An assembled hollow concrete-filled steel tube flared support structure and method

Abstract

The present invention relates to the technical field of foundation pit construction, and particularly relates to an assembled hollow steel pipe concrete flared support structure and method, which includes two flared supports, both of which are hollow structures formed by pouring concrete into steel pipes, with a flare provided at one end, and the two flared supports are butt-jointed at the other end through a butt-joint structure; a capping beam butt-joint assembly, which is connected to the capping beam by means of embedded anchor bolts, and has a flared sleeve that cooperates with the flare, and the flared sleeve is composed of two clamping structures and jointly clamps and covers the flare; in the present invention, a flare is provided at one end of the flared support, and a flared sleeve is used for connection at the connection with the capping beam, which can not only ensure that the flared support has high load-bearing capacity and anti-deformation ability, but also ensure its convenient installation and disassembly due to the adoption of an assembled structure.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation pit construction, and particularly relates to an assembled hollow concrete-filled steel tube flared support structure and method. Background Art

[0002] Traditional cast-in-place concrete supports are widely used in underground projects due to their advantages such as high stiffness, good integrity, safety and reliability. However, there are also prominent problems and disadvantages: (1) The pouring and curing time of the support is long, and a hardening period is required before reaching the design strength and forming a supporting effect, which is not conducive to accelerating the construction progress. This is particularly prominent in soft clay areas, where the retaining wall (pile) is exposed without support for a long time, and the viscous deformation of the soft clay is not conducive to control, resulting in large displacement of the soil-entering part of the wall. (2) It cannot be reused. After construction, it needs to be demolished, which will have a greater impact on the surrounding environment. (3) It has a large self-weight and requires more support columns. (4) It cannot apply prestress to reduce the deformation of the retaining structure.

[0003] Although traditional steel tube supports can be recycled and the construction is relatively convenient, the material stiffness is small and the support integrity is weak. It can only bear pressure between the support and the foundation pit support structure, and it is difficult to meet the requirements of foundation pit engineering. Especially when steel supports are used at the position of the foundation pit capping beam, the support structure is extremely prone to "kicking" at the bottom of the foundation pit, resulting in tension in the steel tube internal support at the capping beam and easy dropping of the steel support. Therefore, steel supports are generally not used at the capping beam position. In view of this, there is an urgent need to invent a support structure that is both cost-saving and safe and reliable to replace traditional cast-in-place reinforced concrete supports and traditional steel tube supports.

[0004] In the prior art, the Chinese invention patent with the application number 202010763025.2 discloses an assembled concrete-filled steel tube support system and its construction method. The assembled concrete-filled steel tube support of the system is spliced by a plurality of concrete-filled steel tube support prefabricated parts; a support assembly is arranged in the capping beam, and both ends of the assembled concrete-filled steel tube support are respectively connected to the two side support assemblies through telescopic connectors. However, it is very difficult to cope with sudden foundation pit accidents such as kicking damage only by bolts at the capping beam. The Chinese utility model patent with the application number 201520968833.7 discloses an assembled foundation pit retaining concrete-filled steel tube support, which includes a waling or ring beam, a steel tube or concrete-filled steel tube support, node connecting concrete and node connecting steel bars. However, when disassembling, it is necessary to cut or break the node connecting concrete, which may cause certain damage to the support end, and the support reuse rate cannot be guaranteed. Summary of the Invention

[0005] The purpose of the present invention is to provide an assembled hollow steel tube concrete expansion support structure and method to solve the above problems existing in the prior art, to improve the stability of the support system, to ensure the safety of the foundation pit project, and to facilitate installation and disassembly, so as to facilitate the recycling of support components. In order to achieve the above purpose, the present invention solves it through the following technical solutions:

[0006] In a first aspect, the present invention provides an assembled hollow steel tube concrete expansion support structure, comprising:

[0007] The two expansion supports are hollow structures formed by pouring concrete in a steel pipe, one end of which is provided with an expansion, and the two expansion supports are butted at the other end by a butt joint structure;

[0008] The crown-beam butt joint assembly is connected to the crown beam by pre-embedded anchor bolts, and is provided with a flaring sleeve matched with the flaring. The flaring sleeve is composed of two clamping structures that jointly cover and clamp the flaring.

