Hollow precast pile and anti-seepage wall groove wall two-way support stability maintaining structure

Abstract

The utility model relates to the construction technical field of cutoff wall and discloses a hollow precast pile and two-way support stability maintaining structure of cutoff wall groove wall. The hollow precast pile comprises a plurality of axially connected pile sections, a through hole is arranged in the center of the pile body to form a hollow structure, a reinforcement cage is arranged in the interior, and male and female joints are embedded at the two ends of the pile section; the rectangular block of the male joint is rotated and dislocated after penetrating the rectangular hole of the female joint to form mechanical locking. An inner barrier and an outer barrier are arranged at the gap between adjacent pile sections, and SAP concrete is filled between the two, which expands after being exposed to water to form an expansion section. The cutoff wall groove wall structure is formed by alternately embedding the hollow precast pile in the soil between the two sides of the cutoff wall groove. The utility model is suitable for soft soil, sand and pebble strata, can effectively reduce the risk of groove wall collapse, improve the support stability maintaining effect, and is convenient, efficient and easy to construct.

Description

Technical Field

[0001] This utility model relates to the field of anti-seepage wall construction technology, specifically to a hollow precast pile and a bidirectional support and stabilization structure for the anti-seepage wall trench. Background Technology

[0002] In the construction of anti-seepage walls, "trenching" is a key process, which requires mechanical excavation to form a continuous trench-shaped space, and then pouring concrete or anti-seepage materials into the trench to form the wall.

[0003] Currently, trenching for seepage prevention walls is mostly carried out using techniques such as hydraulic grab trenching, impact drilling, or milling. However, trenching operations are constrained by complex geological conditions and construction environments. When constructing in soft soil or gravel strata, the risk of trench wall instability increases significantly. This is because soft soil and gravel strata have low cohesion and weak shear strength, and the lateral pressure imbalance of the trench wall during trenching can easily lead to collapse.

[0004] To address the issue of trench wall collapse, existing technologies primarily employ solutions such as mud slurry wall protection and sheet pile support. Mud slurry wall protection relies on a mud cake formed by the mud to balance the pressure on the trench walls. However, in strata with high sand and gravel content and high permeability, the mud is prone to loss, the mud cake formation is ineffective, and the stability of the wall protection is difficult to guarantee. While sheet pile support offers strong resistance to lateral displacement, its construction costs are high, and problems such as pile deformation are prone to occur during deep trench construction.

[0005] In summary, existing anti-seepage wall reinforcement technologies still have shortcomings in terms of adaptability, stability, and economy. Therefore, developing a precast pile structure with reliable structure, strong adaptability, convenient construction, and reasonable cost, along with a matching anti-seepage wall reinforcement system, has become an urgent need to promote the upgrading of anti-seepage wall construction technology and ensure project safety. Utility Model Content

[0006] To solve the above-mentioned technical problems, this utility model proposes a two-way support and stabilization structure for hollow precast piles and anti-seepage wall trenches.

[0007] The technical solution to the technical problem solved by this utility model is as follows: Firstly, this technical solution proposes a hollow precast pile, comprising several pile sections connected in series along the axial direction. Each pile section includes a pile body, the pile body having a through cavity at its center, forming a hollow structure. Several male and female connectors for mutual use are pre-embedded and connected to both ends of the pile body. The male connector includes a first sleeve and a shaft, one end of which is rotatably connected to the first sleeve; the other end of the shaft is connected to a rectangular block. The female connector includes a second sleeve, one end of which is connected to an end cap, the end cap having a through rectangular hole. A rotational space is constructed between the end of the end cap and the other end of the second sleeve, allowing the rectangular block to enter and rotate. The rectangular block can penetrate the rectangular hole and enter the rotational space. When the rectangular block rotates, it can be misaligned with the rectangular hole, forming a mechanical lock.

[0008] Optionally, the outer wall of the shaft is fixedly connected to a hexagonal sleeve or has a mounting hole.

