Composite reinforcement structure for soft ground

Abstract

The application relates to the technical field of geotechnical engineering and foundation treatment, and discloses a composite reinforcing structure of a soft foundation, which comprises a foundation block, a fixed pile is slidably connected to the inner wall of the foundation block, an expansion assembly is arranged in the fixed pile, the expansion assembly is used for increasing the mechanical interlocking force and the lateral frictional resistance between the fixed pile and the surrounding soil layer, a water pumping assembly is further arranged on the outer side of the fixed pile, the water pumping assembly is used for pumping and discharging the pore water in the surrounding soil layer, and an ejection structure is fixedly connected to the bottom of the fixed pile, the ejection structure is used for forcing the flexible capsule at the bottom to expand outward and be ejected by injecting a fluid medium. Through the expansion assembly, after the fixed pile is placed at a specified position, relative movement of the first connecting rod and the second connecting rod is driven by the sliding pipe, the contact area of the pile body and the surrounding soil layer is increased, and mechanical interlocking is formed between the fixed pile and the soil body.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering and foundation treatment technology, specifically a composite reinforcement structure for weak foundations. Background Technology

[0002] In engineering construction, we often encounter soft foundations such as silt, silty soil, or other soft soils with high water content and large porosity. These strata have low natural bearing capacity and high compressibility, so they cannot be used directly as natural foundations for buildings and must be properly reinforced. Currently, using pile foundation structures to penetrate the soft soil layer and transfer the load of the overlying structure to a deeper, stronger bearing layer is a commonly used technique in the field of soft foundation treatment. Therefore, designing a composite reinforcement structure for soft foundations is a conventional research direction in the field of geotechnical engineering.

[0003] Existing foundation reinforcement technologies typically employ precast concrete piles or steel pipe piles directly driven into the ground, or piles formed by drilling and then grouting concrete. These traditional pile foundations mainly rely on the lateral friction generated by the contact between the fixed outer cylindrical surface of the pile and the surrounding soil, as well as the end bearing capacity generated by the contact between the bottom end face of the pile and the underlying soil layer, to bear the load. In some conventional construction schemes, to improve the bearing capacity, after the pile is lowered, construction workers will inject high-pressure cement grout directly into the pile bottom through pre-embedded steel pipes in an open manner, attempting to form a mixed consolidation body in the bottom soil layer to expand the stress area. For the high water content problem in soft soil layers, existing technologies usually involve driving independent plastic drainage boards around the pile before or after pile driving, relying on the soil's own weight or the upper load to slowly squeeze out the water.

[0004] However, the aforementioned existing technologies have technical problems in practical engineering applications, such as insufficient overall bearing capacity and susceptibility to later-stage settlement. This is mainly because the outer wall shape of traditional piles is fixed, making it difficult to generate sufficient lateral friction in soft strata in a fluid state. At the same time, when directly grouting in soft soil, the fluid medium is prone to disorderly loss along the natural pores of the soil and groundwater channels, resulting in the inability to form a regular enlarged bearing base at the ends. In addition, since independent pile foundations cannot actively dehydrate the surrounding high-water-content soil, the soil between the piles remains in an unconsolidated and weak state for a long time, making it impossible for the piles and the surrounding soil layers to form a stable system that cooperates in bearing the load. Ultimately, this leads to the foundation being prone to settlement and instability under long-term loads. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a composite reinforcement structure for soft foundations, which solves the problems of insufficient overall bearing capacity and subsequent settlement caused by low lateral friction, loss of end grout, and inability of soil between piles to actively consolidate in soft strata.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a composite reinforcement structure for weak foundations, comprising a foundation block, wherein a fixed pile is slidably connected to the inner wall of the foundation block, an expansion component is provided inside the fixed pile, the expansion component is used to increase the mechanical interlocking force and lateral frictional resistance between the fixed pile and the surrounding soil layer, a pumping component is also provided outside the fixed pile, the pumping component is used to extract and discharge pore water inside the surrounding soil layer, and a push-out structure is fixedly connected to the bottom of the fixed pile, the push-out structure is used to force the flexible bladder at the bottom to expand outward and push out by injecting a fluid medium.

