Foundation pit temporary steel pipe inclined strut structure under deep soft soil condition and construction method

Abstract

The invention discloses a foundation pit temporary steel pipe inclined strut structure under the deep and thick soft soil condition and a construction method, and relates to the technical field of foundation pit supporting, the foundation pit temporary steel pipe inclined strut structure comprises a foundation pit and a foundation pit supporting, concrete secant piles are arranged on the soil wall around the foundation pit, a top beam is arranged at the tops of the concrete secant piles, and a waist beam is arranged at the position, below the top beam, of the concrete secant piles; supporting piles are inserted in the bottom face of a foundation pit, a fixing structure is arranged on the tops of the supporting piles, a first fixing part is arranged on a top beam, a first steel pipe inclined strut is arranged between the first fixing part and the fixing structure and supports the foundation pit support, and a second fixing part is arranged on a waist beam. And the second steel pipe inclined strut is arranged between the second fixing part and the fixing structure to support the foundation pit support.

Description

Technical Field

[0001] The present application relates to the technical field of foundation pit support, and in particular to a temporary steel pipe diagonal bracing structure and construction method for a foundation pit under deep soft soil conditions. Background Art

[0002] With the rapid decline in urban construction land, new projects are increasingly utilizing underground space to maximize its utilization, leading to ever-higher foundation pit depths. These deep pits often result in construction environments below the groundwater level, which can lead to soil erosion and the risk of pit collapse due to fissure water.

[0003] With respect to the above-mentioned related technologies, the inventors believe that when excavating a foundation pit under deep soft soil conditions, there is a risk that the foundation pit support will be squeezed by the surrounding soil, causing the foundation pit support to collapse and leading to the collapse of the foundation pit. Summary of the Invention

[0004] The purpose of this application is to provide a temporary steel pipe diagonal bracing structure and construction method for foundation pits under deep soft soil conditions, so as to improve the problem that when excavating foundation pits under deep soft soil conditions, the foundation pit supports around the foundation pits will be squeezed by the surrounding soil, causing the foundation pit supports to collapse and the risk of collapse of the foundation pit.

[0005] This application provides a temporary first steel pipe diagonal bracing structure and construction method for a foundation pit under deep soft soil conditions, which adopts the following technical solutions: A temporary steel pipe diagonal brace structure for a foundation pit under deep soft soil conditions includes a foundation pit and a foundation pit support. The foundation pit includes a foundation pit bottom surface and soil walls around it. The foundation pit support is arranged on the side of the soil wall. The foundation pit support includes concrete interlocking piles, crown beams and waist beams. The concrete interlocking piles are inserted into the soil walls. The crown beams are arranged on the tops of the concrete interlocking piles. The waist beams are arranged in the middle of the concrete interlocking piles. A fixed structure is provided on the bottom surface of the foundation pit. A first steel pipe diagonal brace and a second steel pipe diagonal brace are provided on the fixed structure. The first steel pipe diagonal brace is connected to the crown beam, and the second steel pipe diagonal brace is connected to the waist beam.

[0006] By adopting the above technical solution, a first steel pipe diagonal brace is set between the crown beam and the fixed structure, and a second steel pipe diagonal brace is set between the waist beam and the fixed structure to support the foundation pit support, thereby reducing the risk of the concrete interlocking piles of the foundation pit support being squeezed and broken by the soil, causing the foundation pit support to collapse, and avoiding foundation pit collapse.

[0007] Optionally, the first steel pipe diagonal brace is composed of a first supporting steel pipe, a second supporting steel pipe and a connecting steel pipe, and a first fixing part is provided on the crown beam, one end of the first supporting steel pipe is connected to the first fixing part, the other end of the first supporting steel pipe is connected to one end of the connecting steel pipe, one end of the second supporting steel pipe is fixedly connected to the connecting steel pipe, and the other end is connected to the fixed structure.

[0008] By adopting the above technical solution, a first fixing part is set on the crown beam, so that the first steel pipe diagonal brace can be better connected to the crown beam, and the first steel pipe diagonal brace is divided into multiple sections, so that the first steel pipe diagonal brace can be quickly removed after the fixing is completed around the foundation pit, which facilitates the subsequent construction of the foundation pit.