[0009] Optionally, the shaft and the first sleeve are detachably connected, with one end of the shaft inserted into the first sleeve; the outer wall of the shaft has a boss, and a locking sleeve is detachably fitted on the shaft, which can be threadedly connected to the first sleeve, and one end of the locking sleeve abuts against the boss to achieve axial limiting of the shaft.

[0010] Optionally, a pad is provided inside the second sleeve, and the pad is fixedly connected to or detachably connected to the second sleeve; there is a gap between the end cap and the front end of the pad, which forms the rotation space.

[0011] Optionally, the pad and the second sleeve are connected by a threaded connection.

[0012] Optionally, a reinforcing cage is provided inside the pile body, and the male and female connectors are welded and fixed to the vertical bars of the reinforcing cage, respectively.

[0013] Optionally, there is a gap between two adjacent pile sections, which serves as a filling space; it also includes an inner barrier and an outer barrier, the two ends of the inner barrier being inserted and fixed to the cavities of the upper and lower pile sections respectively; the two ends of the outer barrier are connected to the outer walls of the upper and lower pile sections respectively; the area between the inner barrier and the outer barrier is filled with SAP concrete; the SAP concrete is a dry powder mixture of SAP superabsorbent resin particles and well-mixed plain concrete; the SAP concrete expands and is squeezed outwards when it comes into contact with water, and forms an expansion joint in the soil after solidification.

[0014] Optionally, the inner barrier is a filter screen, and the filter screen is wrapped with a first flexible geotextile that is permeable to water.

[0015] Optionally, the outer barrier is a second flexible geotextile, and the inner and / or outer walls of the second flexible geotextile are provided with a water-proof layer.

[0016] Secondly, this technical solution proposes a two-way support and stabilization structure for the anti-seepage wall trench, in which several hollow precast piles are embedded at intervals in the soil on both sides of the anti-seepage wall trench.

[0017] The above technical solution has the following advantages or beneficial effects: 1. In this design, the pile segments utilize a mechanical locking design with male and female connectors. A rigid connection is formed through the rotation and misalignment of rectangular blocks, facilitating easy operation and rapid assembly, thus avoiding the high-temperature deformation risks associated with traditional welding. Standardized factory production of the pile segments and on-site mechanical connection and assembly effectively improve construction efficiency. The hollow structure reduces concrete usage and lowers costs.

[0018] 2. The male and female connectors are welded and fixed to the vertical bars of the reinforcing cage, forming a coordinated force-bearing system of the reinforcing cage, connectors, and pile. This structure significantly improves the bending stiffness of the pile, effectively suppresses the deflection deformation of the pile in the deep trench, and solves the problem of easy buckling of steel sheet piles under high stress.

[0019] 3. By setting internal and external barrier components and SAP concrete, when the SAP absorbs water and expands, it can squeeze the external barrier component to extend towards the surrounding soil, ultimately forming a variable-diameter structure of the pile body + outwardly protruding expansion joint. This variable-diameter design can increase the contact area between the pile body and the soil. Compared with traditional precast piles of the same diameter, the expansion joint can be embedded in the gaps of the surrounding soil, forming a mechanical interlocking effect. In addition, it can also increase the lateral friction resistance. The active compression of the expansion joint on the surrounding soil can enhance the tightness of the fit between the pile body and the soil. Especially for soft soil, gravel and other strata with low cohesion, it can effectively reduce the risk of collapse of the trench wall due to lateral pressure imbalance. Attached Figure Description

[0020] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0021] Figure 1 This is the main structural view of the hollow precast pile proposed in the first example of this utility model.

[0022] Figure 2 yes Figure 1 The three-dimensional structure of the pile segments that make up the hollow precast pile Figure 1 .

[0023] Figure 3 yes Figure 1 The three-dimensional structure of the pile segments that make up the hollow precast pile Figure 2 .

[0024] Figure 4 It is a structural cross-sectional view of a single male and female connector when they are mated.

[0025] Figure 5 It is a sectional view of the separate structure of a single male connector and a female connector.

[0026] Figure 6 This is an exploded view of the female connector.

[0027] Figure 7 This is an exploded view of the male connector.

[0028] Figure 8 This is a structural schematic diagram of the hollow precast pile proposed in the second example.

