CN112502160A

CN112502160A - Post-tensioning precast concrete supporting member, inner supporting system and construction method

Info

Publication number: CN112502160A
Application number: CN202011331822.XA
Authority: CN
Inventors: 欧阳冬; 周兵; 余行; 张波; 张建明; 李成亮; 赵晨阳; 江胜学; 邰家醉; 李�浩
Original assignee: China Railway Siyuan Survey and Design Group Co Ltd
Current assignee: China Railway Siyuan Survey and Design Group Co Ltd
Priority date: 2020-11-24
Filing date: 2020-11-24
Publication date: 2021-03-16

Abstract

The invention belongs to the underground foundation pit engineering field, and particularly relates to a post-tensioning precast concrete supporting member and a construction method thereof, wherein the post-tensioning precast concrete supporting member comprises a concrete structure and two end steel structures; the concrete structure comprises concrete with a hollow part penetrating along the supporting direction, a steel bar framework and a plurality of corrugated pipes are arranged in the concrete, and two ends of the steel bar framework are respectively connected with two end steel structures; prestressed longitudinal ribs are stretched in each corrugated pipe and are filled with cement paste, and two ends of each prestressed longitudinal rib extend out of the corrugated pipe and are anchored in the end steel structure through an anchorage device; the invention also provides an inner support system and a construction method, wherein the adopted assembled inner support is formed by splicing the post-tensioning precast concrete supporting members, and two ends of the assembled support are respectively supported on the vertical adjusting and positioning devices at two sides and are connected with the embedded parts at two sides. The invention can improve the bearing capacity, the anti-deformation capacity, the integrity and the node rigidity of the assembled support and can also realize vertical accurate construction.

Description

Post-tensioning precast concrete supporting member, inner supporting system and construction method

Technical Field

The invention belongs to the technical field of underground foundation pit engineering, and particularly relates to a post-tensioning precast concrete supporting member, an inner supporting system and a construction method.

Background

Traditional cast in situ concrete supports, because of its rigidity is big, the wholeness is good, advantages such as safe and reliable, generally apply to underground works, nevertheless also have outstanding problem and shortcoming: (1) cost, high investment: concrete support belongs to temporary engineering, a main body of a station structure is finished, namely outward transportation is broken, the investment of temporary waste engineering is high, generally, underground stations are millions, complex stations are tens of millions, and the cost of complex stations is tens of millions; (2) time-consuming and long construction period: supporting a formwork by concrete, binding reinforcing steel bars, pouring and vibrating, maintaining and removing at the later stage, wherein the whole process is long for several months, and the site construction progress is seriously restricted; (3) hard, the degree of difficulty is big: the concrete support construction difficulty is high, and a large amount of manpower and material resources are consumed to break the construction after the use; (4) the concrete is not environment-friendly, the waste residues of the concrete are broken to pollute the environment, and the development direction of green construction, environment protection and energy conservation is not met. Advanced products and scientific construction methods are urgently needed to replace the traditional concrete support.

Although the traditional steel pipe support can be recycled and is convenient to construct, the traditional steel pipe support and a foundation pit retaining structure can only bear pressure, and the traditional steel pipe support is poor in integrity and deformation resistance and becomes a weak link for foundation pit safety; and usually, the support seat is required to be constructed firstly to temporarily support the assembled support in the support construction process, but the vertical construction precision is difficult to ensure.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a post-tensioning precast concrete support member, an inner support system and a construction method, which can improve the bearing capacity, the deformation resistance, the integrity and the node rigidity of an assembled support and can realize vertical accurate construction.

In order to achieve the purpose, the technical scheme of the invention is that the post-tensioning precast concrete supporting member comprises a concrete structure and two end steel structures arranged at two ends of the concrete structure in the supporting direction; the concrete structure comprises concrete with a hollow part penetrating along a supporting direction, a steel bar framework and a plurality of corrugated pipes are arranged in the concrete, and two ends of the steel bar framework are connected with two end steel structures respectively; the corrugated pipes are internally tensioned with longitudinal prestressed bars and filled with cement paste, and the two ends of the longitudinal prestressed bars extend out of the corrugated pipes and are respectively anchored in steel structures at the two ends through anchorage devices.

Furthermore, the end steel structure comprises an outer flange and an inner flange which are oppositely arranged, and an inner ring pipe and a plurality of stiffening ribs are arranged between the outer flange and the inner flange; two ends of the inner ring pipe are respectively connected with the outer flange and the inner flange, and three side surfaces of each stiffening rib are respectively connected with the outer flange, the inner ring pipe and the inner flange; the steel bar framework is connected with the inner flange; the inner flange is provided with a prestressed reinforcement tensioning hole, and the end part of the prestressed longitudinal reinforcement penetrates through the prestressed reinforcement tensioning hole and is anchored on the inner flange through an anchorage device.

Furthermore, an outer ring pipe is connected to one side of the inner flange, which is far away from the outer flange, and the end part of the concrete structure is positioned in the outer ring pipe; and a circle of meshing teeth are arranged on the inner wall of one end, far away from the inner flange, of the outer ring pipe and embedded into the concrete.

Furthermore, the cross section of the concrete structure is polygonal, corner angle steels are arranged at corners of the outer surface of the concrete structure, and the adjacent corner angle steels are connected through batten plates to form a lattice shape.

The invention also provides an inner support system, which comprises an envelope structure, a crown beam, a waist beam and an assembled inner support; the top of the enclosure structure is provided with a crown beam, the inner side of the enclosure structure is provided with a waist beam, and the assembled inner supports are supported between two opposite sides of the waist beam and between two opposite sides of the crown beam; the assembled inner support is formed by splicing a plurality of post-tensioned precast concrete supporting members; embedded parts are embedded in the crown beam or the waist beam, vertical adjusting and positioning devices for supporting and adjusting the vertical position of the fabricated inner support are fixed on two opposite side walls of the enclosure structure, and two ends of the fabricated inner support are supported on the vertical adjusting and positioning devices on two sides respectively and are connected with the embedded parts on two sides.

In one embodiment, a detaching pad block is arranged between at least two adjacent post-tensioned precast concrete support members on the fabricated inner support.

As another embodiment, one end of each fabricated inner support is connected with a corresponding embedded part through a telescopic structure, and a jack is arranged between one end of each fabricated inner support, which is connected with the telescopic structure, and the corresponding embedded part, and the jack is electrically connected with the control system.

The invention also provides a construction method of the post-tensioning precast concrete supporting member, which comprises the following steps:

s1, manufacturing an end steel structure in a steel structure processing plant;

s2, binding non-prestressed longitudinal reinforcements and spiral stirrups in a prefabricated part processing plant, and spot welding the non-prestressed longitudinal reinforcements and the spiral stirrups to form a reinforcement cage;

s3, conveying the end steel structure to a prefabricated part processing factory, welding the non-prestressed longitudinal ribs with the inner flanges of the end steel structure, fixing corrugated pipes, reserved slurry pipes and grouting pipes at corresponding positions in a steel reinforcement framework, arranging corner angle steel at the corners of the prefabricated part, and welding the angle steel with batten plates to form a lattice shape;

s4, pouring concrete into the component mould, and curing by high-pressure steam after vibrating to reach the design strength;

s5, placing the component mould and the prefabricated component into a prestress tensioning workbench, penetrating a prestress longitudinal rib into the corrugated pipe, tensioning the prestress longitudinal rib, anchoring the end part of the prestress longitudinal rib into an end steel structure by using an anchorage device, and finally pouring cement slurry into the corrugated pipe through a grouting pipe until slurry in a reserved slurry pouring pipe is poured out, so that the prestress longitudinal rib and the prefabricated component are integrated;

and S6, removing the mould to form the post-tensioning precast concrete supporting member.