[0009] Optionally, the fixed structure includes a temporary pedestal and a fixed bracket, the temporary pedestal is arranged on the bottom surface of the foundation pit, the fixed bracket is arranged on the temporary pedestal, and a rotating seat is provided on the fixed bracket, and the rotating seat is connected to the second supporting steel pipe and the end away from the connecting steel pipe.

[0010] By adopting the above technical solution, a temporary pedestal is set up at the bottom of the foundation pit, so that the first steel pipe diagonal brace can be better fixed to the bottom of the foundation pit, supporting the foundation pit support, and a rotating seat is set on the fixed bracket one, so that the fixed bracket one can be better connected to the first steel pipe diagonal brace.

[0011] Optionally, support piles are provided at the bottom of the fixed structure, the support piles are inserted into the bottom surface of the foundation pit, and the tops of the support piles are connected to temporary caps.

[0012] By adopting the above technical solution, support piles are inserted into the bottom of the foundation pit to fix the temporary foundation pile and prevent the temporary foundation pile from moving, so that the first steel pipe diagonal brace and the second steel pipe diagonal brace are separated from the foundation pit support, causing the foundation pit support to collapse.

[0013] Optionally, a fixing column 1 is provided on the first fixing part, and the fixing column 1 is in contact with the inner wall of the first supporting steel pipe. A fixing groove is provided through the fixing column 1, and a fixing hole is provided through the position of the first supporting steel pipe corresponding to the fixing groove, and fixing parts are inserted into the fixing groove and the fixing hole.

[0014] By adopting the above technical solution, the first supporting steel pipe is restricted by the first fixing column to prevent the first supporting steel pipe from detaching from the first fixing part, and the first supporting steel pipe is fixed by the fixing piece through the fixing hole and the fixing groove to prevent the first supporting steel pipe from sliding off the first fixing column and causing the first steel pipe diagonal support to fall down.

[0015] Optionally, connecting columns are provided at both ends of the connecting steel pipe, and outer side walls at both ends of the connecting columns are respectively fitted with the inner walls of the first supporting steel pipe and the second supporting steel pipe.

[0016] By adopting the above technical solution, the connection between the first supporting steel pipe, the second supporting steel pipe and the connecting steel pipe is internally supported by the connecting column, thereby preventing the connection between the first supporting steel pipe, the second supporting steel pipe and the connecting steel pipe from being disconnected, making it impossible for the first steel pipe diagonal brace to support the foundation pit support.

[0017] Optionally, the second steel pipe diagonal brace is composed of a third supporting steel pipe and a fourth supporting steel pipe, a second fixing part is provided on the waist beam, the second fixing part is connected to one end of the third supporting steel pipe, and the fourth supporting steel pipe is connected to the other end of the third supporting steel pipe, and the fixing structure includes a second fixing bracket, a rotating seat is rotatably connected to the second fixing bracket, and the rotating seat is connected to the fourth supporting steel pipe.

[0018] By adopting the above technical solution, the second steel pipe diagonal brace is divided into several sections of steel pipes for connection, which is convenient for installation and disassembly. The rotating seat on the second fixed bracket can better support the second steel pipe diagonal brace for foundation pit support.

[0019] Optionally, a second fixing column is provided on the second fixing part, and the second fixing column is in contact with the inner wall of the third supporting steel pipe. A fixing groove is provided through the second fixing column, and a fixing hole is opened at a position corresponding to the second fixing column on the third supporting steel pipe, and fixing parts are provided in the fixing hole and the fixing groove.

[0020] By adopting the above technical solution, the third supporting steel pipe can be better connected to the second fixing part, thereby preventing the third supporting steel pipe from falling off from the second fixing part.

[0021] Optionally, a temporary steel pipe diagonal bracing structure and construction method for a foundation pit under deep soft soil conditions includes the following steps: Concrete interlocking piles are set in the soil walls around the foundation pit, a crown beam is set on the top of the concrete interlocking piles, and a waist beam is set below the crown beam; Install the fixed structure on the bottom of the foundation pit. First, insert the support piles into the bottom of the foundation pit. Install a temporary cap on the top of the support piles. Install the fixed bracket 1 and the fixed bracket 2 on the temporary cap. A first steel pipe diagonal brace is provided between the crown beam and the fixed structure, and a second steel pipe diagonal brace is provided between the waist beam and the fixed structure; After the soil walls around the foundation pit are fixed, the first steel pipe diagonal brace and the second steel pipe diagonal brace set between the foundation pit support and the fixed bracket are dismantled, and then the fixed structure is dismantled.

