Gravel soil layer anti-floating pipe pile structure and construction method thereof
By combining a circular hollow cylinder with radial vertical wedge-shaped ribs, the problems of friction coefficient, soil disturbance and water level change faced by traditional anti-buoyancy pipe piles in gravelly soil layers are solved, achieving high-efficiency pull-out resistance and economical construction.
Patent Information
- Application Number
- CN202512020225.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-02-03
AI Technical Summary
When traditional anti-buoyancy pipe piles are used in gravelly soil layers, they face the following problems: the friction coefficient of the pile-soil interface is significantly affected by the soil particle size distribution and density; the soil around the pile is greatly disturbed during the pile driving process; the groundwater level changes have a significant impact; and existing reinforcement measures have problems such as high material cost, complex construction and insufficient durability.
The structure combines a circular hollow cylinder with radial vertical wedge-shaped ribs. Through drag reduction, interlocking and strengthening functions, it reduces pile driving resistance and increases pull-out friction. The shear expansion characteristics of the wedge-shaped ribs form a stable interlock, enhancing the pile tip's resistance to deformation.
It significantly improves pull-out friction, reduces pile driving resistance and soil disturbance, ensures pile stability, adapts to different geological conditions, reduces engineering costs and construction difficulty, and balances pull-out performance and economy.
Smart Images
Figure CN121451585A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of pipe piles, and particularly relates to a sand-gravel soil layer anti-floating pipe pile structure and a construction method thereof. BACKGROUND
[0002] With the rapid development of underground space development, the anti-floating problem is increasingly prominent. The sand-gravel soil layer is a typical ground soil layer, which has the characteristics of large internal friction angle, strong permeability, obvious shear dilation effect and the like. These characteristics make the application of the traditional anti-floating pipe pile in the stratum face special challenges: first, the pile-soil interface friction coefficient is significantly affected by the soil particle grading and density; second, the soil around the pile is greatly disturbed during pile sinking, which affects the later anti-floating performance; third, the change of underground water level has a greater impact on the mechanical properties of the sand-gravel soil layer.
[0003] The existing technical measures for improving the anti-floating bearing capacity of the pipe pile mainly include: first, increasing the pile length so that the pile end enters a deeper bearing layer (such as a round gravel layer) to utilize the anchoring effect of the deep soil body; second, using pile end expansion or rib setting on the pile body to increase the pile-soil contact area and mechanical engagement; third, roughening the surface of the pile body, such as sandblasting or setting threads. However, these methods have obvious limitations: increasing the pile length will greatly increase the material cost and construction difficulty; the expansion or rib setting process is complex, the construction quality is difficult to control, and may affect the compression resistance of the pile body; the surface treatment measures have limited effect, and the long-term durability is questionable. SUMMARY
[0004] In view of the problems in the prior art, the application provides a sand-gravel soil layer anti-floating pipe pile structure and a construction method thereof, which has the advantages of taking a circular ring hollow cylinder as a core bearing body, cooperating with radially distributed vertical wedge-shaped rib plates to realize the functions of drag reduction, interlocking and strengthening, and solves the problems in the prior art.
[0005] The application is implemented as follows: a sand-gravel soil layer anti-floating pipe pile structure, which comprises a pile tip, the pile tip comprises a cylinder and a vertical wedge-shaped rib plate, the cylinder is provided in a circular ring hollow structure, the vertical wedge-shaped rib plate is radially distributed with the center of the circular ring cylinder as the center, the vertical wedge-shaped rib plate is located on the outer surface or the inner surface of the circular ring cylinder, the top of the vertical wedge-shaped rib plate is inclined away from the cylinder to form a wedge-shaped structure, and the surface and the inclined surface of the vertical wedge-shaped rib plate are both planes.
[0006] As preferred of the present application, the pipe pile diameter is 600mm, the cylinder inner diameter is 550mm, the wall thickness is 10mm, the height is 300mm, and the welding gap of 30mm is formed between the pipe pile and the cylinder; 6 groups of the vertical wedge-shaped rib plates are evenly distributed along the cylinder outer side, each group of the vertical wedge-shaped rib plate is isosceles wedge-shaped structure, the thickness is 16mm, the height is 300mm, the bottom width is 35mm, the top width is 70mm, the vertical wedge-shaped rib plate is welded with the cylinder by double fillet weld, and the upper side angle of the vertical wedge-shaped rib plate is 60°.
[0007] As preferred of the present application, the vertical wedge-shaped rib plate is fixedly connected to the inner side wall of the circular ring cylinder, and 3-4 pieces are evenly arranged along the cylinder axis direction, the height is flush with the cylinder, and the inner convex flow guide structure is formed; further comprising annular boss structure, two annular bosses are arranged along the bottom and middle part of the cylinder, the annular boss width is about 20mm, the height is flush with the bottom of the vertical wedge-shaped rib plate, and the thickness is 10mm, which is alternately distributed with the vertical wedge-shaped rib plate.
[0008] As preferred of the present application, the vertical wedge-shaped rib plate is fixedly connected to the outer side wall of the cylinder; the first anti-skid tooth is fixedly connected to the lower part of the outer surface of the cylinder, one straight angle edge of the first anti-skid tooth is perpendicular to the surface of the cylinder, and the other straight angle edge is parallel to the cylinder, forming a right triangle shape; the first anti-skid tooth is fully distributed on the lower circumferential surface of the circular ring cylinder and is welded with the cylinder by double fillet weld; the second anti-skid tooth is fixedly connected to the vertical wedge-shaped rib plate, one straight angle edge of the second anti-skid tooth is perpendicular to the surface of the vertical wedge-shaped rib plate, and the other straight angle edge is parallel to the cylinder, forming a right triangle shape, and the second anti-skid tooth is welded with the vertical wedge-shaped rib plate by double fillet weld.
[0009] As preferred of the present application, the vertical wedge-shaped rib plate is fixedly connected to the outer side wall of the cylinder, the first angle steel protruding structure is fixedly connected to the outer surface of the cylinder, the first angle steel protruding structure is triangularly distributed on the surface of the circular ring cylinder, a plurality of rows are arranged along the cylinder longitudinal direction, and the adjacent two rows of the first angle steel protruding structure are staggered arranged; the first inclined plate structure is fixedly connected to the vertical wedge-shaped rib plate.
