A foundation pit supporting structure in soft soil area

Abstract

The application relates to the technical field of foundation pit support, improves the poor foundation pit support effect in soft soil areas, and discloses a foundation pit support structure in a soft soil area, which comprises a support plate, a fixing cylinder, an anchoring piece and a cast-in-place pile. The support plate can be fixed on the foundation pit through pile nails or anchor piles, the fixing cylinder is arranged on the support plate, the anchoring piece is placed in the fixing cylinder in cooperation, a plurality of anchor claws are arranged in the anchoring piece, and the cast-in-place pile is in abutment with the anchoring piece. The anchoring piece is knocked into the soil through the cast-in-place pile, then concrete is poured into the cast-in-place pile, the concrete flows from the cast-in-place pile to the anchoring piece, the anchor claws are pushed out of the anchoring piece and are unfolded at an angle with the anchoring piece, the concrete flows out of the unfolded anchoring piece and is condensed with the soft soil, the condensation range and volume are increased, the possibility of deformation and subsidence of the foundation pit is reduced, and the support effect is improved.

Description

A foundation pit support structure for soft soil areas Technical Field

[0001] This application relates to the technical field of foundation pit support, and in particular to a foundation pit support structure in soft soil areas. Background Technology

[0002] An excavation pit is a pit dug at the designed location of the building foundation according to the base elevation and foundation plane dimensions. Excavation pit support is an important retaining measure to protect the underground structure construction and the safety of the surrounding environment. Different construction environments have different soil properties. In coastal areas, the soil is softer, has lower strength, and higher compressibility, making it prone to settlement and deformation, which places higher demands on the engineering design of the support system.

[0003] One existing soft soil support structure uses concrete as a curing agent. First, hollow cylindrical piles with perforations on their surfaces are driven vertically into the soil. Then, concrete is poured into the piles to bond the concrete and soft soil together, thereby reinforcing the foundation. However, the concrete poured into the cylindrical piles only partially seeps outwards and to the periphery, resulting in a small volume of reinforcement and thus poor support effect for the foundation pit. Summary of the Invention

[0004] In order to improve the poor support effect of foundation pits in soft soil areas, this application provides a foundation pit support structure for soft soil areas.

[0005] This application provides a foundation pit support structure for soft soil areas, employing the following technical solution:

[0006] A foundation pit support structure in a soft soil area includes a support plate fixed inside the foundation pit. The support plate includes a side support that abuts against the inner side of the foundation pit and a bottom support that abuts against the bottom of the foundation pit. It also includes a fixing cylinder, anchors and cast-in-place piles.

[0007] The fixed cylinder is disposed on the support plate, and the fixed cylinder passes through two end faces in the axial direction to form a channel. The support plate is provided with a clearance hole corresponding to the channel.

[0008] The anchor is placed in the channel and penetrates the top surface to form a first injection hole. Several anchor claws are arranged circumferentially inside the first injection hole. The inner wall of the first injection hole has a movable hole for the anchor claws to pass through. The anchor claws penetrate the top surface to form a second injection hole that communicates with the first injection hole. Several first grout outlet holes that communicate with the second injection hole are opened on the surface of the anchor claws.

[0009] The cast-in-place pile is movably inserted into the fixed cylinder and abuts against the anchor. When the cast-in-place pile moves toward the anchor, it can push the anchor through the clearance hole into the soil of the foundation pit. The two ends of the cast-in-place pile are penetrated along the axial direction to form a third grouting hole for concrete to enter. The third grouting hole is connected to the first grouting hole.

[0010] The anchor claw, pushed by the concrete, can pass through the movable hole and exit the anchor, and the anchor claw is angled to the outer surface of the anchor.

