided in an embodiment of the present invention;

[0042] Fig.13 A schematic diagram of the structure of a hinged support provided by an embodiment of the present invention;

[0043] Fig.14 A side view of an articulated support provided by an embodiment of the present invention;

[0044] Fig.15 for Fig.10 aa view

[0045] Fig.16 A schematic diagram of the structure of a positioning I-shaped steel connecting plate provided in an embodiment of the present invention;

[0046] In the figure: 1. middle section; 2. end section; 3. connection joint; 4. end concrete; 5. crown beam; 6. tie plate; 7. H-beam; 8. flange outer connection steel plate; 9. high-strength bolts; 10. web connection steel plate; 11. flange inner connection steel plate; 12. gantry crane; 13. lifting cable; 14. temporary positioner; 15. long bolt hole; 16. temporary positioning bolt; 17. pressure plate; 18. adjusting nut; 19. balancing pad; 20. fixing steel plate; 21. expansion bolt; 22. ear plate; 23. adjustable pressure rod; 24. adjustable pull rod; 25. positioning I-beam connection plate; 26. T-type connection plate; 27. high-strength friction bolt; 28. oblong hole; 29. ​​positioning I-beam; 30. enclosure structure. DETAILED DESCRIPTION

[0047] 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.

[0048] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0049] like Figure 2-Figure 3 As shown, this embodiment provides an assembled foundation pit steel support structure, including a crown beam 5, a prefabricated steel support, a temporary positioner 14 and a vertical construction error adjuster for adjusting the vertical construction error of the prefabricated steel support; the prefabricated steel support is composed of two end segments 2 and a plurality of intermediate segments 1 arranged between the two end segments 2, which are spliced ​​in sequence through connecting joints 3; the end of the end segment 2 is cast with end concrete 4, and the end of the end segment 2 and the end concrete 4 are partially extended into the crown beam 5, and the end concrete 4 is cast integrally with the crown beam 5; one end of the vertical construction error adjuster is connected to the retaining structure 30, and the other end is connected to the end segment 2 through the temporary positioner 14. In this embodiment, the rigid connection between the segments of the prefabricated steel support is achieved through the connecting joint 3. The rigid connection between the end segment 2 and the crown beam 5 is achieved by partially extending the end of the end segment 2 and the end concrete 4 into the crown beam 5 and integrally casting the end concrete 4 and the crown beam 5. The same or even higher strength as that of conventional concrete supports can be achieved, ensuring the integrity and safety of the foundation pit; and the vertical construction error is accurately adjusted by the vertical construction error adjuster, and the prefabricated steel support is positioned by the temporary positioner 14, so that precise construction can be achieved.

[0050] The crown beam 5 of this embodiment is equipped with steel bars as needed, and the end segment 2 can be tightly connected with the steel bars in the crown beam 5 to improve the integrity and node strength of the steel support structure. After the enclosure structure is constructed, a vertical construction error adjuster can be installed on the inner vertical plane of the enclosure structure every 2-5m.

[0051] Furthermore, the vertical construction error adjuster includes a positioning I-beam 29, a positioning I-beam connecting plate 25, a T-shaped connecting plate 26 and two push-pull mechanisms arranged on both sides of the prefabricated steel support; one end of each push-pull mechanism is connected to the enclosure structure 30, and the other end is connected to a parallel plate of a T-shaped connecting plate 26; the upper flange plate of the positioning I-beam 29 is fixed to the bottom of the end segment 2 through the temporary positioner 14, and the positions on both sides of the prefabricated steel support on the lower flange plate of the positioning I-beam 29 are respectively connected with positioning I-beam connecting plates 25; the vertical plate of the T-shaped connecting plate 26 and the positioning I-beam connecting plate 25 are both provided with oblong holes 28, and the two are fixed by high-strength friction bolts 27 passing through the vertical plate of the T-shaped connecting plate 26 and the oblong holes 28 on the positioning I-beam connecting plate 25. Fig.10 and 15 As shown, the vertical plate of the T-shaped connecting plate 26 of this embodiment is inserted between a pair of positioning I-shaped steel connecting plates 25, and the T-shaped connecting plate 26 and the positioning I-shaped steel connecting plate 25 are transmitted through the friction force of the high-strength friction bolts 27 to ensure the stability of the connection node; the oblong holes 28 are arranged in the vertical direction, such as Fig.16 As shown, the positioning I-shaped steel 29 is driven by the push-pull mechanism to move up and down to cooperate with the oblong hole 28, so as to adjust the error of the prefabricated steel support in the vertical direction.