[0010] As preferred of the present application, the bottom notch is vertically arranged on the lower end of the cylinder, the limit groove is symmetrically arranged on the bottom of the bottom notch, the bottom of the vertical wedge-shaped rib plate is fixedly connected with the limit cylinder, and the limit cylinder is clamped in the limit groove; the thickness of the vertical wedge-shaped rib plate is less than the width of the bottom notch, the vertical wedge-shaped rib plate can extend into the bottom notch, a plurality of clamping interfaces are arranged on the upper edge of the vertical wedge-shaped rib plate, the second annular boss is fixedly connected to the inner wall of the cylinder, the third annular boss is arranged on the lower side of the second annular boss and can move up and down, and the third annular boss can be clamped in the clamping interface.
[0011] As preferred of the present application, the outer surface of the third annular boss is provided with external threads, the inner wall of the barrel is provided with internal threads, and the third annular boss is connected to the inner wall of the barrel through the external threads and the internal threads.
[0012] As preferred of the present application, a screw is arranged on the second annular boss, the bottom of the screw is attached to the upper surface of the third annular boss, and the highest position of the third annular boss can be adjusted by rotating the screw; the inner edge of the vertical wedge-shaped rib plate is fixedly connected with a triangular plate, and a limiting column is arranged on the side of the triangular plate away from the vertical wedge-shaped rib plate; when the upper surface of the third annular boss is attached to the lower surface of the second annular boss, the bottom of the third annular boss is lower than the top of the triangular plate.
[0013] As preferred of the present application, the outer surface of the barrel is fixedly connected with a second angle steel protruding structure, and the outer surface of the barrel is fixedly connected with a third angle steel protruding structure, a central notch is arranged in the middle of the third angle steel protruding structure, and a limiting rod is fixedly connected to the lower end of the central notch. A clamping notch is arranged on the vertical wedge-shaped rib plate and the triangular plate, the clamping notch is arc-shaped, the center of the arc of the clamping notch coincides with the center of the limiting column, and the clamping notch can be clamped on the limiting rod.
[0014] A construction method of a floating-resistant pipe pile structure in a sandy gravel layer, comprising the following steps: Construction preparation: determine the depth parameter of the pile end into the sandy gravel layer in combination with the design bearing capacity requirement and the anti-floating pile tip anti-pulling enhancement characteristics; prefabricate the anti-floating pile tip according to the design requirement and complete quality review; select suitable static pressure pile sinking equipment, drilling device and pressure monitoring components, and complete equipment linkage debugging; Pile body connection: accurately butt joint and position the PHC pipe pile and the anti-floating pile tip, ensure that the coaxiality of the two meets the preset requirement, perform circumferential welding by using gas shielded welding, and after quality acceptance, enter the subsequent process; Composite pile sinking: first, sink the pile body to the preset stratum interface by the static pressure mode, when the pile sinking resistance reaches the preset threshold, start the drilling device to perform hole drilling and soil removal along the internal axis of the pile body, after the hole drilling depth reaches the optimized parameter, lift the drilling device and continue to apply the static pressure load to press the pile body into the preset depth, and complete the pile sinking in cycles; wherein, the pile body comprises the PHC pipe pile and the anti-floating pile tip; Pile completion detection: perform anti-pulling bearing capacity detection by using the load maintenance method, and perform pile body integrity detection by using the low strain detection method, to ensure that the design requirement is met.
[0015] Compared with the prior art, the present application has the following advantages: 1. Using a circular hollow cylinder as the core load-bearing structure, combined with radially distributed vertical wedge-shaped ribs, it achieves drag reduction, interlocking, and reinforcement functions. The hollow cylinder reduces the self-weight of the pile tip and can expel some soil during pile driving, reducing sinking resistance. The wedge design of the vertical wedge-shaped ribs guides gravel particles to slide along the inclined plane during pile driving, significantly reducing the resistance caused by hard compression, while reducing soil disturbance around the pile and preserving the original density of the stratum. During pull-out, the ribs embed into the soil and utilize their shear dilatation characteristics to form a stable interlocking structure, significantly improving pull-out friction resistance. Moreover, the ribs and cylinder form an integral load-bearing structure, enhancing the pile tip's resistance to deformation and stiffness, ensuring uniform load transfer, adapting to the stratum requirements of conventional anti-buoyancy projects, with a simple and universal structure that balances pull-out performance and ease of construction.
[0016] 2. The convex vertical wedge-shaped ribs avoid large-area contact with loose soil, significantly reducing pile driving resistance and preventing pile tilting; the gentle wedge angle forms a natural flow channel, guiding groundwater to flow smoothly and reducing the scouring of the soil at the bottom of the pile tip, thus preventing the weakening of the bearing layer and the resulting decrease in anti-buoyancy performance; the two annular protrusions and ribs are alternately distributed, which not only disperses the reaction force of the stratum and avoids local stress concentration, but also strengthens the overall rigidity of the pile tip, preventing the ribs from falling off or the cylinder from deforming during the pile driving process.
[0017] 3. Addressing the characteristics of high pebble content and heterogeneous gravel layers, a composite external tooth structure consisting of vertical wedge-shaped ribs and double sets of anti-slip teeth is adopted. The right-angled triangular design of the anti-slip teeth can break and separate pebbles during pile driving. Combined with the guiding function of the ribs, it reduces the resistance to traversing heterogeneous strata, ensuring the vertical sinking of the pile. The numerous anti-slip teeth significantly increase the pile-soil contact area and engagement depth, firmly "biting" the gravel particles and pebbles during upward pull. Combined with the interlocking effect of the ribs, a dual pull-out resistance system is formed, significantly improving pull-out friction resistance and impact resistance. The double-sided fillet weld welding process ensures the connection strength between the anti-slip teeth and the cylinder and ribs, preventing them from falling off under high impact loads. It is suitable for harsh strata with hard and randomly distributed particles, solving the pain points of poor wear resistance and insufficient pull-out resistance of traditional pile tips.