[0022] Optionally, the installation of the steel pipe brace includes the following steps: The first steel pipe diagonal brace includes a first supporting steel pipe, a second supporting steel pipe and a connecting steel pipe. Connecting columns are provided at both ends of the connecting steel pipe. The first supporting steel pipe and the second supporting steel pipe are sleeved on the outer surface of the connecting column and connected to the connecting steel pipe. A first fixing portion is provided on the crown beam. The first supporting steel pipe is connected to the first fixing portion. The second supporting steel pipe is connected to the rotating seat on the first fixing bracket. A fixing column 1 is provided on the first fixing part, a fixing groove is provided on the fixing column 1, a fixing hole corresponding to the fixing hole is provided on the first supporting steel pipe, and a fixing piece is inserted into the fixing hole and the fixing groove to fix the first supporting steel pipe; The second steel pipe diagonal brace is composed of a third supporting steel pipe and a fourth supporting steel pipe. A second fixing portion is provided on the waist beam. The third supporting steel pipe is connected to the second fixing portion, and the fourth supporting steel pipe is connected to the rotating seat on the second fixing bracket. A second fixing column is provided on the second fixing portion, a fixing groove is opened on the second fixing column, a fixing hole corresponding to the fixing hole is opened on the third supporting steel pipe, and a fixing piece is inserted into the fixing hole and the fixing groove to fix the third supporting steel pipe; In summary, this application includes at least one of the following beneficial technical effects: 1. The first and second steel pipe diagonal braces support the crown beam and waist beam of the foundation pit support, so that the foundation pit support can better block the four sides of the foundation pit, prevent soil from squeezing into the foundation pit, and avoid the collapse of the foundation pit support. The first and second fixing parts are provided on the crown beam and waist beam to make the connection between the first and second steel pipe diagonal braces more stable, and prevent the first and second steel pipe diagonal braces from falling off the crown beam and waist beam. 2. The first steel pipe diagonal brace is divided into a first supporting steel pipe and a second supporting steel pipe, and the first supporting steel pipe and the second supporting steel pipe are connected by a connecting steel pipe to facilitate the installation and removal of the first steel pipe diagonal brace. The connecting columns provided at both ends of the connecting steel pipe provide internal support for the connection between the first supporting steel pipe and the second supporting steel pipe and the connecting steel pipe to prevent the connection between the first supporting steel pipe and the second supporting steel pipe from being suddenly disconnected and causing the first supporting steel pipe and the second supporting steel pipe to fall; 3. A rotating seat is set on the fixed bracket 1 and the fixed bracket 2, and the connection angle with the first steel pipe diagonal brace and the second steel pipe diagonal brace is adjusted by rotating the rotating seat, so that the first steel pipe diagonal brace and the second steel pipe diagonal brace can better support the foundation pit support. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is an overall schematic diagram of a temporary steel pipe diagonal bracing structure for a foundation pit under deep soft soil conditions.

[0024] Figure 2 It is a cross-sectional view of the steel pipe brace.

[0025] Figure 3 yes Figure 2 A partial enlarged view of middle A.

[0026] In the figure, 1. foundation pit; 11. bottom surface of foundation pit; 12. soil wall; 2. foundation pit support; 21. concrete interlocking pile; 22. crown beam; 23. waist beam; 3. first steel pipe diagonal brace; 31. first supporting steel pipe; 32. second supporting steel pipe; 33. connecting steel pipe; 34. connecting column; 4. second steel pipe diagonal brace; 41. third supporting steel pipe; 42. fourth supporting steel pipe; 5. supporting pile; 6. fixed structure; 61. temporary pedestal; 62. fixed bracket one; 63. fixed bracket two; 64. rotating seat; 7. first fixing part; 8. second fixing part; 9. fixed column one; 10. fixed column two; 13. fixing hole; 14. fixing piece; 15. fixing groove. DETAILED DESCRIPTION

[0027] The following is combined with Figure 1 -Attached Figure 3 , further details of this application are given.