[0009] As a further technical solution, it also includes at least one standard support, which is a hollow structure formed by pouring concrete in a steel pipe and has no expansion, and is arranged between the two expansion supports and connected through the docking structure.

[0010] As a further technical solution, when there are more than or equal to two standard braces, they are butt-jointed via the butt-jointing structure.

[0011] As a further technical solution, the docking structure includes a clamping component and a shearing component.

[0012] As a further technical solution, the clamping assembly includes two semicircular sleeves that are clamped together, and the two semicircular sleeves are clamped by bolts.

[0013] As a further technical solution, the anti-shear component includes a plurality of engaging teeth distributed on the inner walls of the two semicircular sleeves, and an anti-shear ring engaged with the engaging teeth, and each of the expansion supports is provided with an anti-shear ring.

[0014] As a further technical solution, the anti-shear ring is configured with a circular sealing plate, and the two are an integrated structure.

[0015] As a further technical solution, a plurality of longitudinal steel bars are arranged in the circumferential direction in the concrete at the rear edge of the expansion support.

[0016] As a further technical solution, the front edge of the flared sleeve is provided with a tightening portion to cooperate with the flared rear edge.

[0017] In a second aspect, the present invention provides a construction method for the assembled hollow steel tube concrete expansion support structure according to the first aspect, comprising the following steps:

[0018] The prefabricated flared struts are transported to the construction site for standby. The capping beam is poured, and the capping beam docking assembly is connected to the capping beam by means of embedded anchor bolts. One of the prefabricated flared struts is hoisted to the designated construction position by a crane. The flared part is jointly covered and clamped through a flared sleeve. The other flared strut is constructed according to the same method. After completion, the two flared struts are docked through the docking structure.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) The flared strut of the present invention is a hollow structure formed by pouring concrete into a steel pipe, which reduces the self-weight of the precast member and the difficulty of hoisting on the premise of meeting the stress requirements. A flared part is provided at one end, and a flared sleeve is used for connection at the connection with the capping beam, which can not only ensure that the flared strut has high bearing capacity and anti-deformation ability, but also ensure its convenient installation and disassembly due to the use of an assembled structure.

[0021] (2) The flared sleeve of the present invention is equipped with multiple anchor bolts, which are pre-embedded and poured together with the capping beam concrete to ensure reliable connection with the steel bars in the capping beam, and can also ensure the support stability of the flared strut after its connection with the flared strut.

[0022] (3) The docking structure of the present invention includes a tightening assembly and a shear-resistant assembly. The shear-resistant ring engages with the engaging teeth, improving the shear bearing capacity at the docking joint; the tightening assembly includes two semi-circular sleeves that are docked and tightened, and the two semi-circular sleeves are tightened on the two flared struts through bolts. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute a limitation to the present invention. It should also be understood that these drawings are shown for simplicity and clarity and are not necessarily drawn to scale. The present invention will now be described and explained with additional features and details by using the drawings, wherein:

[0024] Figure 1 Shows the front view of the docking of two flared struts in an embodiment of the present invention;

[0025] Figure 2 Shows the side view of the docking of two flared struts in an embodiment of the present invention;

[0026] Figure 3 Shows the schematic cross-sectional view of the flared strut in an embodiment of the present invention;

[0027] Figure 4 Shows the front view of the docking structure in an embodiment of the present invention;

[0028] Figure 5 Shows the isometric view of the semi-circular sleeve in the docking structure in an embodiment of the present invention;

[0029] Figure 6 Shows a schematic diagram of the lower annular cover plate in the embodiment of the present invention;

[0030] Figure 7 Shows a schematic diagram of the upper annular cover plate in the embodiment of the present invention.