[0018] 4. The first angle steel protrusion on the surface of the cylinder and the first inclined plate structure on the vertical wedge-shaped rib form a three-dimensional interlocking system, which greatly increases the roughness of the pile-soil contact and the interlocking depth. It can firmly interlock the particles of high-density soil layer and form a stable interlocking effect by utilizing the shear dilatation characteristics of the soil. The angle steel protrusion and the inclined plate structure simultaneously enhance the bending and shear resistance of the rib, avoid deformation under high stress, and ensure the long-term stability of the interlocking effect. The staggered angle steel protrusions not only improve the pull-out friction but also reduce particle jamming during pile driving, achieving the design goal of increasing friction without reducing drag. While meeting the high anti-buoyancy requirements, there is no need to extend the pile length, which effectively reduces the consumption of engineering materials and construction costs, takes into account both pull-out performance and economy, and is suitable for high-density, medium-pebble gravel layers. Attached Figure Description
[0019] Figure 1 is a three-dimensional structural schematic diagram of the anti-floating pipe pile structure of the sandy soil layer provided in Embodiment 1 of the present application; Figure 2 is a three-dimensional structural schematic diagram of the anti-floating pipe pile structure of the sandy soil layer provided in Embodiment 2 of the present application; Figure 3 is a three-dimensional structural schematic diagram of the anti-floating pipe pile structure of the sandy soil layer provided in Embodiment 3 of the present application; Figure 4 is a three-dimensional structural schematic diagram of the anti-floating pipe pile structure of the sandy soil layer provided in Embodiment 4 of the present application; Figure 5 is a first perspective three-dimensional structural schematic diagram of the anti-floating pipe pile structure of the sandy soil layer provided in Embodiment 5 of the present application; Figure 6 is an enlarged structural schematic diagram of part A in Figure 5 of the present application; Figure 7 is a second perspective three-dimensional structural schematic diagram of the anti-floating pipe pile structure of the sandy soil layer provided in Embodiment 5 of the present application; Figure 8 is an enlarged structural schematic diagram of part B in Figure 7 of the present application; Figure 9 is an enlarged structural schematic diagram of part C in Figure 7 of the present application; Figure 10 is a top view structural schematic diagram of the anti-floating pipe pile structure of the sandy soil layer provided in Embodiment 5 of the present application; Figure 11 is a sectional view structural schematic diagram of part D-D in Figure 10 of the present application; Figure 12 is an enlarged structural schematic diagram of part E in Figure 11 of the present application.
[0020] In the figure: 1, cylinder; 2, vertical wedge-shaped rib plate; 3, annular boss; 4, first anti-skid tooth; 5, second anti-skid tooth; 6, first angle steel protruding structure; 7, first inclined plate structure; 8, bottom notch; 9, limiting groove; 10, limiting cylinder; 11, clamping interface; 12, second annular boss; 13, third annular boss; 14, triangular plate; 15, limiting column; 16, second angle steel protruding structure; 17, third angle steel protruding structure; 18, center notch; 19, limiting rod; 20, clamping notch; 21, screw. DETAILED DESCRIPTION
[0021] In order to further understand the inventive content, characteristics and effects of the present application, the following examples are given below in detail with reference to the accompanying drawings.
[0022] The structure of the present application will be described in detail below with reference to the accompanying drawings.
[0023] The sand and gravel soil layer anti-floating pipe pile structure provided by the embodiment of the present application comprises a pile tip, the pile tip comprises a cylinder 1 and a vertical wedge-shaped rib plate 2, the cylinder 1 is designed as a circular ring hollow structure, the vertical wedge-shaped rib plate 2 is distributed radially with the center of the circular ring cylinder 1 as the center, the vertical wedge-shaped rib plate 2 is located on the outer side surface or the inner side surface of the circular ring cylinder 1, the top of the vertical wedge-shaped rib plate 2 is inclined away from the cylinder 1, forming a wedge-shaped structure, and the surface and the inclined surface of the vertical wedge-shaped rib plate 2 are both planes.
[0024] Embodiment 1
[0025] Referring to Figure 1 , the pipe pile has a diameter of 600 mm, the cylinder 1 has an inner diameter of 550 mm, a wall thickness of 10 mm and a height of 300 mm, and a 30 mm welding gap is formed between the cylinder 1 and the pipe pile; six groups of the vertical wedge-shaped rib plates 2 are uniformly distributed along the outer side of the cylinder 1, each group of the vertical wedge-shaped rib plates 2 is an isosceles wedge-shaped structure, has a thickness of 16 mm, a height of 300 mm, a bottom width of 35 mm and a top width of 70 mm, the vertical wedge-shaped rib plate 2 and the cylinder 1 are welded by double-face fillet welding, and the upper side of the vertical wedge-shaped rib plate 2 has an included angle of 60°.
[0026] In this embodiment, the vertical wedge-shaped rib plate 2 is the same height as the cylinder 1. Specifically, the circular ring cylinder 1 is used as the core bearing body of the pile tip, is designed as a circular ring hollow structure, has a thickness matched with the diameter to match the conventional pile body specifications (for example, when the pipe pile has a diameter of 600 mm, the cylinder 1 has an inner diameter of 550 mm, a wall thickness of 10 mm and a height of 300 mm, and a 30 mm welding gap is formed between the cylinder 1 and the pipe pile), and bears the dual functions of load transmission and structural support. The hollow structure not only reduces the overall self-weight of the pile tip, but also can discharge part of the soil during pile sinking, thereby reducing the sinking resistance. The vertical wedge-shaped rib plate 2 is distributed radially with the center of the cylinder 1 as the center, the bottom of the vertical wedge-shaped rib plate 2 is fully welded with the outer side of the cylinder 1, and the top of the vertical wedge-shaped rib plate 2 is inclined away from the cylinder 1, forming a wedge-shaped structure. The function of the vertical wedge-shaped rib plate 2 is to guide the sand and gravel particles to slide along the inclined surface during pile sinking, thereby reducing the resistance; and to “lock” the sand and gravel particles during pile pulling, thereby limiting the shear expansion sliding of the sand and gravel layer and improving the anti-pulling friction.