[0029] Figure 9 yes Figure 8 Rear view of a hollow precast pile.

[0030] Figure 10 It is a sectional view along the AA direction.

[0031] Figure 11 yes Figure 10 Enlarged schematic diagram of the structure of region B in the middle.

[0032] Figure 12 This is an exploded view of the internal barrier component.

[0033] Figure 13 This is a 3D view of the external barrier.

[0034] Figure 14 This is a three-dimensional view of the two-way support and stabilization structure of the anti-seepage wall trench proposed in this utility model.

[0035] Explanation of reference numerals in the attached figures: 1. Pile section; 11. Male connector; 111. First sleeve; 112. Shaft; 113. Boss; 114. Hexagonal sleeve; 115. Locking sleeve; 1151. First through hole; 1121. Second through hole; 116. Locking pin; 117. Rectangular block; 12. Female connector; 121. Second sleeve; 122. Spacer block; 1221. Force application hole; 123. End cap; 1231. Rectangular hole; 124. Rotation space; 13. Vertical reinforcement; 2. External barrier; 3. SAP concrete; 4. Internal barrier; 41. Filter screen; 42. First flexible geotextile; 5. Anti-seepage wall trench. Detailed Implementation

[0036] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0037] Example 1: like Figure 1 - Figure 7 As shown, this embodiment proposes a hollow precast pile, comprising several pile sections 1 connected in series along the axial direction. Each pile section 1 includes a pile body with a through cavity at its center, forming a hollow structure. The hollow structure reduces the amount of concrete used, thereby lowering the overall cost of the precast pile. Several male connectors 11 and female connectors 12 are pre-embedded at both ends of the pile body for mutual use; wherein: The male connector 11 includes a first sleeve 111 and a shaft 112. One end of the shaft 112 is rotatably connected to the first sleeve 111. The shaft 112 can only rotate and cannot move axially, possessing only one degree of freedom: rotation. The other end of the shaft 112 is connected to a rectangular block 117, forming a T-shaped plug.

[0038] The female connector 12 includes a second sleeve 121, one end of which is connected to an end cap 123. The end cap 123 can be welded to the second sleeve 121 or threaded to it. The end cap 123 has a through rectangular hole 1231, which is adapted to a rectangular block 117. A rotation space 124 is formed between the end of the end cap 123 and the other end of the second sleeve 121, allowing the rectangular block 117 to enter and rotate. The rectangular block 117 can pass through the rectangular hole 1231 into the rotation space 124. When the rectangular block 117 rotates, it can be misaligned with the rectangular hole 1231 to form a mechanical lock.

[0039] There are several methods for constructing the rotation space 124, including direct and indirect construction. One method involves a well-designed size, with a pre-designed gap between the end cap 123 and the closed end of the second sleeve 121, which serves as the rotation space 124. Another method involves providing a pad 122 inside the second sleeve 121, which can be fixedly or detachably connected to the second sleeve 121, for example, by using a threaded connection. A gap exists between the end cap 123 and the front end of the pad 122, forming the rotation space 124.

[0040] In this embodiment, to facilitate the rotation of the shaft 112, a hexagonal sleeve 114 is fixedly connected to the outer wall of the shaft 112, or an installation hole is provided. The hexagonal sleeve 114 is directly welded to the outer wall of the shaft 112. During construction, a wrench is used to engage the hexagonal sleeve 114 to achieve tightening; alternatively, a screwdriver or insert rod is used to insert into the installation hole to achieve tightening. Both methods are feasible and suitable for actual construction environments.

[0041] Regarding the rotary connection between shaft 112 and first sleeve 111, the following structure can be adopted: The shaft 112 and the first sleeve 111 are detachably connected. One end of the shaft 112 is inserted into the first sleeve 111, forming a plug-in detachable fit. The outer wall of the shaft 112 has a boss 113, forming a stepped shaft shape. The boss 113 provides a rigid reference for axial positioning. A locking sleeve 115 is detachably fitted on the shaft 112. The locking sleeve 115 can be threadedly connected to the first sleeve 111, and one end of the locking sleeve 115 abuts against the boss 113 to achieve axial positioning of the shaft 112.