The invention also provides a construction method of the internal support system, which comprises the following steps:

s1, prefabricating the post-tensioning precast concrete supporting member, the embedded part and the disassembly cushion block in a factory, and transporting to a construction site;

s2, splicing the post-tensioning precast concrete supporting members with different lengths section by section through bolts according to the width of the foundation pit, and meanwhile installing a disassembling cushion block between at least two adjacent post-tensioning precast concrete supporting members to assemble an assembled support with the length matched with the width of the foundation pit;

s3, overexcavating the foundation pit, and then installing a vertical adjusting and positioning device at the specified position on the side wall of the enclosure structure;

s4, placing the assembled supports after hoisting and assembling on a vertical adjusting and positioning device, and adjusting the assembled supports to a designed vertical position; fixing an embedded part at a support design position in a crown beam or a waist beam to be poured;

s5, pouring a crown beam or a waist beam, and embedding the embedded part in the crown beam or the waist beam;

s6, after the crown beam or the waist beam reaches the design strength, fixing the end part of the assembled support with the embedded part to complete the installation of the end part node, and disassembling and recovering the vertical adjusting and positioning device;

s7, after construction, firstly unscrewing bolts on two post-tensioning precast concrete supporting members with disassembly cushion blocks arranged in the middle, and disassembling the disassembly cushion blocks;

and S8, unscrewing the bolts section by section, recovering the post-tensioning precast concrete supporting members, and unscrewing the threaded steel bars at the end nodes for recovery.

The invention also provides another construction method of the inner support system, which comprises the following steps:

s1, prefabricating the post-tensioning precast concrete supporting member, the embedded part, the first expansion joint and the second expansion joint in a factory, and transporting to a construction site;

s2, splicing the post-tensioning precast concrete supporting members with different lengths section by section through bolts according to the width of the foundation pit, and assembling into an assembly type support with the length matched with the width of the foundation pit; connecting a first expansion joint of the telescopic structure with a post-tensioning precast concrete supporting member at one end of the assembled support through a screw rod;

s3, placing the embedded part at a support design position in the crown beam or the waist beam to be poured, and then pouring the crown beam or the waist beam to embed the embedded part therein;

s4, after the crown beam or the waist beam reaches the design strength, fixing the second expansion joint of the telescopic structure and the embedded part in an expansion mode;

s5, overexcavating the foundation pit, and then installing a vertical adjusting and positioning device at the specified position on the side wall of the enclosure structure;

s6, hanging the assembled support, placing the assembled support on a vertical adjusting and positioning device, clamping a U-shaped steel plate of the first expansion joint in a U-shaped steel plate of the second expansion joint, and fixing a post-tensioning precast concrete supporting member at the other end of the assembled support with an embedded part at the other side;

s7, placing a jack in the U-shaped steel plate, and applying pressure to a designed value through a control system to enable two ends of the jack to be tightly propped against the solid steel plate of the first expansion joint and the solid steel plate of the second expansion joint respectively;

s8, inserting adjusting bolts into the long round bolt holes in the side walls of the U-shaped steel plates of the first telescopic joint and the second telescopic joint, screwing the adjusting bolts, completing the installation of end nodes, and disassembling and recovering the vertical adjusting and positioning device;

and S9, after the construction is finished, loosening the jack, unscrewing the adjusting bolt, dismantling the expansion joint and the bolt, and recovering the post-tensioning precast concrete supporting member.

Compared with the prior art, the invention has the following beneficial effects:

(1) the assembled support is formed by splicing the post-tensioning precast concrete support members, the two ends of each post-tensioning precast concrete support member adopt end steel structures to increase the bearing capacity of a joint, a hollow concrete structure is adopted in the middle of each post-tensioning precast concrete support member, a steel bar framework and a plurality of prestressed longitudinal bars are arranged in each post-tensioning precast concrete support member to improve the strength, and the steel bar frameworks and the prestressed longitudinal bars are connected with the end steel structures to promote the end steel structures and the concrete structures to be integrated, so that the assembled support has high bearing capacity (strength) and large deformation resistance (rigidity), and can meet or even exceed the safety requirement of the conventional concrete support; meanwhile, the steel support is light in weight, high in strength, convenient to recycle, convenient to transport and mount and higher in economical efficiency than a pure assembly type steel support; the manufacturing equipment is simple, a tensioning pedestal is not needed, and the production is flexible;

(2) according to the vertical supporting position, the vertical adjusting and positioning device is fixed on the side wall of the building enclosure, so that the vertical position of the supporting member can be accurately positioned according to different overexcavation depths and supporting vertical elevations, the construction error can be adjusted at any time, the vertical accurate construction is realized, and meanwhile, temporary support is provided for the supporting member in the construction process;

(3) rigid connection is adopted between the prefabricated support components and the crown beam or the waist beam, so that the integrity and the safety of the foundation pit are ensured; and the prefabricated supporting members and the embedded parts are connected by bolts or screws, so that the prefabricated supporting members are convenient to mount and dismount, and the prefabricated supporting members can be recycled.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a plan view of one of the internal support systems provided by embodiments of the present invention;

FIG. 2 is a plan view of another internal support system provided by an embodiment of the present invention;

FIG. 3 is a longitudinal sectional view of a post-tensioned precast concrete supporting member according to an embodiment of the present invention;

fig. 4 is a longitudinal sectional view (unstretched tendons) of a post-tensioned precast concrete supporting member according to an embodiment of the present invention;

FIG. 5 is a cross-sectional view of a post-tensioned precast concrete supporting member at an intermediate position according to an embodiment of the present invention;

FIG. 6 is a cross-sectional view of a post-tensioned precast concrete support element termination location provided in accordance with an embodiment of the present invention;

FIG. 7 is a longitudinal sectional view (without a knock-out block) of a connecting joint structure of a post-tensioned precast concrete supporting member according to an embodiment of the present invention;

FIG. 8 is a longitudinal sectional view (with a knock-out block) of a connecting joint structure of a post-tensioned precast concrete supporting member according to an embodiment of the present invention;

FIG. 9 is a cross-sectional view of a connection node structure of a post-tensioned precast concrete support member according to an embodiment of the present invention;

FIG. 10 is a schematic view illustrating a connection of a post-tensioned precast concrete supporting member directly to a crown beam according to an embodiment of the present invention;

fig. 11 is a schematic view of an embedded inner steel plate according to an embodiment of the present invention;

fig. 12 is a schematic view of an embedded outer steel plate according to an embodiment of the present invention;

FIG. 13 is a schematic view illustrating a connection between a post-tensioned precast concrete supporting member and a crown beam through a telescopic structure according to an embodiment of the present invention;

FIG. 14 is a schematic view of a U-hole steel plate according to an embodiment of the present invention;

FIG. 15 is a schematic view of a solid steel plate according to an embodiment of the present invention;

FIG. 16 is a schematic view of a stiffener plate provided in accordance with an embodiment of the present invention;

FIG. 17 is a schematic illustration of an inner flange provided in accordance with an embodiment of the present invention;

FIG. 18 is a schematic view of an outer flange provided by an embodiment of the present invention;

FIG. 19 is a schematic illustration of a stiffener according to an embodiment of the present invention;

FIG. 20 is a schematic view of a post-tensioned precast concrete supporting member according to an embodiment of the present invention positioned on an I-shaped steel;

FIG. 21 is a schematic view of a first fastener and a second fastener provided in accordance with an embodiment of the present invention;

FIG. 22 is a side view of a first fastener and a second fastener provided in accordance with an embodiment of the present invention;

