A reinforcing device and a supporting method for a super-large deep foundation pit in coastal soft soil

Abstract

The present application relates to the technical field of supporting and reinforcing of soft soil foundation pit, in particular to a reinforcing device and a supporting method for coastal soft soil geological super-large deep foundation pit, the double-layer grid assembly comprises a pair of parallel distributed rear grid and front grid, the rear grid and the front grid are telescopically connected with the inserting column, one end of the extruding inserting plate is fixed on the telescopic rod of the hydraulic machine, and the beneficial effect is that: by installing the side plate on one side of the existing triaxial mixing pile, the foundation is loosened and connected with the side plate during the mixing process, and the grid assembly is installed on one side close to the triaxial mixing pile waterproof curtain by using the inserting and extruding mode, the grid assembly forms a vertical distribution of concrete reinforcing wall by using high-pressure guniting during resetting, and is connected with the waterproof curtain, thereby forming effective lateral support plate reinforcement for the waterproof curtain, greatly improving the stability of the structure, and reducing the requirements for subsequent pipe pile density and depth.

Description

Technical Field

[0001] This invention relates to the field of support and reinforcement technology for soft soil foundation pits, specifically to a reinforcement device and support method for ultra-large and deep foundation pits in coastal soft soil geology. Background Technology

[0002] Traditional support methods for soft soil in coastal areas use cast-in-place piles, mixing piles for water stoppage, and internal support structures. For soft soil foundation pits deeper than 12m, two internal support structures are required. The internal support structures affect the construction progress of the basement structure, and the lattice columns need to penetrate the basement floor slab and floor slab, causing a significant risk of leakage in the floor slab.

[0003] In existing technologies, to enhance the reinforcement of foundation pit support, double rows of piles are typically installed on both the inner and outer sides of the mixing pile waterstop curtain, along with pipe piles. However, this not only requires a high density of pipe piles but also poses a risk of water seepage. Furthermore, during the support process, the lateral pressure generated by grouting can easily cause the mixing pile waterstop curtain to crack. Since the mixing pile waterstop curtain is simply cast with concrete slurry and lacks internal reinforcement devices, it can only provide waterproofing and lacks sufficient support strength. Moreover, the structure of the pipe piles is separated from the mixing pile waterstop curtain, which makes the waterstop structure prone to cracking. Summary of the Invention

[0004] The purpose of this invention is to provide a reinforcement device and support method for ultra-large deep foundation pits in coastal soft soil geology, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A reinforcement device for supporting ultra-large deep foundation pits in coastal soft soil geology is disclosed. The reinforcement device includes a triaxial mixing pile and a hydraulic press. A drive top seat is provided at the front end of the triaxial mixing pile. Three sets of spaced spiral mixing piles are provided at the lower end of the drive top seat. An ear seat is provided on one side of the lower end of the drive top seat. A side plate parallel to the three sets of spiral mixing piles is inserted into the ear seat. A double-layer grid assembly is installed in the middle section of the side plate. A lower insert plate with a tapered port is provided at the lower end of the side plate for insertion. An upper plate for insertion of a limiting insert plate and a pressing insert plate is provided at the upper end of the side plate. An upper insertion port communicating with the double-layer grid assembly is provided on the upper plate. The double-layer grid assembly includes a pair of parallel rear grids and a front grid. An insert post is telescopically inserted between the rear grid and the front grid. One end of the pressing insert plate is fixed to the telescopic rod of the hydraulic press.

[0007] Preferably, the drive top seat is provided with a drive assembly for driving the three sets of spiral mixing piles to rotate, the upper end of the drive top seat is provided with a lifting shaft for lifting and lowering drive, and the lower end of the spiral mixing pile is provided with a spray nozzle for grouting.

[0008] Preferably, the ear seat is provided with an adjustment groove for an elongated groove post, and a pair of adjustment rods are provided on the side wall of the upper plate. The adjustment rods extend to the outside of the adjustment groove, and the ends of the adjustment rods are fixed by locking nuts. A top plate is provided at the upper end of the upper plate. The outer contour of the top plate is larger than the port of the adjustment groove, and the top plate is pressed against the upper end face of the ear seat.