[0052] As an embodiment, the push-pull mechanism includes a length-adjustable pressure rod 23 and a length-adjustable pull rod 24; one end of the length-adjustable pull rod 24 and one end of the length-adjustable pressure rod 23 are respectively connected to the enclosure structure 30 through a hinged support, the other end of the length-adjustable pull rod 24 is connected to the length-adjustable pressure rod 23, and the other end of the length-adjustable pressure rod 23 is connected to the parallel plate of the T-shaped connecting plate 26. Fig.10 As shown, the length-adjustable pull rod 24 is located above the length-adjustable pressure rod 23 and is connected to the length-adjustable pressure rod 23 . The vertical construction error can be adjusted by the cooperation of the length-adjustable pressure rod 23 and the length-adjustable pull rod 24 .

[0053] Furthermore, the temporary positioner 14 includes a pressure plate 17, a temporary positioning bolt 16, an adjusting nut 18 and a balancing pad 19; one end of the pressure plate 17 presses the bottom of the end segment 2 on the upper flange plate of the positioning I-shaped steel 29, and the other end presses on the upper flange plate of the positioning I-shaped steel 29 through the balancing pad 19; the temporary positioning bolt 16 passes through the pressure plate 17 and the upper flange plate of the positioning I-shaped steel 29 and is fixed by the adjusting nut 18. The upper flange plate of the positioning I-shaped steel 29 of this embodiment is provided with a long bolt hole 15, such as Fig.12As shown, the position matches the installation position of the H-shaped steel 7 of the prefabricated steel support, and a long bolt hole 15 is opened at the corresponding position on the pressure plate 17. The pressure plate 17 and the positioning I-shaped steel 29 are connected by passing the temporary positioning bolt 16 through the long bolt hole 15, so that the bottom of the end segment 2 is fixed on the positioning I-shaped steel 29. In addition, the pressure plate 17 of the temporary positioner 14 is connected to the positioning I-shaped steel 29 of the vertical construction error adjuster by bolts, which is convenient for installation and disassembly, so as to facilitate the recycling of the temporary positioner 14 and the vertical construction error adjuster.

[0054] Furthermore, the hinged support includes a fixed steel plate 20 and an ear plate 22, the ear plate 22 is fixed on the fixed steel plate 20, and the fixed steel plate 20 is connected to the enclosure structure 30 through an expansion bolt 21; one end of the length-adjustable pull rod 24 or one end of the length-adjustable pressure rod 23 is hinged to the ear plate 22 to form a rotatable hinge node.

[0055] Furthermore, the end segment 2 and the middle segment 1 are both double H-shaped steel structures, formed by welding two H-shaped steels 7 side by side along their length direction. Figure 2-4 As shown, the upper flange plates and lower flange plates of the two H-shaped steels 7 of the middle segment 1 and the end segment 2 of this embodiment are respectively welded through the gusset plates 6, and the formed supporting section has good strength, rigidity and stability; wherein, the size of the H-shaped steel 7 is selected according to the calculated force of the foundation pit, and the common models on the market are preferred; the gusset plates 6 are arranged at intervals along the supporting direction, with a spacing of 0.6-1.0m preferably, and a square shape preferably, with a side length the same as the distance between the center lines of the webs of the two H-shaped steels 7 of the double H-shaped steel, and a thickness of not less than 10mm.

