Pile foundation construction method and pile tip for penetrating complex strata

Abstract

This invention discloses a pile foundation construction method and pile tip for traversing complex strata. The pile foundation construction method includes the following steps: pile driving: pressure is applied to the top of the pipe pile, and the conical flaps push some of the complex strata material outwards through the inclined plane, while the other part enters the pipe pile through the hollow area formed by the flaps and the connecting groove at the bottom of the guide tube; pile end expansion: the connecting rod drives the flaps to rotate outwards and expand, and a high-pressure grouting pump injects cement grout through the grouting pipe pre-embedded in the pipe pile. This invention, through the flap pile tip structure that can be folded into a cone shape and expanded into an expanded end, realizes the conversion of the pile tip function, improves construction speed, reduces overall cost, achieves pile driving to complete penetration and reinforcement in one go, and improves the end bearing capacity and pull-out bearing capacity of a single pile.

Description

Technical Field

[0001] This invention relates to the technical field, specifically to a pile foundation construction method and pile tip for traversing complex strata. Background Technology

[0002] In the fields of geotechnical engineering and building construction, static pressure precast piles are widely used in various building foundations due to their advantages such as fast construction speed and stable quality. However, during the construction of static pressure piles, traditional solid conical or cross-shaped pile tips are difficult to penetrate dense sand, gravel, and pebble layers. The huge and concentrated resistance in front of the pile tip can cause the pile to be crushed and the pile to fail to sink to the design elevation.

[0003] Traditional piling methods involve pre-drilling holes at the pile location using a drilling rig, drilling through hard interlayers that are difficult to penetrate, such as pebble layers, and then pressing the precast piles in. This method increases the number of procedures, lengthens the construction period, and increases costs. In addition, there is mud skin or gaps between the hole wall formed by drilling and the pressed pile body, which seriously weakens the side friction of the pile, which is an important part of the pile's bearing capacity.

[0004] Patent CN217231800U discloses a pile tip structure for penetrating hard interlayers. The above patent has achieved the breakthrough of hard interlayers, allowing square piles to be used in hard soil layers, improving the strength of the pile foundation itself, avoiding the situation that is prone to damage when penetrating hard interlayers, and ensuring normal construction.

[0005] The aforementioned patent solves the current problem that it is impossible to overcome hard interlayers, which is not durable enough and seriously restricts the use of square piles in hard soil layers. In addition, the piles themselves are not strong enough and are prone to damage when passing through hard interlayers, which affects normal construction. However, there is still room for optimization in terms of pile tip drag reduction. This application solves the problem that direct pile driving cannot penetrate the crushed stone replacement layer and pebble layer.

[0006] Therefore, this application proposes a pile foundation construction method and a pile tip for traversing complex strata to realize the conversion of the pile tip function. Summary of the Invention

[0007] The purpose of this invention is to provide a pile foundation construction method and pile tip for penetrating complex strata, so as to solve the technical problem mentioned in the background art that direct pile driving cannot penetrate the crushed stone replacement layer and the pebble layer.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a pile foundation construction method for traversing complex strata, the pile foundation construction method comprising the following steps: S1. Pile driving: Pressure is applied to the top of the pipe pile by a static pile driver, and the closed valve and pipe pile are pressed into the stratum. The conical valve pushes some of the complex stratum material to the surrounding area through the inclined surface, and the other part enters the pipe pile through the hollow area formed by the valve and the connecting groove at the bottom of the guide tube. S2. Pile End Enlargement: When the pipe pile penetrates to the predetermined depth, the pressure on the top of the pipe pile is stopped, and the independent auxiliary pressure device on the pile driver is activated to apply pressure to the top of the guide tube inside the pipe pile. The guide tube and the center rod move down synchronously. The center rod drives the connecting rod, and the connecting rod drives the valve to rotate outward and expand. The high-pressure grouting pump injects cement grout through the grouting pipe embedded in the pipe pile. The cement grout passes through the one-way valve and sprays out from the opened grouting hole.