[0028] Example 1 A temporary steel pipe diagonal bracing structure and construction method for foundation pit under deep soft soil conditions, referring to Figure 1 and Figure 2 , including a foundation pit 1 and a foundation pit support 2, the foundation pit 1 is composed of a foundation pit bottom surface 11 and a soil wall 12, the concrete interlocking piles 21 of the foundation pit 1 support 2 block the soil wall 12 of the foundation pit 1, and the crown beam 22 on the top of the concrete interlocking pile 21 is poured with concrete, and a first fixing part 7 is fixed on the crown beam 22 with bolts, and the first fixing part 7 is evenly distributed on the crown beam 22. A fixed structure 6 is arranged on the bottom surface of the foundation pit 1, and the fixed structure 6 includes a temporary cap 61, a fixed bracket 1 62 and a fixed bracket 2 63. A supporting pile 5 is inserted into the bottom surface of the foundation pit 1, and a temporary cap 61 is fixed on the top of the supporting pile 5 by pre-buried bolts, and the fixed bracket 1 62 and the fixed bracket 2 63 are fixed to the temporary cap 61 by bolts. The rotating shafts welded on both sides of the rotating seat 64 are connected to the fixed bracket 1 62 and the fixed bracket 2 63 respectively through bearings, and the first steel pipe diagonal brace 3 and the second steel pipe diagonal brace 4 can be better connected to the rotating seat 64 through the rotation of the rotating seat 64.

[0029] Reference Figures 1 to 3 The first steel pipe brace 3 includes a first supporting steel pipe 31, a second supporting steel pipe 32 and a connecting steel pipe 33. A fixing column 9 is welded on the first fixing part 7. A fixing groove 15 is provided on the fixing column 9. The inner wall of the first supporting steel pipe 31 fits with the fixing column 9. The first supporting steel pipe 31 has a fixing hole 13 at a position corresponding to the fixing groove 15. A fixing member 14 is inserted in the fixing hole 13 and the fixing groove 15. The fixing member 14 is a fixing pin, which makes the connection between the first supporting steel pipe 31 and the first fixing part 7 more stable.

[0030] Reference Figure 1 and Figure 2The other end of the first supporting steel tube 31 is fixed to the connecting steel tube 33 by bolts, and one end of the second supporting steel tube 32 is fixed to the other end of the connecting steel tube 33 by bolts. Connecting columns 34 are welded at both ends of the connecting steel tube 33. The outer surface of the connecting column 34 fits with the inner wall of the first supporting steel tube 31 and the second supporting steel tube 32, making the connection between the first supporting steel tube 31 and the second supporting steel tube 32 and the connecting steel tube 33 more stable. The other end of the second supporting steel tube 32 is connected to the rotating seat 64 by bolts.

[0031] Reference Figure 1 and Figure 2 A waist beam 23 is cast below the crown beam 22, and a second fixing portion 8 is fixed to the waist beam 23 with bolts. The second fixing portions 8 are evenly distributed on the waist beam 23. A second steel pipe diagonal brace 4 is connected between the second fixing portion 8 and the second fixing bracket 63. A second fixing column 10 is welded on the second fixing portion 8. The second steel pipe diagonal brace 4 includes a third supporting steel pipe 41 and a fourth supporting steel pipe 42. One end of the third supporting steel pipe 41 is connected to the second fixing portion 8 by bolts. The inner side wall of the third supporting steel pipe 41 is fitted with the second fixing column 10, and a fixing groove is provided on the second fixing column 10. 15. The third supporting steel pipe 41 is provided with a fixing hole 13 at a position corresponding to the fixing groove 15. A fixing member 14 is inserted into the fixing hole 13 and the fixing groove 15. The fixing member 14 is a fixing pin, which makes the connection between the third supporting steel pipe 41 and the second fixing part 8 more stable. The other end of the third supporting steel pipe 41 is fixedly connected to the fourth supporting steel pipe 42 by bolts. The fourth supporting steel pipe 42 is connected to the rotating seat 64 on the second fixing bracket 63 by bolts. The waist beam 23 is supported by the third supporting steel pipe 41 and the fourth supporting steel pipe 42, thereby supporting the foundation pit 1.