[0009] Preferably, an installation groove is provided on the middle outer wall of the side plate near the spiral mixing pile, and the double-layer grid assembly is slidably disposed in the installation groove, with the gap width between the side plate and the spiral mixing pile being less than twice the thickness of the double-layer grid assembly.

[0010] Preferably, the inner wall of the adjusting groove is provided with sliding grooves symmetrically distributed front and back, and the side wall of the upper plate is provided with side blocks that are slidably inserted into the sliding grooves.

[0011] Preferably, a guide groove is provided between the upper plate and the mounting groove. The guide groove is provided on the upper inner wall of the mounting groove, and the guide groove is inclined along the side away from the mounting groove. The guide groove is in contact with the lower end of the extrusion plate.

[0012] Preferably, both the rear grille and the front grille are composed of multiple sets of intersecting beam arms. Each beam arm is welded together from a pair of spaced steel bars. The rear grille is provided with multiple sets of first end plates, which are located at the connection points of the intersecting beam arms. The first end plates are provided with inserts extending forward from the front grille.

[0013] Preferably, the front and rear sidewalls of the front grille are respectively provided with a second end plate and a third end plate, the positions of the second end plate and the third end plate correspond one-to-one with the first end plate, the four corners of the second end plate and the third end plate are provided with bolt holes for mounting bolts, and the middle of the second end plate and the third end plate is provided with a through hole facing the insertion post.

[0014] Preferably, a boss is provided on the side of the insertion post near the first end plate, the outer diameter of the boss is larger than the inner diameter of the through insertion hole, the insertion post is tubular, and a side hole is provided on the outer wall of the end of the insertion post near the boss.

[0015] A method for supporting ultra-large deep foundation pits in coastal soft soil geology using a reinforcement device, the method comprising the following steps:

[0016] Step 1: First, level the side that needs support and install a three-axis mixing pile. Install a hydraulic press on the other side and set up a concrete mixer on site. Use the concrete mixer to feed material to the three-axis mixing pile. The telescopic end of the hydraulic press is connected to the extrusion plate.

[0017] Step 2: Place a double-layer grid assembly on the side plate and insert a limiting plate extending to the middle gap of the double-layer grid assembly at the upper end. Stir and penetrate the coastal soft soil through the spiral mixing pile, and perform the initial spraying and mixing at the same time. As the mixing is carried out, the geology becomes loose, which makes it easier for the side plate to be inserted synchronously.

[0018] Step 3: After the insertion is in place, remove the limiting plate so that the extrusion plate is aligned with the upper insertion port. At this time, the hydraulic press drives the extrusion plate to descend, thereby extruding the double-layer grid assembly laterally to the outside of the side plate. While extruding laterally, the reaction force of the soil is used to make the rear grid and the front grid fit together, so that the insertion post extends to the outside of the front grid and is inserted and connected to the side using the spiral mixing pile.

[0019] Step 4: The spiral mixing pile rotates in the opposite direction and rises. During the rising process, grout is sprayed again for mixing, and the pressure of the grout is increased so that the concrete slurry penetrates along the inserted column to one side of the double-layer grid assembly, and the side plate is pulled up at the same time.

[0020] Step 5: After solidification, fill the long groove formed by the side plate insertion with grout.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This invention installs a side plate on one side of an existing triaxial mixing pile, using the mixing process to soften the foundation and insert the side plate. Simultaneously, the grid assembly is installed on the side close to the water-stop curtain of the triaxial mixing pile using an insertion and extrusion method. High-pressure grouting during resetting causes the grid assembly to form a vertically distributed concrete reinforcement wall and connect with the water-stop curtain, forming an effective lateral support plate reinforcement for the water-stop curtain. This greatly improves the stability of the structure and reduces the requirements for the density and depth of subsequent pipe piles. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 This is a schematic diagram of the downward grouting structure of the present invention;

[0025] Figure 3 This is a three-dimensional structural diagram of the double-layer grid assembly of the present invention mounted on the side plate;

[0026] Figure 4 This is a schematic diagram of the three-dimensional structure of the side plate of the present invention;

[0027] Figure 5 The double-layer grid assembly of the present invention;

[0028] Figure 6 This is a schematic diagram of the rear three-dimensional structure of the side plate of the present invention;

[0029] Figure 7 This is a three-dimensional structural diagram of the rear grille of the present invention;

[0030] Figure 8 This is a schematic diagram of the three-dimensional structure of the front grille of the present invention.

