Foundation pit diagonal bracing structure utilizing the original soil beneath the basement floor slab

Abstract

This utility model discloses a foundation pit inclined bracing support structure utilizing the undisturbed soil beneath a basement floor slab, comprising support piles, a water-stop curtain, a capping beam, reaction piers, and inclined braces. The support piles are spaced apart around the perimeter of the foundation pit; the water-stop curtain is located outside the support piles; the capping beam connects along its length to the tops of the rows of support piles; the reaction piers are made of reinforced concrete or plain concrete and are located in the undisturbed soil beneath the basement floor slab; both ends of the inclined braces are pre-embedded in the reaction piers and the capping beam, respectively. This structure utilizes the undisturbed soil instead of the basement floor slab to bear the horizontal reaction force, reducing the thickness requirement of the basement floor slab and allowing for single-stage casting of the basement floor slab, thus saving costs and construction time.

Description

Technical Field

[0001] This utility model belongs to the field of foundation pit support, specifically relating to a foundation pit inclined bracing support structure that utilizes the original soil under the basement floor slab. Background Technology

[0002] When installing diagonal bracing for foundation pits, the common practice is to place the lower end of the diagonal brace on the top surface of the foundation slab and connect the diagonal brace to the foundation slab using corbel members. This setup requires pre-embedding the corbel members within the foundation slab and relying on the foundation slab to bear the horizontal force transmitted by the diagonal brace. To ensure the foundation slab can withstand sufficient horizontal force, it needs to have adequate thickness and requires multiple pours of the foundation slab (first pouring the portion that bears the diagonal brace, then pouring the rest), which not only increases costs but also delays the construction period. Utility Model Content

[0003] The purpose of this utility model is to provide a foundation pit inclined bracing support structure that utilizes the original soil under the basement floor slab. By using the original soil instead of the basement floor slab to bear the horizontal reaction force, the thickness requirement of the basement floor slab can be reduced, and the basement floor slab can be poured in one go, saving costs and construction time.

[0004] The technical solution adopted in this utility model is:

[0005] A foundation pit inclined bracing support structure utilizing the undisturbed soil beneath the basement floor slab includes support piles, a water-stop curtain, a capping beam, reaction piers, and inclined braces. The support piles are spaced apart around the perimeter of the foundation pit. The water-stop curtain is located outside the support piles. The capping beam is connected along the line to the top of the rows of support piles. The reaction piers are made of reinforced concrete or plain concrete and are located in the undisturbed soil beneath the basement floor slab. The two ends of the inclined braces are respectively embedded in the reaction piers and the capping beam.

[0006] Preferably, the reaction piers avoid the designed locations of the foundation components within the excavation pit.

[0007] Preferably, the reaction pier has a cross-section that is larger at the top and smaller at the bottom, with the side closest to the diagonal brace being a straight surface and the side furthest from the diagonal brace being a sloping surface.

[0008] Preferably, the diagonal brace has an end plate at one end inside the reaction pier.

[0009] Preferably, the diagonal brace has a transverse water-stop steel plate at the middle position of the area passing through the basement floor slab.

[0010] Preferably, a mesh is installed on the inner side of the row of support piles, extending from the ground to the top of the support piles, and concrete is sprayed onto the mesh to form a mesh concrete layer.

[0011] Preferably, plain concrete is backfilled at the bottom between the inner side of the wire mesh concrete layer and the outer side of the underground structure in the foundation pit, and soil is backfilled on top of the plain concrete. The plain concrete and the basement floor slab use the same type of concrete. The plain concrete is backfilled to the height of the basement floor slab, and the connecting reinforcing bars at the bottom of the wire mesh concrete layer are pre-embedded in the plain concrete.

[0012] Preferably, a water-retaining sill is provided at the top of the water-stop curtain.

[0013] Preferably, the diagonal bracing is made of structural steel.

[0014] Preferably, the support piles are cast-in-place piles or precast piles.

[0015] The beneficial effects of this utility model are:

[0016] This structure can be used when the original soil beneath the basement floor slab has a certain thickness and can withstand a certain horizontal reaction force. In this structure, the reaction piers, diagonal braces, capping beams, and support piles are connected in sequence to form a co-supporting system, which can ensure the support effect. The key is that by using the original soil instead of the basement floor slab to bear the horizontal reaction force, the thickness requirement of the basement floor slab can be reduced, and the basement floor slab can be poured in one go, saving costs and construction time. Attached Figure Description

[0017] Figure 1 This is a plan view of the foundation pit inclined bracing support structure utilizing the original soil under the basement floor slab in this utility model during construction.