[0031] In the figure: 1, flared support; 2, rib support; 3, sealing plate; 4, shear-resistant ring; 5, sleeve docking plate; 6, bolt hole; 7, engaging teeth; 8, semi-circular sleeve; 9, hollow part; 10, concrete; 11, steel bars; 12, upper annular cover plate; 13, upper crown beam docking plate; 14, lower annular cover plate; 15, anchor bolt; 16, nut; 17, lower crown beam docking plate; 18, circular steel plate; 19, constriction part. Specific embodiments

[0032] Next, the technical solutions in the typical embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0033] Embodiment 1

[0034] As Figures 1 - 7 shown, this embodiment provides a prefabricated hollow steel pipe concrete flared support structure, including a flared support 1, a crown beam docking assembly and a standard support.

[0035] Both flared supports 1 are hollow structures formed by pouring concrete 10 into steel pipes, with a flare provided at one end, and the two flared supports 1 are docked at the other end through a docking structure.

[0036] The steel pipe thickness of the flared support 1 can be between 5 - 20 mm. The steel pipe thickness adopted in this embodiment is 6 mm, the steel grade is Q355B, the support radius is 349 mm, and the radius at the flare is 449 mm; the material of the flared support 1 can be high-strength steel or alloy steel, as long as it meets the force requirements and is easy to weld.

[0037] As Figure 2 shown, the concrete 10 filled in the flared support 1 can be high-strength concrete, ultra-high-strength concrete, etc., but it needs to meet the strength requirements and should not be too heavy. Its thickness takes a small value under the condition of meeting the support stiffness, reducing the self-weight of the precast component. In this embodiment, ultra-high-strength concrete with a strength grade of C105 is adopted, and the thickness is taken as 100 mm. The hollow part 9 of the flared support 1 can be without any inner wall, or can adopt the form of having an inner wall. The inner wall material can be steel pipe, PVC, etc. In this embodiment, a steel pipe is selected as the inner wall material.

[0038] The crown beam docking assembly is connected to the crown beam by the pre-embedded method of anchor bolts 15, and has a flared sleeve that fits the flare. The flared sleeve is composed of two clamping structures and jointly wraps and clamps the flare.

[0039] As Figure 6 andFigure 7 As shown, the two clamping structures of the flared sleeve are the upper annular cover plate 12 and the lower annular cover plate 14 respectively. The upper annular cover plate 12 is connected to the lower crown beam docking plate 17 by high-strength bolts through the upper crown beam docking plate 13, and forms a flared sleeve with the lower annular cover plate 14.

[0040] Among them, the lower annular cover plate 14 is welded to a circular steel plate 18, and a plurality of anchor bolts 15 are provided on the circular steel plate 18, which can effectively integrate the flared sleeve with the concrete at the crown beam, strengthen the connection strength and stiffness between the flared sleeve and the flared support 1, and are fixed with corresponding nuts 16; the anchor bolts 15 need to have sufficient anchorage length in the crown beam, and the number thereof can be determined according to the actual situation. In this embodiment, 25 anchor bolts 15 are arranged on the circular steel plate 18, and the anchorage length is 1 m.

[0041] The flared support 1 of this embodiment is a hollow structure formed by pouring concrete 10 into a steel pipe, which reduces the self-weight of the precast member and the difficulty of hoisting on the premise of meeting the stress requirements. One end is provided with a flare, and the connection with the crown beam is connected by a flared sleeve, which can not only ensure that the flared support 1 has high bearing capacity and anti-deformation ability, but also ensure its convenient installation and disassembly due to the use of an assembled structure.