FIG. 23 is a schematic view of a first adjustable length rod according to an embodiment of the present invention;

in the figure: 1. an enclosure structure; 2. a crown beam; 3. prefabricating a concrete supporting member by a post-tensioning method; 4. embedding parts; 5. a tip steel structure; 6. a vertical adjusting and positioning device; 7. an inner ring pipe; 8. an outer flange; 9. a stiffening rib; 10. an inner flange; 11. an outer annular tube; 12. non-prestressed longitudinal bars; 13. pre-stressed longitudinal bars; 14. a spiral stirrup; 15. concrete; 16. a bolt; 17. corner angle steel; 18. bolt holes; 19. pre-burying an outer steel plate; 20. a reinforcing steel bar spiral sleeve; 21. embedding an anchoring steel bar; 22. pre-burying an inner steel plate; 23. a threaded steel bar; 24. reserving a pore channel for the post-tensioning prestressed tendon; 25. a bellows; 26. an anchorage device; 27. engaging the teeth; 28. a batten plate; 29. tensioning holes of the prestressed tendons; 30. positioning the I-shaped steel; 31. a first length adjustable rod; 32. a second length adjustable rod; 33. a third length adjustable rod; 34. a fourth length adjustable rod; 35. an ear plate; 36. an expansion bolt; 37. fixing a steel plate; 38. a first expansion joint; 39. a second expansion joint; 40. a screw; 41. a screw hole; 42. a solid steel plate; 43. a U-hole steel plate; 44. a stiffening plate; 45. a U-shaped steel plate; 46. a long round bolt hole; 47. adjusting the bolt; 48. A jack; 49. a wire; 50. a control system; 51. a water drain hole; 52. an outer ring plate; 53. an inner ring plate; 54. pre-burying a screw; 55. reserving a pulp overflowing pipe; 56. disassembling the cushion block; 57. and (6) pre-burying a steel plate.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

As shown in fig. 3-6, the embodiment provides a post-tensioning precast concrete supporting member 3, which includes a concrete structure and two end steel structures 5 disposed at two ends of the concrete structure in a supporting direction; the concrete structure comprises concrete 15 with a hollow part penetrating along a supporting direction, a steel reinforcement framework and a plurality of corrugated pipes 25 are arranged in the concrete 15, and two ends of the steel reinforcement framework are respectively connected with two end steel structures 5; the corrugated pipes 25 are internally tensioned with longitudinal prestressed ribs 13 and filled with cement paste, and two ends of the longitudinal prestressed ribs 13 extend out of the corrugated pipes 25 and are respectively anchored in the two end steel structures 5 through anchors 26. The middle of the precast concrete supporting member of the embodiment adopts a hollow concrete structure, and the two ends adopt end steel structures 5, so that the advantages of two materials, namely steel and concrete, can be fully exerted; the end steel structure 5 is added at the end head, so that the rigid connection between two prefabricated supporting members is facilitated, and the bearing capacity at the joint is increased; the middle of the hollow concrete structure is a pure hollow reinforced concrete structure, the bearing capacity is sufficient, the manufacturing cost can be effectively reduced, a steel reinforcement framework and a plurality of prestressed longitudinal ribs 13 are arranged in the middle hollow concrete structure, the prestressed longitudinal ribs 13 can enable concrete to be kept in a compressed state after the hollow concrete supporting member is formed, the concrete is high in strength, concrete cracking is prevented during transportation and use, the problem that the hollow concrete is supported by bending can be solved through the steel reinforcement framework, the supporting strength is increased, the steel reinforcement framework and the prestressed longitudinal ribs 13 are connected with the end steel structure 5, the end steel structure 5 and the concrete 15 are enabled to be integrated, the bearing capacity (strength) of the prefabricated supporting member is high, the deformation resistance (rigidity) is large, the safety requirement of even exceeding that conventional concrete is supported can be achieved, and the prefabricated supporting member is not easy to damage; meanwhile, the steel support is light in weight, high in strength, convenient to recycle, convenient to transport and mount and higher in economical efficiency than a pure assembly type steel support; and the manufacturing equipment is simple, a tensioning pedestal is not needed, and the production is flexible.

In this embodiment, the concrete 15 may be made of other materials such as ultra-high strength concrete, the concrete 15 is hollow, the thickness is about 100mm-200mm, and a small value is preferably selected when the support rigidity is satisfied, so as to reduce the dead weight of the member, the hollow portion in the concrete 15 may not be provided with any inner wall, or may be in the form of an inner wall, and the inner wall material may be a steel pipe, PVC, etc.; the end steel structure 5 is made of high-strength steel; anchor 26 may be a JM-type anchor.

Further, the end steel structure 5 comprises an outer flange 8 and an inner flange 10 which are oppositely arranged, and an inner ring pipe 7 and a plurality of stiffening ribs 9 are arranged between the outer flange 8 and the inner flange 10; two ends of the inner ring pipe 7 are respectively connected with the outer flange 8 and the inner flange 10, and three side surfaces of each stiffening rib 9 are respectively connected with the outer flange 8, the inner ring pipe 7 and the inner flange 10; the steel reinforcement framework is connected with the inner flange 10; the inner flange 10 is provided with a prestressed tendon tensioning hole 29, and the end part of the prestressed longitudinal tendon 13 passes through the prestressed tendon tensioning hole 29 and is anchored on the inner flange 10 through an anchorage device 26. As shown in fig. 3 to 4, the inner collar 7, the outer flange 8, the inner flange 10 and the stiffener 9 at the end of the post-tensioning precast concrete supporting member 3 of this embodiment form a shoe beam joint to increase the rigidity of the joint, and three sides of the stiffener 9 are welded to the inner collar 7, the outer flange 8 and the inner flange 10, respectively, to ensure the rigidity of the joint at the joint.

In the embodiment, the inner ring pipe 7 can be a steel pipe with the wall thickness of 10-30mm, the inner diameter of the steel pipe is consistent with that of a concrete hollow part in a concrete structure, two ends of the inner ring pipe 7 are respectively welded with an outer flange 8 and an inner flange 10, and a stiffening rib 9 is welded on the outer wall of the inner ring pipe 7; as shown in fig. 18, the outer flange 8 may be a steel ring with a wall thickness of 10-30mm, the inner and outer diameters of the steel ring are completely the same as the inner and outer diameters of the concrete 15 in the concrete structure, and a plurality of bolt holes 18 are uniformly arranged in the circumferential direction of the outer flange 8; as shown in fig. 17, the size of the inner flange 10 is completely consistent with that of the outer flange 8, the thickness is preferably 10-30mm, the prestressed tendon tensioning holes 29 are circumferentially and uniformly arranged, the prestressed tendon tensioning holes 29 are aligned with the post-tensioned prestressed tendon reserved hole 24 in the corrugated pipe 25, the number of the prestressed tendon tensioning holes 29 is consistent with that of the corrugated pipe 25 and the prestressed longitudinal tendons 13, one side of the inner flange 10 is welded with the inner ring pipe 7 and the stiffening ribs 9, and the other side is welded with the non-prestressed longitudinal tendons 12, the spiral stirrups 14 and the outer ring pipe 11, so as to play a role in connecting the concrete structure and the end steel structure 5; and the shapes of the inner ring pipe 7, the outer flange 8 and the inner flange 10 are matched with the shape of the cross section of the concrete structure, for example, when the cross section of the concrete structure is square ring, the inner ring pipe 7 is square, and the outer flange 8 and the inner flange 10 are both square ring.

Furthermore, the stiffening rib 9 is a rectangular steel plate with chamfered corners, and two corners of the side edge of the stiffening rib 9 connected with the inner ring pipe 7 are both chamfered. As shown in fig. 3, 4 and 19, three sides of the stiffener 9 of the present embodiment are respectively welded to the inner ring pipe 7, the outer flange 8 and the inner flange 10, and two corners of the side edge connecting the stiffener 9 and the inner ring pipe 7 are chamfered to form a chamfer structure, thereby effectively reducing stress concentration during welding; wherein, the thickness of the stiffening rib 9 is preferably 20-30mm, the length is the same as the inner ring pipe 7, and the height is the difference of the inner diameter and the outer diameter of the outer flange 8 to reduce the thickness of the inner ring pipe 7; a plurality of stiffeners 9 may be arranged between the outer flange 8 and the inner flange 10 in the manner shown in fig. 9.