[0011] By adopting the above technical solution, during construction, the anchor is first placed inside the fixing cylinder, and then the cast-in-place pile is placed inside the fixing cylinder to abut against the anchor. The anchor is then pushed into the soil by striking the cast-in-place pile. Concrete is poured into the cast-in-place pile, and the concrete enters the first grouting port through the third grouting port. Then, the anchor claw is pushed out of the anchor and unfolded. The concrete enters the second grouting port of the anchor claw from the first grouting port and finally flows out from the first grout outlet, thus mixing with the soft soil and solidifying. The unfolded anchor claw increases the range and volume of concrete and soil solidification, further reducing the possibility of foundation pit deformation and settlement, and improving the stability of the support.

[0012] Optionally, the side surface of the anchor is provided with a stepped structure, and the movable hole is provided on the stepped surface of the stepped structure; the anchor claw is correspondingly provided above the movable hole and slidably connected to the inner surface of the anchor, the anchor claw includes an insertion part and a sliding part and a pushing part respectively connected to the insertion part, the inner surface of the anchor is provided with a first groove for the sliding part to slide, the pushing part is set at an angle to the insertion part, and the pushing part can be driven by concrete to drive the insertion part to slide through the movable hole in a direction away from the anchor.

[0013] By adopting the above technical solution, after the concrete enters the second injection port, the anchor claw can be pushed out of the anchor by the pushing part along a straight line.

[0014] Optionally, the sliding part has a rotating groove on its surface facing the sliding direction, and a rotating shaft is provided at the bottom of the inner wall of the first sliding groove; the anchor claw can slide away from the anchor and engage with the rotating shaft in the rotating groove, and the anchor is connected to the movable hole and has a rotating hole for the anchor claw to rotate around the rotating shaft.

[0015] By adopting the above technical solution, the anchor claw is pushed down by the concrete and slides down. When it reaches the bottom, the rotating shaft is engaged in the rotating groove, thereby restricting the anchor claw from continuing to slide. As the concrete continues to act on the pushing part, the anchor claw will rotate upward around the rotating shaft and unfold. Therefore, the concrete can flow out from the unfolded anchor claw through the first grout outlet.

[0016] Optionally, two adjacent pushing parts abut against each other, and the ends of several pushing parts away from the soil entry part abut against each other.

[0017] By adopting the above technical solution, the mutual abutment of the pushing parts of several anchor claws can increase the contact area between the concrete and the pushing parts, thereby increasing the pushing force of the concrete on the anchor claws.

[0018] Optionally, the anchor has a second grout outlet at one end away from the cast-in-place pile, which communicates with the first grouting hole; the anchor is provided with a backflow preventer that restricts soil from entering the first grouting hole when the anchor moves away from the cast-in-place pile.

[0019] By adopting the above technical solution, when the anchor is pushed into the soil by the cast-in-place pile, the anti-reverse component can restrict the soil from entering the interior of the anchor; while when the concrete is poured, the concrete can push the anti-reverse component outward from the anchor, thereby opening the second grout outlet hole to allow it to enter the soil. This not only increases the volume of the concrete solidified with the soil, but also improves the fluidity of the concrete, so as to continuously push the anchor claw.

[0020] Optionally, the fixing cylinder is inclinedly disposed at the junction of the side support and the bottom support. The side surface of the cast-in-place pile is hinged with a diagonal brace. Two diagonal braces are disposed opposite each other. The end of the diagonal brace away from the cast-in-place pile is hinged with a sliding member. The two sliding members are slidably connected to the side support and the bottom support, respectively. When the cast-in-place pile moves toward the anchor, the diagonal brace rotates away from the surface of the cast-in-place pile. The cast-in-place pile is provided with a limiting member to restrict the diagonal brace from rotating to be perpendicular to the cast-in-place pile.

[0021] By adopting the above technical solution, while the cast-in-place pile pushes the anchor, the inclined bracing also rotates. When the cast-in-place pile extends into the designated position, the inclined bracing unfolds to be perpendicular to the cast-in-place pile. The two inclined bracing are located on the same straight line and form a triangular structure with the side support and the bottom support, which further improves the support strength and stability of the support structure.