[0042] When the locking sleeve 115 is tightened to the preset position, its end face abuts tightly against the annular boss 113 of the shaft 112. The thread preload and the mechanical limiting of the boss 113 create a dual constraint, achieving both a detachable connection between the shaft 112 and the first sleeve 111 and completely restricting the axial movement of the shaft 112, retaining only its single degree of freedom of rotation around its own axis. This design ensures that when the shaft 112 drives the rectangular block 117 to rotate, it always remains within the preset rotation space 124 of the female connector 12, preventing the rectangular block 117 from deviating from the locking position due to axial movement, thus guaranteeing the reliability and accuracy of the mechanical locking of the male and female connector 12.

[0043] In addition, after rotating the shaft 112, in order to lock and position the shaft 112 and prevent accidental rotation, various methods can be used. For example, the shaft 112 can be welded and fixed to the first sleeve 111; another method is to use a detachable method, such as setting a locking pin 116. A radial first through hole 1151 is opened on the locking sleeve 115, and a radial second through hole 1121 is opened on the shaft 112. The first through hole 1151 or the second through hole 1121 is a threaded hole, and the locking pin 116 has external threads. By inserting the locking pin 116 into the first through hole 1151 and the second through hole 1121, the shaft 112 is limited.

[0044] In some embodiments, the pad 122 is provided with a force application hole 1221, which can be an internal hexagonal hole, a cross groove, or a slotted groove. The pad 122 can be easily screwed on with existing screwdrivers or other tools.

[0045] In some embodiments, a reinforcing cage is provided inside the pile body, and the male connector 11 and the female connector 12 are welded and fixed to the vertical bars 13 of the reinforcing cage, respectively. The reinforcing cage uses multiple longitudinally continuous vertical bars 13 as the core load-bearing skeleton, and is combined with ring stirrups tied or welded at intervals to form a three-dimensional grid structure, which not only provides tensile and shear support for the pile concrete, but also becomes the key carrier for achieving rigid connection between the male connector 11, the female connector 12 and the pile body.

[0046] The first sleeve 111 of the male connector 11 and the second sleeve 121 of the female connector 12 need to be fully welded to the vertical bars 13 at the ends of the reinforcing cage at both ends of the pile section 1 during the prefabrication process in the factory. This creates a collaborative force-bearing system of "connection-reinforcing cage-pile concrete". On the one hand, the longitudinal tensile force and lateral shear force transmitted by the male and female connectors 12 can be directly transmitted to the vertical bars 13 of the reinforcing cage through the weld, and then distributed to the entire pile body by the vertical bars 13, avoiding local stress concentration caused by the connector relying solely on the pile concrete to transmit force. On the other hand, the reinforcing cage forms a positioning constraint on the connectors at both ends of the pile section 1, ensuring that the male connector 11 and the female connector 12 are always coaxial with the pile axis, avoiding connector offset during prefabrication, and providing a basic guarantee for the accurate alignment of the male and female connectors 12 when the pile section 1 is spliced ​​later.

[0047] The above solution has the following technical effects: 1. In this design, pile section 1 employs a mechanical locking design with male connector 11 and female connector 12. A rigid connection is formed by rotating and misaligning rectangular blocks 117, which is convenient to operate and allows for rapid assembly, avoiding the risk of high-temperature deformation associated with traditional welding operations. Pile section 1 is manufactured in a standardized factory and assembled mechanically on-site, effectively improving construction efficiency. The hollow structure reduces concrete usage and lowers costs.

[0048] 2. The male connector 11 and the female connector 12 are welded and fixed to the vertical reinforcement bars 13 of the steel cage, forming a steel cage-connector-pile collaborative stress-bearing system. This structure significantly improves the bending stiffness of the pile, effectively suppresses the deflection deformation of the pile in the deep trench, and solves the problem of easy buckling of steel sheet piles under high stress.