[0031] In the diagram: 1. Drive top seat; 2. Lifting shaft; 3. Extrusion insert plate; 4. Ear seat; 5. Side plate; 6. Spiral mixing pile; 7. Limiting insert plate; 8. Double-layer grid assembly; 9. Adjusting rod; 10. Adjusting groove; 11. Nozzle; 12. Mounting groove; 13. Side block; 14. Upper plate; 15. Top plate; 16. Upper insertion port; 17. Lower insert plate; 18. Locking nut; 19. Rear grid; 20. Front grid; 21. Guide sloping groove; 22. First end plate; 23. Boss; 24. Insert column; 25. Side hole; 26. Second end plate; 27. Third end plate; 28. Through insertion hole; 29. ​​Bolt hole. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figures 1 to 8 The present invention provides a technical solution:

[0034] A reinforcement device for supporting ultra-large deep foundation pits in coastal soft soil geology is disclosed. The reinforcement device includes a triaxial mixing pile and a hydraulic press. A drive top seat 1 is provided at the front end of the triaxial mixing pile. Three sets of spaced spiral mixing piles 6 are provided at the lower end of the drive top seat 1. A drive assembly for driving the three sets of spiral mixing piles 6 to rotate is provided on the drive top seat 1. A lifting shaft 2 for lifting and lowering is provided at the upper end of the drive top seat 1. A spray nozzle 11 for grouting is provided at the lower end of the spiral mixing piles 6.

[0035] The lifting and lowering is achieved by the lifting rod 2, the spiral mixing pile 6 is used for rotation and mixing, and the nozzle 11 is used for spraying grout to achieve full mixing of soft soil and concrete slurry, forming a sealed water-stop curtain.

[0036] A lug 4 is provided on one side of the lower end of the drive top seat 1. A side plate 5 parallel to the three sets of spiral mixing piles 6 is inserted into the lug 4. A double-layer grid assembly 8 is installed in the middle section of the side plate 5. A lower insert plate 17 with a tapered port is provided at the lower end of the side plate 5 for insertion. An upper plate 14 is provided at the upper end of the side plate 5 for insertion of a limiting insert plate 7 and a pressing insert plate 3. An upper insertion port 16 communicating with the double-layer grid assembly 8 is provided on the upper plate 14. The double-layer grid assembly 8 includes a pair of parallel rear grids 19 and front grids 20. An insert post 24 is telescopically inserted between the rear grids 19 and the front grids 20. One end of the pressing insert plate 3 is fixed to the telescopic rod of the hydraulic press.

[0037] In the initial state, by inserting the limiting plate 7, the lower end of the limiting plate 7 extends between the rear grille 19 and the front grille 20, thereby allowing the double-layer grille assembly 8 to be stably installed on the side plate 5 and lowered accordingly. After lowering, the limiting plate 7 is removed, and the hydraulic press drives the extrusion plate 3 to lower. The extrusion laterally extrudes the double-layer grille assembly 8, causing the double-layer grille assembly 8 to separate from the side plate 5. The insertion column 24 is used to break the gap between the side plate 5 and the spiral mixing pile 6, so that it is connected to the water-stop curtain. Then, through secondary casting, the double-layer grille assembly 8 forms a concrete reinforced wall connected to the water-stop curtain.