[0007] Preferably, the expansion assembly includes a sliding tube disposed inside the fixed pile. A sliding sleeve is slidably connected to the outside of the sliding tube, and a first fixing block is fixedly connected to the outside of the sliding sleeve. A first connecting rod is rotatably connected to the outside of the first fixing block. A second fixing block is fixedly connected to the outside of the sliding tube, and a second connecting rod is rotatably connected to the outside of the second fixing block. The inside of the second connecting rod is rotatably connected to the inside of the first connecting rod, and an expansion plate is fixedly connected to the outside of the second connecting rod. Multiple expansion grooves are formed on the outside of the fixed pile.

[0008] Preferably, a first fixing block is fixedly connected to the outer side of the sliding sleeve, and the other end of the first fixing block is fixedly connected to the inner side of the fixing pile.

[0009] Preferably, the pumping assembly includes multiple filter screens, which are fixedly connected to the outside of the fixed pile. A pumping pipe is installed inside the fixed pile, and a water storage tank is formed between the inside of the fixed pile and the outside of the sliding pipe.

[0010] Preferably, the ejection structure includes a connecting column, which is fixedly connected to the bottom of the fixed pile, and a conveying channel is provided inside the sliding tube, with a high-strength bag fixedly connected to the other end of the conveying channel.

[0011] Preferably, the high-strength bladder is disposed inside the connecting post, and a conical drill is fixedly connected to the bottom of the connecting post.

[0012] Preferably, the foundation block is provided with multiple reinforcing bars, which are arranged in a mesh pattern to form a skeleton inside the foundation block. The outer peripheral wall of the fixed pile is provided with multiple sets of friction grooves in a ring, and the inner wall of the friction grooves has a rough structure.

[0013] Preferably, the conical drill has a cone-shaped structure that gradually tapers from top to bottom, and the tip of the conical drill penetrates from top to bottom through the upper compacted sealing layer, the horizontal drainage cushion layer, and the weak soil layer, and is deeply embedded in the deep bearing layer.

[0014] Preferably, a soft soil layer is provided outside the fixed pile, and a horizontal drainage mattress layer is provided outside the fixed pile. The horizontal drainage mattress layer is laid flat on the upper surface of the soft soil layer, and the height of the filter screen corresponds to the depth of the soft soil layer.

[0015] Preferably, an upper compacted sealing layer is provided on the outside of the fixed pile, and the upper compacted sealing layer is laid flat and covers the horizontal drainage mattress layer.

[0016] This invention provides a composite reinforcement structure for weak foundations. It has the following beneficial effects: 1. This invention, by setting up an expansion component, after the fixed pile is lowered to the designated position, drives the first connecting rod and the second connecting rod to move relative to each other by operating the sliding tube. This drives the expansion plate to extend outward from the expansion groove on the side of the fixed pile and forcefully insert it into the surrounding soft soil layer. This structure not only increases the effective contact area between the pile and the surrounding soil layer, forming a deep mechanical interlock between the fixed pile and the soil, but also transforms the original single surface sliding friction into an active anti-shear support. This multi-point radial anchoring greatly restricts the degree of freedom of the fixed pile in the vertical direction, thereby effectively overcoming the axial slippage and sagging phenomenon that is prone to occur in conventional smooth-surfaced piles in soft fluid plastic strata, and improving the bearing stability of the foundation.

[0017] 2. This invention installs a pumping component on the outside of the fixed pile. Since the installation height of the filter screen corresponds to the depth of the soft soil layer, under the action of the external pumping equipment, the pore water inside the soft soil layer can enter the water storage tank and be actively discharged through the pumping pipe. At the same time, it works in conjunction with the horizontal drainage cushion layer above to laterally disperse the water below the ground surface. This process accelerates the dissipation of excess pore water pressure in the soft soil layer, causing the soft soil in a fluid state to undergo rapid volume shrinkage and physical consolidation. This active intervention method significantly improves the mechanical properties of the soil around and between the piles, transforming the traditional passive single pile bearing into active pile-soil synergistic force bearing, fundamentally reducing the risk of uneven settlement of the foundation due to long-term high soil moisture content.