[0027] The arrangement form of the vertical wedge-shaped rib plate 2 is relatively simple, the vertical wedge-shaped rib plate 2 has the functions of structural rigidity reinforcement, load transmission and pile sinking guiding, and is a general form of the foundation of the anti-floating pile tip. The vertical wedge-shaped rib plate 2 is suitable for conventional anti-floating projects without special complex geological conditions, such as silty clay, silt, low-density sand and the like. The wedge-shaped design of the vertical wedge-shaped rib plate 2 can cut the soil and guide the sinking of the pile tip when the pile is sunk, so as to reduce the sinking resistance. Meanwhile, the rib plate and the cylinder 1 form an integral force structure, which can significantly improve the anti-deformation ability and rigidity of the pile tip, and when subjected to the floating force, the floating force can be uniformly transmitted to the pile body, so as to ensure the anti-floating stability. The overall structure design is simple and has strong universality.
[0028] Example 2
[0029] Referring to Figure 2 The vertical wedge-shaped rib plate 2 is fixedly connected to the inner side wall of the circular ring-shaped cylinder 1 and is uniformly arranged at 3-4 pieces along the axis direction of the cylinder 1, has the same height as the cylinder 1, and forms an inner convex flow guiding structure. The structure further comprises annular bosses 3, two annular bosses 3 are arranged along the bottom and middle part of the cylinder 1 in the circumferential direction, the width of the annular boss 3 is about 20 mm, the height is flush with the bottom of the vertical wedge-shaped rib plate 2, and the thickness is 10 mm. The vertical wedge-shaped rib plate 2 and the annular boss 3 are alternately distributed.
[0030] The vertical wedge-shaped rib plate 2 is designed inside the circular ring-shaped cylinder 1, is uniformly arranged at 3-4 pieces along the axis direction of the cylinder 1, has the same thickness as the foundation type (h=16 mm), but has a more gentle wedge angle (about 15°), has the same height as the cylinder 1, and forms an inner convex flow guiding structure. The vertical wedge-shaped rib plate 2 is fixed by full welding with the inside of the cylinder 1, and a triangular reinforcing weld is additionally arranged at the connection position to avoid falling off under stress. The annular boss 3 has a width of about 20 mm and is arranged above and below the vertical wedge-shaped rib plate 2 respectively, has a thickness of 10 mm, and forms a composite structure system of the inner convex flow guiding structure and the annular boss 3.
[0031] This example is suitable for low-density and high-permeability sandy gravel layers. The soil particles of the low-density stratum are loose, and the high permeability leads to active underground water flow. The pile tip is designed to meet the requirements as follows: first, the internal vertical wedge-shaped rib plate 2 avoids large-area contact with the loose soil, greatly reduces the soil resistance when the pile is sunk, and avoids the pile body from being skewed; second, the gentle wedge-shaped structure forms a natural flow guiding channel, guides the underground water to flow smoothly along the surface of the vertical wedge-shaped rib plate 2, reduces the erosion of the water flow to the soil at the bottom of the pile tip, and avoids the decrease of the anti-floating performance of the pile tip due to soil loss; third, the annular bosses 3 are uniformly distributed along the circumferential direction of the circular ring-shaped cylinder 1, can effectively disperse the reaction force of the stratum to the pile tip, avoid stress concentration on the local rib plate, improve the overall anti-deformation ability of the pile tip, ensure the structural stability in the complex stratum, smoothly complete the penetration, and play the anti-floating role. The overall structure realizes the dual effects of resistance reduction and flow guiding, and ensures the anti-floating stability of the pile body under the complex hydrogeological conditions.
[0032] Example 3
[0033] Referring to Figure 3 , the vertical wedge-shaped rib plate 2 is fixedly connected to the outer lateral wall of the barrel 1; the outer surface of the barrel 1 is fixedly connected with a first anti-skid tooth 4, one of the right-angle edges of the first anti-skid tooth 4 is perpendicular to the surface of the barrel 1, and the other right-angle edge is parallel to the barrel 1, forming a right-angled triangle shape; the first anti-skid tooth 4 is distributed on the circumferential surface of the lower part of the circular barrel 1 and is welded with the barrel 1 by double fillet welding; the vertical wedge-shaped rib plate 2 is fixedly connected with a second anti-skid tooth 5, one of the right-angle edges of the second anti-skid tooth 5 is perpendicular to the surface of the vertical wedge-shaped rib plate 2, and the other right-angle edge is parallel to the barrel 1, forming a right-angled triangle shape, and the second anti-skid tooth 5 is welded with the vertical wedge-shaped rib plate 2 by double fillet welding.
[0034] This embodiment is suitable for high pebble content and inhomogeneous gravel layers. The particles of such strata are hard and distributed in disorder, and the wear resistance, impact resistance and pullout resistance of the pile tip are extremely high. The composite external tooth structure formed by the vertical wedge-shaped rib plate 2 and the anti-skid tooth can effectively disperse the local impact load of pebbles on the pile tip, avoid stress concentration from causing deformation and damage of the vertical wedge-shaped rib plate 2 or the barrel 1, and significantly improve the overall impact resistance of the pile tip; the right-angled triangle structure of the anti-skid tooth can crush and separate the pebbles in front when the pile is sinking, and in combination with the wedge-shaped guiding function of the vertical wedge-shaped rib plate 2, the resistance of penetrating the inhomogeneous strata is reduced, and the pile body is ensured to sink vertically; the anti-skid tooth greatly increases the contact area and engagement depth of the pile and soil, and can firmly “engage” the gravel particles and pebbles when pulling out, limit the shear dilation and sliding of the strata, and at the same time, the right-angle surface provides a stable friction force surface, in combination with the interlocking effect of the vertical wedge-shaped rib plate 2, the pullout friction is significantly improved, and the pile tip is ensured to stably play the anti-floating role in the complex strata.
[0035] Example 4
[0036] Referring to Figure 4 , the vertical wedge-shaped rib plate 2 is fixedly connected to the outer lateral wall of the barrel 1, the outer surface of the barrel 1 is fixedly connected with a first angle steel protruding structure 6, the first angle steel protruding structure 6 is distributed in a triangular shape on the surface of the circular barrel 1, a plurality of rows are arranged along the longitudinal direction of the barrel 1, and adjacent two rows of the first angle steel protruding structure 6 are arranged in a staggered manner; the vertical wedge-shaped rib plate 2 is fixedly connected with a first inclined plate structure 7.
