An easy-to-disassemble assembled foundation pit support structure and construction method

Abstract

The present invention belongs to the technical field of underground foundation pit engineering, and specifically relates to an assembled foundation pit support structure and construction method that is easy to disassemble, including a retaining structure and an assembled support; a crown beam is provided on the top of the retaining structure, a waist beam is provided on the inner side of the retaining structure, and the assembled support is supported between the opposite sides of the crown beam and between the opposite sides of the waist beam; the assembled support is spliced ​​by a plurality of prefabricated support segments, and a disassembly gasket is provided between at least two adjacent prefabricated support segments. The present invention arranges a disassembly gasket between at least two adjacent prefabricated support segments in the assembled support, so that the disassembly gasket can be removed first during disassembly, thereby eliminating the axial force between the prefabricated support segments, reducing the difficulty of disassembling the prefabricated support segments, and improving the disassembly efficiency of the assembled support.

Description

Technical Field

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

[0002] Traditional cast-in-place concrete supports are widely used in underground projects due to their advantages such as high rigidity, good integrity, safety and reliability. However, they also have prominent problems and disadvantages: (1) Costly and high investment: Concrete supports are temporary projects. Once the main structure of the station is completed, they are demolished and transported away. The investment in temporary abandoned projects is high, with a general underground station costing millions and a complex station costing tens of millions; (2) Time-consuming and long construction period: Concrete support formwork, steel bar binding, pouring, vibration, maintenance, and later demolition take several months, which seriously restricts the progress of on-site construction; (3) Laborious and difficult: Concrete support construction is difficult, and demolition after use requires a lot of manpower and material resources; (4) Not environmentally friendly, concrete demolition waste pollutes the environment, which does not conform to the development direction of green construction, environmental protection and energy saving. Advanced products and scientific construction methods are urgently needed to replace traditional concrete supports.

[0003] The prefabricated supports currently seen are usually under great pressure and are long when dismantled. Therefore, if the bolts between the prefabricated support segments are unscrewed under huge compressive stress, it is still difficult to dismantle the prefabricated supports that are several meters long. Although the traditional steel pipe supports can be recycled and are more convenient to construct, they can only withstand pressure between the foundation pit support structure, have poor integrity and poor deformation resistance, and become a weak link in the safety of the foundation pit. 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 easy-to-disassemble assembled foundation pit support structure and construction method, reduce the difficulty of disassembling prefabricated support segments, and improve the disassembly efficiency of assembled supports.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is an assembled support structure in a foundation pit that is easy to disassemble, including a retaining structure and an assembled support; a crown beam is provided on the top of the retaining structure, a waist beam is provided on the inner side of the retaining structure, and the assembled support is supported between the opposite sides of the crown beam and between the opposite sides of the waist beam; the assembled support is spliced ​​by a plurality of prefabricated support segments, and a disassembly gasket is provided between at least two adjacent prefabricated support segments.

[0006] Furthermore, the prefabricated support segment includes a steel pipe, an inner ring plate and an outer ring plate; the end faces at both ends of the steel pipe are welded with inner ring plates, and the outer walls at both ends of the steel pipe are circumferentially welded with outer ring plates; the inner ring plate and the outer ring plate at the same end of the steel pipe are connected by stiffening ribs, and the stiffening ribs are welded to the steel pipe; the inner ring plate and the outer ring plate are both provided with a plurality of screw holes at intervals along the circumferential direction, and the screw holes on the outer ring plate correspond one by one to the screw holes on the inner ring plate; the corresponding screw holes on the inner ring plates and the outer ring plates on adjacent prefabricated support segments are respectively installed with screws and fixed by nuts.

[0007] Furthermore, the disassembly gasket is provided with a plurality of screw holes, and the screw holes on the disassembly gasket correspond one-to-one with the screw holes on the outer ring plate and the screw holes on the inner ring plate; the screw passes through the corresponding screw holes on the disassembly gasket.

[0008] Furthermore, filling concrete is poured inside the steel pipe, and the filling concrete has a hollow portion running through the steel pipe in the axial direction; sealing plates are welded to the end faces at both ends of the steel pipe, and the inner ring plate is welded to a surface of the sealing plate that is away from the steel pipe.