[0009] Preferably, the pile driving penetration stage further includes the following steps: During the process of applying pressure to the top of the pipe pile by the static pile driver, the pressure sensor continuously measures the working oil pressure of the hydraulic system of the static pile driver, the displacement sensor continuously measures the settlement displacement of the top of the pipe pile relative to the fixed reference point, and the dual-axis digital inclinometer continuously measures the tilt angle of the pipe pile body in two orthogonal directions. Based on the collected working oil pressure, sinking displacement, and tilt angle, the data of pile driving force, penetration speed, and pile verticality are identified. The three sets of data are displayed synchronously on the same monitoring interface. When the pile driving force curve reaches a peak, it drops slightly and then fluctuates within a narrow range to stabilize. At the same time, the penetration speed curve shows that the sinking speed recovers and remains at a stable and slow value, and the changes in the pile verticality data stop. Pressurization on the top of the pipe pile is stopped, and the current penetration stage is determined to be completed.

[0010] Preferably, the pile end enlargement stage further includes the following steps: When the valve is extended to its maximum design angle, the locking block fixed on the valve moves to a specific position, and the abutment block is engaged in the abutment groove on the side of the locking block to lock the position of the valve and maintain the valve in its extended state.

[0011] Preferably, the steps for opening the grouting holes within the expanded pile end are as follows: While the connecting rod drives the valve, it also drives transmission plate 2 and transmission plate 1 to move synchronously. Transmission plate 1 then drives the sealing plate to release the seal on the grouting hole.

[0012] Preferably, the device includes a pipe pile and a valve. The pipe pile is circumferentially hinged with a valve. A guide cylinder is installed inside the pipe pile. A central rod is fixedly connected to the center of the guide cylinder. A connecting plate is fixedly connected to the outer wall of the central rod. A connecting rod is hinged to one side wall of the connecting plate. The valve is hinged to the side wall of the connecting rod. A connecting groove and a grouting hole are circumferentially opened at the bottom of the guide cylinder. A one-way valve is installed at the top of the grouting hole. The one-way valve is fixedly connected to the bottom of the guide cylinder and is connected to the grouting pipe pre-embedded in the pipe pile.

[0013] Preferably, a locking block is fixedly connected to the side wall of the valve, an arc-shaped sleeve is fixedly connected to the inner wall of the pipe pile, the arc-shaped sleeve is movably fitted onto the outer wall of the locking block, a spring is fixedly connected to the inner wall of the locking block, an abutment block is fixedly connected to the end of the spring, an arc-shaped groove is provided on the side wall of the locking block, the arc-shaped groove is movably fitted onto the outer wall of the abutment block, and an abutment groove is provided on the side wall of the locking block.

[0014] Preferably, a transmission plate is rotatably connected to the bottom of the guide cylinder, a sealing plate is fixedly connected to one side wall of the transmission plate, the sealing plate is located below the grouting hole, a transmission plate is hinged to one side wall of the transmission plate, and a connecting rod is hinged to the side wall of the transmission plate.

[0015] Preferably, a second connecting plate is circumferentially mounted on the central rod. An adjusting arm is hinged to the side wall of the second connecting plate, an extension plate is hinged to the side wall of the adjusting arm, a valve is slidably connected to the side wall of the extension plate, a long rod is fixedly connected to the top of the second connecting plate, the long rod passes through the guide cylinder, a connecting ring plate is fixedly connected to the top of the long rod, the connecting ring plate is movably fitted onto the outer wall of the central rod, a limit plate is fixedly connected to the side wall of the valve, and an extension plate is slidably connected to the inner wall of the limit plate.

[0016] Preferably, a connecting frame is fixedly connected to the outer wall of the connecting ring plate circumferentially, a second spring is fixedly connected to the inner wall of the connecting frame, a weight is fixedly connected to the end of the second spring, an arc-shaped block is fixedly connected to the side wall of the weight, the arc-shaped block has a bottom arc surface and a top plane, the arc-shaped block penetrates the connecting ring plate, and an arc-shaped ring body is fixedly connected to the outer wall of the central rod axially, the arc-shaped ring body has a bottom plane and a top arc surface.