[0037] For example, the first angle steel protruding structure 6 is cut from an L60x3.5 equal angle steel (limb length 60 mm, thickness 3.5 mm) and is distributed in a triangular shape on the surface of the circular cylindrical body 1 with a height of 30 mm and a width of 30 mm. One row is arranged every 150 mm along the longitudinal direction of the cylindrical body 1, and the adjacent two rows of first angle steel protruding structures 6 are arranged in a staggered manner (to avoid resistance concentration when the pile is sunk). The first angle steel protruding structure 6 is fixed to the cylindrical body 1 by three-sided welding (welding seam length 30 mm, height 5 mm), which not only improves the roughness of the pile-soil contact to enhance the anti-floating friction, but also reduces the particle jamming when the pile is sunk and provides a stable friction surface when pulled up. The first inclined plate structure 7 is fixedly welded to the vertical wedge-shaped rib plate 2 and has the same function as the first angle steel protruding structure 6.
[0038] The embodiment is suitable for high-density and medium-pebble content gravel layers. The soil particles in the high-density stratum are tightly engaged, and the anti-floating relies on the interlocking friction force between the pile tip and the stratum. The first angle steel protruding structure 6 and the first inclined plate structure 7 greatly increase the contact area and interlocking depth of the pile tip and the stratum, can tightly engage the particles in the high-density soil layer, and form a stable interlocking effect. At the same time, the bending and shearing resistance of the rib plate is improved, the deformation under high stress is avoided, and the interlocking effect is ensured to be stable for a long time. The overall design significantly improves the anti-floating friction by increasing the contact area and improving the friction coefficient, and meets the engineering scene with high anti-floating requirements.
[0039] Embodiment 5
[0040] Referring to Figures 5-12 , a bottom gap 8 is arranged at the lower end of the cylindrical body 1 in a vertical manner, a limiting groove 9 is arranged at the bottom of the bottom gap 8 in a symmetrical manner, a limiting cylinder 10 is fixedly connected to the bottom of the vertical wedge-shaped rib plate 2, and the limiting cylinder 10 is clamped in the limiting groove 9. The thickness of the vertical wedge-shaped rib plate 2 is less than the width of the bottom gap 8, the vertical wedge-shaped rib plate 2 can extend into the bottom gap 8, a plurality of clamping interfaces 11 are arranged at the upper edge of the vertical wedge-shaped rib plate 2, a second annular boss 12 is fixedly connected to the inner wall of the cylindrical body 1, a third annular boss 13 is arranged on the lower side of the second annular boss 12 and can move up and down, and the third annular boss 13 can be clamped in the clamping interface 11.
[0041] Through the above arrangement, the following functions are achieved: The vertical wedge-shaped rib plate 2 is rotatably connected to the limiting groove 9 of the bottom gap 8 of the cylindrical body 1 through the limiting cylinder 10 at the bottom, can freely flip around the limiting cylinder 10, and forms two installation directions: Overhanging mode: the vertical wedge-shaped rib plate 2 is flipped to the outside of the cylindrical body 1, is suitable for conventional anti-floating scenes (such as medium-low density sand soil and silty clay), uses the wedge-shaped inclined surface to guide the soil slip to reduce the resistance when the pile is sunk, and embeds the soil through the overhanging vertical wedge-shaped rib plate 2 when pulled up; Inner convex mode: the vertical wedge-shaped rib plate 2 is turned to the inside of the cylinder 1, which is suitable for low density and high permeability gravel layer, simulates the "inner rib resistance reduction and guide type" pile tip function, avoids large area contact with loose soil, and forms an internal guide channel. After switching in two directions, they are fixed through the cooperation of the third annular boss 13 and the clamping interface 11 / triangular plate 14, which ensures the stability of the structure under stress.
[0042] Secondly, the lower end of the third annular boss 13 is clamped in different clamping interfaces 11, which can make the vertical wedge-shaped rib plate 2 present different degrees of inclination, so as to adjust according to the specific soil quality (the vertical wedge-shaped rib plate 2 can rotate around the limiting cylinder 10 as the axis). For example, the more the upper side of the vertical wedge-shaped rib plate 2 protrudes outside the cylinder 1, the more it can play a role of interlocking, significantly improve the anti-pulling friction, and ensure that the pile tip plays a stable anti-floating role in complex strata.
[0043] Further, the outer surface of the third annular boss 13 is provided with external threads, the inner wall of the cylinder 1 is provided with internal threads, and the third annular boss 13 is connected to the inner wall of the cylinder 1 through external threads and internal threads. By rotating the third annular boss 13, the interface adjusts its height, so that it is stably clamped in the clamping interface 11. The second annular boss 12 is provided with a screw 21, the bottom of which is attached to the upper surface of the third annular boss 13, and by rotating the screw 21, the highest position of the third annular boss 13 can be adjusted; the inner edge of the vertical wedge-shaped rib plate 2 is fixedly connected with a triangular plate 14, and the side away from the vertical wedge-shaped rib plate 2 of the triangular plate 14 is provided with a limiting column 15; when the upper surface of the third annular boss 13 is attached to the lower surface of the second annular boss 12, the bottom of the third annular boss 13 is lower than the top of the triangular plate 14.