[0009] Furthermore, the sealing plate, the inner ring plate and the outer ring plate are all annular, and the inner ring size of the sealing plate and the inner ring size of the inner ring plate are the same as the size of the hollow part filled with concrete, and the inner ring size of the outer ring plate is the same as the outer ring size of the steel pipe.

[0010] Furthermore, a plurality of circumferential stirrups and a plurality of longitudinal bars are arranged in the filling concrete, the plurality of circumferential stirrups are arranged at intervals along the supporting direction, the plurality of longitudinal bars are arranged at intervals along the inner side of the circumferential stirrups, and each of the longitudinal bars is connected to the plurality of circumferential stirrups, and both ends of the longitudinal bars are connected to the sealing plates at both ends of the steel pipe by perforated plug welding.

[0011] Furthermore, a plurality of the stiffening ribs are arranged at intervals along the circumferential direction between the inner ring plate and the outer ring plate, and the stiffening ribs and the screw rods are arranged alternately.

[0012] Furthermore, the stiffening rib is a chamfered rectangular steel plate, and both side corners of the stiffening rib connected to the steel pipe are chamfered.

[0013] Furthermore, embedded parts are embedded in the crown beam and the waist beam, and the embedded parts include embedded steel plates and multiple embedded screws; one ends of the multiple embedded screws pass through the embedded steel plates in sequence, and the other ends extend out of the crown beam or the waist beam and pass through the multiple screw holes on the inner ring plate and the multiple screw holes on the outer ring plate of the assembled support end in sequence, and then are fixed by nuts.

[0014] The present invention also provides a construction method of the above-mentioned assembled foundation pit support structure, comprising the following steps:

[0015] S1. According to the design drawings, prefabricated support segments and embedded parts are manufactured in the factory and transported to the construction site;

[0016] S2. Splice the prefabricated support segments one by one by means of screws and nuts, and install disassembly gaskets between at least two adjacent prefabricated support segments to assemble into an assembled support; and connect the embedded parts at both ends of the assembled support by means of screws;

[0017] S3. Embed the bearing at the supporting position in the foundation pit;

[0018] S4. The assembled support is hoisted and placed on the support, so that the embedded parts at both ends of the assembled support are placed at the position of the crown beam or waist beam to be cast;

[0019] S5. Cast the crown beam or waist beam so that the embedded parts are buried therein;

[0020] S6. After the construction is completed, first unscrew the screws on the two prefabricated support segments with disassembly gaskets installed in the middle, and remove the disassembly gaskets;

[0021] S7. Unscrew the screws segment by segment and recycle the prefabricated support segments.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention provides a disassembly gasket between at least two adjacent prefabricated support segments in the assembled support, so that the disassembly gasket can be removed first during disassembly, thereby eliminating the axial force between the prefabricated support segments, reducing the difficulty of disassembling the prefabricated support segments, and improving the disassembly efficiency of the assembled support;

[0024] (2) The prefabricated support segments of the present invention are connected by multiple screws to ensure the rigid connection of the intermediate nodes, achieve equal strength between the nodes and the components, ensure the safety and stability of the foundation pit project, and are easy to install and disassemble, facilitating factory production and large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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.

[0026] Figure 1 A plan view of a prefabricated foundation pit support structure that is easy to disassemble provided by an embodiment of the present invention;

[0027] Figure 2 A longitudinal section view of a prefabricated support segment provided by an embodiment of the present invention;

[0028] Figure 3 A cross-sectional view of a prefabricated support segment when the steel pipe provided in an embodiment of the present invention is circular;

[0029] Figure 4 A cross-sectional view of a prefabricated support segment when the steel pipe provided in an embodiment of the present invention is square;

[0030] Figure 5 A longitudinal section view of a connection node structure of a prefabricated support segment provided in an embodiment of the present invention (without a disassembly gasket);

[0031] Figure 6 A longitudinal section view of a connection node structure of a prefabricated support segment provided in an embodiment of the present invention (with a disassembly gasket);

[0032] Figure 7 A cross-sectional view of a connection node structure of a prefabricated support segment provided by an embodiment of the present invention;

[0033] Figure 8 A schematic diagram of an inner ring plate when the steel pipe provided in an embodiment of the present invention is circular;

[0034] Fig. 9 A schematic diagram of an outer ring plate when the steel pipe provided in an embodiment of the present invention is circular;

[0035] Fig.10 A schematic diagram of a stiffening rib provided in an embodiment of the present invention;