[0042] As Figure 1 and Figure 3 shown, a number of longitudinal steel bars 11 are circumferentially arranged in the inner circumference of the concrete 10 at the trailing edge of the flared support 1. The steel bars are longitudinally arranged along the axis direction of the flared support 1. The specification of the steel bar 11 is HRB500, the diameter is 20 mm, and the length is 1 m. Its reinforcement position should be at the trailing edge of the flared part of each flared support 1, and the number thereof is preferably 10 - 20. In this embodiment, 15 steel bars 11 are configured and evenly distributed within the circumference of the annular concrete 10. The arrangement of the steel bars 11 can enhance the strength of the trailing edge part of the flare and improve the overall bearing capacity of the flared support 1.

[0043] As Figure 6 shown, a constriction part 19 is provided at the leading edge of the flared sleeve to cooperate with the trailing edge of the flare, which is equivalent to the flare of the flared support 1 being fitted into the flared sleeve to ensure stable docking of the two.

[0044] As Figure 1 and Figure 2 shown, the docking structure includes a tightening component and a shear-resistant component. The inner walls of the butting interfaces of the two flared supports 1 are connected by the shear-resistant component, and the outer walls are connected by the covering tightening component.

[0045] Specifically, as Figure 4 and Figure 5As shown in the figure, the hoop tightening assembly includes two semi-circular sleeves 8 that are butted and tightened. The two semi-circular sleeves 8 are tightened by bolts. The semi-circular sleeve 8 is made of a steel pipe with a thickness of 15 mm and 460C, which is used to connect two adjacent sections of steel pipe supports. Its inner diameter should be the same as the outer diameter of the flared support 1. During use, the sleeve docking plates 5 on the upper and lower semi-circular sleeves 8 should be rigidly connected by high-strength bolts.

[0046] The shear resistance assembly includes a number of engaging teeth 7 distributed on the inner walls of the two semi-circular sleeves 8, and a shear resistance ring 4 that engages with the engaging teeth 7. One shear resistance ring 4 is configured for each flared support 1. The shear resistance ring 4 is configured with a circular sealing plate 3, and the two are an integral structure.

[0047] The shear resistance ring 4 is made of a steel pipe with a thickness of 22 mm and 355C. Its radius should be the same as the radius of the flared support 1. As a component connecting the sealing plate 3 and the flared support 1, it is welded to the flared support 1 and the sealing plate 3 as a whole; the close engagement between the shear resistance ring 4 and the engaging teeth 7 serves to connect the semi-circular sleeve 8 and the flared support 1; the detailed groove dimensions can be taken between 10 - 20 mm to ensure one-to-one correspondence with the engaging teeth 7.

[0048] The thickness of the sealing plate 3 is 20 mm. Its radius should be the same as the support radius and is welded to the shear resistance ring 4 and the flared support 1 as a whole.

[0049] The sleeve docking plate 5 is made of a steel plate with a thickness of 24 mm and 460C. Its dimensions can be determined according to the actual project; the sleeve docking plate 5 is provided with a number of bolt holes 6 to meet the requirements of rigid connection and equal-strength connection at the middle node, ensuring that the concrete-filled steel pipe support reaches a strength and stiffness similar to or even higher than that of the cast-in-place concrete support; the number of bolt holes 6 can be determined according to the size of the sleeve docking plate 5. In this embodiment, each sleeve docking plate 5 used is provided with 5 bolt holes 6.

[0050] The standard support is a hollow structure formed by pouring concrete 10 into a steel pipe without a flare, and is arranged between two flared supports 1 and is docked through a docking structure. When there are two or more standard supports, they are docked through the docking structure.

[0051] The standard support is arranged in the middle section. The precast components can be designed with several fixed modulus sections of appropriate lengths according to needs. If the length is too long, it is not suitable for hoisting construction. If the length is too short, it will result in too many joints and difficult connections; standard moduli such as 5 m, 6 m, and 7 m can be designed. According to the actual foundation pit needs, flared supports 1 with completely the same, not completely the same, or completely different length specifications can be selected and combined with the standard supports to meet the needs of foundation pit supports with different widths and lengths, and have general applicability.

