Prestress support changing structure of foundation slab

Abstract

The utility model discloses a prestress support changing structure of a foundation slab. The foundation bottom plate prestress support changing structure is arranged between a foundation pit enclosure wall and a basement outer wall, the foundation bottom plate prestress support changing structure comprises a concrete bracket, a concrete force transmission cushion block, an embedded steel plate and a jack, and the concrete bracket is arranged on a foundation pit bottom plate and fixedly connected with the foundation pit bottom plate; the concrete force transmission cushion block is fixedly installed on the inner side wall, close to the foundation pit bottom plate, of the foundation pit enclosure wall. Embedded steel plates are laid on the inner sides of the concrete force transfer cushion blocks and the sides, close to the foundation pit enclosure wall, of the concrete brackets; a base of a jack is fixedly installed on the embedded steel plate on the side, close to the foundation pit enclosure wall, of the concrete bracket, and a jack head of the jack is in tight contact with the embedded steel plate on the inner side of the concrete force transfer cushion block. According to the utility model, the additional internal force and additional deformation of the foundation pit due to the enclosure structure during the support dismounting are actively compensated through the foundation slab prestress support replacing structure, so that the safety of the support dismounting of the foundation pit is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of foundation pit construction, in particular to a prestressed support replacement structure for a foundation bottom plate. Background Art

[0002] Nowadays, due to the complex environment and limited space around the city, large underground spaces are often close to sensitive structures such as high-rise buildings or existing subways. Therefore, some scientific and strict deformation control measures are needed to reduce the impact of foundation pit construction on adjacent sensitive structures. The supporting structure of the foundation pit project needs to be dismantled layer by layer in the order from bottom to top during the basement backbuilding process. In order to ensure the stability and safety of the foundation pit in this stage of the project, the "foundation pit replacement" measure is usually adopted, that is, the water and soil pressure on the supporting structure is transferred to the basement structure with the help of the replacement support structure. Since this process will affect the foundation pit and surrounding structures, it is necessary to specially design the size and number of the replacement support structure and verify the safety of this construction process. The traditional bottom plate replacement support structure is a force transmission belt formed by pouring concrete along the periphery of the foundation pit. The additional internal force and additional deformation of the enclosure structure caused by the removal of the support are transmitted to the bottom plate replacement support structure. The bottom plate replacement support structure passively transmits the additional internal force to the bottom plate of the main structure. This type of "passive" force transmission structure cannot actively regulate the deformation of the enclosure structure. When the distance between the lowest support of the foundation pit and the bottom plate of the foundation pit is large, the retaining structure or the soil outside the pit is prone to excessive deformation risk during the removal of the lowest support. At this time, the deformation of the retaining structure can only be controlled by adjusting the construction process or the construction rate. This method of controlling deformation is inefficient and affects the overall progress of the project.

[0003] In view of the problems existing in the above-mentioned traditional foundation pit floor support replacement structure, a prestressed foundation floor support replacement structure has been developed. The structure is composed of concrete brackets, jacks, and concrete force transfer pads, which are arranged inside the foundation pit at a certain interval. By applying the jacking force step by step, the additional internal force and additional deformation of the foundation pit due to the removal of the support are actively compensated, which effectively improves the safety of the foundation pit removal and ensures the efficiency and progress of the foundation pit construction. The utility model is developed under such a background and is applied in actual construction to produce good economic and social benefits. Utility Model Content

[0004] The utility model aims to solve the problem that active deformation control cannot be performed in the existing foundation pit bottom plate support replacement technology, and proposes a foundation bottom plate prestressed support replacement structure.