[0018] Figure 2 This is a cross-sectional view of the foundation pit inclined bracing support structure utilizing the original soil under the basement floor slab during construction, as described in this utility model.

[0019] Figure 3 This is a schematic diagram of the connection between the diagonal brace and the reaction pier in this utility model.

[0020] In the diagram: 1-Water-stop curtain; 2-Support pile; 3-Cover beam; 4-Diagonal brace; 5-Reaction pier; 6-Foundation component; 7-Earth platform; 8-Basement floor slab; 9-Water-stop steel plate; 10-Plain concrete; 11-Wire mesh concrete layer; 12-Backfill soil; 13-Water retaining sill; 14-End plate. Detailed Implementation

[0021] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0022] This embodiment discloses a foundation pit inclined bracing support structure utilizing the undisturbed soil beneath the basement floor slab, such as... Figure 1 and Figure 2As shown, the structure includes retaining piles 2, a water-stop curtain 1, a capping beam 3, reaction piers 5, and diagonal braces 4. The retaining piles 2 are spaced apart around the perimeter of the foundation pit. The water-stop curtain 1 is located outside the retaining piles 2. The capping beam 3 connects along the line to the tops of the rows of retaining piles 2. The reaction piers 5 are made of reinforced concrete or plain concrete and are located in the undisturbed soil below the basement floor slab 8. The two ends of the diagonal braces 4 are pre-embedded in the reaction piers 5 and the capping beam 3, respectively. This structure can be used when the undisturbed soil below the basement floor slab 8 has a certain thickness and can withstand a certain horizontal reaction force. In this structure, the reaction piers 5, diagonal braces 4, capping beam 3, and retaining piles 2 are connected sequentially to form a cohesive force-bearing system, ensuring sufficient support effect. Crucially, utilizing the undisturbed soil instead of the basement floor slab 8 to bear the horizontal reaction force reduces the thickness requirement of the basement floor slab 8 and allows for one-time casting of the basement floor slab 8, saving costs and construction time.

[0023] like Figure 1 As shown, in this embodiment, preferably, the reaction pier 5 avoids the designed position of the foundation component 6 in the foundation pit to avoid interference.

[0024] like Figure 1 As shown, in this embodiment, preferably, a hanging net is provided on the inner side of the row of support piles 2, the hanging net extends from the ground to the top of the support piles 2, and concrete is sprayed onto the hanging net to form a hanging net concrete layer 11 to prevent the soil between the piles from being exposed.

[0025] like Figure 1 As shown, in this embodiment, preferably, plain concrete 10 is backfilled at the bottom between the inner side of the wire mesh concrete layer 11 and the outer side of the underground structure in the foundation pit, and soil is backfilled on the plain concrete 10. The plain concrete 10 and the basement floor 8 use the same type of concrete. The plain concrete 10 is backfilled to the height of the basement floor 8, and the bottom connecting reinforcement bars of the wire mesh concrete layer 11 are pre-embedded in the plain concrete 10.

[0026] like Figure 1 As shown, in this embodiment, preferably, a water-blocking sill 13 is provided at the top of the water-stop curtain 1.

[0027] like Figure 2 and Figure 3 As shown, in this embodiment, preferably, the cross-section of the reaction pier 5 is a right trapezoid with a larger top and a smaller bottom. The side of the reaction pier 5 that is close to the inclined support 4 is a straight surface, and the side that is away from the inclined support 4 is an inclined surface. This can optimize the force transmission of the reaction pier 5 to the original soil and expand the contact area of ​​the reaction pier 5 to transmit force to the original soil.

[0028] like Figure 2 As shown, in this embodiment, preferably, the diagonal brace 4 is provided with a horizontal water-stop steel plate 9 at the middle position of the area passing through the basement floor slab 8, which can prevent water seepage.

[0029] like Figure 3As shown, in this embodiment, preferably, the diagonal brace 4 has an end plate 14 at one end inside the reaction pier 5, which can enhance the connection strength between the diagonal brace 4 and the reaction pier 5.

[0030] In this embodiment, preferably, the diagonal brace 4 is made of steel, and the support pile 2 is made of cast-in-place piles or precast piles.