[0036] Fig.11 A schematic diagram of a disassembly gasket provided in an embodiment of the present invention;

[0037] Fig.12 A schematic diagram of the connection between the prefabricated support segment and the crown beam provided in an embodiment of the present invention;

[0038] Fig.13 A schematic diagram of an embedded part provided in an embodiment of the present invention;

[0039] Fig.14 A cross-sectional view of a support provided by an embodiment of the present invention;

[0040] Fig.15 A top view of a support provided by an embodiment of the present invention;

[0041] In the figure: 1. enclosure structure; 2. crown beam; 3. prefabricated supporting segment; 4. embedded parts; 5. embedded steel plate; 6. embedded screw; 7. support; 8. outer ring plate; 9. stiffening rib; 10. inner ring plate; 11. steel pipe; 12. stirrups; 13. longitudinal reinforcement; 14. sealing plate; 15. perforation plug welding; 16. filling concrete; 17. screw; 18. nut; 19. screw hole; 20. disassembly gasket; 21. concave steel block; 22. steel leg; 23. concrete base. DETAILED DESCRIPTION

[0042] 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.

[0043] 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.

[0044] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0045] Embodiment 1

[0046] like Figure 1 and Figure 6As shown, this embodiment provides an assembled support structure in a foundation pit that is easy to disassemble, including a retaining structure 1 and an assembled support; a crown beam 2 is provided on the top of the retaining structure 1, a waist beam is provided on the inner side of the retaining structure 1, and the assembled support is supported between the opposite sides of the crown beam 2 and between the opposite sides of the waist beam; the assembled support is spliced ​​by a plurality of prefabricated support segments 3, and a disassembly gasket 20 is provided between at least two adjacent prefabricated support segments 3. At least one disassembly gasket 20 is provided in the assembled support of this embodiment, and the disassembly gasket 20 is placed between two of the prefabricated support segments 3, so that the disassembly gasket 20 can be removed first during disassembly to eliminate the axial force between the prefabricated support segments 3, and the remaining prefabricated support segments 3 can be easily disassembled, effectively solving the problem of difficulty in disassembling assembled supports that are several meters long, and improving the disassembly efficiency of assembled supports.

[0047] In this embodiment, the disassembly gasket 20 can be a solid steel ring with a thickness of 3-10cm, or a solid steel ring spliced ​​from multiple sections, such as two semicircular steel rings or multiple fan-shaped steel rings, and the multiple sections of the steel rings are not connected; the surface of the disassembly gasket 20 needs to be smooth, and a layer of lubricant can be applied to both sides of the disassembly gasket 20 before installation. The difficulty of disassembly gasket 20 is much smaller, and once the disassembly gasket 20 is removed, the axial force between the prefabricated support segments 3 will also disappear, and the remaining prefabricated support segments 3 can be easily removed. The accompanying drawings of this embodiment are described by taking the crown beam 2 as an example, and the situation of the waist beam refers to the crown beam 2.

[0048] The prefabricated support segment 3 of this embodiment can be supported by hollow steel tube concrete, such as Figure 3 and Figure 4 As shown, pure steel support and pure concrete support can also be used, and high-strength alloy steel materials or a combination of steel and concrete can also be used; and the prefabricated support segment 3 can be designed with several fixed modulus segments of appropriate lengths as needed. It should not be too long, as a long length is not suitable for hoisting construction, and a short length leads to too many joints and difficulty in connection. As an implementation method, the prefabricated support segment 3 can be designed with standard moduli of 4m, 5m, 6m and other specifications and an end segment modulus of 2m. According to the actual needs of the foundation pit, prefabricated support segments 3 with completely identical, non-completely identical or completely different length specifications can be selected for assembly to meet the needs of foundation pit supports of different widths and lengths, and have universal applicability.