[0022] Optionally, the support plate is provided with a locking component for preventing the sliding member from sliding when the diagonal brace is perpendicular to the grouting pile.

[0023] By adopting the above technical solution, the limiting component on the cast-in-place pile abuts against the inclined brace, which can restrict the rotation of the inclined brace. The locking component can further lock the sliding component, and the amount of the inclined brace is limited, which further improves the stability of the support structure.

[0024] Optionally, the locking assembly includes a locking block, and the surface of the support plate is provided with a second sliding groove for the slider to slide and a locking groove communicating with the second sliding groove. The locking block is movably connected to the locking groove in the direction of entering or moving away from the locking groove. An elastic member is provided in the locking groove to drive the locking block to move away from the locking groove. When the inclined brace is perpendicular to the grouting pile, the two opposite sides of the slider abut against the inner surfaces of the locking block and the second sliding groove, respectively.

[0025] By adopting the above technical solution, after the sliding member slides to the point of contact and passes the locking block, the elastic element drives the locking block to return to its original state, thereby restricting the sliding block from sliding back. The structure is simple and does not require the use of tools or other parts for fixed connection, thus improving construction efficiency.

[0026] Optionally, the diagonal brace is provided with a slot for the locking block to be inserted into.

[0027] By adopting the above technical solution, after the inclined brace is unfolded to be perpendicular to the cast-in-place pile, the two sides of the sliding member abut against the inner surfaces of the locking block and the second sliding groove, respectively. At the same time, the end of the locking block is engaged with the groove of the inclined brace, further improving the stability of the support structure.

[0028] In summary, this application includes at least one of the following beneficial effects:

[0029] 1. The anchor is driven into the soil by hammering the cast-in-place pile. Then, concrete is poured into the cast-in-place pile. The concrete enters the first injection port through the third injection port. The concrete pushes the anchor claw out of the anchor and causes the anchor claw to unfold. The concrete enters the second injection port of the anchor claw from the first injection port and finally flows out from the first grout outlet, thus mixing with the soft soil and solidifying. The concrete also flows out from the second injection port at the bottom of the anchor, increasing the range and volume of concrete solidification with the soil, further reducing the possibility of foundation pit deformation and settlement.

[0030] 2. By increasing the range and volume of concrete bonding with soil, and by deploying diagonal supports, the stability and strength of the support structure are improved. The diagonal supports are also locked at both ends by limiting components and locking components.

[0031] 3. The operation is more convenient and the construction efficiency is improved by using concrete to push the anchor claws out and by using elastic elements to automatically return the locking elements to their original state. Attached Figure Description

[0032] Figure 1 is a schematic diagram of the foundation pit support structure in soft soil area in an embodiment of this application;

[0033] Figure 2 is a cross-sectional view of the foundation pit support structure in the soft soil area before installation in an embodiment of this application;

[0034] Figure 3 is a cross-sectional view of the foundation pit support structure in the soft soil area after installation in an embodiment of this application.

[0035] Figure 4 is a schematic diagram of the structure of the anchor in the embodiment of this application;

[0036] Figure 5 is an enlarged view of point A in Figure 2.

[0037] Explanation of reference numerals in the attached drawings: 1. Support plate; 11. Side support; 12. Bottom support; 13. Clearance hole; 14. Second sluice; 15. Locking groove; 2. Fixing cylinder; 21. Channel; 3. Anchor; 31. First grouting hole; 32. Movable hole; 33. Stepped surface; 34. First sluice; 35. Rotating shaft; 36. Rotating hole; 37. Second grout outlet; 38. Snap-fit ​​part; 4. Anchor claw; 41. Second grouting hole 42. Grouting hole; 43. Soil entry part; 44. Sliding part; 441. Rotating groove; 45. Pushing part; 5. Cast-in-place pile; 51. Third grouting hole; 52. Limiting component; 53. Snap-fit ​​groove; 6. Anti-reverse component; 61. Stop ball; 62. Connecting rope; 7. Diagonal brace; 71. Snap groove; 8. Sliding component; 9. Locking component; 91. Locking block; 92. Elastic component; 93. Second limiting part. Detailed Implementation

[0038] The present application will be further described in detail below with reference to Figures 1-5.