[0017] Preferably, the connecting ring plate has an annular groove, and the arc-shaped ring body is located within the annular groove.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes a hinged pile tip structure that can be folded into a cone shape and unfolded into an enlarged bottom end. During pile driving, it serves as an acute cone for penetration and drag reduction, while upon reaching the bearing layer, it becomes an enlarged head for load bearing and anchoring. This achieves a functional transformation of the pile tip. The folded hinged cone tip reduces the peak penetration resistance in dense gravel layers through the synergy of lateral compression of soil and hollow internal soil discharge, enabling static pressure piles to directly and continuously penetrate the gravel layer. This eliminates the time and equipment costs required for pre-drilling in traditional processes, increases construction speed, reduces overall costs, and achieves penetration and reinforcement in a single pile driving operation. The unfolded hinged cone increases the pile end area, which, combined with high-pressure grouting, improves the end bearing capacity and pull-out bearing capacity of a single pile. 2. This invention achieves comprehensive digital perception of the static pressure pile driving process through real-time monitoring, solving the problem of relying on single experience and lacking process basis for the state transition of the flap retraction and unfolding, thus improving the accuracy of construction control. By using data on pile driving force, penetration speed, and pile verticality, it determines whether the pile tip has reached the stratum that can provide stable reaction force, ensuring that the flap unfolds in an effective position. This solves the problems of insufficient bearing capacity due to premature flap unfolding and waste of resources or even damage to the pile body due to delayed flap unfolding. 3. This invention achieves locking of the working state of the valve through a one-way self-locking mechanical structure composed of locking blocks, abutting blocks, etc. During the valve's unfolding stroke, the valve is allowed to unfold. When it reaches the maximum unfolding position, the abutting block is locked into the abutting groove to form a mechanical lock. When the valve attempts to rebound, a rigid block is formed, which improves the reliability of the pile foundation in long-term operation, ensures the stability of the bearing state, and solves the problem of reduced bottom expansion effect caused by soil rebound. 4. This invention achieves automatic switching between the protection state and the working state of the grouting hole by mechanically linking the control mechanism of the sealing plate at the grouting hole with the valve drive linkage. While the valve performs the bottom expansion action, it automatically rotates to cover the sealing plate of the grouting hole. During the pile driving stage, the grouting hole is covered by the sealing plate, preventing soil, gravel, and groundwater from flowing in and clogging the grouting hole and the one-way valve. This solves the problem of the grouting hole being blocked during the pile driving process, which prevents subsequent grouting from being carried out. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of the central rod and connecting ring plate of the present invention; Figure 2 This is a schematic diagram of the valve-closing structure of the present invention; Figure 3 This is a schematic diagram of the flap deployment structure of the present invention; Figure 4 This is a schematic diagram of the extended plate connection structure of the present invention; Figure 5 This is a schematic cross-sectional view of the central rod structure of the present invention; Figure 6 This is a schematic diagram of the cross-sectional structure of the arc-shaped sleeve of the present invention; Figure 7 This is a schematic cross-sectional view of the connecting ring plate of the present invention; Figure 8 This is a cross-sectional view of the guide cylinder structure of the present invention.