Furthermore, an outer collar 11 is connected to the inner flange 10 on the side away from the outer flange 8, and the end of the concrete structure is located in the outer collar 11; a circle of meshing teeth 27 are arranged on the inner wall of one end, far away from the inner flange 10, of the outer ring pipe 11, and the meshing teeth 27 are embedded in the concrete 15. The outer sleeve 11 of the concrete structure end of this embodiment, not only can protect the concrete of the end, make the support difficult to receive the damage, but also has established the common atress tie of end steel construction 5 and middle concrete structure through outer ring 11. Wherein, the shape of the outer ring pipe 11 is matched with the shape of the cross section of the concrete structure, and can be a steel pipe with the wall thickness of 8-20mm, and the material can be high-strength steel, alloy steel and other materials; the length of the outer ring pipe 11 is about 300-500mm, and one end of the outer ring pipe is welded with the inner flange 10 and is stressed together with the inner flange; and the end of the outer ring pipe 11 far away from the inner flange 10 is provided with meshing teeth 27 to form a common stressed whole with the concrete 15, wherein the meshing teeth 27 are steel blocks protruding towards the interior of the concrete 15 and are uniformly welded on the inner wall of the outer ring pipe 11, and the number of the meshing teeth is preferably 10-20.

Further, the cross section of the concrete structure is polygonal, corner angle steels 17 are arranged at corners of the outer surface of the concrete structure, and the adjacent corner angle steels 17 are connected through a batten plate 28 to form a lattice shape. In this embodiment, the cross section of concrete structure is concrete tubular structure, can be square ring shape, also can be regular hexagon ring shape etc. through all setting up bight angle steel 17 protection bight concrete in each bight department at concrete structure surface, reduce stress concentration, prevent that bight from damaging, and adjacent bight angle steel 17 connects through a plurality of lacing plates 28 along support direction interval arrangement and forms the lattice form to protect inside concrete structure, the both ends of bight angle steel 17 can be connected with the outer ring tube 11 at concrete structure both ends.

Further, the steel bar framework comprises a spiral stirrup 14 and a plurality of non-prestressed longitudinal bars 12, wherein the non-prestressed longitudinal bars 12 are arranged at intervals along the outer side of the spiral stirrup 14 and are connected with the spiral stirrup 14; a plurality of longitudinal prestressed tendons 13 are arranged at intervals along the inner side of the spiral stirrup 14. As shown in fig. 3 to 6, a plurality of non-prestressed longitudinal bars 12 are disposed in the concrete 15 of this embodiment along the supporting direction, and the plurality of non-prestressed longitudinal bars 12 are disposed at intervals outside the spiral stirrup 14 and welded to the spiral stirrup 14, so as to improve the strength of the concrete structure; and the two ends of the non-prestressed longitudinal ribs 12 are respectively welded with the inner sides of the inner flanges 10 of the two end steel structures 5, the two ends of the spiral stirrup 14 can be respectively welded with the inner sides of the inner flanges 10 of the two end steel structures 5, so that the concrete structure and the end steel structures 5 are tightly connected into a whole, the integrity of the prefabricated component is improved, the non-prestressed longitudinal ribs 12 can solve the bending problem of the fabricated support, the ductility of the concrete prefabricated support is improved, and in the concrete pouring process, the spiral stirrup 14 can play a role of a hoop on the concrete 15, and the support strength is improved.

Example two

As shown in fig. 1 and 2, the present embodiment provides an internal support system, which includes a building envelope 1, a crown beam 2, a wale and a fabricated internal support; the top of the enclosure structure 1 is provided with a crown beam 2, the inner side of the enclosure structure 1 is provided with a waist beam, and the assembled inner supports are supported between two opposite sides of the waist beam and between two opposite sides of the crown beam 2; the assembled inner support is formed by splicing a plurality of post-tensioning precast concrete supporting members 3 provided by the first embodiment; embedded parts 4 are embedded in the crown beam 2 or the waist beam, vertical adjusting and positioning devices 6 for supporting and adjusting the vertical position of the fabricated inner support are fixed on two opposite side walls of the envelope structure 1, and two ends of the fabricated inner support are respectively supported on the vertical adjusting and positioning devices 6 on two sides and connected with the embedded parts 4 on two sides. According to the embodiment, the vertical adjusting and positioning device 6 is fixed on the side wall of the building enclosure 1 according to the supporting vertical position, the vertical position of the supporting member can be accurately positioned according to different over-excavation depths and supporting vertical elevations, the construction error can be adjusted at any time, vertical accurate construction is realized, and meanwhile, temporary support is provided for the supporting member. The drawings of the present embodiment are explained taking the crown beam 2 as an example, and the case of the wale refers to the crown beam 2.

The hollow parts of the post-tensioning precast concrete supporting members 3 of the fabricated inner support of the embodiment are communicated, so that the fabricated support has higher bearing capacity and stronger deformation resistance; the post-tensioning precast concrete supporting member 3 can be designed with a plurality of fixed modulus sections with proper lengths according to requirements, and is not suitable for overlong, hoisting construction due to overlong length, and difficult connection due to too many joints due to too short length; as an implementation mode, the post-tensioning precast concrete supporting members 3 can be designed with standard modulus of 4m, 5m, 6m and the like and end section modulus of 2m, and the post-tensioning precast concrete supporting members 3 with completely the same, different or completely different length specifications are selected for assembly according to the actual foundation pit requirements, so that the requirement of supporting foundation pits with different widths and lengths is met, and the universal applicability is achieved.

Further, the vertical adjusting and positioning device 6 comprises a positioning i-shaped steel 30 for positioning the post-tensioning precast concrete supporting member 3 and an adjusting mechanism for adjusting the vertical position of the post-tensioning precast concrete supporting member 3; one end of the adjusting mechanism is fixed on the side wall of the envelope structure 1, and the other end of the adjusting mechanism is connected with the positioning I-shaped steel 30; the positioning of the post-tensioning precast concrete supporting member 3 is supported on the upper flange plate of the positioning i-shaped steel 30, as shown in fig. 20.

Further, the adjusting mechanism includes a first length-adjustable rod 31, a second length-adjustable rod 32, a third length-adjustable rod 33, and a fourth length-adjustable rod 34; as shown in fig. 13, the first length-adjustable rod 31 is horizontally arranged, and the positioning i-section steel 30 is fixed to the first length-adjustable rod 31; the first length adjustable rod 31, the second length adjustable rod 32 and the third length adjustable rod 33 are connected end to form a triangular shape; the connection part of the second length adjustable rod 32 and the third length adjustable rod 33 is connected with the first fixing part on the side wall of the building envelope 1; one end of the fourth length adjustable rod 34 is connected to the connection point of the first length adjustable rod 31 and the third length adjustable rod 33, and the other end is connected to the second fixing member on the sidewall of the enclosure 1. As shown in fig. 10 and 13, in the present embodiment, by adjusting the lengths of the second length adjustable rod 32, the third length adjustable rod 33 and the fourth length adjustable rod 34, it is ensured that the first length adjustable rod 31 is kept horizontal and reaches a specified vertical elevation, and accurate positioning of the vertical position is achieved; the sizes of the first length-adjustable rod 31, the second length-adjustable rod 32, the third length-adjustable rod 33 and the fourth length-adjustable rod 34, as well as the space between the positioning devices 7 and the size of the positioning i-section steel 30 are determined according to the stress calculation.

The first fixing piece is positioned below the second fixing piece, and the first fixing piece and the second fixing piece have the same structure and respectively comprise an expansion bolt 36, a fixing steel plate 37 and an ear plate 35; as shown in fig. 21-22, the fixing steel plate 37 is fixed on the side wall of the building envelope 1 by expansion bolts 36, and the ear plate 35 is fixed on the fixing steel plate 37; the second length adjustable rod 32 and the third length adjustable rod 33 are both hinged to the ear plate 35 of the first fixing member, and the fourth length adjustable rod 34 is hinged to the ear plate 35 of the second fixing member.