[0056] Furthermore, if Figure 5-6 As shown, the connection joint 3 includes a flange outer connection steel plate 8, a flange inner connection steel plate 11 and a web connection steel plate 10; the outer side and the inner side of the flange plate of the H-beam 7 at the joint of the two sections are respectively provided with the flange outer connection steel plate 8 and the flange inner connection steel plate 11, and the flange outer connection steel plate 8, the flange inner connection steel plate 11 and the flange plates of the H-beam 7 of the two sections are connected by high-strength bolts 9; web connection steel plates 10 are provided on both sides of the web of the H-beam 7 at the joint of the two sections, and the web connection steel plates 10 on both sides are connected to the web of the H-beam 7 of the two sections by high-strength bolts 9. In this embodiment, bolt holes for high-strength bolts 9 to pass through are reserved on the flange plates and web plates of the H-shaped steel 7 at the joints of the two segments. Bolt holes for high-strength bolts 9 to pass through are also reserved at corresponding positions on the flange outer connecting steel plate 8, the web connecting steel plate 10 and the flange inner connecting steel plate 11. The rigid connection between the segments of the prefabricated steel support is achieved through the connecting joint 3 to ensure the stiffness and strength of the prefabricated steel support. The two segments are connected to the connecting joint 3 by bolts, which is easy to install and disassemble, thereby facilitating recycling and reuse.

[0057] In this embodiment, the flange outer connecting steel plate 8, the web connecting steel plate 10 and the flange inner connecting steel plate 11 can be changed in shape, size and thickness as needed; the number and diameter of the high-strength bolts 9 need to be determined according to calculations to ensure the rigid connection of the connection node 3; as an implementation method, Figure 7-9 As shown, the flange outer connecting steel plate 8 is located above and below the flange of the joint, and is in the shape of a square with grooves. The grooves provide space for tightening the high-strength bolts 9, and it can also be without grooves. The width of the flange outer connecting steel plate 8 is the same as the width of the prefabricated steel support; the flange inner connecting steel plate 11 is located on the inner side of the flange of the H-shaped steel 7, and there are 4 pieces in total. They are rectangular steel plates, and the position and length of the bolt holes are the same as those of the flange outer connecting steel plate 8; the web connecting steel plate 10 is a rectangular steel plate, which is used to fix the web of the H-shaped steel 7. Four web connecting steel plates 10 are used at the ends of the two H-shaped steels 7 to connect through high-strength bolts 9.

[0058] like Figure 1-16 As shown, this embodiment also provides a construction method for the above-mentioned assembled foundation pit steel support structure, comprising the following steps:

[0059] S1. According to the design drawings, the end segment 2 and the middle segment 1 of the prefabricated steel support are manufactured in the factory, as well as the flange outer connecting steel plate 8, the web connecting steel plate 10 and the flange inner connecting steel plate 11 of the connecting joint 3 are manufactured and transported to the construction site;

[0060] S2. According to the width of the foundation pit, several intermediate segments 1 are assembled in sequence through the connecting joints 3; the intermediate segments 1 of this embodiment are assembled in advance and hoisted into the foundation pit by the gantry crane 12, or they can be hoisted into the foundation pit section by section and assembled in the foundation pit;

[0061] S3, installing a vertical construction error adjuster, and connecting one end of the vertical construction error adjuster to the enclosure structure 30;

[0062] Specifically, the enclosure structure 30 is first constructed, and after the enclosure structure 30 is constructed, the expansion bolts 21 are driven into the enclosure structure 30, the fixed steel plate 20 is fixed to the enclosure structure 30 by the expansion bolts 21, and the ear plate 22 is welded to the fixed steel plate 20;

[0063] Then one end of the length-adjustable pressure rod 23 and one end of the length-adjustable pull rod 24 are respectively hinged to the corresponding ear plate 22, the other end of the length-adjustable pull rod 24 is connected to the length-adjustable pressure rod 23, and the other end of the length-adjustable pressure rod 23 is welded to the horizontal plate of a T-shaped connecting plate 26;