[0018] 3. This invention incorporates a top-out structure at the bottom of the fixed pile. Once the conical drill penetrates and embeds into the deep bearing layer, a high-pressure fluid medium is injected into the high-strength bag through a delivery channel. The sealed high-strength bag expands forcefully outward under internal pressure, thereby compressing and compacting the bearing soil layer at the bottom and the surrounding soft soil layers. The expanded bag forms a controllable enlarged head base at the pile bottom, significantly increasing the bearing area at the bottom of the fixed pile and improving the end bearing capacity of the overall structure. Simultaneously, the sealed high-strength bag effectively encapsulates and isolates the injected grout medium, completely avoiding construction defects such as grout leakage, cross-contamination, and borehole wall collapse that frequently occur in conventional direct grouting processes in soft, high-water-content foundations, ensuring the compactness and forming quality of the enlarged bottom structure. Attached Figure Description

[0019] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the foundation block of the present invention; Figure 3 This is a schematic diagram of the fixed pile of the present invention; Figure 4 This is a schematic diagram of the structure of the high-strength pouch of the present invention; Figure 5 This is a schematic diagram of the structure of the filter screen of the present invention; Figure 6 for Figure 5 Enlarged view of point A in the middle; Figure 7 This is a schematic diagram of the sliding tube structure of the present invention; Figure 8 for Figure 7 Enlarged view of point A in the middle.

[0020] The components include: 1. Foundation block; 2. Deep bearing layer; 3. Soft soil layer; 4. Horizontal drainage cushion layer; 5. Upper compacted sealing layer; 6. Fixed pile; 7. Expansion assembly; 701. Sliding pipe; 702. Sliding sleeve; 703. First fixed block; 704. First connecting rod; 705. Second fixed block; 706. Second connecting rod; 707. Expansion plate; 708. Expansion groove; 8. Pumping assembly; 801. Filter screen; 802. Pumping pipe; 803. Water storage tank; 9. Top-out structure; 901. Conveying channel; 902. High-strength bag; 903. Connecting column; 10. Reinforcing steel bar; 11. Conical drill; 12. Friction groove. Detailed Implementation

[0021] The technical solutions in 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.

[0022] Please see the appendix Figure 1 -Appendix Figure 8This invention provides a composite reinforcement structure for weak foundations, including a foundation block 1, which is generally made of reinforced concrete and is used to bear the load transmitted from the building structure above and to evenly distribute the load to the fixed piles 6 below. The fixed piles 6 are slidably connected to the inner wall of the foundation block 1. An expansion component 7 is provided inside the fixed piles 6. The expansion component 7 is used to increase the mechanical interlocking force and lateral frictional resistance between the fixed piles 6 and the surrounding soil layers. A pumping component 8 is also provided on the outside of the fixed piles 6. The pumping component 8 is used to extract and discharge pore water inside the surrounding soil layers. A push-out structure 9 is fixedly connected to the bottom of the fixed piles 6. The push-out structure 9 is used to force the flexible bladder at the bottom to expand outward and push out by injecting a fluid medium.