[0032] Example 2 S100: Concrete interlocking piles 21 are installed on the soil wall 12 around the foundation pit 1 to block the soil wall 12. A crown beam 22 is cast on top of the concrete interlocking piles 21. After the crown beam 22 is completed, a waist beam 23 is cast below the crown beam 22. S200: Install the fixed structure 6 on the foundation pit bottom surface 11. The fixed structure 6 includes a temporary cap 61, a first fixing bracket 62, and a second fixing bracket 63. First, insert the support pile 5 into the foundation pit bottom surface 11. Install the temporary cap 61 on the top of the support pile 5. Install the first fixing bracket 62 and the second fixing bracket 63 on the temporary cap 61. Install the rotating seat 64 on the first fixing bracket 62 and the second fixing bracket 63. S300: A first steel pipe diagonal brace 3 is provided between the crown beam 22 and the fixed structure 6 for support, and a second steel pipe diagonal brace 4 is provided between the waist beam 23 and the fixed structure 6 for support; S310, the first steel pipe brace 3 includes a first supporting steel pipe 31, a second supporting steel pipe 32, and a connecting steel pipe 33. Connecting columns 34 are welded to both ends of the connecting steel pipe 33. The first and second supporting steel pipes 31, 32 are sleeved on the outer surfaces of the connecting columns 34, and the ends of the connecting steel pipe 33 are abutted and connected to the connecting steel pipe 33. A first fixing portion 7 is provided on the crown beam 22. The first supporting steel pipe 31 is connected to the first fixing portion 7, and the second supporting steel pipe 32 is connected to the rotating seat 64 on the fixing bracket 1 62. S311: A fixing column 9 is provided on the first fixing portion 7, and a fixing groove 15 is formed in the fixing column 9. A fixing hole 13 corresponding to the fixing groove 15 is formed in the first supporting steel tube 31. A fixing member 14 is inserted into the fixing hole 13 and the fixing groove 15 to fix the first supporting steel tube 31. S320, the second steel pipe diagonal brace 4 is composed of a third supporting steel pipe 41 and a fourth supporting steel pipe 42. A second fixing portion 8 is provided on the waist beam 23. The third supporting steel pipe 41 is connected to the second fixing portion 8, and the fourth supporting steel pipe 42 is connected to the rotating seat 64 on the second fixing bracket 63. S321, install a second fixing column 10 on the second fixing portion 8, define a fixing groove 15 on the second fixing column 10, define a fixing hole 13 corresponding to the fixing groove 15 on the third support steel tube 41, insert a fixing member 14 into the fixing hole 13 and the fixing groove 15, and fix the third support steel tube 41; S400, after the soil walls 12 around the foundation pit 1 are fixed, the first steel pipe diagonal brace 3 and the second steel pipe diagonal brace 4 set between the foundation pit 1 support and the fixed structure 6 are dismantled, and then each section of the first steel pipe diagonal brace 3 and the second steel pipe diagonal brace 4 is dismantled, and then the fixed structure 6 is dismantled.

[0033] The implementation principle of the embodiment of this application is: Concrete interlocking piles 21 are set on the soil walls 12 around the foundation pit 1, a crown beam 22 is set on the top of the concrete interlocking pile 21, a waist beam 23 is set at the position of the concrete interlocking pile 21 below the crown beam 22, a supporting pile 5 is inserted into the bottom surface 11 of the foundation pit, a temporary base 61 is installed on the top of the supporting pile 5, a fixed bracket 1 62 and a fixed bracket 2 63 are installed on the temporary base 61, and a rotating seat 64 is respectively installed on the fixed bracket 1 62 and the fixed bracket 2 63 through a rotating shaft. The first fixing part 7 is evenly arranged on the crown beam 22. The first fixing part 7 is provided with a fixing column 9, and connecting columns 34 are provided at both ends of the connecting steel pipe 33. The first supporting steel pipe 31 and the second supporting steel pipe 32 are connected to the connecting steel pipe 33 through the connecting column 34 to form a first steel pipe diagonal brace 3. The first supporting steel pipe 31 is connected to the first fixing part 7 through the fixing column 9, and the fixing piece 14 is inserted into the fixing hole 13 on the first supporting steel pipe 31 and the fixing groove 15 on the fixing column 9 for fixing. After adjusting the angle of the rotating seat 64, it is connected to the second supporting steel pipe 32, so that the first steel pipe diagonal brace 3 supports the foundation pit 1. The waist beam 23 is provided with a second fixing portion 8, and the second fixing portion 8 is provided with a second fixing column 10. The third supporting steel pipe 41 and the fourth supporting steel pipe 42 are connected to form the second steel pipe diagonal brace 4. The third supporting steel pipe 41 passes through the second fixing column 10 and is connected to the second fixing portion 8. The fixing piece 14 is inserted into the fixing hole 13 on the third supporting steel pipe 41 and the fixing groove 15 on the second fixing column 10 for fixing. The rotating seat 64 is adjusted in angle and connected to the fourth supporting steel pipe 42, so that the second steel pipe diagonal brace 4 supports the foundation pit 1. After the foundation pit 1 is fixed, the first steel pipe diagonal brace 3 and the second steel pipe diagonal brace 4 are removed, and then each section of the first steel pipe diagonal brace 3 and the second steel pipe diagonal brace 4 is removed.