[0005] In order to achieve the purpose, the technical solution provided by the utility model is:

[0006] The prestressed replacement support structure of the foundation slab is arranged between the foundation pit retaining wall and the outer wall of the basement, and is characterized in that the prestressed replacement support structure of the foundation slab includes a concrete corbel, which is arranged on the foundation pit slab and fixedly connected to the foundation pit slab; it also includes a concrete force transfer pad, which is fixedly installed on the inner wall of the foundation pit retaining wall close to the foundation pit slab; it also includes an embedded steel plate, and the inner side of the concrete force transfer pad and the side of the concrete corbel close to the foundation pit retaining wall are both paved with embedded steel plates; it also includes a jack, and the base of the jack is fixedly installed on the embedded steel plate on the side of the concrete corbel close to the foundation pit retaining wall, and the head of the jack is in close contact with the embedded steel plate on the inner side of the concrete force transfer pad.

[0007] There are multiple prestressed replacement support structures for the foundation slab between the foundation pit retaining wall and the basement outer wall, and the distance between two adjacent prestressed replacement support structures for the foundation slab is set to 6000mm~10000mm.

[0008] The distance between the outer side surface of the concrete corbel and the foundation pit retaining wall is set at 3000mm~3500mm.

[0009] The distance between two adjacent concrete corbels is 6000mm~10000mm.

[0010] The concrete corbel is integrally cast with the foundation pit bottom plate.

[0011] A plurality of I-beams with vertical axes are buried in the concrete corbel and the foundation pit floor. The plurality of I-beams are arranged in parallel and at intervals. The upper portion of each I-beam is buried in the concrete corbel, and the lower portion of each I-beam is buried in the foundation pit floor.

[0012] The concrete corbel is fixedly connected to the embedded steel plate through a plurality of steel bars.

[0013] The jack includes a pressurizing box, a round-head support rod and a disc top; the pressurizing box serves as the base of the jack, the bottom of the pressurizing box is fixedly connected to the embedded steel plate of the concrete corbel, the top of the pressurizing box is welded with a round-head support rod, the round-head support rod is hinged to the disc top, and the disc top is in close contact with the embedded steel plate of the concrete force transmission pad.

[0014] The embedded steel plate is an embedded square steel plate.

[0015] Compared with the prior art, the technical solution provided by the utility model has the following beneficial effects:

[0016] The utility model arranges a prestressed support replacement structure on the inner side of the foundation pit, and applies the jacking force of the jack so that the jack pushes into the retaining structure in advance, thereby reducing the horizontal component of the retaining structure on the foundation pit bottom plate to reduce the axial force value of the horizontal support, and actively compensates for the additional internal force and additional deformation of the retaining structure caused by the foundation pit when the support is removed, thereby effectively improving the safety of the foundation pit support removal.

[0017] The jacking force of the prestressed replacement support structure of the foundation bottom plate can be applied independently or by a number of jacks in a coordinated manner. The application range of the jacking force and the working surface can be flexibly adjusted and the application conditions are wide.

[0018] The universal support head welded on the jack head can realize automatic axis adjustment compensation of the jacking force, avoiding the deviation of the jacking force application point caused by installation error.

[0019] Concrete corbels, jacks, and concrete force transfer pads are of fixed sizes (except for the thickness of the concrete force transfer pads), and the various components are interchangeable, which can greatly improve the construction progress during the production process.

[0020] The jack can be installed and removed by bolts, which is convenient and quick. It can also be reused, reducing application costs and improving project economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a top view of the prestressed replacement support structure of the foundation bottom plate;

[0022] Figure 2(a) is a top view of a concrete corbel;

[0023] Figure 2(b) is the concrete corbel section Figure 1 ;

[0024] Figure 2(c) is a second cross-sectional view of a concrete corbel;

[0025] Figure 3(a) is the embedded steel plate sample Figure 1 ;

[0026] Figure 3(b) is the second large-scale drawing of the embedded steel plate;

[0027] Figure 4(a) shows the round head support rod and the disc head. Figure 1 ;

[0028] Figure 4(b) is a second large-scale drawing of the round head support rod and the disc head;

[0029] In the figure: 1. Concrete corbel; 1-1. I-beam; 1-2. Embedded steel plate; 1-3. Rebar; 2. Jack; 2-1. Pressure box; 2-2. Round head support rod; 2-3. Disc top; 3. Concrete force transfer pad; 4. Bolt; 5. Foundation pit retaining wall; 6. Foundation pit bottom plate. DETAILED DESCRIPTION

[0030] In order to further understand the content of the utility model, the utility model is described in detail in conjunction with embodiments. The following embodiments are used to illustrate the utility model but are not used to limit the scope of the utility model.