[0049] Example 2: like Figure 8 - Figure 13 As shown, based on Example 1, the hollow precast pile proposed in this example further includes the following structure: There is a gap between two adjacent pile sections 1. This gap serves as a filling space. It should be noted that this gap is not a construction error, but a functional space specifically designed for SAP concrete filling. The hollow precast pile also includes an inner barrier 4 and an outer barrier 2. The two ends of the inner barrier 4 are respectively inserted and fixed to the cavities of the upper and lower pile sections 1. The two ends of the outer barrier 2 are respectively connected to the outer walls of the upper and lower pile sections 1, forming a wrapping structure. The area between the inner barrier 4 and the outer barrier 2 is filled with SAP concrete 3. SAP concrete 3 is a dry powder mixture of SAP super absorbent resin particles and well-mixed plain concrete. When SAP concrete 3 comes into contact with water, it expands and is squeezed outward. After solidification, it forms an expansion joint in the soil.

[0050] The inner barrier 4 is a filter screen 41, wrapped with a first flexible geotextile 42 that allows water to pass through. Its main function is to achieve water permeability and prevent leakage while restraining internal expansion. The filter screen 41 can be made of galvanized steel wire mesh to provide rigid support. The outer side of the mesh is entirely wrapped with short-fiber needle-punched nonwoven geotextile to prevent material leakage while ensuring water permeability. The inner barrier 4 is generally annular, with pre-reserved insertion sections at both ends, allowing it to be directly inserted into the cavities of the upper and lower piles.

[0051] The outer barrier 2 is a second flexible geotextile, with a waterproof layer on its inner and / or outer walls. This waterproof layer can be a waterproof adhesive layer or a 0.1–0.2 mm thick HDPE film laminated to the outer wall of the geotextile to enhance its waterproofing effect. It is important to note that during installation, a 20%–30% slack allowance should be left in the middle of the outer barrier 2 to provide sufficient outward deformation space for subsequent SAP expansion.

[0052] When driving the pile, the waterproof layer of the outer barrier 2 can completely block the water in the surrounding soil from seeping into the filling space, and prevent the SAP concrete from absorbing water and expanding before the pile is in place. If the SAP expands in advance, it will cause the outer barrier 2 to bulge, which will hinder the driving of the pile and make it easy to get stuck in the soil.

[0053] After the pile is installed, water is filled into the pile through the hole. The water can seep into the filling space through the permeable pores of the geotextile, providing a water source for the SAP particles to absorb water and expand. When the SAP concrete absorbs water and expands, the inner barrier 4 can withstand the radially inward expansion pressure, restraining the SAP concrete from overflowing into the hollow hole of the pile, and ensuring that the expansion force is directed entirely towards the outer soil.

[0054] Application results: By setting up an inner barrier 4, an outer barrier 2, and SAP concrete 3, when the SAP absorbs water and expands, it can squeeze the outer barrier 2 to extend towards the surrounding soil, ultimately forming a variable-diameter structure of the pile body + the outward-protruding expansion joint. This variable-diameter design can increase the contact area between the pile body and the soil. Compared with traditional precast piles of the same diameter, the expansion joint can be embedded in the gaps of the surrounding soil, forming a mechanical interlocking effect. In addition, it can also increase the lateral friction resistance. The active compression of the expansion joint on the surrounding soil can enhance the tightness of the fit between the pile body and the soil. Especially for soft soil, gravel, and other strata with low cohesion, it can effectively reduce the risk of collapse of the trench wall due to lateral pressure imbalance.

[0055] Example 3: like Figure 14 As shown, based on the aforementioned structural advantages of hollow precast piles, this embodiment also proposes a bidirectional support and stabilization structure for the anti-seepage wall trench 5. Several hollow precast piles are embedded at intervals in the soil on both sides of the anti-seepage wall trench 5. The structural strength of the precast piles themselves offsets the lateral pressure on the trench wall, specifically addressing the collapse problem caused by low cohesion and weak shear strength in soft soil and gravel strata, thus reducing the risk of trench wall instability. Furthermore, the spacing between the precast piles and the trench wall can be flexibly adjusted, optimizing the pile spacing according to the trench wall depth and stratum characteristics, further enhancing the targetedness and stability of the reinforcement effect.