[0039] Referring to Figures 1 and 2, this application discloses a foundation pit support structure in soft soil areas, including a support plate 1, a fixing cylinder 2, anchors 3, and cast-in-place piles 5. The support plate 1 can be fixed to the foundation pit by pile nails or anchor piles. The fixing cylinder 2 is set on the support plate 1, and the anchors 3 are placed inside the fixing cylinder 2. The anchors 3 are provided with several anchor claws 4. The cast-in-place piles 5 abut against the anchors 3. By hammering the cast-in-place piles 5, the anchors 3 are driven into the soil. Then, concrete is poured into the cast-in-place piles 5. The concrete flows from the cast-in-place piles 5 to the anchors 3, pushing the anchor claws 4 out of the anchors 3 and spreading them at an angle. The concrete flows out from the spread anchors 3 and solidifies with the soft soil, thereby increasing the solidification range and volume, reducing the possibility of foundation pit deformation and subsidence, and improving the support effect.

[0040] Referring to Figures 2 and 3, the support plate 1 includes a side support 11 that abuts against the inner side of the pit and a bottom support 12 that abuts against the bottom of the pit. The fixing cylinder 2 can be disposed on the side support 11 or the bottom support 12. In this embodiment, the fixing cylinder 2 is preferably disposed at the junction of the side support 11 and the bottom support 12. The fixing cylinder 2 penetrates through both end faces in the axial direction to form a channel 21. The support plate 1 has a clearance hole 13 corresponding to the channel 21. The cast-in-place pile 5 is movably inserted into the fixing cylinder 2 and abuts against the anchor 3. The end of the cast-in-place pile 5 that abuts against the anchor 3 can be provided with several snap-fit ​​grooves 53 in the circumferential direction. The end of the anchor 3 is provided with a snap-fit ​​part 38 that engages with the snap-fit ​​grooves 53, thereby making the connection tighter. When the cast-in-place pile 5 moves toward the anchor 3, the cast-in-place pile 5 can push the anchor 3 through the relief hole 13 and enter the soil of the foundation pit. The two ends of the cast-in-place pile 5 penetrate along the axial direction to form a third grouting hole 51 for concrete to enter.

[0041] Referring to Figures 4 and 5, the anchor 3 penetrates the top surface to form a first grouting hole 31, and a third grouting hole 51 communicates with the first grouting hole 31; the anchor claw 4 penetrates the top surface to form a second grouting hole 41 communicating with the first grouting hole 31, and the surface of the anchor claw 4 is provided with a plurality of first grout outlet holes 42 respectively communicating with the second grouting hole 41. The inner wall of the first grouting hole 31 is provided with movable holes 32 for the anchor claw 4 to pass through. Specifically, the side surface of the anchor 3 is provided with a stepped structure. In order to increase the setting range of concrete and soil, the stepped structure can be provided with multiple levels. The movable holes 32 are arranged in a circumferential array on the stepped surface 33 of the stepped structure, and a plurality of anchor claws 4 are arranged above the movable holes 32 corresponding to the positions of the movable holes 32 and are slidably connected to the inner surface of the anchor 3.

[0042] Referring to Figure 5, the anchor claw 4 includes an insertion part 43, a sliding part 44, and a pushing part 45, which are respectively connected to the insertion part 43. The inner surface of the anchor 3 has a first groove 34 for the sliding part 44 to slide. The insertion part 43 abuts against the inner wall of the anchor 3. The width of the insertion part 43 is greater than the width of the first groove 34 to reduce the possibility of concrete entering the first groove 34 and restricting the sliding part 44 from sliding. The pushing part 45 is angled to the insertion part 43. When pushed by concrete, the pushing part 45 can drive the insertion part 43 to slide through the movable hole 32 away from the anchor 3.