[0049] As an embodiment, the prefabricated support segment 3 includes a steel tube 11, an inner ring plate 10 and an outer ring plate 8; the end faces of both ends of the steel tube 11 are welded with inner ring plates 10, and the outer walls of both ends of the steel tube 11 are circumferentially welded with outer ring plates 8; the inner ring plate 10 and the outer ring plate 8 at the same end of the steel tube 11 are connected by stiffening ribs 9, and the stiffening ribs 9 are welded to the steel tube 11; the inner ring plate 10 and the outer ring plate 8 are both provided with a plurality of screw holes 19 at intervals along the circumferential direction, and the screw holes 19 on the outer ring plate 8 correspond one by one to the screw holes 19 on the inner ring plate 10; the corresponding screw holes 19 on the inner ring plates 10 and the outer ring plates 8 on adjacent prefabricated support segments 3 are respectively installed with screws 17 and fixed by nuts 18. Figure 5 and Figure 6 As shown, the inner ring plate 10, the stiffening rib 9 and the outer ring plate 8 at the end of the steel tube 11 constitute a boot beam node to increase the joint stiffness, wherein the outer ring plate 8 is circumferentially welded to the steel tube 11, the inner side of the outer ring plate 8 is welded to the stiffening rib 9, the inner side of the inner ring plate 10 is respectively welded to the stiffening rib 9, the steel tube 11 and the sealing plate 14, and the three sides of the stiffening rib 9 are respectively welded to the outer ring plate 8, the inner ring plate 10 and the steel tube 11 to ensure the stiffness of the connection node at the joint; and the boot beam node at the end of the prefabricated support segment 3 is connected by a plurality of screws 17 , ensuring the rigid connection of the intermediate nodes, achieving equal strength between the nodes and components, ensuring that the prefabricated supports achieve similar or even higher strength and rigidity as cast-in-place concrete supports, ensuring the safety and stability of the foundation pit project, and convenient installation and disassembly, facilitating factory production and large-scale promotion and application; when splicing, align the multiple screw holes 19 on the two prefabricated support segments 3 respectively, and then install the screws 17 in the screw holes 19 located on the same straight line and fix them through the nuts 18 to achieve splicing between the prefabricated support segments 3.

[0050] Furthermore, the disassembly gasket 20 is provided with a plurality of screw holes 19, and the screw holes 19 on the disassembly gasket 20 correspond to the screw holes 19 on the outer ring plate 8 and the screw holes 19 on the inner ring plate 10 one by one; the screw 17 passes through the corresponding screw holes 19 on the disassembly gasket 20. Figure 6 and Fig.11 As shown, in this embodiment, the size of the disassembly gasket 20 can be the same as that of the inner ring plate 10, and a plurality of screw holes 19 are evenly arranged along the circumferential direction on the outer edge, and the screw holes 19 on the disassembly gasket 20 correspond one-to-one to the screw holes 19 on the inner ring plate 10 and the outer ring plate 8 of the prefabricated support segment 3.

[0051] As another embodiment, on the basis of the prefabricated support segment 3 of the above-mentioned steel structure, filling concrete 16 is poured in the steel pipe 11, and the filling concrete 16 has a hollow portion running through it along the axial direction; the end faces of both ends of the steel pipe 11 are welded with sealing plates 14, and the inner ring plate 10 is welded to the side of the sealing plate 14 facing away from the steel pipe 11. In this embodiment, filling concrete 16 is poured in the steel pipe 11 to form a hollow structure, which can not only give full play to the advantages of the two materials of steel pipe 11 and concrete, but also be cost-effective. At the same time, it is lightweight and high-strength, easy to recycle, transport and install. Compared with pure steel support, it has significant economic benefits. Compared with concrete support, it has higher rigidity, and the steel pipe 11 is the outer skin of the prefabricated support, which can protect the internal filling concrete 16 from damage, so that the prefabricated components can be recycled for many times. At the same time, the hoop effect of the steel pipe 11 can significantly improve the bearing capacity of the internal filling concrete, so that the hollow steel pipe 11 concrete support has high bearing capacity (strength) and strong deformation resistance (rigidity), which can achieve the same or even higher strength and rigidity as conventional concrete support, ensuring the safety of foundation pit engineering; and the hollow parts of multiple prefabricated support segments 3 of the prefabricated support are connected, so that the bearing capacity of the prefabricated support is higher and the deformation resistance is stronger.