[0044] Through this setting, the third annular boss 13 can not be clamped in the clamping interface 11, and has two use modes: First, when the vertical wedge-shaped rib plate 2 is towards the outside of the cylinder 1, the bottom of the third annular boss 13 is lower than the highest point of the triangular plate 14, so that the triangular plate 14 can be limited, thereby preventing the triangular plate 14 and the vertical wedge-shaped rib plate 2 from rotating towards the inside of the cylinder 1. When drilling down, the threaded drill bit is inserted into the cylinder 1 and rotates in one direction, which does not drive the rotation. After reaching the preset position, the threaded drill bit can be reversed to rotate the third annular boss 13 in the opposite direction (for example, the threaded drill bit is slightly tilted and contacts the inner circle of the third annular boss 13), thereby pressing the triangular plate 14 and making the upper side of the vertical wedge-shaped rib plate 2 extend outward (the vertical wedge-shaped rib plate 2 rotates around the limiting cylinder 10 as the axis), until the limiting column 15 is attached to the inner wall of the cylinder 1. The advantage is that when the pile is sunk, the vertical wedge-shaped rib plate 2 does not extend much, which can better guide the gravel particles to slide along the inclined surface and reduce resistance. After reaching the preset position, the vertical wedge-shaped rib plate 2 extends more, and the "locking" of the gravel particles during the upward pulling limits the shear dilation sliding of the gravel layer and improves the pullout friction. Of course, the vertical wedge-shaped rib plate 2 can also be extended to the outermost position by rotating the third annular boss 13 before use. Second, when the vertical wedge-shaped rib plate 2 is installed in the opposite direction, towards the inside of the cylinder 1, the limiting column 15 is located on the outside at this time, and the third annular boss 13 is lowered to press the triangular plate 14, thereby extending more towards the inside. The specific performance is that the inclination of the vertical wedge-shaped rib plate 2 is greater.
[0045] Further, the second angle steel protruding structure 16 is fixedly connected to the outer surface of the cylinder, and the third angle steel protruding structure 17 is fixedly connected to the outer surface of the cylinder, a central notch 18 is formed in the middle of the third angle steel protruding structure 17, and a limiting rod 19 is fixedly connected to the lower end of the central notch 18; a clamping notch 20 is formed on the vertical wedge-shaped rib plate 2 and the triangular plate 14, the clamping notch 20 is arc-shaped, the center of the arc coincides with the center of the limiting cylinder 10, and the clamping notch 20 can be clamped on the limiting rod 19.
[0046] The third angle steel protruding structure 17 and the second angle steel protruding structure 16 have the same function as the first angle steel protruding structure; the third angle steel protruding structure 17 also has the following functions: First, because of the central notch 18, the surface of the vertical wedge-shaped rib plate 2 is attached to the central notch 18, which can limit the vertical wedge-shaped rib plate 2 and prevent it from tilting left and right, thereby increasing its firmness.
[0047] Secondly, the limiting rod 19 also has the effect of limiting the vertical wedge-shaped rib plate 2, preventing it from falling downward. Because whether it is the limiting cylinder 10 or the third annular boss 13, it is all upper limiting for the vertical wedge-shaped rib plate 2, but it cannot prevent the vertical wedge-shaped rib plate 2 from falling downward. The limiting rod 19 can limit the vertical wedge-shaped rib plate 2 through the clamping notch 20, and will not hinder the rotation adjustment of the vertical wedge-shaped rib plate 2.
[0048] A construction method of a sand-gravel soil layer anti-floating pipe pile structure, comprising the following steps: Construction preparation: determine the pile end sand-gravel layer depth parameter in combination with the design bearing capacity requirement and the anti-floating pile tip anti-pulling enhancement characteristic; prefabricate the anti-floating pile tip according to the design requirement and complete quality review; select suitable static pressure pile sinking equipment, drilling device and pressure monitoring component, and complete equipment linkage debugging; Pile body connection: accurately butt joint and position the PHC pipe pile and the anti-floating pile tip, ensure that the coaxiality of the two meets the preset requirement, perform circumferential welding by using gas shielded welding, and after quality acceptance, enter the subsequent process; Composite pile sinking: first, sink the pile body to the preset stratum interface by the static pressure mode, when the pile sinking resistance reaches the preset threshold value, start the drilling device to perform hole drilling and soil removal operation along the internal axis of the pile body, after the hole drilling depth reaches the optimized parameter, lift the drilling device and continue to apply the static pressure load to press the pile body into the preset depth, and complete the pile sinking in cycles; wherein the pile body comprises the PHC pipe pile and the anti-floating pile tip; Pile completion detection: perform anti-pulling bearing capacity detection by using the load maintenance method, and perform pile body integrity detection by using the low strain detection method, to ensure that the design requirement is met.
[0049] Specifically, the construction method of the sand-gravel soil layer anti-floating pipe pile structure comprises the following steps: First, the construction preparation stage 1. Related parameter review: reasonably calculate and determine the initial pile end sand-gravel layer depth in combination with the anti-pulling bearing capacity, anti-pressure bearing capacity design requirement, and reference the anti-pulling enhancement effect of the pile tip of the application.
[0050] 2. Pile tip prefabrication and quality detection: prefabricate the anti-floating pile tip according to the design parameter, sample review the welding quality, vertical wedge-shaped rib plate 2 angle and angle steel protrusion size, and ensure the structural size precision.
[0051] 3. Equipment selection and debugging: select the hole drilling type static pressure pile machine of the adaptive tonnage (determined according to the calculated maximum pile sinking resistance), match the spiral hole drilling (the drilling rod diameter is adaptive to the pile tip cylinder size), pressure sensor (real-time monitoring of pile sinking pressure), etc., and perform the equipment empty load linkage test during debugging, verify the pressure control precision, the matching of the drilling rod rotating speed and the pile sinking speed, and ensure the stable operation of the coordinated systems.
[0052] Third, the pile tip and the pipe pile connection 1. Butt joint positioning: Use the hole type static pressure pile machine to hoist the PHC pipe pile to the vertical state, align the pile end with the top end of the circular cylinder, and fix the relative position of the two through the adjustable positioning fixture (with a horizontal bubble) to ensure that the outer diameter of the pipe pile and the inner diameter of the cylinder are concentric (e.g. 600mm pipe pile and 550mm cylinder inner diameter form a 30mm annular welding gap), the coaxiality deviation is controlled within ≤2mm, and the stress bias load of the pile body after connection is avoided.
[0053] 2. Welding process: After butt joint positioning, use carbon dioxide gas shielded welding for circumferential welding. Select appropriate welding wire, clean the welding surface before welding to expose the metal luster; weld in two layers: the first layer is the backing weld, continuously weld along the gap to ensure root fusion and no lack of penetration defects; after the backing weld cools naturally, perform the second layer of filler welding to cover the entire gap, and use the segmented back welding method to reduce welding deformation during welding; clean the surface slag after welding, and naturally cool to the ambient temperature to avoid cracking of the weld due to sudden cooling.