[0020] In the diagram: 1. Pipe pile; 2. Valve; 3. Center rod; 4. Connecting rod; 5. Guide cylinder; 6. One-way valve; 7. Grouting hole; 8. Sealing plate; 9. Transmission plate one; 10. Transmission plate two; 11. Arc sleeve; 12. Locking block; 13. Abutment groove; 14. Abutment block; 15. Spring one; 16. Connecting groove; 17. Long rod; 18. Connecting plate one; 19. Connecting plate two; 20. Adjusting arm; 21. Extension plate; 22. Limiting plate; 23. Connecting ring plate; 24. Arc groove; 25. Arc ring body; 26. Connecting frame; 27. Spring two; 28. Weight; 29. ​​Arc block; 30. Annular groove. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Please see Figure 2 and Figure 3This invention provides an embodiment of a pile foundation construction method for traversing complex strata and its pile tip. The pile foundation construction method includes the following steps: S1, pile driving: Pressure is applied to the top of the pipe pile 1 using a static pile driver, pressing the closed flap 2 and the pipe pile 1 into the strata. The conical flap 2 pushes some of the complex strata material outwards through the inclined surface, while the other part enters the pipe pile 1 through the connecting groove 16 at the bottom of the guide cylinder 5 through the hollow area formed by the flap 2; S2, pile tip widening: When the pipe pile 1 has penetrated to a predetermined depth, the pressure on the top of the pipe pile 1 is stopped, and an independent auxiliary pressure device on the pile driver is activated to apply pressure to the top of the guide cylinder 5 inside the pipe pile 1. The guide cylinder 5 and the central rod 3 move down synchronously, and the central rod 3... Rod 3 drives connecting rod 4, which in turn drives valve 2 to rotate outward and expand. The high-pressure grouting pump injects cement grout through the grouting pipe embedded in the pipe pile 1. The cement grout passes through one-way valve 6 and is ejected from the opened grouting hole 7. The system includes pipe pile 1 and valve 2. Valve 2 is hinged to the circumference of pipe pile 1. A guide cylinder 5 is installed inside pipe pile 1. A central rod 3 is fixedly connected to the center of the guide cylinder 5. A connecting plate 18 is fixedly connected to the outer wall of the central rod 3. A connecting rod 4 is hinged to the side wall of the connecting plate 18. Valve 2 is hinged to the side wall of the connecting rod 4. A connecting groove 16 and a grouting hole 7 are opened circumferentially at the bottom of the guide cylinder 5. A one-way valve 6 is installed at the top of the grouting hole 7. The one-way valve 6 is fixedly connected to the bottom of the guide cylinder 5 and is connected to the grouting pipe embedded in the pipe pile 1.