[0052] In this embodiment, the cross section of the steel pipe 11 can be circular, square, rectangular, polygonal, etc., and can be made of high-strength steel or alloy steel, etc., as long as it can bear the force and be easy to weld. In this embodiment, the filling concrete 16 can be other materials such as high-strength concrete, lightweight concrete or foam concrete, and the strength must meet the design requirements; the filling concrete 16 is hollow inside, and it can be formed by centrifugal process or other processes. The thickness of the filling concrete 16 is about 100mm-200mm. It is advisable to take a small value under the condition of supporting stiffness to reduce the self-weight of the prefabricated component; the hollow part of the filling concrete 16 can be without any inner wall, or it can be in the form of an inner wall. The inner wall material can be steel pipe, PVC, etc., and its cross section is not limited to circular, and can also be square, polygonal and other shapes. The sealing plate 14 can protect the filling concrete 16 at the end; the sealing plate 14, the inner ring plate 10, the outer ring plate 8, the stiffening rib 9 and the steel pipe 11 can be prefabricated as a whole, or they can be prefabricated separately and then welded into one.

[0053] Furthermore, the sealing plate 14, the inner ring plate 10 and the outer ring plate 8 are all annular, and the inner ring size of the sealing plate 14 and the inner ring size of the inner ring plate 10 are the same as the size of the hollow part filled with concrete 16, and the inner ring size of the outer ring plate 8 is the same as the outer ring size of the steel pipe 11. In this embodiment, the shapes and sizes of the sealing plate 14, the inner ring plate 10 and the outer ring plate 8 match the shapes and sizes of the steel pipe 11; when the steel pipe 11 is circular, the sealing plate 14, the inner ring plate 10 and the outer ring plate 8 are all annular steel plates, such as Figure 3 and Figure 8 , Fig. 9 As shown, the inner diameter of the outer ring plate 8 is the same as the outer diameter of the steel pipe 11, the inner diameter of the inner ring plate 10 and the inner diameter of the sealing plate 14 are the same as the inner diameter of the hollow portion filled with concrete 16, the outer diameter of the sealing plate 14 can be the same as the outer diameter of the steel pipe 11, and the outer diameter of the inner ring plate 10 can be the same as the outer diameter of the outer ring plate 8; when the steel pipe 11 is square, as shown Figure 4 As shown, the sealing plate 14, the inner ring plate 10 and the outer ring plate 8 are all square ring steel plates, and the inner ring size and / or outer ring size of the sealing plate 14, the inner ring plate 10 and the outer ring plate 8 are also adjusted accordingly, which will not be described in detail here.

[0054] Furthermore, the filling concrete 16 is provided with a plurality of circumferential stirrups 12 and a plurality of longitudinal bars 13, the plurality of circumferential stirrups 12 are arranged at intervals along the supporting direction, the plurality of longitudinal bars 13 are arranged at intervals along the inner side of the circumferential stirrups 12, and each of the longitudinal bars 13 is connected to the plurality of circumferential stirrups 12, and both ends of the longitudinal bars 13 are connected to the sealing plates 14 at both ends of the steel pipe 11 by perforated plug welding 15. Figure 2-Figure 4 As shown, in the filling concrete 16 of this embodiment, a plurality of longitudinal bars 13 are arranged along the supporting direction, and the plurality of longitudinal bars 13 are arranged on the inner side of the annular stirrups 12 and connected to the plurality of annular stirrups 12, so as to enhance the tight connection effect between the concrete and the steel pipe 11, so as to ensure that the steel pipe 11 and the concrete work effectively together, and the rigidity thereof is relatively large, far exceeding the concrete support of the concrete size; wherein, the diameter and the number of the longitudinal bars 13 and the annular stirrups 12 can be determined according to the actual situation, and can be arranged in the middle of the filling concrete 16; the two ends of the longitudinal bars 13 are respectively welded to the sealing plates 14 at the two ends of the steel pipe 11 by perforated plug welding 15 as a whole, so as to promote the integration of the steel pipe 11 structure with the core-filling concrete, improve the integrity of the prefabricated components, and ensure the rigidity of the nodes.

[0055] Furthermore, a plurality of the stiffening ribs 9 are arranged between the inner ring plate 10 and the outer ring plate 8 in an annular direction, and the stiffening ribs 9 and the screw rods 17 are arranged alternately. Figure 7 As shown, the stiffening ribs 9 are arranged between the pairs of screw holes 19 of the inner and outer ring plates, the number of stiffening ribs 9 and the screw holes 19 are consistent, and multiple stiffening ribs 9 and multiple screws 17 are arranged alternately to improve the strength and rigidity of the connection node; the thickness of the stiffening ribs 9 is determined according to the force, and a redundancy is reserved.