[0031] like Figure 1 As shown, the prestressed replacement support structure of the foundation slab includes a concrete corbel 1, a jack 2, a concrete force transfer pad 3, bolts 4 and embedded steel plates 1-2; the outer wall of the basement is located at the concrete corbel 1, the concrete corbel 1 is arranged on the foundation pit bottom slab 6 and the concrete corbel 1 is fixedly connected to the foundation pit bottom slab 6 by steel parts, and the main reinforcement 7-1 of the retaining structure is embedded in the foundation pit retaining wall 5; the inner wall of the foundation pit retaining wall 5 close to the foundation pit bottom slab 6 is fixedly installed with a concrete force transfer pad 3, and the inner side of the concrete force transfer pad 3 and the side of the concrete corbel 1 close to the foundation pit retaining wall 5 are paved with embedded steel plates 1-2, and the base of the pressurized box 2-1 of the jack 2 is fixedly installed on the embedded steel plate 1-2 on the side of the concrete corbel 1 close to the foundation pit retaining wall 5, and the top head of the jack 2 is in close contact with the embedded steel plate 1-2 on the inner side of the concrete force transfer pad 3, so as to support the outer wall of the basement at the foundation pit bottom slab 6.

[0032] As shown in FIG. 2( a ), a plurality of prestressed replacement support structures of the foundation slab between the foundation pit retaining wall 5 and the basement outer wall are provided, and the distance between two adjacent prestressed replacement support structures of the foundation slab is set to 6000 mm to 10000 mm.

[0033] The distance between the outer side surface of the concrete corbel 1 and the foundation pit retaining wall 5 is set at 3000mm~3500mm.

[0034] The distance between two adjacent concrete corbels 1 is 6000mm~10000mm.

[0035] The concrete corbel 1 and the foundation pit bottom plate 6 are integrally cast and formed by the same formwork. As shown in (b) and (c) of FIG. 2 , multiple I-beams 1-1 with vertical axes are buried in the concrete corbel 1 and the foundation pit bottom plate 6. The multiple I-beams 1-1 are arranged in parallel and at intervals. The upper part of each I-beam 1-1 is buried in the concrete corbel 1, and the lower part of each I-beam 1-1 is buried in the foundation pit bottom plate 6. In the specific implementation, 15 vertical I-beams are inserted inside during casting; the I-beam adopts No. 10 I-beam, which extends into the foundation pit bottom plate 300mm, the top surface of the I-beam is 30mm away from the top surface of the concrete corbel, and the spacing between adjacent I-beams is 300mm. As shown in (a) and (b) of FIG. 3 , the concrete corbel 1 is fixedly connected to the embedded steel plate 1-2 by multiple (such as 16) steel bars 1-3. The size of the embedded steel plate is 800mm×800mm and the thickness is 30mm; the size of the steel bar is 25mm in diameter and 200mm in length. The embedded steel plate 1-2 is an embedded square steel plate.

[0036] As shown in (a) and (b) of FIG. 4 , the jack 2 includes a pressurizing box 2-1, a round-head support rod 2-2 and a disc head 2-3; the pressurizing box 2-1 serves as the base of the jack 2, the bottom of the pressurizing box 2-1 is fixedly connected to the embedded steel plate 1-2 of the concrete corbel 1, the top of the pressurizing box 2-1 is welded with a round-head support rod 2-2, the round-head support rod 2-2 is hinged to the disc head 2-3, and the round-head support rod and the 745mm diameter disc head are combined to form a universal jacking structure. The disc head 2-3 is in close contact with the embedded steel plate 1-2 of the concrete force transfer pad 3. The cross-sectional size of the concrete force transfer pad is 850mm×850mm, and the thickness is determined according to the actual reserved space at the construction site; the end of the concrete force transfer pad is connected to the embedded steel plate through 16 steel bars.