[0038] A method for supporting ultra-large and deep foundation pits in coastal soft soil geology using a reinforcement device, the method comprising the following steps:

[0039] Step 1: First, level the side that needs support and install a three-axis mixing pile. Install a hydraulic press on the other side and set up a concrete mixer on site. Use the concrete mixer to feed material to the three-axis mixing pile. The telescopic end of the hydraulic press is connected to the extrusion plate 3.

[0040] Step 2: Place the double-layer grid assembly 8 on the side plate 5, and insert the limiting plate 7 extending to the middle gap of the double-layer grid assembly 8 at the upper end. Stir and probe the soft soil geology of the coastal area through the spiral mixing pile 6, and at the same time carry out the initial grouting and mixing. As the geology is loosened by stirring, it is easier for the side plate 5 to be inserted synchronously.

[0041] Step 3: After the insertion is in place, remove the limiting plate 7 so that the extrusion plate 3 is aligned with the upper insertion port 16. At this time, the hydraulic press drives the extrusion plate 3 to descend, thereby extruding the double-layer grid assembly 8 laterally to the outside of the side plate 5. While extruding laterally, the reaction force of the soil is used to make the rear grid 19 and the front grid 20 fit together, so that the insertion post 24 extends to the outside of the front grid 20 and is inserted and connected to the side using the spiral mixing pile 6.

[0042] Step 4: The spiral mixing pile 6 rotates in the opposite direction and rises. During the rising process, grout is sprayed again for mixing, and the pressure of the grout is increased so that the concrete slurry penetrates along the insert column 24 to one side of the double-layer grid assembly 8, and the side plate 5 is pulled up at the same time.

[0043] Step 5: After solidification, fill the long groove formed by the insertion of side plate 5 with grout and cast.

[0044] Example 2: Based on Example 1, in order to facilitate the adjustment of the gap width between the side plate 5 and the spiral mixing pile 6 and to facilitate the wall breaking and connection when the insertion column 24 is inserted, an adjustment groove 10 with an elongated groove pile is provided on the ear seat 4. A pair of adjustment rods 9 are provided on the side wall of the upper plate 14. The adjustment rods 9 extend to the outside of the adjustment groove 10, and the ends of the adjustment rods 9 are fixed by locking nuts 18. A top plate 15 is provided at the upper end of the upper plate 14. The outer contour of the top plate 15 is larger than the port of the adjustment groove 10. The top plate 15 is pressed against the upper end face of the ear seat 4. A sliding groove symmetrically distributed in front and behind is provided on the inner wall of the adjustment groove 10. A side block 13 that is slidably inserted into the sliding groove is provided on the side wall of the upper plate 14.

[0045] The lateral position of the side plate 5 is adjusted by setting an elongated oval adjustment groove 10, the side plate 5 is smoothly slidable by using the side block 13, and the side plate 5 is conveniently fixed by using the cooperation of the adjustment rod 9 and the locking nut 18.

[0046] Example 3: Based on Example 2, in order to facilitate the insertion and lateral extrusion of the extrusion plate 3, an installation groove 12 is provided on the middle outer wall of the side plate 5 near the spiral mixing pile 6. The double-layer grid assembly 8 is slidably disposed in the installation groove 12. The gap width between the side plate 5 and the spiral mixing pile 6 is less than twice the thickness of the double-layer grid assembly 8. A guide groove 21 is provided between the upper plate 14 and the installation groove 12. The guide groove 21 is disposed on the upper inner wall of the installation groove 12. The guide groove 21 is inclined along the side away from the installation groove 12. The guide groove 21 is in contact with the lower end of the extrusion plate 3.

[0047] By setting the guide groove 21, the lower end of the extrusion plate 3 is positioned, and then the inclined surface is used to achieve smooth descent and insertion, ensuring the stable installation of the double-layer grid assembly 8 and avoiding mutual jamming between the double-layer grid assembly 8. At the same time, by using the relative spacing width, the insertion of the column 24 is prevented from interfering with the spiral mixing pile 6.