[0056] Furthermore, the stiffening rib 9 is a chamfered rectangular steel plate, and the two corners of the side of the stiffening rib 9 connected to the steel pipe 11 are chamfered. Figure 5 , Figure 6 and Fig.10As shown, this embodiment forms a chamfered structure by chamfering the two side corners where the stiffening rib 9 is connected to the steel pipe 11, thereby effectively reducing stress concentration during welding; wherein, the side of the stiffening rib 9 facing away from the steel pipe 11 can be flush with the outer side of the outer ring plate 8.

[0057] Furthermore, embedded parts 4 are embedded in the crown beam 2 and the waist beam, and the embedded parts 4 include two embedded steel plates 5 and multiple embedded screws 6; one end of the multiple embedded screws 6 passes through the two embedded steel plates 5 in sequence and is welded to the two embedded steel plates 5, and the other end extends out of the crown beam 2 or the waist beam and passes through the multiple screw holes 19 on the inner ring plate 10 of the assembled support end and the multiple screw holes 19 on the outer ring plate 8 in sequence, and then is fixed by the nut 18. Figure 12-13 As shown, the two embedded steel plates 5 of this embodiment are arranged relatively to each other and buried in the crown beam 2 or the waist beam to play an anchoring role; a plurality of screw holes 19 are provided on the two embedded steel plates 5, and correspond one to one with the plurality of screw holes 19 on the inner ring plate 10 and the outer ring plate 8, one end of the plurality of embedded screws 6 passes through the corresponding screw holes 19 on the two embedded steel plates 5 and is welded to the embedded steel plates 5, and the other end passes through the plurality of screw holes 19 on the inner ring plate 10 and the plurality of screw holes 19 on the outer ring plate 8 and is fixed by a nut 18.

[0058] In this embodiment, all steel structures such as steel pipe 11, inner ring plate 10, outer ring plate 8 and other parts that are directly in contact with the outside world need to be pre-coated with anti-rust material to prevent rust damage to the surface of the steel structure, which will lead to reduced strength; the nuts 18 should be stacked in two to prevent loosening, and a pad can be provided under the nuts 18 as needed.

[0059] Embodiment 2

[0060] This embodiment provides a construction method of the assembled foundation pit support structure provided in the first embodiment, comprising the following steps:

[0061] S1. According to the design drawings, prefabricated support segments 3 and embedded parts 4 are manufactured in the factory and transported to the construction site;

[0062] S2, splicing the prefabricated support segments 3 section by section through screws 17 and nuts, and installing disassembly gaskets 20 between at least two adjacent prefabricated support segments 3 to assemble into an assembled support; and connecting the embedded parts 4 at both ends of the assembled support through screws 17;

[0063] S3, burying the support 7 at the supporting position in the foundation pit;

[0064] S4, the assembled support is hoisted and placed on the support 7, so that the embedded parts 4 at both ends of the assembled support are placed at the position of the crown beam 2 or waist beam to be cast;

[0065] S5, pouring the crown beam 2 or the waist beam, so that the embedded parts 4 are buried therein;

[0066] S6. After the construction is completed, first unscrew the screws 17 on the two prefabricated support segments 3 with the disassembly gaskets 20 installed in the middle, and remove the disassembly gaskets 20;

[0067] S7, unscrewing the screw rod 17 segment by segment and recovering the prefabricated support segment 3.

[0068] In this embodiment, the embedded parts 4 at both ends of the assembled support are first placed at the position of the crown beam 2 or waist beam to be cast, and then the crown beam 2 or waist beam is cast, and the embedded parts 4 at both ends of the assembled support are cast therein, so as to improve the strength of the nodes between the two ends of the assembled support and the crown beam 2 or waist beam, and ensure the safety and stability of the foundation pit project. The assembled support in this embodiment can be rigidly connected with the crown beam 2 or waist beam, so that in the ultra-deep foundation pit, the assembled support can replace multiple traditional concrete supports and improve the assembly rate.