[0037] The above is a detailed description of the utility model in combination with the embodiments, but the contents described are only preferred embodiments of the utility model and cannot be considered to limit the scope of implementation of the utility model. All equivalent changes and improvements made within the scope of application of the utility model should still fall within the scope of the patent coverage of the utility model.

Claims

1. A prestressed support replacement structure for a foundation slab, the prestressed support replacement structure for a foundation slab being arranged between a foundation pit retaining wall (5) and an outer wall of a basement, characterized in that: The foundation slab prestressed replacement support structure comprises a concrete corbel (1), which is arranged on a foundation pit slab (6) and is fixedly connected to the foundation pit slab (6); a concrete force transmission pad (3), which is fixedly installed on the inner wall of a foundation pit retaining wall (5) close to the foundation pit slab (6); an embedded steel plate (1-2), which is laid on the inner side of the concrete force transmission pad (3) and on the side of the concrete corbel (1) close to the foundation pit retaining wall (5); and a jack (2), which has a base of the jack (2) fixedly installed on the embedded steel plate (1-2) on the side of the concrete corbel (1) close to the foundation pit retaining wall (5), and a top of the jack (2) is in close contact with the embedded steel plate (1-2) on the inner side of the concrete force transmission pad (3).

2. A prestressed support replacement structure for the foundation slab according to claim 1, characterized in that: A plurality of prestressed foundation slab replacement support structures are provided between the foundation pit retaining wall (5) and the basement outer wall, and the distance between two adjacent prestressed foundation slab replacement support structures is set to 6000 mm to 10000 mm.

3. The prestressed support replacement structure of the foundation slab according to claim 1 is characterized in that: The distance between the outer side surface of the concrete corbel (1) and the foundation pit retaining wall (5) is set at 3000 mm to 3500 mm.

4. The prestressed support replacement structure of the foundation slab according to claim 1 is characterized in that: The distance between two adjacent concrete corbels (1) is 6000 mm to 10000 mm.

5. The prestressed support replacement structure of the foundation slab according to claim 1 is characterized in that: The concrete corbel (1) and the foundation pit bottom plate (6) are integrally cast and formed.

6. A prestressed support replacement structure for the foundation slab according to claim 1 or 5, characterized in that: A plurality of I-beams (1-1) with their axes in a vertical direction are buried in the concrete corbel (1) and the foundation pit bottom plate (6); the plurality of I-beams (1-1) are arranged in parallel and at intervals; the upper portion of each I-beam (1-1) is buried in the concrete corbel (1), and the lower portion of each I-beam (1-1) is buried in the foundation pit bottom plate (6).

7. The prestressed support replacement structure of the foundation slab according to claim 1 is characterized in that: The concrete corbel (1) is fixedly connected to the embedded steel plate (1-2) via a plurality of steel bars (1-3).

8. The prestressed support replacement structure of the foundation slab according to claim 1 is characterized in that: The jack (2) comprises a pressurizing box (2-1), a round-head support rod (2-2) and a disc top head (2-3); the pressurizing box (2-1) serves as the base of the jack (2); the bottom of the pressurizing box (2-1) is fixedly connected to the embedded steel plate (1-2) of the concrete corbel (1); the top of the pressurizing box (2-1) is welded with a round-head support rod (2-2); the round-head support rod (2-2) is hinged to the disc top head (2-3); and the disc top head (2-3) is in close contact with the embedded steel plate (1-2) of the concrete force transmission pad (3).

9. A prestressed support replacement structure for a foundation slab according to claim 1 or 7, characterized in that: The embedded steel plates (1-2) are embedded square steel plates.

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