[0031] The following steps are used during construction:

[0032] S1. Construct support piles 2 and water-stop curtain 1 around the foundation pit. Support piles 2 can be cast-in-place piles or precast piles. A water-stop sill 13 can be set on the top of the water-stop curtain 1. Then excavate the soil inside the foundation pit and leave a soil platform 7 around the foundation pit.

[0033] S2. When the excavation reaches the bottom elevation of the foundation layer of the capping beam 3, construct the capping beam 3. In the pit, make a trench and construct the reaction pier 5 in the original soil below the basement floor slab 8. The reaction pier 5 is made of reinforced concrete or plain concrete. The reaction pier 5 avoids the design position of the foundation component 6 in the foundation pit. Make a trench on the soil platform 7 to construct the diagonal brace 4. The diagonal brace 4 is made of steel. The upper and lower ends of the diagonal brace 4 are pre-embedded in the capping beam 3 and the reaction pier 5 respectively. The diagonal brace 4 has an end plate 14 inside the reaction pier 5. The diagonal brace 4 has a transverse water-stop steel plate 9 in the middle position of the area passing through the basement floor slab 8.

[0034] After S3, the cap beam 3 and the reaction pier 5 reach the design strength, the soil platform 7 is excavated layer by layer from top to bottom. The wire mesh concrete layer 11 is constructed inside the support pile 2. The wire mesh is installed first, and then the concrete is sprayed.

[0035] S4. Construct the basement floor slab 8. After the basement floor slab 8 reaches the design strength, remove the diagonal bracing 4 and complete the underground structure.

[0036] S5. Between the inner side of the wire mesh concrete layer 11 and the outer side of the underground structure, backfill plain concrete 10 at the bottom and backfill soil on top of plain concrete 10.

[0037] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A foundation pit bracing structure using the in-situ soil under the basement floor, characterized by: It includes retaining piles, water-stop curtain, capping beam, reaction piers and diagonal bracing; the retaining piles are arranged at intervals around the perimeter of the foundation pit; the water-stop curtain is set outside the retaining piles; the capping beam is connected to the top of the rows of retaining piles along the line; the reaction piers are made of reinforced concrete or plain concrete and are set in the original soil below the basement floor slab; the two ends of the diagonal bracing are respectively embedded in the reaction piers and the capping beam.

2. The foundation pit inclined bracing support structure utilizing the undisturbed soil beneath the basement floor slab as described in claim 1, characterized in that: The reaction piers avoid the designed locations of the foundation components within the excavation pit.

3. The excavation batter strut support structure using the in-situ soil under the basement floor slab according to claim 1, characterized in that: The reaction pier has a cross-section that is a right trapezoid with a larger top and a smaller bottom. The side closest to the diagonal brace is a straight surface, and the side furthest from the diagonal brace is a sloping surface.

4. The excavation batter strut support structure using the in-situ soil under the basement floor slab according to claim 1, characterized in that: The diagonal brace has an end plate at one end inside the reaction pier.

5. The excavation batter strut support structure using the in-situ soil under the basement floor slab according to claim 1, characterized in that: A horizontal waterstop steel plate is installed at the middle position of the diagonal brace passing through the basement floor slab area.

6. The foundation excavation batter strut support structure using the in-situ soil under the basement floor slab according to any one of claims 1 to 5, characterized in that: The inner side of the rows of support piles is equipped with a hanging net, which extends from the ground to the top of the support piles. Concrete is sprayed onto the hanging net to form a hanging net concrete layer.

7. The excavation batter strut support structure using the in-situ soil under the basement floor slab according to claim 6, characterized by: Plain concrete is backfilled at the bottom between the inner side of the wire mesh concrete layer and the outer side of the underground structure in the foundation pit, and soil is backfilled on top of the plain concrete. The plain concrete and the basement floor slab use the same type of concrete. The plain concrete is backfilled to the height of the basement floor slab, and the connecting reinforcing bars at the bottom of the wire mesh concrete layer are pre-embedded in the plain concrete.

8. The excavation batter strut support structure using the in-situ soil under the basement floor slab according to any one of claims 1 to 5, characterized in that: The top of the water-stop curtain is equipped with a water-retaining sill.

9. The excavation batter strut support structure using the in-situ soil under the basement floor slab according to any one of claims 1 to 5, characterized in that: The diagonal bracing is made of structural steel.

10. The excavation batter strut support structure using the in-situ soil under the basement floor slab according to any one of claims 1 to 5, characterized by: The support piles are cast-in-place piles or precast piles.

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