Furthermore, a plurality of bolt holes 18 are circumferentially arranged on the outer flange 8 of the end steel structure 5 of the post-tensioning precast concrete supporting member 3, and the corresponding bolt holes 18 on the adjacent outer flanges 8 of the adjacent post-tensioning precast concrete supporting members 3 are respectively connected through bolts 16. As shown in fig. 7 and 8, the end of the post-tensioned precast concrete supporting member 3 of the embodiment adopts a shoe beam joint, and is connected by a plurality of bolts 16, so that the rigid connection of the middle joint is ensured, the equal strength of the joint and the member is realized, the integrity, the rigidity and the bearing capacity which are the same as or similar to those of the cast-in-place concrete support are ensured, the safety of the foundation pit is ensured, the installation and the disassembly are convenient, and the factory production and the large-area popularization and application are facilitated.

As an embodiment, a detaching pad block 56 is arranged between at least two adjacent post-tensioning precast concrete support members 3 on the fabricated inner support; and two ends of the assembled inner support are directly connected with the corresponding embedded parts 4. As shown in fig. 1, at least one disassembly cushion block 56 is arranged in the fabricated inner support of the embodiment, and the disassembly cushion block 56 is placed between two post-tensioning precast concrete supporting members 3, so that the disassembly cushion block 56 can be disassembled firstly during disassembly, the axial force between the post-tensioning precast concrete supporting members 3 is eliminated, other precast members can be disassembled easily, the problem of difficulty in disassembling the fabricated support with the length of several meters is solved effectively, and the disassembly efficiency of the fabricated support is improved.

A plurality of bolt holes are formed in the disassembling cushion block 56 in the circumferential direction, and the bolt holes in the disassembling cushion block 56 correspond to the bolt holes 18 in the outer flange 8 one by one; for the post-tensioning precast concrete supporting members 3 with the disassembling cushion blocks 56 arranged between them, the bolts 16 sequentially pass through the corresponding bolt holes 18 on the outer flange 8 of one of the post-tensioning precast concrete supporting members 3, the corresponding bolt holes on the disassembling cushion blocks 56 and the corresponding bolt holes 18 on the outer flange 8 of the other post-tensioning precast concrete supporting member 3, so as to realize the splicing of the adjacent post-tensioning precast concrete supporting members 3; the disassembling cushion block 56 can be a steel ring with the thickness of 30-100mm, the size of the disassembling cushion block is completely the same as that of the outer flange 8, or a plurality of sections of spliced steel rings, such as two semicircular steel rings or a plurality of fan-shaped steel rings, are not connected; the surface of the disassembly cushion block 56 needs to be smooth, and a layer of lubricant can be coated on the two side surfaces of the disassembly cushion block 56 before construction, so that the disassembly difficulty is reduced.

As another embodiment, one end of each fabricated inner support is connected to the corresponding embedded part 4 through a telescopic structure, the other end of each fabricated inner support is directly connected to the corresponding embedded part 4, a jack 48 is arranged between one end of each fabricated inner support, which is connected to the telescopic structure, and the corresponding embedded part 4, and the jack 48 is electrically connected to the control system 50. As shown in fig. 2, the length of the end joint can be adjusted by the telescopic structure in the embodiment, so that the construction error can be adjusted; meanwhile, a jack 48 is arranged, the jack 48 is an intelligent jack, the jack has enough jacking force, can sense self stress and transmit the self stress to a control system 50 through a lead 49, the control system 50 makes corresponding response according to the stress to adjust the jacking force and the elongation of the jack, an intelligent stress compensation device is formed, prestress can be constructed according to needs, the requirements of prestress loss and support relaxation for repeated loading are met, stress compensation is timely carried out when the stress relaxation phenomenon occurs in the use process of the assembled support, early warning is timely carried out when the stress is too large, and the local instability of the foundation pit is prevented, so that the whole foundation pit is damaged; the jack 48 should not be oversized to avoid affecting the connections of the telescoping structures.

As shown in fig. 13, the telescopic structure includes a first telescopic joint 38 and a second telescopic joint 39, the first telescopic joint 38 and the second telescopic joint 39 are respectively connected with the post-tensioning precast concrete supporting member 3 and the embedded part 4, have the same structure, and each of the first telescopic joint 38 and the second telescopic joint 39 includes a solid steel plate 42, a U-hole steel plate 43, a U-shaped steel plate 45 and a stiffening plate 44; one end of the U-shaped steel plate 45 penetrates through a U-shaped hole in the U-shaped hole steel plate 43 and is welded with the solid steel plate 42, and two side walls of the other end of the U-shaped steel plate are provided with a plurality of rows of long round bolt holes 46; the solid steel plate 42 is connected with the U-hole steel plate 43 through a stiffening plate 44, and the side wall of the U-shaped steel plate 45 is welded with the U-hole steel plate 43; the U-shaped steel plate 45 of the first telescopic joint 38 is clamped in the U-shaped steel plate 45 of the second telescopic joint 39, and an oblong bolt hole 46 in the first telescopic joint 38 is connected with an oblong bolt hole 46 in the second telescopic joint 39 through an adjusting bolt 47; the front and rear ends of the jack 48 abut against the solid steel plate 42 of the first telescopic joint 38 and the solid steel plate 42 of the second telescopic joint 39, respectively. The U-shaped steel plate 45 of this embodiment is provided with multiple rows of long round bolt holes 46, and the long round bolt holes 46 are arranged along the supporting direction, the long round bolt holes 46 on the first expansion joint 38 are connected with the long round bolt holes 46 on the second expansion joint 39 through adjusting bolts 47, the end part of the supporting component and the crown beam 2 or waist beam node adopt the variable-length long round bolt hole 46 steel box slot node, the rigid connection and equal-strength connection requirements of the edge node can be met, the engineering safety and the end part node detachability are ensured, the prefabricated component recycling is facilitated, meanwhile, the relative position of the long round bolt holes 46 can be adjusted according to the requirements to change the length of the joint, and therefore the construction error is adjusted. Optimally, drain holes 51 are reserved on the bottom plate of the U-shaped steel plate 45 to prevent rainwater in the U-shaped space where the jack 48 is located from accumulating and damaging the jack 48; meanwhile, the size of the drain hole 51 is not too large, so that the steel plate at the joint is prevented from being weakened.

The size of the U-shaped steel plate 45 of the first expansion joint 38 is smaller than that of the U-shaped steel plate 45 of the second expansion joint 39, so that the U-shaped steel plate 45 of the first expansion joint 38 can be just clamped in the U-shaped steel plate 45 of the second expansion joint 39 to form a U-shaped groove, but the oblong bolt hole 46 in the U-shaped steel plate 45 of the first expansion joint 38 and the oblong bolt hole 46 in the U-shaped steel plate 45 of the second expansion joint 39 are required to be at the same height and have the same distance; in addition, as shown in fig. 14 to 15, the solid steel plate 42 and the U-hole steel plate 43 may be square, or may have other shapes, and the U-shaped hole on the U-hole steel plate 43 matches with the ruler of the U-shaped steel plate 45, the U-shaped steel plate 45 penetrates through the U-shaped hole on the U-hole steel plate 43 and is welded to the U-hole steel plate 43, and meanwhile, a plurality of stiffening plates 44 arranged at intervals along the outer wall of the U-shaped steel plate 45 are used to connect the solid steel plate 42 and the U-hole steel plate 43, and the inner sides of the stiffening plates 44 are welded to the U-shaped steel plate 45, so as to improve the rigidity at the connection node, ensure that the side nodes and the support members have the same or similar integrity, rigidity and bearing capacity as those of the cast-in-place. As shown in fig. 16, the stiffener plate 44 of the present embodiment has the same structure as the stiffener 9.