[0048] Example 4: Based on Example 3, in order to stabilize the structure of the double-layer grille assembly 8, both the rear grille 19 and the front grille 20 are composed of multiple sets of intersecting beam arms. The beam arms are welded together by a pair of steel bars that are spaced apart. The rear grille 19 is provided with multiple sets of first end plates 22. The first end plates 22 are located at the connection position of the intersecting beam arms. The first end plates 22 are provided with inserts 24 extending to the front grille 20. The front and rear side walls of the front grille 20 are respectively provided with second end plates 26 and third end plates 27. The positions of the second end plates 26 and third end plates 27 correspond one-to-one with the first end plates 22. The four corners of the second end plates 26 and third end plates 27 are provided with bolt holes 29 for mounting bolts. The middle of the second end plates 26 and third end plates 27 is provided with through holes 28 facing the inserts 24.

[0049] By setting the end plate structure, the insertion post 24 can be easily installed, and then the initial insertion of the insertion post 24 can be used to realize the telescopic connection between the rear grille 19 and the front grille 20.

[0050] Example 5: Based on Example 4, in order to ensure the forming quality of the concrete reinforced wall, a boss 23 is provided on the side of the insert 24 near the first end plate 22. The outer diameter of the boss 23 is larger than the inner diameter of the through hole 28. The insert 24 is tubular, and a side hole 25 is provided on the outer wall of the end of the insert 24 near the boss 23.

[0051] By setting the boss 23 to form a step between the boss and the insert 24, the rear grid 19 and the front grid 20 are prevented from being completely fitted due to the lateral compression of the extrusion plate 3, thereby reducing the contact with the concrete slurry and thus reducing the strength of the reinforced wall. At the same time, by setting the tubular insert 24 and the side hole 25, the high-pressure permeated concrete slurry at the front end of the insert is accurately delivered to the gap between the rear grid 19 and the front grid 20 for casting, further ensuring the forming quality of the concrete reinforced wall.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A reinforcement device for supporting ultra-large deep foundation pits in coastal soft soil geology, the reinforcement device comprising a triaxial mixing pile and a hydraulic press, wherein a drive top seat (1) is provided at the front end of the triaxial mixing pile, and three sets of spaced spiral mixing piles (6) are provided at the lower end of the drive top seat (1), characterized in that: A lug (4) is provided on one side of the lower end of the drive top seat (1). A side plate (5) parallel to the three sets of spiral mixing piles (6) is inserted into the lug (4). A double-layer grid assembly (8) is installed in the middle section of the side plate (5). A lower insert plate (17) with a tapered port is provided at the lower end of the side plate (5). An upper plate (14) for inserting the limiting insert plate (7) and the extrusion insert plate (3) is provided at the upper end of the side plate (5). An upper insertion port (16) communicating with the double-layer grid assembly (8) is provided on the upper plate (14). The double-layer grid assembly (8) includes a pair of parallel rear grids (19) and front grids (20). An insert post (24) is telescopically inserted between the rear grids (19) and the front grids (20). One end of the extrusion insert plate (3) is fixed on the telescopic rod of the hydraulic press. The side plate (5) has an installation groove (12) on the middle outer wall near the spiral mixing pile (6). The double-layer grid assembly (8) is slidably disposed in the installation groove (12). The gap width between the side plate (5) and the spiral mixing pile (6) is less than twice the thickness of the double-layer grid assembly (8).

2. The reinforcement device for supporting ultra-large deep foundation pits in coastal soft soil geology according to claim 1, characterized in that: The drive top seat (1) is provided with a drive assembly for driving the three sets of spiral mixing piles (6) to rotate. The upper end of the drive top seat (1) is provided with a lifting shaft (2) for lifting drive, and the lower end of the spiral mixing pile (6) is provided with a spray nozzle (11) for spraying.

3. The reinforcement device for supporting ultra-large deep foundation pits in coastal soft soil geology according to claim 2, characterized in that: The ear seat (4) is provided with an elongated groove-shaped adjustment groove (10). A pair of adjustment rods (9) are provided on the side wall of the upper plate (14). The adjustment rods (9) extend to the outside of the adjustment groove (10), and the ends of the adjustment rods (9) are fixed by locking nuts (18). The upper end of the upper plate (14) is provided with a top plate (15). The outer contour of the top plate (15) is larger than the port of the adjustment groove (10). The top plate (15) is pressed against the upper end face of the ear seat (4).