[0023] Please see the appendix Figure 4 - Appendix Figure 6 In a preferred embodiment of the present invention, the expansion assembly 7 includes a sliding tube 701. The sliding tube 701 is used to receive the pushing and pulling force of the external driving mechanism and generate vertical axial displacement, thereby linking the internal mechanism to generate relative motion. The sliding tube 701 is disposed inside the fixed pile 6. A sliding sleeve 702 is slidably connected to the outside of the sliding tube 701. A first fixing block 703 is fixedly connected to the outside of the sliding sleeve 702. The first fixing block 703 is used to fix one end of the first connecting rod 704 in a relatively static position, serving as a static support point for subsequent lever transmission. The first connecting rod 704 is rotatably connected to the outside of the first fixing block 703, and the outside of the sliding tube 701 is fixed. A second fixing block 705 is connected, and a second connecting rod 706 is rotatably connected to the outside of the second fixing block 705. The second connecting rod 706 deflects outward with the support of the first connecting rod 704 to push the expansion plate 707 radially outward. The inside of the second connecting rod 706 is rotatably connected to the inside of the first connecting rod 704. The expansion plate 707 is fixedly connected to the outside of the second connecting rod 706. Multiple expansion grooves 708 are opened on the outside of the fixing pile 6. The expansion grooves 708 are used to provide a penetration channel for the expansion plate 707 to extend outward. A first fixing block 703 is fixedly connected to the outside of the sliding sleeve 702. The other end of the first fixing block 703 is fixedly connected to the inside of the fixing pile 6.

[0024] Please see the appendix Figure 2 - Appendix Figure 8 In a preferred embodiment of the present invention, the pumping assembly 8 includes a plurality of filter screens 801. The filter screens 801 are used to block the mud and sand particles in the soft soil layer 3 during pumping, allowing only pore water to permeate into the water storage tank 803, thus preventing pipe blockage. The plurality of filter screens 801 are fixedly connected to the outside of the fixed pile 6. A pumping pipe 802 is provided inside the fixed pile 6. One end of the pumping pipe 802 is connected to an external device, and the other end is connected to the water storage tank 803, which is used to pump the collected pore water and discharge it to the ground surface. The inside of the fixed pile 6 and the outside of the sliding pipe 701 form the water storage tank 803.

[0025] Please see the appendix Figure 2- Appendix Figure 7 In a preferred embodiment of the present invention, the ejector structure 9 includes a connecting column 903, which is used to receive the high-strength bag 902 in its initial state and serves as a structural support for connecting the conical drill 11 downwards. The connecting column 903 is fixedly connected to the bottom of the fixed pile 6. A conveying channel 901 is provided inside the sliding tube 701. The high-strength bag 902 is fixedly connected to the other end of the conveying channel 901. The high-strength bag 902 is usually made of high-molecular tensile fiber material and is used to expand violently outwards after receiving high-pressure fluid medium, squeezing the surrounding soil and preventing the fluid medium injected inside from leaking outwards. The high-strength bag 902 is disposed inside the connecting column 903, and the conical drill 11 is fixedly connected to the bottom of the connecting column 903.

[0026] Please see the appendix Figure 1 - Appendix Figure 8 In a preferred embodiment of the present invention, a plurality of reinforcing steel bars 10 are provided inside the foundation block 1. The reinforcing steel bars 10 are used to enhance the overall structural strength and tensile and shear resistance of the foundation block 1. The plurality of reinforcing steel bars 10 are distributed in a mesh pattern inside the foundation block 1 to form a skeleton. The outer peripheral wall of the fixed pile 6 has a plurality of friction grooves 12 arranged in a ring. The friction grooves 12 are used to increase the surface friction resistance between the fixed pile 6 and the surrounding soft soil layer 3 after the fixed pile 6 is lowered. The inner wall of the friction grooves 12 has a rough structure. The conical drill 11 has a cone structure that gradually tapers from top to bottom. The conical drill 11 is used to break the fixed pile 6 during the downward driving of the pile. In addition to the resistance of the soil layer below, and to guide the overall structure to be deeply embedded in the deep bearing layer 2, the tip of the conical drill 11 penetrates from top to bottom through the upper compacted sealing layer 5, the horizontal drainage cushion layer 4, and the soft soil layer 3 and is deeply embedded in the deep bearing layer 2. The soft soil layer 3 is set on the outside of the fixed pile 6, and the horizontal drainage cushion layer 4 is set on the outside of the fixed pile 6. The horizontal drainage cushion layer 4 is laid flat on the upper surface of the soft soil layer 3. The height position of the filter screen 801 corresponds to the depth position of the soft soil layer 3. The upper compacted sealing layer 5 is set on the outside of the fixed pile 6 and is laid flat on top of the horizontal drainage cushion layer 4.