[0043] After the soil-entry part 43 slides out of the anchor 3, it needs to expand in a direction away from the surface of the anchor 3. Therefore, the sliding part 44 has a rotating groove 441 on the surface facing the sliding direction. The bottom of the inner wall of the first sliding groove 34 is provided with a rotating shaft 35. The anchor claw 4 can slide in a direction away from the anchor 3 until it is engaged with the rotating shaft 35 and abuts against the rotating groove 441. The anchor 3 is connected to the movable hole 32 and has a rotating hole 36 for the anchor claw 4 to rotate around the rotating shaft 35.

[0044] Referring to Figure 5, to increase the pushing force of the concrete on the anchor claw 4, the pushing part 45 is preferably arranged perpendicularly to the soil-entry part 43, with two adjacent pushing parts 45 abutting against each other, and the ends of several pushing parts 45 away from the soil-entry part 43 also abutting against each other, thereby increasing the contact area between the concrete and the pushing part 45. The pushing part 45 is pushed by the concrete, causing the anchor claw 4 to slide downwards. When it reaches the bottom, the rotating shaft 35 engages in the rotating groove 441, thus restricting the anchor claw 4 from continuing to slide. As the concrete continues to act on the pushing part 45, the pushing part 45 will rotate around the rotating shaft 35, that is, it will cause the soil-entry part 43 to rotate upwards and unfold. In order to improve the fluidity of the concrete to ensure that the concrete continues to act on the pushing part 45 to make it rotate, the end of the anchor 3 away from the cast-in-place pile 5 is provided with a second grout outlet 37 communicating with the first grouting hole 31.

[0045] Referring to Figure 5, the anchor 3 is equipped with a backflow preventer 6 that restricts soil from entering the first grouting hole 31 when the anchor 3 moves away from the grouting pile 5. The second grout outlet hole 37 is flared away from the anchor 3. The backflow preventer 6 includes a retaining ball 61 located at the flared end of the second grout outlet hole 37 and a connecting rope 62 connected to the inner wall of the anchor 3. One end of the connecting rope 62 away from the inner wall of the anchor 3 is connected to the retaining ball 61. The diameter of the retaining ball 61 is larger than the inner diameter of the narrowest part of the second grout outlet hole 37 and smaller than the inner diameter of the widest part of the flared end of the second grout outlet hole 37. The retaining ball 61 is made of a lightweight material such as plastic, and the connecting rope 62 can be a nylon rope. Preferably, the edge of the flared end can be toothed to facilitate the anchor 3 entering the soil.

[0046] Referring to Figure 3, to further improve the support strength and stability of the support structure, a diagonal brace 7 is hinged to the side surface of the cast-in-place pile 5. Two diagonal braces 7 are arranged opposite each other. A sliding member 8 is hinged to the end of the diagonal brace 7 away from the cast-in-place pile 5. The two sliding members 8 are slidably connected to the side support 11 and the bottom support 12, respectively. The surfaces of the side support 11 and the bottom support 12 are provided with a second sliding groove 14 for the sliding member 8 to slide. The sliding member 8 is provided with a first limiting part that restricts the sliding member 8 from disengaging from the groove opening of the second sliding groove 14. When the cast-in-place pile 5 moves towards the anchor 3, the diagonal brace 7 rotates away from the surface of the cast-in-place pile 5. A limiting part 52 is provided on the cast-in-place pile 5 to restrict the diagonal brace 7 from rotating to be perpendicular to the cast-in-place pile 5. In a preferred embodiment, when the diagonal brace 7 is perpendicular to the cast-in-place pile 5, one side of the diagonal brace 7 abuts against the limiting part 52 and the other side abuts against the end face of the fixing cylinder 2.