[0064] The positioning I-shaped steel connecting plate 25 is welded on the positioning I-shaped steel 29, and the two are fixed by high-strength friction bolts 27 that penetrate the vertical plate of the T-shaped connecting plate 26 and the oblong hole 28 of the positioning I-shaped steel connecting plate 25;

[0065] S4, splicing the end segments 2 at the ends of the middle segments 1 at both ends through the connecting joints 3 to form a prefabricated steel support;

[0066] S5. Before the construction of the crown beam 5, the crown beam 5 is positioned in advance, and the gantry crane 12 is used to hoist the prefabricated steel support into the specified position, so that the two end segments 2 of the prefabricated steel support are respectively supported on the enclosure structure 30 on both sides, and the end segments 2 of the prefabricated steel support are also supported on the positioning I-shaped steel 29. After rough positioning, the vertical construction error of the prefabricated steel support is adjusted by the length-adjustable pressure rod 23 and the length-adjustable pull rod 24; after the error adjustment is completed, the positioning I-shaped steel 29 and the end segment 2 are connected through the temporary positioner 14, specifically: the bottom of the end segment 2 is pressed on the upper flange plate of the positioning I-shaped steel 29 through one end of the pressure plate 17 of the temporary positioner 14, and the other end of the pressure plate 17 is pressed on the upper flange plate of the positioning I-shaped steel 29 through the balancing pad 19; then a temporary positioning bolt 16 is used to pass through the pressure plate 17 and the upper flange plate of the positioning I-shaped steel 29 and fixed through the adjusting nut 18 to achieve the purpose of temporary positioning;

[0067] S6. Cast the end concrete 4 and the crown beam 5 at the end of the end segment 2 as a whole, so that the prefabricated steel support and the crown beam 5 form a rigid whole.

[0068] After the foundation pit is excavated and the internal structure construction is completed, the connection joint 3 is removed, the end concrete 4 is chiseled out, the temporary positioner 14 is removed, and the end segment 2, the middle segment 1 and the vertical construction error adjuster are recycled, which solves the pain points of cast-in-place concrete and demolition, and is green and environmentally friendly.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An assembled foundation pit steel support structure, characterized in that: It comprises a crown beam, a prefabricated steel support, a temporary positioner and a vertical construction error adjuster for adjusting the vertical construction error of the prefabricated steel support; the prefabricated steel support is formed by two end segments and a plurality of intermediate segments arranged between the two end segments, which are sequentially spliced ​​through connecting joints; the ends of the end segments are cast with end concrete, the ends of the end segments and the end concrete both partially extend into the crown beam, and the end concrete and the crown beam are cast and formed as a whole; one end of the vertical construction error adjuster is connected to the enclosure structure, and the other end is connected to the end segment through a temporary positioner; The vertical construction error adjuster includes a positioning I-beam, a positioning I-beam connecting plate, a T-shaped connecting plate, and two push-pull mechanisms arranged on both sides of the prefabricated steel support; one end of each of the push-pull mechanisms is connected to the enclosure structure, and the other end is connected to a parallel plate of a T-shaped connecting plate; the upper flange plate of the positioning I-beam is fixed to the bottom of the end segment through the temporary positioner, and the positions on both sides of the prefabricated steel support on the lower flange plate of the positioning I-beam are respectively connected with positioning I-beam connecting plates; the vertical plate of the T-shaped connecting plate and the positioning I-beam connecting plate are both provided with oblong holes, and the two are fixed by high-strength friction bolts passing through the oblong holes on the vertical plate of the T-shaped connecting plate and the positioning I-beam connecting plate; The push-pull mechanism comprises a length-adjustable pressure rod and a length-adjustable pull rod; one end of the length-adjustable pull rod and one end of the length-adjustable pressure rod are respectively connected to the enclosure structure through a hinged support, the other end of the length-adjustable pull rod is connected to the length-adjustable pressure rod, and the other end of the length-adjustable pressure rod is connected to the parallel plate of the T-shaped connecting plate; The temporary locator includes a pressure plate, a temporary positioning bolt, an adjusting nut and a balancing pad; one end of the pressure plate presses the bottom of the end segment on the upper flange plate of the positioning I-beam, and the other end presses the upper flange plate of the positioning I-beam through a balancing pad; the temporary positioning bolt passes through the pressure plate and the upper flange plate of the positioning I-beam and is fixed by an adjusting nut.