[0034] The examples of this specific embodiment are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, any equivalent changes made based on the structure, shape, and principle of this application should be included in the scope of protection of this application.

Claims

1. A temporary steel pipe bracing structure for a foundation pit under deep soft soil conditions, comprising a foundation pit (1) and a foundation pit support (2), wherein the foundation pit (1) comprises a foundation pit bottom surface (11) and surrounding earth walls (12), the foundation pit support (2) is arranged on the side of the earth wall (12), the foundation pit support (2) comprises a concrete bite pile (21), a crown beam (22) and a waist beam (23), the concrete bite pile (21) is inserted into the earth wall (12), the crown beam (22) is arranged on the top of the concrete bite pile (21), and the waist beam (23) is arranged in the middle of the concrete bite pile (21), characterized in that: The bottom surface (11) of the foundation pit is provided with a fixed structure (6), and a first steel pipe diagonal brace (3) and a second steel pipe diagonal brace (4) are provided on the fixed structure (6), the first steel pipe diagonal brace (3) is connected to a crown beam (22), and the second steel pipe diagonal brace (4) is connected to a waist beam (23).

2. The temporary steel pipe bracing structure for foundation pits in deep soft soil according to claim 1, characterized in that: The first steel pipe diagonal brace (3) is composed of a first supporting steel pipe (31), a second supporting steel pipe (32) and a connecting steel pipe (33); a first fixing portion (7) is provided on the crown beam (22); one end of the first supporting steel pipe (31) is connected to the first fixing portion (7); the other end of the first supporting steel pipe (31) is connected to one end of the connecting steel pipe (33); one end of the second supporting steel pipe (32) is fixedly connected to the connecting steel pipe (33), and the other end is connected to the fixed structure (6).

3. The temporary steel pipe bracing structure for foundation pits in deep soft soil according to claim 2, characterized in that: The fixed structure (6) includes a temporary support (61) and a fixed bracket (62), wherein the temporary support (61) is arranged on the bottom surface of the foundation pit (11), and the fixed bracket (62) is arranged on the temporary support (61). A rotating seat (64) is arranged on the fixed bracket (62), and the rotating seat (64) is connected to the second supporting steel pipe (32) and the end away from the connecting steel pipe (33).

4. The temporary steel pipe bracing structure for foundation pits in deep soft soil according to claim 3 is characterized by: A supporting pile (5) is provided at the bottom of the fixed structure (6), the supporting pile (5) is inserted into the bottom surface (11) of the foundation pit, and the top of the supporting pile (5) is connected to a temporary bearing platform (61).

5. The temporary steel pipe bracing structure for foundation pits in deep soft soil according to claim 2, characterized in that: A fixing column (9) is provided on the first fixing portion (7), and the fixing column (9) is in contact with the inner wall of the first supporting steel pipe (31). A fixing groove (15) is provided through the fixing column (9), and a fixing hole (13) is provided through a position of the first supporting steel pipe (31) corresponding to the fixing groove (15). Fixing members (14) are inserted into the fixing groove (15) and the fixing hole (13).

6. The temporary steel pipe bracing structure for foundation pits in deep soft soil according to claim 2, characterized in that: Connecting columns (34) are provided at both ends of the connecting steel pipe (33), and the outer walls of both ends of the connecting column (34) are respectively fitted with the inner walls of the first supporting steel pipe (31) and the second supporting steel pipe (32).