[0047] To further improve structural stability, the support plate 1 is equipped with a locking assembly 9 for locking the sliding member 8 when the diagonal brace 7 is perpendicular to the grouting pile 5. The locking assembly 9 includes a locking block 91. The support plate 1 has a connecting locking groove 15 on the bottom surface of the second sliding groove 14. The locking block 91 is movably connected to the locking groove 15 in the direction of entering or moving away from the locking groove 15. An elastic member 92 is provided in the locking groove 15 to drive the locking block 91 to move away from the locking groove 15. The elastic member 92 can be a spring with a large elastic force. One side of the locking block 91 is set as an inclined surface to facilitate the sliding member 8 to press through. When the diagonal brace 7 is perpendicular to the grouting pile 5, the two opposite sides of the sliding member 8 abut against the inner surfaces of the locking block 91 and the second sliding groove 14, respectively. The diagonal brace 7 has a slot 71 for the end of the locking block 91 to be inserted.

[0048] In other embodiments, the locking component 9 can be a locking bolt, the sliding member 8 has a through hole, and the support plate 1 has a threaded hole corresponding to the through hole that is connected to the locking bolt. The locking bolt passes through the through hole and the threaded hole in sequence to fix the sliding member 8.

[0049] The implementation principle of a foundation pit support structure in soft soil areas according to an embodiment of this application is as follows:

[0050] During construction, the anchor 3 is first placed inside the fixing cylinder 2, and then the grouting pile 5 is placed inside the fixing cylinder 2 to abut against the anchor 3. Then, the anchor 3 is pushed into the soil by tapping the grouting pile 5. At the same time, the inclined support 7 gradually unfolds to be perpendicular to the grouting pile 5, and the sliding part 8 pushes against and passes over the locking block 91. The two sides of the sliding part 8 abut against the inner surface of the locking block 91 and the second sliding groove 14, respectively.

[0051] Concrete is poured into the cast-in-place pile 5. The concrete enters the first injection port through the third injection port, and then the anchor claw 4 is pushed out of the anchor 3 and the anchor claw 4 is unfolded. The concrete enters the second injection port of the anchor claw 4 from the first injection port, and finally flows out from the first grout outlet 42, thus mixing and solidifying with the soft soil. The concrete can push the retaining ball 61 outward from the anchor 3, thereby opening the second grout outlet 37 and entering the soil, increasing the range and volume of concrete and soil solidification, and improving the support effect.

[0052] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A foundation pit support structure in soft soil areas, comprising a support plate (1) fixed within the foundation pit, wherein the support plate (1) includes a side support (11) abutting against the inner side of the foundation pit and a bottom support (12) abutting against the bottom surface of the foundation pit, characterized in that: It also includes a fixed cylinder (2), anchors (3) and cast-in-place piles (5); the fixed cylinder (2) is disposed on the support plate (1), the fixed cylinder (2) penetrates through the two end faces of the axial direction to form a channel (21), and the support plate (1) is provided with a clearance hole (13) corresponding to the channel (21); the anchors (3) are placed in the channel (21), the anchors (3) penetrate through the top surface to form a first grouting hole (31), a plurality of anchor claws (4) are arranged circumferentially in the first grouting hole (31), the inner wall of the first grouting hole (31) is provided with a movable hole (32) for the anchor claws (4) to pass through, the anchor claws (4) penetrate through the top surface to form a second grouting hole (41) communicating with the first grouting hole (31), and the surface of the anchor claws (4) The surface is provided with a plurality of first grout outlet holes (42) that are respectively connected to the second grouting hole (41); the grouting pile (5) is movably inserted into the fixed cylinder (2) and abuts against the anchor (3). When the grouting pile (5) moves toward the anchor (3), the grouting pile (5) can push the anchor (3) through the clearance hole (13) into the foundation pit soil. The two ends of the grouting pile (5) are penetrated along the axial direction to form a third grouting hole (51) for concrete to enter. The third grouting hole (51) is connected to the first grouting hole (31). The anchor claw (4) is pushed by the concrete and can pass through the movable hole (32) to pass out of the anchor (3). The anchor claw (4) and the outer surface of the anchor (3) are angled.