[0052] Embodiment Two

[0053] This embodiment provides a construction method for the assembled hollow concrete-filled steel pipe flared support structure as described in the embodiment, including the following steps:

[0054] (1) Prefabricate the flaring support 1 according to the requirements of the drawing and transport it to the construction site for standby. Among them, the flaring support 1, the shear-resistant ring 4, and the plugging plate 3 are welded into a whole and then poured.

[0055] (2) Pour the capping beam, and connect the capping beam docking assembly to the capping beam by means of embedded anchor bolts. Specifically, the lower annular cover plate 14 and the anchor bolts 15 are poured into the capping beam. The anchor bolts are fixed with the corresponding number of nuts 16 and cured to the design strength. Then, the upper annular cover plate 12 is welded to the upper capping beam docking plate 13, and the lower capping beam docking plate 17 is welded to the lower annular cover plate 14. The lower annular cover plate 14 is first welded to the circular steel plate 18.

[0056] (3) Use a crane to hoist one of the flaring supports 1 to the designated position in the construction drawing. The flaring part of the flaring support 1 is embedded into the lower annular cover plate 14, and the upper annular cover plate 12 is connected to the lower capping beam docking plate 17 through the upper capping beam docking plate 13 with high-strength bolts to form a flaring sleeve, completing the installation of the first section of the support.

[0057] Construct the other flaring support 1 according to the same method. After completion, the two flaring supports 1 are docked through the docking structure.

[0058] Although the present invention has been disclosed above with preferred embodiments, it is not used to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. An assembled hollow steel tube concrete flared support structure, characterized in that, Including: Two flared braces, both of which are hollow structures formed by pouring concrete into steel pipes, with a flare provided at one end, and the two flared braces are butt-jointed through a butt-joint structure at the other end; A capping beam butt-joint assembly, which is connected to the capping beam by means of embedded anchor bolts and has a flared sleeve that cooperates with the flare. The flared sleeve is composed of two clamping structures and jointly clamps the flare; The butt-joint structure includes a hoop-tightening assembly and a shear-resistant assembly. The hoop-tightening assembly includes two semi-circular sleeves that are butted and tightened. The two semi-circular sleeves are tightened by bolts. The shear-resistant assembly includes a number of engaging teeth distributed on the inner walls of the two semi-circular sleeves, and a shear-resistant ring that engages with the engaging teeth. Each flared brace is provided with one of the shear-resistant rings; A constriction part is provided at the leading edge of the flared sleeve to cooperate with the trailing edge of the flare.

2. The prefabricated concrete-filled steel tubular flared bracing structure according to claim 1, wherein It further includes at least one standard brace, which is a hollow structure formed by pouring concrete into a steel pipe and has no flare, and is arranged between the two flared braces and butt-jointed through the butt-joint structure.

3. The assembled hollow steel tube concrete flared support structure according to claim 2, characterized in that, When there are two or more standard braces, they are butt-jointed through the butt-joint structure.

4. The prefabricated hollow concrete-filled steel tube flared support structure according to claim 1, characterized in that, The shear-resistant ring is provided with a circular sealing plate, and the two are of an integral structure.

5. The prefabricated concrete-filled steel tubular flared support structure according to claim 1, wherein A number of longitudinal steel bars are circumferentially arranged in the concrete at the trailing edge of the flared brace.

6. The construction method of the assembled hollow steel tube concrete flared support structure according to any one of claims 1, 4 - 5, characterized in that, Including the following steps: Transport the prefabricated flared braces to the construction site for standby. Pour the capping beam, connect the capping beam butt-joint assembly to the capping beam by means of embedded anchor bolts. Use a crane to hoist one of the prefabricated flared braces to the designated construction position, and jointly clamp the flare through the flared sleeve. Construct the other flared brace according to the same method. After completion, butt-joint the two flared braces through the butt-joint structure.

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