In the above two embodiments, the structures of the embedded parts 4 in the crown beam or the wale at the two ends of the fabricated support may be the same, and both adopt the structures shown in fig. 10 or fig. 13, or may be different, wherein one end adopts the structure shown in fig. 10, and the other end adopts the structure shown in fig. 13, as shown in fig. 1 and fig. 2.

The structure of the embedded part 4 shown in fig. 10 includes an embedded outer steel plate 19, a steel bar spiral sleeve 20, an embedded anchor steel bar 21, an embedded inner steel plate 22 and a threaded steel bar 23, the embedded outer steel plate 19 is fixed on the inner wall of the crown beam 2 or the waist beam, the embedded inner steel plate 22 is embedded in the crown beam 2 or the waist beam, a plurality of embedded anchor steel bars 21 are fixed on the embedded inner steel plate 22, the steel bar spiral sleeve 20 is fixed at one end of each embedded anchor steel bar 21, and the threaded steel bars 23 sequentially pass through corresponding bolt holes 18 on the outer flange 8 and the embedded outer steel plate 19 and are fixed with the steel bar spiral sleeve 20; the pre-buried outer steel plate 19 is matched with the prefabricated support section in form and can be a rectangular steel plate, the thickness is preferably 10-20mm, and the size is slightly larger than the outer diameter of the prefabricated support section; a plurality of bolt holes 18 are uniformly distributed in the embedded outer steel plate 19 along the circumferential direction, the number and the arrangement positions of the bolt holes 18 are the same as those of the outer flange 8, and as shown in fig. 12, the embedded outer steel plate can be used as a template for pouring the crown beam 2 or the waist beam; the shape and the size of the embedded inner steel plate 22 can be completely consistent with those of the outer flange 8, as shown in fig. 11, and the thickness is selected according to the requirement; the embedded inner steel plate 22 is deeply embedded in the crown beam 2 or the waist beam, mainly plays a role in anchoring the embedded anchoring steel bar 21, cannot be recycled, and can be made of a material lower than that of a steel member of the end steel structure 5 to save cost; the steel bar spiral sleeve 20 is a steel sleeve with threads inside, and the inside diameter of the steel bar spiral sleeve is consistent with the outside diameter of the embedded anchoring steel bar 21; one end of the steel bar spiral sleeve 20 is connected with the embedded anchoring steel bar 21, and the embedded inner steel plate 22, the embedded anchoring steel bar 21 connected with the steel bar spiral sleeve 20, the pre-embedded outer steel plate 19 and the crown beam are integrally constructed; when the end part node is constructed, a plurality of steel bars with threads 23 sequentially penetrate through the corresponding bolt holes 18 on the outer flange 8, the corresponding bolt holes 18 on the pre-embedded outer steel plate 19 and the corresponding steel bar spiral sleeves 20 to be screwed, so that the prefabricated part is connected with the crown beam 2 or the waist beam; when the steel bar screw sleeve is disassembled, the steel bar screw sleeve 20 is screwed on the short threaded steel bar 23, so that the disassembly can be realized, the required construction space is small, and the construction is convenient.

The embedded part 4 structure shown in fig. 13 includes two embedded steel plates 57 and a plurality of embedded screws 54 which are oppositely arranged; one of the embedded steel plates 57 is fixed on the inner wall of the crown beam 2 or the waist beam and can be used as a template for pouring the crown beam 2 or the waist beam, and the other embedded steel plate 57 is embedded in the crown beam 2 or the waist beam and plays a role in anchoring; a plurality of screw holes are formed in the two embedded steel plates 57, one end of each of the plurality of pre-embedded screws 54 sequentially penetrates through the corresponding screw holes in the two embedded steel plates 57 and is welded with the two embedded steel plates 57, and the other end of each of the plurality of pre-embedded screws extends out of the crown beam 2 or the waist beam; the end of the post-tensioning precast concrete supporting component 3 can adopt the structure shown in fig. 13, the inner flange 10 is directly welded with an outer ring plate 52, an inner ring plate 53 is welded outside the outer ring pipe 11, the outer ring plate 52 and the inner ring plate 53 are welded through a plurality of stiffening plates 44, the shapes of the outer ring plate 52 and the inner ring plate 53 are matched with the precast concrete, and a plurality of screw holes are arranged on the outer ring plate 52 and the inner ring plate 53; when the embedded part 4 is directly connected with the post-tensioning precast concrete supporting component 3, one end of each embedded screw 54 extending out of the crown beam 2 or the wale sequentially penetrates through the corresponding screw holes on the outer ring plate 52 and the inner ring plate 53 and then is fixed through the nuts, so that the connection between the crown beam 2 or the wale and the end part fixing node of the assembly type support is realized; when the embedded part 4 is connected with the post-tensioning precast concrete supporting component 3 through a telescopic structure, a plurality of screw holes are respectively arranged on the solid steel plate 42 and the U-hole steel plate 43 of the first telescopic joint 38 and the second telescopic joint 39, one end of a plurality of embedded screws 54 sequentially penetrates through corresponding screw holes on the two embedded steel plates 57 and is welded with the two embedded steel plates 57, the other end extends out of the crown beam 2 or the waist beam and respectively sequentially penetrates through corresponding screw holes on the solid steel plate 42 and the U-hole steel plate 43 of the second telescopic joint 39 and then is fixed through screw caps, and a plurality of screws 40 sequentially penetrate through corresponding screw holes on an inner ring plate 53 and an outer ring plate 52 of the prefabricated part and corresponding screw holes on a solid steel plate 42 and a U-hole steel plate 43 of the first expansion joint 38 and then are fixed through nuts, so that the connection between the crown beam 2 or the waist beam and the telescopic node at the end part of the assembled support is realized.

In this embodiment, all the steel structures such as the inner ring pipe 7, the outer flange 8, the outer ring pipe 11, the inner flange 10, the stiffening ribs 9, the outer ring plate 52, the inner ring plate 53, the solid steel plate 42, the U-hole steel plate 43, the U-shaped steel plate 45 and other parts directly contacting with the outside need to be coated with antirust materials in advance, so as to prevent the surface of the steel structures from rusting and damaging, which leads to the reduction of strength; the bolts 16 are high-strength bolts.

EXAMPLE III

The present embodiment provides a construction method of a post-tensioning precast concrete supporting member 3 according to the first embodiment, including the steps of:

s1, manufacturing an end steel structure 5 in a steel structure processing plant;

s2, binding the non-prestressed longitudinal reinforcements 12 and the spiral stirrups 14 in the prefabricated part processing plant, and spot-welding the non-prestressed longitudinal reinforcements 12 and the spiral stirrups 14 to form a steel reinforcement framework;

s3, conveying the end steel structure 5 to a prefabricated part processing factory, welding the non-prestressed longitudinal ribs 12 with the inner flange 10 of the end steel structure 5, fixing the corrugated pipe 25, the reserved slurry pipes 55 and the grouting pipes at corresponding positions in the steel reinforcement framework, arranging corner angle steel 17 at the corners of the prefabricated part, and welding the corner angle steel 17 with the batten plate 28 to form a lattice shape;

s4, pouring high-strength concrete 15 into the component mould, and curing by high-pressure steam after vibrating to reach the design strength;

s5, placing the component mould and the prefabricated component into a prestress tensioning workbench, penetrating a prestress longitudinal rib 13 into a corrugated pipe 25, tensioning the prestress longitudinal rib 13, anchoring the end part of the prestress longitudinal rib 13 into an end steel structure 5 by using an anchorage device 26, and finally pouring cement slurry into the corrugated pipe 25 through a grouting pipe until slurry overflows from a reserved slurry overflow pipe 55, so that the prestress longitudinal rib 13 and the prefabricated component are integrated;

and S6, removing the mould to form the post-tensioning precast concrete supporting member 3.