7. The temporary steel pipe bracing structure for foundation pits in deep soft soil according to claim 1, characterized in that: The second steel pipe diagonal brace (4) is composed of a third supporting steel pipe (41) and a fourth supporting steel pipe (42); a second fixing portion (8) is provided on the waist beam (23); the second fixing portion (8) is connected to one end of the third supporting steel pipe (41); the fourth supporting steel pipe (42) is connected to the other end of the third supporting steel pipe (41); the fixing structure (6) includes a second fixing bracket (63); a rotating seat (64) is rotatably connected to the second fixing bracket (63); and the rotating seat (64) is connected to the fourth supporting steel pipe (42).

8. A temporary steel pipe diagonal bracing structure for a foundation pit (1) under deep soft soil conditions according to claim 7, characterized in that: The second fixing portion (8) is provided with a second fixing column (10), the second fixing column (10) is in contact with the inner wall of the third supporting steel pipe (41), a fixing groove (15) is provided through the second fixing column (10), the third supporting steel pipe (41) is provided with a fixing hole (13) at a position corresponding to the second fixing column (10), and a fixing member (14) is provided in the fixing hole (13) and the fixing groove (15).

9. A temporary steel pipe bracing structure and construction method for a foundation pit under deep soft soil conditions, characterized by: It comprises the temporary steel pipe diagonal bracing structure for foundation pit under deep soft soil conditions as described in any one of claims 1 to 8, S100, concrete interlocking piles (21) are arranged on the soil walls (12) around the foundation pit (1), a crown beam (22) is arranged on the top of the concrete interlocking piles (21), and a waist beam (23) is arranged below the crown beam (22); S200, a fixed structure (6) is provided on the bottom surface of the foundation pit (11), the fixed structure (6) including a temporary bearing platform (61), a fixed support 1 (62) and a fixed support 2 (63), the support pile (5) is first inserted into the bottom surface of the foundation pit (11), the temporary bearing platform (61) is provided on the top of the support pile (5) for installation, and the fixed support 1 (62) and the fixed support 2 (63) are installed on the temporary bearing platform (61); S300, a first steel pipe diagonal brace (3) is provided between the crown beam (22) and the fixed structure (6), and a second steel pipe diagonal brace (4) is provided between the waist beam (23) and the fixed structure (6); S400, after the soil walls (12) around the foundation pit (1) are fixed, the first steel pipe diagonal brace (3) and the second steel pipe diagonal brace (4) provided between the foundation pit support (2) and the fixed structure (6) are dismantled, and then the fixed structure (6) is dismantled.

10. A temporary steel pipe diagonal bracing structure and construction method for a foundation pit (1) under deep soft soil conditions according to claim 9, characterized in that: S310, the first steel pipe diagonal brace (3) includes a first supporting steel pipe (31), a second supporting steel pipe (32) and a connecting steel pipe (33), connecting columns (34) are provided at both ends of the connecting steel pipe (33), the first supporting steel pipe (31) and the second supporting steel pipe (32) are sleeved on the outer surface of the connecting column (34) and connected to the connecting steel pipe (33), a first fixing portion (7) is provided on the crown beam (22), the first supporting steel pipe (31) is connected to the first fixing portion (7), and the second supporting steel pipe (32) is connected to the rotating seat (64) on the fixing bracket (62); S311, a fixing column (9) is provided on the first fixing portion (7), a fixing groove (15) is provided on the fixing column (9), a fixing hole (13) corresponding to the fixing groove (15) is provided on the first supporting steel pipe (31), a fixing member (14) is inserted into the fixing hole (13) and the fixing groove (15), and the first supporting steel pipe (31) is fixed; S320, the second steel pipe diagonal brace (4) is composed of a third supporting steel pipe (41) and a fourth supporting steel pipe (42), a second fixing portion (8) is provided on the waist beam (23), the third supporting steel pipe (41) is connected to the second fixing portion (8), and the fourth supporting steel pipe (42) is connected to the rotating seat (64) on the second fixing bracket (63); S321, a second fixing column (10) is provided on the second fixing portion (8), a fixing groove (15) is provided on the second fixing column (10), a fixing hole (13) corresponding to the fixing groove is provided on the third supporting steel pipe (41), a fixing member (14) is inserted into the fixing hole (13) and the fixing groove (15), and the third supporting steel pipe (41) is fixed.

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