2. The assembled foundation pit steel support structure according to claim 1, characterized in that: The hinged support includes a fixed steel plate and an ear plate, the ear plate is fixed to the fixed steel plate, and the fixed steel plate is connected to the enclosure structure through expansion bolts; one end of the length-adjustable pull rod or one end of the length-adjustable pressure rod is hinged to the ear plate.

3. An assembled foundation pit steel support structure according to any one of claims 1 to 2, characterized in that: The end segment and the middle segment are both double H-shaped steel structures, formed by welding two H-shaped steels side by side along their length directions.

4. The assembled foundation pit steel support structure according to claim 3, characterized in that: The connection joint includes a flange outer connection steel plate, a flange inner connection steel plate and a web connection steel plate; the outer side and the inner side of the H-shaped steel flange plate at the joint of the two sections are respectively provided with the flange outer connection steel plate and the flange inner connection steel plate, and the flange outer connection steel plate, the flange inner connection steel plate and the H-shaped steel flange plates of the two sections are connected by high-strength bolts; web connection steel plates are provided on both sides of the H-shaped steel web at the joint of the two sections, and the web connection steel plates on both sides are connected to the H-shaped steel webs of the two sections by high-strength bolts.

5. A construction method for an assembled foundation pit steel support structure according to any one of claims 1 to 4, characterized in that: The steps include: S1. The end segments and middle segments of prefabricated steel supports are manufactured in the factory and transported to the construction site; S2. According to the width of the foundation pit, several intermediate segments are assembled in sequence through connecting joints; S3, installing a vertical construction error adjuster, and connecting one end of the vertical construction error adjuster to the enclosure structure; S4, splicing the end segments at the ends of the middle segments at both ends through connecting joints to form a prefabricated steel support; S5. Before the construction of the crown beam, the prefabricated steel support is hoisted by a gantry crane and placed in a designated position, so that the two end segments of the prefabricated steel support are respectively supported on the enclosure structures on both sides, and the end segments of the prefabricated steel support are also supported on the other end of the vertical construction error adjuster, and the vertical construction error of the prefabricated steel support is adjusted by the vertical construction error adjuster; after the error adjustment is completed, the other end of the vertical construction error adjuster and the end segment are connected by a temporary positioner; S6. Cast the end concrete and the crown beam at the end of the end segment into one piece.

6. The construction method of the assembled foundation pit steel support structure according to claim 5, characterized in that: The specific method of installing the vertical construction error adjuster in step S3 is: Drive expansion bolts into the enclosure structure, fix the fixed steel plate to the enclosure structure through the expansion bolts, and weld lugs on the fixed steel plate; One end of the length-adjustable pressure rod and one end of the length-adjustable pull rod are respectively hinged to the corresponding ear plates, the other end of the length-adjustable pull rod is connected to the length-adjustable pressure rod, and the other end of the length-adjustable pressure rod is connected to the horizontal plate of a T-shaped connecting plate; A positioning I-shaped steel connecting plate is welded on the positioning I-shaped steel, and the two are fixed by high-strength friction bolts passing through the vertical plate of the T-shaped connecting plate and the oblong holes on the positioning I-shaped steel connecting plate.

7. The construction method of the assembled foundation pit steel support structure according to claim 6, characterized in that: In step S5, the vertical construction error of the prefabricated steel support is adjusted by the length-adjustable pressure rod and the length-adjustable pull rod. After the error adjustment is completed, the bottom of the end segment is pressed against the upper flange plate of the positioning I-beam through one end of the pressure plate of the temporary positioner, and the other end of the pressure plate is pressed against the upper flange plate of the positioning I-beam through a balancing pad; then a temporary positioning bolt is used to pass through the pressure plate and the upper flange plate of the positioning I-beam and fixed through the adjusting nut.

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