In the production process, the end steel structure 5 is prefabricated by a steel structure processing factory, and the concrete pouring is completed in a prefabricated part processing factory, so that the steel structure processing and the concrete pouring are separated, the advantages of the steel structure processing factory and the prefabricated part processing factory can be fully exerted, the field welding operation in a prefabricated concrete factory is avoided, and the product quality is ensured.

Example four

As shown in fig. 1, this embodiment provides a construction method of an internal support system with a detachable spacer 56 according to the second embodiment, including the following steps:

s1, prefabricating the post-tensioning precast concrete supporting members 3, the embedded parts 4 and the disassembly cushion blocks 56 in a factory, and transporting to a construction site; the post-tensioning precast concrete supporting member 3 can be manufactured by the construction method provided by the third embodiment;

s2, splicing the post-tensioning precast concrete supporting members 3 with different lengths section by section through bolts 16 according to the width of the foundation pit, and meanwhile installing a disassembling cushion block 56 between at least two adjacent post-tensioning precast concrete supporting members 3 to assemble an assembled support with the length matched with the width of the foundation pit;

when the two post-tensioning precast concrete supporting members 3 are spliced, the outer flanges 8 at the end parts of the two precast members are aligned, and then bolts 16 sequentially penetrate through the outer flanges 8 at the end parts of the two precast members to realize the splicing of the two precast members; when two prefabricated parts with the disassembly cushion blocks 56 mounted in the middle are assembled, firstly, a layer of lubricant is coated on two side surfaces of the disassembly cushion blocks 56, then the disassembly cushion blocks 56 are placed between the two prefabricated parts, and bolts 16 sequentially penetrate through the bolt holes 18 on the outer flange 8 at the end part of one prefabricated part, the bolt holes on the disassembly cushion blocks 56 and the bolt holes 18 on the outer flange 8 at the end part of the other prefabricated part;

s3, performing foundation pit overexcavation, then driving expansion bolts 36 into the side wall of the enclosure structure 1 at specified positions of every 2-4m, installing a fixed steel plate 37, welding an ear plate 35, and installing and fixing a vertical adjusting and positioning device 6; constructing a steel connecting beam for a foundation pit provided with the middle temporary upright post;

s4, placing the assembled supports after hoisting and assembling on a vertical adjusting and positioning device 6, and adjusting the assembled supports to a designed vertical position through the vertical adjusting and positioning device 6, wherein the center line of the prefabricated support needs to be ensured to be horizontal and the center of the prefabricated support needs to be positioned in the center of the crown beam 2 or the waist beam; for the construction of the steel connecting beam, the assembled supports are placed on the vertical adjusting and positioning device 6 and the steel connecting beam; fixing the embedded part 4 at a support design position in the crown beam 2 or the waist beam to be poured;

when the embedded parts 4 at two ends of the assembled support adopt the structure shown in FIG. 10, fixing an embedded outer steel plate 19, an embedded inner steel plate 22 and embedded anchoring steel bars 21 connected with a steel bar spiral sleeve 20 of the embedded parts 4 at the support design position in the crown beam 2 or the waist beam to be cast; when the embedded parts 4 at two ends of the assembled support adopt the structure shown in fig. 13, fixing two embedded steel plates 57 and a plurality of embedded screws 54 of the embedded parts 4 at the support design positions in the crown beam 2 or the waist beam to be cast; when the embedment 4 of one end of the fabricated support adopts the structure shown in fig. 10 and the embedment 4 of the other end adopts the structure shown in fig. 13, reference is made to the above-mentioned procedures, respectively, and details thereof are not described;

s5, pouring the crown beam 2 or the waist beam, and taking the embedded outer steel plate 19 or the embedded steel plate 57 of the embedded part 4 as a template of the crown beam 2 or the waist beam; embedding the embedded inner steel plates 22 and the embedded anchoring steel bars 21 connected with the steel bar spiral sleeves 20 in the embedded inner steel plates, reserving a pore passage for installing the threaded steel bars 23 on the crown beam 2 or the waist beam, and/or embedding the two embedded steel plates 57 and the embedded screw rods 54 in the pore passage;

s6, after the crown beam 2 or the waist beam reaches the designed strength, the threaded steel bar 23 penetrates through the bolt hole 18 on the outer flange 8 of the end steel structure of the assembled supporting end and the bolt hole 18 of the pre-embedded outer steel plate 19 to be screwed with the steel bar spiral sleeve 20, and/or the pre-embedded screw 54 penetrates through the screw hole on the end steel structure of the assembled supporting end and then is fixed through a nut, so that the installation of the end node is completed, and the vertical adjusting and positioning device 6 is disassembled and recovered;

s7, after the construction is finished, firstly, unscrewing the bolts 16 on the two post-tensioning precast concrete supporting members 3 with the disassembly cushion blocks 56 arranged in the middle, and disassembling the disassembly cushion blocks 56;

and S8, unscrewing the bolts 16 section by section, recovering the post-tensioning precast concrete supporting members 3, and unscrewing the threaded steel bars 23 at the end nodes for recovery.

The cushion 56 is dismantled in this embodiment through the installation between at least wherein two adjacent post-tensioning precast concrete supporting members 3, and the effect lies in dismantling the assembled support for first breakthrough point, dismantles that the cushion 56 size is less and paint emollient, and it is much less to dismantle the degree of difficulty, and in case dismantle cushion 56 is dismantled, the axial force of whole assembled support just disappears, can easily dismantle precast concrete supporting member one by one, reduces the degree of difficulty that precast concrete supporting member dismantled, improves the dismantlement efficiency that the assembled supported.

EXAMPLE five

The present embodiment provides a construction method of an internal support system with a scalable structure according to the second embodiment, including the following steps:

s1, prefabricating the post-tensioning precast concrete supporting member 3, the embedded part 4, the first expansion joint 38 and the second expansion joint 39 in a factory, and transporting to a construction site; the post-tensioning precast concrete supporting member 3 can be manufactured by the construction method provided by the third embodiment;

s2, splicing the post-tensioning precast concrete supporting members 3 with different lengths section by section through bolts 16 according to the width of the foundation pit, and assembling into an assembly type support with the length matched with the width of the foundation pit; and a first expansion joint 38 of a telescopic structure is connected with a post-tensioning precast concrete supporting member 3 at one end of the assembled support through a screw 40;

s3, placing the embedded part 4 at a support design position in the crown beam 2 or the waist beam to be cast, and then casting the crown beam 2 or the waist beam to embed the embedded part 4 therein;

when the crown beam 2 or the wale is poured, the embedded outer steel plate 19 or the embedded steel plate 57 of the embedded part 4 is used as a template of the crown beam 2 or the wale; embedding the embedded inner steel plates 22 and the embedded anchoring steel bars 21 connected with the steel bar spiral sleeves 20 in the embedded inner steel plates, and simultaneously reserving a pore passage for installing the threaded steel bars 23 on the crown beam 2 or the waist beam, and/or embedding two embedded steel plates 57 and embedded screws 54 in the pore passage;

s4, after the crown beam 2 or the waist beam reaches the designed strength, fixing a second expansion joint 39 of a telescopic structure on an embedded screw 54 extending out of the embedded part 4 on one side through a nut, or screwing a threaded steel bar 23 with threads through bolt holes 18 of the second expansion joint 39 and the embedded outer steel plate 19 and a steel bar spiral sleeve 20;

s5, performing foundation pit overexcavation, then driving expansion bolts 36 into the side wall of the enclosure structure 1 at specified positions of every 2-4m, installing a fixed steel plate 37, welding an ear plate 35, and installing and fixing a vertical adjusting and positioning device 6;