4. The reinforcement device for supporting ultra-large deep foundation pits in coastal soft soil geology according to claim 3, characterized in that: The inner wall of the adjustment groove (10) is provided with sliding grooves symmetrically distributed front and back, and the side wall of the upper plate (14) is provided with side blocks (13) that are slidably inserted into the sliding grooves.

5. A reinforcement device for supporting ultra-large deep foundation pits in coastal soft soil geology according to claim 4, characterized in that: A guide groove (21) is provided between the upper plate (14) and the mounting groove (12). The guide groove (21) is provided on the upper inner wall of the mounting groove (12). The guide groove (21) is inclined along the side away from the mounting groove (12). The guide groove (21) is in contact with the lower end of the extrusion plate (3).

6. A reinforcement device for supporting ultra-large deep foundation pits in coastal soft soil geology according to claim 5, characterized in that: Both the rear grille (19) and the front grille (20) are composed of multiple sets of intersecting beam arms. The beam arms are welded together by a pair of steel bars that are spaced apart. The rear grille (19) is provided with multiple sets of first end plates (22). The first end plates (22) are located at the connection position of the intersecting beam arms. The first end plates (22) are provided with inserts (24) extending to the front grille (20).

7. A reinforcement device for supporting ultra-large deep foundation pits in coastal soft soil geology according to claim 6, characterized in that: The front and rear side walls of the front grille (20) are respectively provided with a second end plate (26) and a third end plate (27). The positions of the second end plate (26) and the third end plate (27) correspond one-to-one with the first end plate (22). The four corners of the second end plate (26) and the third end plate (27) are provided with bolt holes (29) for mounting bolts. The middle of the second end plate (26) and the third end plate (27) is provided with a through hole (28) facing the insert post (24).

8. A reinforcement device for supporting ultra-large deep foundation pits in coastal soft soil geology according to claim 7, characterized in that: The insert (24) has a boss (23) on the side near the first end plate (22). The outer diameter of the boss (23) is larger than the inner diameter of the through hole (28). The insert (24) is tubular, and a side hole (25) is provided on the outer wall of the end of the insert (24) near the boss (23).

9. The support method for the reinforcement device for ultra-large deep foundation pits in coastal soft soil as described in any one of claims 1-8, characterized in that: The support method includes the following steps: Step 1: First, level the side that needs support and install the three-axis mixing pile. Install the hydraulic press on the other side and set up a concrete mixer on site. Use the concrete mixer to supply material to the three-axis mixing pile. The telescopic rod of the hydraulic press is connected to the extrusion plate (3). Step 2: Place the double-layer grid assembly (8) on the side plate (5) and insert the limiting plate (7) extending to the middle gap of the double-layer grid assembly (8) at the upper end. Stir and probe the coastal soft soil through the spiral mixing pile (6) and perform the initial grouting. As the mixing is carried out, the geology becomes loose, which makes it easier for the side plate (5) to be inserted synchronously. Step 3: After the lowering is in place, remove the limiting insert plate (7) so that the extrusion insert plate (3) is aligned with the upper insertion port (16). At this time, the hydraulic press drives the extrusion insert plate (3) to descend, thereby extruding the double-layer grid assembly (8) laterally to the outside of the side plate (5). While extruding laterally, the reaction force of the soil is used to make the rear grid (19) and the front grid (20) fit together, so that the insert (24) extends to the outside of the front grid (20) and is inserted and connected to the side using the spiral mixing pile (6). Step 4: The spiral mixing pile (6) rotates in the opposite direction and rises. During the rising process, it is sprayed and mixed again, and the pressure of the sprayed grout is increased so that the concrete slurry penetrates along the insert column (24) to one side of the double-layer grid assembly (8), and simultaneously pulls the side plate (5) to rise. Step 5: After solidification, fill the long groove formed by the insertion of the side plate (5) with grout.

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