[0054] 3. Quality acceptance: The appearance inspection of the weld surface needs to be smooth and continuous, and the height needs to meet the design requirements; perform ultrasonic flaw detection on a proportional sample to ensure that the weld quality meets the standards; at the same time, recheck the overall perpendicularity of the pile tip and the pipe pile to ensure uniform load transmission when under stress, and only after passing the acceptance, can the pile sinking process begin.
[0055] Third, static pressure pile sinking and middle excavation method collaborative construction 1. Initial static pressure pile sinking: After the pile tip and pipe pile connection acceptance, start the hole type static pressure pile machine, first slowly sink the pipe pile (including anti-floating pile tip) through static pressure, and use the structural characteristics of the vertical wedge-shaped rib plate 2 and the angle steel protrusion of the pile tip to guide the sliding of the surface loose sand and gravel particles. In this stage, do not start the auger rod, and only rely on static pressure load to gradually cut the pile body into the stratum until the pile tip contacts the surface of the sand and gravel or round gravel layer, record the sinking pressure and sinking depth at this time as the judgment basis for starting the middle excavation method.
[0056] 2. Inserting the auger rod: When the pipe pile is pressed to the surface of the round gravel layer, the static pressure resistance increases significantly, and it is difficult for the static pressure pile machine to continue to press the pile in, stop the static pressure, and insert the long auger rod provided by the pile machine into the precast pile pipe along the central axis of the pipe pile, preparing for the hole drilling operation.
[0057] 3. Synchronous drilling and soil removal: During the hole drilling process, the hydraulic power head drives the pipe pile screw rod to rotate, and at the same time, the screw rod drills and removes soil under the pressurized force provided by the winch, and according to the characteristics of high hardness of sand and gravel or round gravel layer particles, adjust the rotation speed of the auger rod to match the characteristics of the stratum to ensure effective crushing of the sand and gravel; the drilling slag is discharged to the outside of the pile along the auger rod blades.
[0058] 4. Jacking rod and pile pressing cooperation: when the depth of the guide hole reaches the optimal advanced guide hole amount selected by the guide hole and pile pressing parameter optimization model, the pressure winch drives the screw rod to lift into the precast pile pipe, avoiding the screw rod from being stuck during the pile pressing process; then continue to apply static pressure load to press the pipe pile along the guide hole channel, and use the pile tip structure to guide the smooth sliding of the broken gravel particles, repeat the "drilling-jacking rod-pile pressing" cycle until the pile end reaches the design depth.
[0059] Fourth, pile forming detection 1. Uplift capacity detection: according to the "Technical Code for Building Foundation Pile Detection", use slow sustained load method, load in stages, record the pile top displacement after each load is applied and maintained for a certain period of time; when the load reaches the corresponding multiple of the design value and the pile top displacement is stable, the uplift capacity is determined to be qualified.
[0060] 2. Pile integrity detection: use low-strain reflected wave method to detect the pile, focus on checking the pile tip and pipe pile connection part, and the integrity of the pile concrete, to ensure that there are no defects such as broken piles and cracks, and to verify the overall reliability of the structure.
[0061] Working principle: (1) Pile sinking stage: guide the sand and gravel particles to slide along the inclined surface by the wedge structure of the vertical wedge rib plate 2, reduce the hard extrusion between the pile body and the soil; the triangular staggered arrangement of the angle steel protrusions avoids the particles from being concentrated and stuck, reduces the pile sinking resistance, and reduces the disturbance to the soil around the pile, preserving its original density and strength.
[0062] (2) Uplift stage: during uplift, the vertical wedge rib plate 2 embeds and extrudes the sand and gravel particles, fully utilizes the shear dilation characteristics of the soil to provide the main uplift embedded force; the angle steel protrusions increase the roughness of the pile-soil contact, the right-angle structure forms stable friction with the sand and gravel particles, and the two work together to improve the uplift capacity, and are less affected by changes in underground water, and have more stable performance.
[0063] (3) Mechanical mechanism: the stress characteristics of traditional uplift piles are similar to nails, with insufficient uplift capacity, which can only increase the pile length to improve the side wall friction; the stress characteristics of the new pile tip structure are similar to expansion bolts, which rely on the bottom to increase the upward uplift force against the soil, and the uplift force and the weight of the soil together form a self-locking. The stress mode changes from the traditional side wall friction to the pile end uplift force and the side wall friction.
[0064] It is to be understood that the terminology used herein such as first and second, and the like, is only used to distinguish one entity or action from another entity or action, and does not necessarily require or imply any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.
[0065] While embodiments of the present application have been shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the application. The scope of the application is defined by the appended claims and their equivalents.
Claims
1. A gravelly soil layer anti-buoyancy pipe pile structure, comprising a pile tip, characterized in that: The pile tip includes a cylindrical body (1) and a vertical wedge-shaped rib (2). The cylindrical body (1) is configured as a circular hollow structure. The vertical wedge-shaped rib (2) is radially distributed with the center of the circular cylindrical body (1) as the center. The vertical wedge-shaped rib (2) is located on the outer or inner surface of the circular cylindrical body (1). The top of the vertical wedge-shaped rib (2) is inclined away from the cylindrical body (1) to form a wedge-shaped structure. The surface and inclined surface of the vertical wedge-shaped rib (2) are both planes.
2. The anti-buoyancy pipe pile structure for gravelly soil layers as described in claim 1, characterized in that: The pipe pile has a diameter of 600mm, the inner diameter of the cylinder (1) is 550mm, the wall thickness is 10mm, the height is 300mm, and a 30mm welding gap is formed between it and the pipe pile. Six sets of vertical wedge-shaped ribs (2) are evenly distributed along the outer circumference of the cylinder (1). Each set of vertical wedge-shaped ribs (2) is an isosceles wedge structure with a thickness of 16 mm, a height of 300 mm, a bottom width of 35 mm, and a top width of 70 mm. The vertical wedge-shaped ribs (2) are welded to the cylinder (1) by double-sided fillet welds. The upper included angle of the vertical wedge-shaped ribs (2) is 60°.