s6, hoisting the assembled support, placing the assembled support on a vertical adjusting and positioning device 6, adjusting the assembled support to a designed vertical position through the vertical adjusting and positioning device 6, clamping the U-shaped steel plate 45 of the first expansion joint 38 in the U-shaped steel plate 45 of the second expansion joint 39, and screwing the post-tensioned precast concrete supporting member 3 at the other end of the assembled support with the steel bar spiral sleeve 20 in the embedded part 4 at the other side through the threaded steel bar 23 or fixing the post-tensioned precast concrete supporting member with the embedded screw rod 54 in the embedded part 4 at the other side through a nut;

s7, placing a jack 48 in the U-shaped steel plate 45, and applying pressure to a designed value through a control system to enable two ends of the jack 48 to be tightly propped against the solid steel plate 42 of the first expansion joint 38 and the solid steel plate 42 of the second expansion joint 39 respectively;

s8, inserting adjusting bolts 47 into the long round bolt holes 46 in the side walls of the U-shaped steel plates 45 of the first expansion joint 38 and the U-shaped steel plates 45 of the second expansion joint 39, screwing the adjusting bolts to complete the installation of end nodes, and detaching and recovering the vertical adjusting and positioning device 6;

s9, after the construction is finished, the jack 48 is loosened, the adjusting bolt 47 and the nut are unscrewed, the expansion joint and the bolt 16 are removed, and the post-tensioning precast concrete supporting component 3 is recovered.

The first expansion joint 38 and the second expansion joint 39 of this embodiment are connected through adjusting bolt 47, the first expansion joint 38 is connected through screw 40 with the prefabricated bracing member that one end was supported to the assembled, the second expansion joint 39 is connected through embedded screw 54 with embedded part 4, the prefabricated bracing member that the assembled supported the other end is connected through threaded steel 23 with embedded part 4, realize dismantling easily, therefore, after foundation ditch engineering construction finishes, loosen jack 48, can relax pressure after dismantling the adjusting bolt 47 of connecting first expansion joint 38 with second expansion joint 39 earlier, then will demolish screw 40 and bolt 16, twist out threaded steel 23, can dismantle prefabricated bracing member one by one, and retrieve prefabricated bracing member, realize many times cyclic utilization, reduce cost.

In the step S2 of this embodiment, when the prefabricated support members are spliced section by section, the outer flanges 8 at the ends of the two prefabricated support members are aligned, and then the bolts 16 sequentially penetrate through the outer flanges 8 at the ends of the two prefabricated support members to splice the two prefabricated support members; when the first expansion joint 38 is spliced with the prefabricated support member at the end, the screw hole on the outer ring plate 52 at the end of the prefabricated support member is aligned with the screw hole 41 on the solid steel plate 42 of the first expansion joint 38, and then the screw 40 sequentially passes through the screw holes on the inner ring plate 53 and the outer ring plate 52 at the end of the prefabricated support member, the solid steel plate 42 of the first expansion joint 38 and the U-hole steel plate 43 and is fixed through a nut.

The fabricated supports in the fourth embodiment and the fifth embodiment of the invention can be rigidly connected with the crown beam 2 or the wale, and can replace a plurality of traditional concrete supports in an ultra-deep foundation pit, so that the assembly rate is improved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, but rather as the subject matter of the invention is to be construed in all aspects and equivalents thereof.

Claims

1. The utility model provides a post-tensioned precast concrete supporting member which characterized in that: the device comprises a concrete structure and two end steel structures arranged at two ends of the concrete structure in the supporting direction; the concrete structure comprises concrete with a hollow part penetrating along a supporting direction, a steel reinforcement framework and a plurality of corrugated pipes are arranged in the concrete, and two ends of the steel reinforcement framework are connected with two end steel structures respectively; each corrugated pipe is internally tensioned with longitudinal prestressed bars and filled with cement paste, and the two ends of the longitudinal prestressed bars extend out of the corrugated pipe and are respectively anchored in steel structures at the two ends through anchors.

2. The post-tensioned precast concrete supporting member as recited in claim 1, wherein: the end steel structure comprises an outer flange and an inner flange which are oppositely arranged, and an inner ring pipe and a plurality of stiffening ribs are arranged between the outer flange and the inner flange; two ends of the inner ring pipe are respectively connected with the outer flange and the inner flange, and three side surfaces of each stiffening rib are respectively connected with the outer flange, the inner ring pipe and the inner flange; the steel bar framework is connected with the inner flange; the inner flange is provided with a prestressed tendon tensioning hole, and the end part of the prestressed longitudinal tendon passes through the prestressed tendon tensioning hole and is anchored on the inner flange through an anchorage device.

3. A post-tensioned precast concrete supporting member as recited in claim 2, wherein: one side of the inner flange, which is far away from the outer flange, is connected with an outer ring pipe, and the end part of the concrete structure is positioned in the outer ring pipe; and a circle of meshing teeth are arranged on the inner wall of one end, far away from the inner flange, of the outer ring pipe and embedded into the concrete.

4. The post-tensioned precast concrete supporting member as recited in claim 1, wherein: the cross section of the concrete structure is polygonal, corner angle steel is arranged at the corner of the outer surface of the concrete structure, and the adjacent corner angle steel is connected through batten plates to form a lattice shape.

5. An internal support system, characterized by: the prefabricated beam comprises an enclosure structure, a crown beam, a waist beam and an assembled inner support; the top of the enclosure structure is provided with a crown beam, the inner side of the enclosure structure is provided with a waist beam, and the assembled inner supports are supported between two opposite sides of the waist beam and between two opposite sides of the crown beam; the fabricated inner support is spliced by a plurality of post-tensioned precast concrete support members according to any one of claims 1 to 4; embedded parts are embedded in the crown beam or the waist beam, vertical adjusting and positioning devices for supporting and adjusting the vertical position of the fabricated inner support are fixed on two opposite side walls of the enclosure structure, and two ends of the fabricated inner support are supported on the vertical adjusting and positioning devices on two sides respectively and are connected with the embedded parts on two sides.

6. An internal support system as defined in claim 5, wherein: and a disassembly cushion block is arranged between at least two adjacent post-tensioning precast concrete supporting members on the assembled inner support.

7. An internal support system as defined in claim 5, wherein: one end of each fabricated inner support is connected with the corresponding embedded part through a telescopic structure, a jack is arranged between one end of each fabricated inner support, which is connected with the telescopic structure, and the corresponding embedded part, and the jack is electrically connected with the control system.

8. A construction method of a post-tensioned precast concrete supporting member according to any one of claims 1 to 4, comprising the steps of:

s1, manufacturing an end steel structure in a steel structure processing plant;

s2, binding non-prestressed longitudinal bars and spiral stirrups in the prefabricated part processing plant, and spot-welding the non-prestressed longitudinal bars and the spiral stirrups to form a reinforcement cage;

9. A method of constructing an internal support system as claimed in claim 6, comprising the steps of:

10. A method of constructing an internal support system as claimed in claim 7, comprising the steps of:

s2, splicing the post-tensioning precast concrete supporting members with different lengths section by section through bolts according to the width of the foundation pit, and assembling into an assembled support with the length matched with the width of the foundation pit; connecting a first expansion joint of the telescopic structure with a post-tensioning precast concrete supporting member at one end of the assembled support through a screw rod;

s6, hanging and assembling the assembled support, and placing the assembled support on a vertical adjusting and positioning device to enable the U-shaped steel plate of the first expansion joint to be clamped in the U-shaped steel plate of the second expansion joint, and fixing the post-tensioning precast concrete supporting member at the other end of the assembled support with the embedded part at the other side;

s8, inserting adjusting bolts into the long round bolt holes in the side walls of the U-shaped steel plates of the first telescopic joint and the second telescopic joint, screwing the adjusting bolts, completing the installation of end joints, and disassembling and recovering the vertical adjusting and positioning device;