[0025] Furthermore, a static pressure is applied to the top of the pipe pile 1 using a static pile driver, vertically pressing the entire pipe pile 1, along with the tapered tip of the retracted flap 2, into the stratum. During penetration, the flap 2 at the bottom of the pile is in a closed state. At this time, each flap 2 retracts inward, and the outer surface of the flap 2 together forms a hollow 15° to 30° tapered tip. The tapered tip formed by the flap 2 can convert the huge resistance directly in front into oblique compressive force, thereby squeezing or compacting dense gravel, pebbles, and other complex strata materials towards the lower periphery of the pipe pile 1, reducing the peak pressure required to penetrate dense and dispersed strata. At the same time, the hollow area enclosed by the flap 2 and the guide The connecting groove 16 at the bottom of the casing 5 together form a channel, allowing other strata materials, such as small-diameter gravel and soil, to be squeezed into the interior of the pipe pile 1. This reduces the occlusion effect and penetration resistance at the pile tip, making it easier to penetrate dense gravel and crushed stone layers that are difficult for traditional pile tips to enter. Traditional construction methods, such as hammer piles or ordinary static pressure piles, often fail to penetrate dense gravel and crushed stone layers due to extremely high penetration resistance, easily leading to pile crushing, pile head damage, or failure to reach the design elevation. Therefore, before driving the pile, it is necessary to pre-drill holes in the soil layer using methods such as pilot holes, drilling, or percussion. The process of inserting the pile into the hole for driving or construction increases the number of construction steps, time, and cost. The cone-shaped closed valve 2 can transform the huge, concentrated resistance from the pebbles directly in front of the valve 2 into an oblique compressive force, squeezing or compacting the pebbles to the side and downward of the pipe pile 1, rather than directly confronting the front of the pipe pile 1. Through the combined action of lateral compression and internal soil removal, it can directly penetrate the dense pebble layer that is difficult for traditional pile tips to enter with relatively low static pressure. This allows the construction to skip the tedious, time-consuming step of pre-drilling through the pebble layer, which may cause hole collapse and diameter reduction. The construction process is simplified to direct... Pipe pile 1 with a special pile tip is driven into the stratum to directly reach the bearing layer, solving the problem of directly driving piles in complex strata including gravel layers without pre-drilling. This avoids the problem of direct pile driving not being able to penetrate the gravel layer, simplifies the construction process, improves efficiency, and avoids problems such as verticality deviation and mud pollution that may be caused by pre-drilling. During the driving process of valve 2, the cone tip of valve 2 continuously compacts the soil around pipe pile 1, achieving close contact between the pile and the stratum, protecting and even enhancing the pile side friction resistance. This solves the problem that the traditional method of drilling first and then driving piles will form a loose mud skin or gap between the pile body and the gravel layer, which seriously weakens the pile side friction resistance. When the pipe pile 1 penetrates to the predetermined depth, no more pressure is applied to the pipe pile 1. Instead, downward pressure is applied to the guide cylinder 5 inside the pipe pile 1. The guide cylinder 5 drives the central rod 3, which is fixed at its center, to move downwards simultaneously. As the central rod 3 moves downwards, it drives the connecting plate 18 to move downwards. The connecting plate 18 drives the connecting rod 4, causing the connecting rod 4 to move downwards while deflecting around the hinge point between the connecting rod 4 and the connecting plate 18. The end of the connecting rod 4 away from the connecting plate 18 gradually moves away from the central rod 3, thereby causing the connecting rod 4 to drive the flap 2 to rotate outwards around its hinge point with the pipe pile 1, forming an outwardly expanded anchoring end. This significantly increases the bearing area and pull-out resistance of the pipe pile 1, effectively improving the vertical bearing capacity and pull-out performance of the pipe pile 1, and solving the problem of insufficient anchoring effect of traditional pile tips in complex strata. At the same time as the flap 2 unfolds, cement grout is injected into the grouting pipe through the grouting pipe pre-embedded in the pipe pile 1. The grouting pipe is connected to a high-pressure grouting pump. The grout, passing through the one-way valve 6, is ejected from the grouting hole 7, which is now open at the bottom of the guide cylinder 5. The grout penetrates the pile tip of the pipe pile 1 and the surrounding soil, solidifying to form a high-strength composite, further enhancing its bearing capacity and stability. The converging cone tip of the hinge 2 enables low-resistance penetration through complex strata. Upon reaching the bearing layer, the hinge 2 expands into an expanded anchoring end, and grouting reinforcement of the pile tip of the pipe pile 1 is carried out simultaneously. This effectively solves the problems of difficult penetration and insufficient bearing capacity of traditional pile foundations in complex strata. The hinge 2 transforms from a converging cone tip shape to an expanded anchoring end, and its working surface changes from being used for piercing to being used for bearing pressure and pull-out resistance, thereby increasing the effective contact area between the pile tip of the pipe pile 1 and the bearing layer. It also provides significant end bearing capacity and pull-out resistance through mechanical interlocking. The liquid permeates and fills the pores in the soil at the pile tip and around the pipe pile 1, solidifying to form a high-strength cement-soil composite. This fills any gaps that may exist after the flap 2 unfolds, and improves and reinforces the bearing soil below and around the pile tip of pipe pile 1. By utilizing the retractable pile tip, the complex strata are directly penetrated by static pressure through a conical drag reduction and internal soil discharge method. After reaching the bearing layer, the pile tip is unfolded into an enlarged bottom end and grouting is performed simultaneously to obtain high bearing capacity. Thus, the two goals of overcoming obstacles and enhancing bearing capacity are achieved sequentially in a single pile driving process through a convertible pile tip structure, thereby improving construction efficiency, reducing construction risks, and ultimately enhancing the bearing performance of the pile foundation.