[0027] Working principle: When reinforcing a weak foundation, a horizontal drainage cushion layer 4 is first laid flat on the surface above the weak soil layer 3, and then covered with an upper compacted sealing layer 5. Subsequently, a fixed pile 6 is driven vertically downwards into the soil using a pile driving device. During the driving process, the conical drill 11 at the bottom of the fixed pile 6 effectively breaks through the soil resistance, and its tip penetrates the upper compacted sealing layer 5, the horizontal drainage cushion layer 4, and the weak soil layer 3 sequentially from top to bottom, finally embedding itself deeply into the hard, deep bearing layer 2 for anchoring. During the driving process, the friction grooves 12, which are distributed in a ring on the outer wall of the fixed pile 6 and have a rough inner wall, generate initial frictional resistance with the surrounding soil. After the fixed pile 6 is driven into place, its top slides and connects with the inner wall of the foundation block 1, which is filled with a reinforced steel reinforcement skeleton 10, thus forming an initial force-bearing system with a deep bearing layer at the bottom and the upper supporting foundation block 1. Once the fixed pile 6 is in place, the internal expansion assembly 7 is activated to enhance lateral friction. The piling equipment first clamps the sliding tube 701, pulling it upwards and causing axial displacement within the fixed pile 6. Since the sliding sleeve 702 and its outer first fixing block 703 are fixedly connected to the inner wall of the fixed pile 6, they remain stationary; while the second fixing block 705 moves synchronously with the sliding tube 701. This relative motion forces the second connecting rod 706, which is rotatably connected to the second fixing block 705, to experience... The compression causes the first connecting rod 704 to deflect outwards as a hinge support point. Under the lever pushing action of the connecting rod mechanism, the expansion plate 707 fixedly connected to the outside of the second connecting rod 706 is radially pushed out and smoothly passes through the multiple expansion slots 708 reserved on the outside of the fixed pile 6. It is forced to penetrate and deeply embedded in the surrounding soft soil layer 3. This structure uses pure mechanical linkage to expand laterally like a barb deep underground, which greatly increases the mechanical interlocking force and pull-out force between the fixed pile 6 and the surrounding soil layer, effectively preventing the pile body from settling. During or after mechanical expansion, the foundation is subjected to both physical and chemical modifications using the pumping assembly 8 and the jacking structure 9. First, an external vacuum pump draws water through the pumping pipe 802, generating negative pressure in the water storage tank 803 formed between the inner wall of the fixed pile 6 and the outer side of the sliding pipe 701. At this time, the abundant water inside the soft soil layer 3 is drawn into the water storage tank 803 and discharged to the surface through the filter screen 801 of the corresponding height under the action of negative pressure, causing the soft soil layer 3 to quickly dehydrate, solidify, shrink in volume, and harden.

[0028] Subsequently, a high-pressure injection of cement slurry and other fluid media is carried into the conveying channel 901 inside the sliding pipe 701 by an external grouting pump. The high-pressure fluid flows directly into the high-strength bladder 902 at the bottom through the channel, forcing the high-strength bladder 902 to fill rapidly. Under extremely high pressure, the high-strength bladder 902 expands violently outward like a balloon and pushes out, forcibly compacting the deep bearing layer 2 at the bottom and the overlying soil layer. It instantly expands at the bottom of the pile to form a huge spherical enlarged head base. This process not only provides huge end bearing capacity, but the expanded and consolidated bladder, together with the mechanical expansion plate 707 above and the soft soil hardened by dewatering, forms an indestructible three-dimensional reinforcement structure.