[0056] After the hollow precast pile is installed, the SAP concrete expansion joint is triggered by water filling the hollow cavity of the pile to form an outward convex ring structure. This expansion joint can be embedded in the pores of the soil on both sides, forming a mechanical interlocking effect, enhancing the tightness of the pile and soil, increasing the pile-soil friction resistance, and indirectly improving the support force transmission efficiency. In addition, the active compression of the soil by the expansion joint can compact the surrounding loose soil and reduce soil permeability.

[0057] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0058] Although the specific embodiments of the utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the utility model. Based on the technical solution of the utility model, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the utility model.

Claims

1. A hollow precast pile, comprising a plurality of pile sections (1) connected in series along the axial direction, characterized in that, The pile section (1) includes a pile body, the pile body having a through cavity at its center, forming a hollow structure; several male connectors (11) and female connectors (12) are pre-embedded at both ends of the pile body for use; wherein: the male connector (11) includes a first sleeve (111) and a shaft (112), one end of the shaft (112) is rotatably connected to the first sleeve (111); the other end of the shaft (112) is connected to a rectangular block (117); the female connector (12) includes a second sleeve (121), the second sleeve... One end of the cylinder (121) is connected to an end cap (123), and the end cap (123) has a through rectangular hole (1231); a rotating space (124) is constructed between the end of the end cap (123) and the other end of the second sleeve (121) to allow the rectangular block (117) to enter and rotate. The rectangular block (117) can pass through the rectangular hole (1231) and enter the rotating space (124). When the rectangular block (117) rotates, it can be misaligned with the rectangular hole (1231) to form a mechanical lock.

2. A hollow precast pile according to claim 1, characterized in that, The outer wall of the shaft (112) is fixedly connected to a hexagonal sleeve (114) or has an installation hole.

3. A hollow precast pile according to claim 1, characterized in that, The shaft (112) and the first sleeve (111) are detachably connected. One end of the shaft (112) is inserted into the first sleeve (111). The outer wall of the shaft (112) has a boss (113). A locking sleeve (115) is detachably fitted on the shaft (112). The locking sleeve (115) can be threadedly connected to the first sleeve (111), and one end of the locking sleeve (115) abuts against the boss (113) to achieve axial limiting of the shaft (112).

4. A hollow precast pile according to claim 1, characterized in that, The second sleeve (121) has a pad (122) inside, and the pad (122) is fixedly connected to the second sleeve (121) or detachably connected; there is a gap between the end cap (123) and the front end of the pad (122), and the gap forms the rotation space (124).

5. A hollow precast pile according to claim 4, characterized in that, The pad (122) and the second sleeve (121) are connected by a threaded connection.

6. A hollow precast pile according to claim 1, characterized in that, The pile body is equipped with a steel cage, and the male connector (11) and female connector (12) are welded and fixed to the vertical bars (13) of the steel cage, respectively.

7. A hollow precast pile according to claim 1, characterized in that, There is a gap between two adjacent pile sections (1), which serves as a filling space; it also includes an inner barrier (4) and an outer barrier (2), the two ends of the inner barrier (4) are respectively inserted and fixed to the cavities of the upper and lower pile sections (1); the two ends of the outer barrier (2) are respectively connected to the outer walls of the upper and lower pile sections (1); the area between the inner barrier (4) and the outer barrier (2) is filled with SAP concrete (3); the SAP concrete (3) is a dry powder of SAP super absorbent resin particles and well mixed plain concrete; the SAP concrete (3) expands and is squeezed outward after encountering water, and forms an expansion joint in the soil after solidification.

8. A hollow precast pile according to claim 7, characterized in that, The inner barrier (4) is a filter screen, and the filter screen is wrapped with a first flexible geotextile that is permeable to water.

9. A hollow precast pile according to claim 7, characterized in that, The outer barrier (2) is a second flexible geotextile, and a water-proof layer is provided on the inner wall and / or outer wall of the second flexible geotextile.

10. A bidirectional support and stabilization structure for a seepage-proof wall trench, characterized in that, Several hollow precast piles as described in any one of claims 1-9 are embedded at intervals in the soil on both sides of the anti-seepage wall trench (5).

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