[0026] Please see Figure 2This invention provides an embodiment of a pile foundation construction method for traversing complex strata. The pile driving penetration stage further includes the following steps: During the process of a static pile driver applying pressure to the top of the pipe pile 1, a pressure sensor continuously measures the working oil pressure of the static pile driver's hydraulic system, a displacement sensor continuously measures the sinking displacement of the top of the pipe pile 1 relative to a fixed reference point, and a biaxial digital inclinometer continuously measures the tilt angle of the pipe pile 1 in two orthogonal directions. Based on the collected working oil pressure, sinking displacement, and tilt angle, the pile driving force, penetration speed, and pile verticality data are identified. These three sets of data are displayed synchronously on the same monitoring interface. When the pile driving force curve reaches a peak, it slightly declines and then fluctuates within a narrow range until it stabilizes. Simultaneously, the penetration speed curve shows that the sinking speed recovers and remains at a stable and slow value, and the pile verticality data stops changing. Pressure is then applied to the top of the pipe pile 1, and the current penetration stage is considered complete.Furthermore, the pressure sensor is integrated into the main oil circuit of the static pile driver's hydraulic system, with a sampling frequency set to ≥10 Hz; a rope-type displacement sensor or laser rangefinder is installed on the top of the pipe pile 1 or on the pressure beam, aligned with a stable benchmark outside the construction area; a dual-axis digital inclinometer is installed on the top of the pipe pile 1 or on the side of the pile exposed above the ground, with an accuracy ≤0.1°, and the X and Y orthogonal measurement axes are set; the data acquisition system is started, and each sensor is zeroed and calibrated while the pipe pile 1 is suspended, ensuring that the timestamps of the three sets of data—pile driving force, displacement, and incline—are synchronized. The pressure sensor continuously measures the working oil pressure of the hydraulic system, which is converted into the actual pile driving force applied to the pile top. The pile driving force = system oil pressure × effective working area of ​​the hydraulic cylinder; during the initial penetration stage, i.e., the soft soil layer from 0 to 5m, the initial pile driving force is controlled to ≤500 kN; the downward speed of the pile driver is set to ≤1.0. The speed should be maintained at a constant m / min; the pile frame should be adjusted to ensure that the initial verticality deviation is ≤0.3%, and the pile driving force and displacement curves should be continuously recorded to confirm that the data is stable without sudden changes; during the complex strata crossing stage, the changes in the data curves should be continuously monitored. When the pile driving force reading suddenly and sharply increases, that is, when the pile driving force rises sharply to 1.5 to 2.0 times the design characteristic value, where the design characteristic value specifically refers to the characteristic value of the vertical bearing capacity of a single pile, the slow-advance mode should be switched, that is, the penetration speed should be reduced to 0.1 to 0.3 m / min. The speed is set to m / min to prevent brittle failure of pipe pile 1. A correction threshold is set for pipe pile 1, with a verticality deviation warning value of 0.5% and a correction action value of 0.8%, where verticality deviation = tan(inclination angle °) × 100%. Furthermore, if the pressure curve exhibits sawtooth fluctuations but the inclination angle remains stable, the current pile driving force is maintained for continuous penetration. If the inclination angle in a certain direction continues to increase unidirectionally at a rate > 0.1° / m, the static pressure pile driver is immediately stopped, and correction is performed by fine-tuning the pile frame or clamps until the inclination angle of pipe pile 1 stabilizes. During the bearing stratum determination stage, when a significant peak is observed in the pile driving force curve, followed by a decline and stabilization within 2.0 to 2.5 times the design characteristic value, and the penetration speed of pipe pile 1 automatically slows down and stabilizes at < 10 m / min, the pile driving force is determined. If the penetration speed is mm / min and the inclination change rate is <0.05° / min, and this continues for 2 to 3 minutes, if the penetration depth of pipe pile 1 reaches the design elevation, it is determined that pipe pile 1 has entered the bearing layer, and the static pressure pile driver's pile driving work is stopped, preparing to trigger the valve 2 base expansion action; in addition, when the pile driving force exceeds the design value of the ultimate bearing capacity of the pile body, such as pile driving force > 3.0 times the design characteristic value, and the verticality deviation of pipe pile 1 continues to exceed the standard and cannot be corrected, such as verticality deviation > 1.0%, then the static pressure pile driver is stopped immediately, and technical personnel are organized to conduct on-site verification of the integrity of pipe pile 1, the cause of verticality deviation, and the stratum conditions. If the pipe pile 1 is found to have cracks, fractures, or other damage, it is necessary to assess whether it can continue to be used according to the degree of damage; if the verticality cannot be corrected due to complex strata or obstacles, the pile position should be adjusted and the pile driving operation should be carried out again to avoid affecting the stability and bearing capacity of the overall pile foundation project.

[0027] Please see Figure 2 , Figure 3 and Figure 6 The present invention provides an embodiment of a pile foundation construction method for traversing complex strata and its pile tip. The pile tip enlargement stage further includes the following steps: when the flap 2 is expanded to the maximum design angle, the locking block 12 fixed on the flap 2 moves to a specific position, and the abutment block 14 is inserted into the abutment groove 13 on the side of the locking block 12 to lock the position of the flap 2 and maintain the expanded state of the flap 2; the locking block 12 is fixedly connected to the side wall of the flap 2, the arc sleeve 11 is fixedly connected to the inner wall of the pipe pile 1, the arc sleeve 11 is movably fitted on the outer wall of the locking block 12, the spring 15 is fixedly connected to the inner wall of the locking block 12, the abutment block 14 is fixedly connected to the end of the spring 15, the arc groove 24 is movably fitted on the outer wall of the abutment block 14, and the abutment groove 13 is provided on the side wall of the locking block 12.