2. The foundation pit support structure in soft soil area according to claim 1, characterized in that: The side surface of the anchor (3) is set in a stepped structure, and the movable hole (32) is set on the stepped surface (33) of the stepped structure. The anchor claw (4) is set above the movable hole (32) and is slidably connected to the inner surface of the anchor (3). The anchor claw (4) includes a soil-entry part (43) and a sliding part (44) and a pushing part (45) respectively connected to the soil-entry part (43). The inner surface of the anchor (3) is provided with a first groove (34) for the sliding part (44) to slide. The pushing part (45) is set at an angle to the soil-entry part (43). The pushing part (45) is pushed by concrete and can drive the soil-entry part (43) to slide away from the anchor (3) through the movable hole (32).

3. The foundation pit support structure in soft soil area according to claim 2, characterized in that: The sliding part (44) has a rotating groove (441) on its surface facing the sliding direction, and a rotating shaft (35) is provided at the bottom of the inner wall of the first sliding groove (34); the anchor claw (4) can slide away from the anchor (3) to the rotating shaft (35) and abut against the rotating groove (441); the anchor (3) is connected to the movable hole (32) and has a rotating hole (36) for the anchor claw (4) to rotate around the rotating shaft (35).

4. The foundation pit support structure in soft soil area according to claim 2, characterized in that: Two adjacent pushing parts (45) abut against each other, and the ends of several pushing parts (45) away from the soil entry part (43) abut against each other.

5. A foundation pit support structure for soft soil areas according to claim 1 or 2, characterized in that: The anchor (3) has a second grout outlet (37) at one end away from the grout pile (5) that communicates with the first grouting hole (31); the anchor (3) is provided with a backflow preventer (6) that restricts soil from entering the first grouting hole (31) when the anchor (3) moves away from the grout pile (5).

6. The foundation pit support structure in soft soil area according to claim 1, characterized in that: The fixed cylinder (2) is inclinedly disposed at the junction of the side support (11) and the bottom support (12). The side surface of the cast-in-place pile (5) is hinged with a diagonal brace (7). There are two diagonal braces (7) arranged opposite each other. The end of the diagonal brace (7) away from the cast-in-place pile (5) is hinged with a sliding member (8). The two sliding members (8) are slidably connected to the side support (11) and the bottom support (12) respectively. When the cast-in-place pile (5) moves toward the anchor (3), the diagonal brace (7) rotates away from the surface of the cast-in-place pile (5). The cast-in-place pile (5) is provided with a limiting member (52) to restrict the diagonal brace (7) from rotating to be perpendicular to the cast-in-place pile (5).

7. A foundation pit support structure for soft soil areas according to claim 6, characterized in that: The support plate (1) is provided with a locking component (9) for locking the sliding member (8) when the diagonal brace (7) is perpendicular to the grouting pile (5).

8. A foundation pit support structure for soft soil areas according to claim 7, characterized in that: The locking assembly (9) includes a locking block (91). The surface of the support plate (1) is provided with a second sliding groove (14) for the sliding member (8) to slide and a locking groove (15) communicating with the second sliding groove (14). The locking block (91) is movably connected to the locking groove (15) in the direction of entering or moving away from the locking groove (15). An elastic member (92) is provided in the locking groove (15) to drive the locking block (91) to move away from the locking groove (15). When the inclined support member (7) is perpendicular to the grouting pile (5), the two opposite sides of the sliding member (8) abut against the inner surfaces of the locking block (91) and the second sliding groove (14), respectively.

9. A foundation pit support structure for soft soil areas according to claim 8, characterized in that: The diagonal brace (7) has a slot (71) for the locking block (91) to be inserted into.

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