[0069] The specific method for manufacturing the prefabricated support segment 3 in the factory in step S1 of this embodiment may be:

[0070] S11. Prepare the steel pipe 11, the sealing plate 14, the inner ring plate 10 and the outer ring plate 8 according to the design drawings;

[0071] S12, disposing annular stirrups 12 and a plurality of longitudinal bars 13 in the steel pipe 11;

[0072] S13, welding sealing plates 14 to the end surfaces of both ends of the steel pipe 11, and connecting the two ends of the longitudinal reinforcement 13 to the sealing plates 14 at both ends of the steel pipe 11 through perforation plug welding 15;

[0073] S14, first weld the inner ring plate 10 on the side of the closing plate 14 away from the steel pipe 11, circumferentially weld the outer ring plate 8 on the outer walls at both ends of the steel pipe 11, and weld the stiffening ribs 9 between the inner ring plate 10 and the outer ring plate 8; then pour and fill concrete 16 in the steel pipe 11 and reserve a hollow part to complete the production of the hollow steel pipe 11 concrete support prefabricated part; or first pour and fill concrete 16 in the steel pipe 11 and reserve a hollow part, then weld the inner ring plate 10 on the side of the closing plate 14 away from the steel pipe 11, circumferentially weld the outer ring plate 8 on the outer walls at both ends of the steel pipe 11, and weld the stiffening ribs 9 between the inner ring plate 10 and the outer ring plate 8 to complete the production of the hollow steel pipe 11 concrete support prefabricated part.

[0074] In this embodiment, a centrifugal process can be used to pour and fill concrete 16 in the steel pipe 11, which can automatically form an internal hollow, and the steel pipe 11 can be used as an external template for the centrifugal process without removal. At the same time, compared with the conventional cast-in-place vibration process, the centrifugal process is convenient for achieving high-strength concrete, and the concrete of the hollow steel pipe 11 has higher bearing capacity and deformation resistance and better durability; other processes can also be used to complete it.

[0075] When the prefabricated support segments 3 are spliced ​​in step S2 of the present embodiment, the inner ring plates 10 at the ends of the two prefabricated support segments 3 are first aligned, and then the screw rod 17 is passed through the outer ring plate 8 and the inner ring plate 10 at the end of one of the prefabricated support segments 3, and the inner ring plate 10 and the outer ring plate 8 at the end of the other prefabricated support segment 3 in sequence and fixed by the nut 18 to realize the splicing of the two prefabricated support segments 3; and when assembling the two prefabricated support segments 3 with the disassembly gasket 20 installed in the middle, firstly on both sides of the disassembly gasket 20 Apply a layer of lubricant on the surface, then place the disassembly gasket 20 between the two prefabricated support segments 3, and pass the screw 17 through the outer ring plate 8 and the inner ring plate 10 at the end of one of the prefabricated support segments 3, the disassembly gasket 20, the inner ring plate 10 at the end of the other prefabricated support segment 3, and fix it through the nut 18. When disassembling, first remove the screw 17 and the nut 18, then remove the disassembly gasket 20, eliminate the axial force between the prefabricated components, and then disassemble the prefabricated support segments 3 section by section. In this embodiment, due to the wall protection function of the external steel pipe 11, the support is not easily damaged, and the joint is connected by a high-strength screw 17. The removal of the high-strength screw 17 can realize the recovery of the prefabricated support segment 3, and it can be recycled many times to reduce costs.

[0076] The specific method of embedding the support 7 in step S3 of this embodiment is: first construct a concrete base 23, and embed the steel leg 22 on the concrete base 23, and then weld the concave steel block 21 with a groove on the upper surface to the steel leg 22. Figure 14-15 As shown, the upper surface of the concave steel block 21 has a groove that is sunken downward, and the groove matches the shape of the steel pipe 11 of the prefabricated support segment 3, so as to facilitate the placement of the assembled support and play a temporary supporting role. The support 7 of this embodiment can also adopt other structural forms, which can play a temporary supporting role for the assembled support; the various components of the support 7 are as small as possible to reduce the dead weight while being able to bear the dead weight of the prefabricated support.

[0077] 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 easily disassembled assembled support structure in a foundation pit, characterized in that: It comprises a protective structure and an assembled support; a crown beam is arranged on the top of the protective structure, a waist beam is arranged on the inner side of the protective structure, and the assembled support is supported between the opposite sides of the crown beam and between the opposite sides of the waist beam; the assembled support is formed by splicing a plurality of prefabricated support segments, and a disassembly gasket is arranged between at least two adjacent prefabricated support segments; the thickness of the disassembly gasket is 3-10cm, and the surface of the disassembly gasket is smooth and a layer of lubricant is applied to both sides.