3. The anti-buoyancy pipe pile structure in gravelly soil layer as described in claim 1, characterized in that: The vertical wedge-shaped ribs (2) are fixedly connected to the inner wall of the annular cylinder (1), and 3-4 pieces are evenly arranged along the axis of the cylinder (1), with the height being flush with the cylinder (1), forming an inwardly convex flow guiding structure; It also includes an annular boss (3) structure, with two annular bosses (3) arranged circumferentially along the bottom and middle of the cylinder (1). The annular bosses (3) are about 20 mm wide, the height is flush with the bottom of the vertical wedge ribs (2), and the thickness is 10 mm. They are distributed alternately with the vertical wedge ribs (2).
4. The anti-buoyancy pipe pile structure for gravelly soil layers as described in claim 1, characterized in that: The vertical wedge-shaped rib (2) is fixedly connected to the outer wall of the cylinder (1); a first anti-slip tooth (4) is fixedly connected to the lower part of the outer surface of the cylinder (1). One right-angled side of the first anti-slip tooth (4) is perpendicular to the surface of the cylinder (1), and the other right-angled side is parallel to the cylinder (1), forming a right-angled triangle shape; the first anti-slip tooth (4) is fully distributed on the lower circumferential surface of the annular cylinder (1) and is welded to the cylinder (1) by double-sided fillet weld. The vertical wedge rib (2) is fixedly connected with a second anti-slip tooth (5). One right-angled side of the second anti-slip tooth (5) is perpendicular to the surface of the vertical wedge rib (2), and the other right-angled side is parallel to the cylinder (1), forming a right-angled triangle shape. It is welded to the vertical wedge rib (2) with a double-sided fillet weld.
5. The anti-buoyancy pipe pile structure and its construction method in gravelly soil layer as described in claim 1, characterized in that: The vertical wedge-shaped rib (2) is fixedly connected to the outer wall of the cylinder (1). The outer surface of the cylinder (1) is fixedly connected to a first angle steel protrusion structure (6). The first angle steel protrusion structure (6) is distributed in a triangular pattern on the surface of the annular cylinder (1). Multiple rows are arranged along the longitudinal direction of the cylinder (1). The first angle steel protrusion structures (6) of adjacent rows are arranged alternately. The vertical wedge-shaped rib (2) is fixedly connected to a first inclined plate structure (7).
6. The anti-buoyancy pipe pile structure in gravelly soil layer as described in claim 1, characterized in that: The lower end of the cylinder (1) is provided with a vertically arranged bottom notch (8), and the bottom of the bottom notch (8) is provided with symmetrically arranged limiting grooves (9). The bottom of the vertical wedge-shaped rib (2) is fixedly connected to a limiting cylinder (10), and the limiting cylinder (10) is engaged in the limiting groove (9). The thickness of the vertical wedge rib (2) is less than the width of the bottom notch (8). The vertical wedge rib (2) can extend into the bottom notch (8). The upper edge of the vertical wedge rib (2) is provided with several locking interfaces (11). The inner wall of the cylinder (1) is fixedly connected with a second annular boss (12). The lower side of the second annular boss (12) is provided with a third annular boss (13) that can move up and down. The third annular boss (13) can be locked into the locking interface (11).
7. The anti-buoyancy pipe pile structure for gravelly soil layers as described in claim 6, characterized in that: The outer surface of the third annular boss (13) is provided with external threads, and the inner wall of the cylinder (1) is provided with internal threads. The third annular boss (13) is connected to the inner wall of the cylinder (1) through the external and internal threads. By rotating the third annular boss (13), the height of the interface is adjusted so that it is stably locked in the locking interface (11).
8. The anti-buoyancy pipe pile structure in gravelly soil layer as described in claim 7, characterized in that: The second annular boss (12) is provided with a screw (21), the bottom of which is in contact with the upper surface of the third annular boss (13). By rotating the screw (21), the highest position of the third annular boss (13) can be adjusted. The inner edge of the vertical wedge rib (2) is fixedly connected with a triangular plate (14). The side of the triangular plate (14) away from the vertical wedge rib (2) is provided with a limiting post (15). When the upper surface of the third annular boss (13) is in contact with the lower surface of the second annular boss (12), the bottom of the third annular boss (13) is lower than the top of the triangular plate (14).
9. The anti-buoyancy pipe pile structure in gravelly soil layer as described in claim 8, characterized in that: The outer surface of the cylinder is fixedly connected to a second angle steel protrusion structure (16), and the outer surface of the cylinder is fixedly connected to a third angle steel protrusion structure (17). The third angle steel protrusion structure (17) has a central notch (18) in the middle, and a limit rod (19) is fixedly connected to the lower end of the central notch (18). The vertical wedge-shaped rib (2) and the triangular plate (14) are provided with a snap-fit notch (20). The snap-fit notch (20) is arc-shaped, and the center of the arc coincides with the center of the limiting cylinder (10). The snap-fit notch (20) can snap onto the limiting rod (19).
10. A construction method for an anti-buoyancy pipe pile structure in gravelly soil layers, characterized in that, Includes the following steps: Construction preparation: Based on the design bearing capacity requirements and the pull-out enhancement characteristics of the anti-buoyancy pile tip, determine the parameters of the pile tip penetration depth into the gravel layer; prefabricate the anti-buoyancy pile tip according to the design requirements and complete the quality verification; select suitable static pressure pile driving equipment, drilling device and pressure monitoring components, and complete the equipment linkage debugging. Pile connection: The PHC pipe pile and the anti-buoyancy pile tip are precisely aligned and positioned to ensure that the coaxiality of the two meets the preset requirements. Gas shielded welding is used for circumferential welding. After passing the quality inspection, the subsequent process is carried out. Composite pile driving: First, the pile body is driven to a preset stratum interface by static pressure. When the pile driving resistance reaches a preset threshold, the drilling device is started to perform pre-hole drilling and soil removal operation along the internal axis of the pile body. After the pre-hole depth reaches the optimized parameters, the drilling device is lifted out and static pressure load is continued to press the pile body into the preset depth. The pile driving is completed by cycle. The pile body includes a PHC pipe pile and an anti-buoyancy pile tip. Pile testing: The load maintenance method is used to test the pull-out bearing capacity, and the low-strain testing method is used to test the integrity of the pile body to ensure that the design requirements are met.