[0029] 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 composite reinforcement structure for weak foundations, comprising a foundation block (1), characterized in that, The foundation block (1) is slidably connected to a fixed pile (6). An expansion component (7) is provided inside the fixed pile (6). The expansion component (7) is used to increase the mechanical interlocking force and lateral frictional resistance between the fixed pile (6) and the surrounding soil layer. A pumping component (8) is also provided on the outside of the fixed pile (6). The pumping component (8) is used to extract and discharge pore water inside the surrounding soil layer. A push-out structure (9) is fixedly connected to the bottom of the fixed pile (6). The push-out structure (9) is used to force the flexible bladder at the bottom to expand outward and push out by injecting fluid medium.

2. The composite reinforcement structure for weak foundations according to claim 1, characterized in that, The expansion assembly (7) includes a sliding tube (701), which is disposed inside the fixed pile (6). A sliding sleeve (702) is slidably connected to the outside of the sliding tube (701). A first fixed block (703) is fixedly connected to the outside of the sliding sleeve (702). A first connecting rod (704) is rotatably connected to the outside of the first fixed block (703). A second fixed block (705) is fixedly connected to the outside of the sliding tube (701). A second connecting rod (706) is rotatably connected to the outside of the second fixed block (705). The inside of the second connecting rod (706) is rotatably connected to the inside of the first connecting rod (704). An expansion plate (707) is fixedly connected to the outside of the second connecting rod (706). Multiple expansion slots (708) are provided on the outside of the fixed pile (6).

3. The composite reinforcement structure for weak foundations according to claim 2, characterized in that, The outer side of the sliding sleeve (702) is fixedly connected to a first fixing block (703), and the other end of the first fixing block (703) is fixedly connected to the inner side of the fixing pile (6).

4. The composite reinforcement structure for weak foundations according to claim 2, characterized in that, The pumping assembly (8) includes multiple filter screens (801), which are fixedly connected to the outside of the fixed pile (6). A pumping pipe (802) is provided inside the fixed pile (6), and a water storage tank (803) is formed between the inside of the fixed pile (6) and the outside of the sliding pipe (701).

5. The composite reinforcement structure for weak foundations according to claim 2, characterized in that, The ejection structure (9) includes a connecting column (903), which is fixedly connected to the bottom of the fixed pile (6). The sliding tube (701) is provided with a conveying channel (901), and a high-strength bag (902) is fixedly connected to the other end of the conveying channel (901).

6. The composite reinforcement structure for weak foundations according to claim 5, characterized in that, The high-strength bag (902) is disposed inside the connecting post (903), and a conical drill (11) is fixedly connected to the bottom of the connecting post (903).

7. The composite reinforcement structure for weak foundations according to claim 1, characterized in that, The foundation block (1) is provided with multiple reinforcing steel bars (10), and the multiple reinforcing steel bars (10) are arranged in a net-like pattern to form a skeleton inside the foundation block (1). The outer peripheral wall of the fixed pile (6) is provided with multiple sets of friction grooves (12) in a ring shape, and the inner wall of the friction grooves (12) has a rough structure.

8. The composite reinforcement structure for weak foundations according to claim 6, characterized in that, The conical drill (11) has a cone structure that gradually tapers from top to bottom. The tip of the conical drill (11) penetrates from top to bottom through the upper compacted sealing layer (5), the horizontal drainage mattress layer (4), the soft soil layer (3), and is deeply embedded in the deep bearing layer (2).

9. The composite reinforcement structure for weak foundations according to claim 4, characterized in that, A soft soil layer (3) is provided on the outside of the fixed pile (6), and a horizontal drainage mattress layer (4) is provided on the outside of the fixed pile (6). The horizontal drainage mattress layer (4) is laid flat on the upper surface of the soft soil layer (3), and the height position of the filter screen (801) corresponds to the depth position of the soft soil layer (3).

10. The composite reinforcement structure for weak foundations according to claim 8, characterized in that, An upper compacted sealing layer (5) is provided on the outside of the fixed pile (6), and the upper compacted sealing layer (5) is laid flat and covers the horizontal drainage mattress layer (4).

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