2. The easily disassembled assembled support structure in a foundation pit according to claim 1, characterized in that: The prefabricated support segment includes a steel pipe, an inner ring plate and an outer ring plate; the end faces at both ends of the steel pipe are welded with inner ring plates, and the outer walls at both ends of the steel pipe are circumferentially welded with outer ring plates; the inner ring plate and the outer ring plate at the same end of the steel pipe are connected by stiffening ribs, and the stiffening ribs are welded to the steel pipe; the inner ring plate and the outer ring plate are both provided with a plurality of screw holes at intervals along the circumferential direction, and the screw holes on the outer ring plate correspond one by one to the screw holes on the inner ring plate; the corresponding screw holes on the inner ring plates and the outer ring plates on adjacent prefabricated support segments are respectively installed with screws and fixed by nuts.

3. The easily disassembled assembled support structure in a foundation pit according to claim 2, characterized in that: The disassembly gasket is provided with a plurality of screw holes, and the screw holes on the disassembly gasket correspond one-to-one to the screw holes on the outer ring plate and the screw holes on the inner ring plate; the screw passes through the corresponding screw holes on the disassembly gasket.

4. The easily disassembled assembled support structure in a foundation pit according to claim 2, characterized in that: Filling concrete is poured in the steel pipe, and the filling concrete has a hollow portion penetrating along the axial direction; end faces at both ends of the steel pipe are welded with sealing plates, and the inner ring plate is welded to the side of the sealing plate facing away from the steel pipe.

5. The easily disassembled assembled support structure in a foundation pit according to claim 4, characterized in that: The sealing plate, the inner ring plate and the outer ring plate are all annular, and the inner ring size of the sealing plate and the inner ring size of the inner ring plate are the same as the size of the hollow part filled with concrete, and the inner ring size of the outer ring plate is the same as the outer ring size of the steel pipe.

6. The easily disassembled assembled support structure in a foundation pit according to claim 4, characterized in that: A plurality of circumferential stirrups and a plurality of longitudinal bars are arranged in the filling concrete, the plurality of circumferential stirrups are arranged at intervals along the supporting direction, the plurality of longitudinal bars are arranged at intervals along the inner side of the circumferential stirrups, and each of the longitudinal bars is connected to the plurality of circumferential stirrups, and both ends of the longitudinal bars are connected to the sealing plates at both ends of the steel pipe by perforated plug welding.

7. The easily disassembled assembled support structure in a foundation pit according to claim 2, characterized in that: A plurality of the stiffening ribs are arranged between the inner ring plate and the outer ring plate at intervals along the circumferential direction, and the stiffening ribs and the screw rods are arranged alternately.

8. The easily disassembled assembled support structure in a foundation pit according to claim 7, characterized in that: The stiffening rib is a chamfered rectangular steel plate, and both side corners of the stiffening rib connected to the steel pipe are chamfered.

9. The easily disassembled assembled support structure in a foundation pit according to claim 2, characterized in that: Embedded parts are embedded in the crown beam and the waist beam, and the embedded parts include embedded steel plates and multiple embedded screws; one end of the multiple embedded screws passes through the embedded steel plates in sequence, and the other end extends out of the crown beam or the waist beam and passes through the multiple screw holes on the inner ring plate and the multiple screw holes on the outer ring plate of the assembled support end in sequence, and then is fixed by a nut.

10. A construction method for a prefabricated foundation pit support structure that is easy to disassemble as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1. According to the design drawings, prefabricated support segments and embedded parts are manufactured in the factory and transported to the construction site; S2. Splice the prefabricated support segments one by one by means of screws and nuts, and install disassembly gaskets between at least two adjacent prefabricated support segments to assemble into an assembled support; and connect the embedded parts at both ends of the assembled support by means of screws; S3. Embed the bearing at the supporting position in the foundation pit; S4. The assembled support is hoisted and placed on the support, so that the embedded parts at both ends of the assembled support are placed at the position of the crown beam or waist beam to be cast; S5. Cast the crown beam or waist beam so that the embedded parts are buried therein; S6. After the construction is completed, first unscrew the screws on the two prefabricated support segments with disassembly gaskets installed in the middle, and remove the disassembly gaskets; S7. Unscrew the screws segment by segment and recycle the prefabricated support segments.

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