[0028] Furthermore, the locking block 12 is fixed on the side of the valve 2 facing the center of the pipe pile 1. As the valve 2 opens, the locking block 12 rotates around the hinge point between the valve 2 and the pipe pile 1. The locking block 12 drives the arc-shaped groove 24, causing the abutment block 14 to gradually pass through the arc-shaped groove 24. When the valve is not fully extended, the abutment block 14 slides tightly against the bottom surface of the arc-shaped groove 24 under the pressure of the spring 15. When the valve 2 is about to extend to its limit position, the abutment block 14 is about to enter the abutment groove 13. As the locking block 12 and the arc-shaped groove 24 move further, the inclined surface at the top of the arc-shaped groove 24 touches the abutment block 14, thereby causing the abutment block 14 to compress the spring 15. The abutment block 14 gradually moves out of the arc-shaped groove 24 and finally enters the abutment groove 13. Under the elastic force of the spring 15, Under the action, the contact block 14 pops out, so that the contact groove 13 fits tightly with the contact block 14. The side wall of the contact groove 13 forms a physical block against the contact block 14, thereby locking the valve 2 and fixing the position of the valve 2. Even if the driving pressure is removed later, the upper soil at the pile end of the pipe pile 1 will rebound due to elasticity and try to push the valve 2 back to its original position. The contact block 14 is stuck in the contact groove 13 to form a mechanical block, which will prevent the reverse movement of the locking block 12, thereby preventing the valve 2 from closing. This ensures that the anchor end shape of the valve 2 after the bottom expansion is stable and irreversible, solving the problem of the valve's bottom expansion effect and bearing capacity reduction caused by soil creep or external vibration. It ensures that the pile foundation has a long-term end expansion bearing surface, improving the reliability and safety of the structure in long-term operation.

[0029] Please see Figure 2 , Figure 3 and Figure 8An embodiment of the present invention provides a pile foundation construction method for traversing complex strata and its pile tip. The steps for opening the grouting hole 7 in the expanded base of the pile end are as follows: while the connecting rod 4 drives the valve 2, the connecting rod 4 drives the transmission plate 2 10 and the transmission plate 1 9 to move synchronously. The transmission plate 1 9 drives the sealing plate 8 to release the sealing of the grouting hole 7. The method includes a pipe pile 1 and a valve 2. A central rod 3 is fixedly connected to the center of the guide cylinder 5. The bottom of the guide cylinder 5 is rotatably connected to the transmission plate 1 9. The side wall of the transmission plate 1 9 is fixedly connected to the sealing plate 8. The sealing plate 8 is set below the grouting hole 7. The side wall of the transmission plate 1 9 is hinged to the transmission plate 2 10. The side wall of the transmission plate 2 10 is hinged to the connecting rod 4.

[0030] Furthermore, the grouting hole 7 and the one-way valve 6 are circumferentially opened at the bottom of the guide cylinder 5. The one-way valve 6 is connected to the grouting pipe pre-embedded in the pipe pile 1. The one-way valve 6 is used to prevent grout backflow during grouting. The sealing plate 8 is located at the bottom of the guide cylinder 5, and its initial position is exactly below the outlet of the grouting hole 7, which plays a sealing and protective role, preventing the formation material in the hollow part of the valve 2 from blocking the grouting hole 7 and the one-way valve 6. During the pile driving stage, the valve 2 is in a closed state, and the connecting rod 4 connected to the valve 2 is in the initial position. The transmission plate 1 When the transmission plate 1 and 9 are in their initial positions, the sealing plate 8 covers the outlet of the grouting hole 7, effectively preventing soil, gravel, and other debris from passing through the grouting hole 7, preventing blockage and damage to the one-way valve 6, and ensuring the feasibility of subsequent grouting. When it is necessary to expand the bottom, the external drive device presses down the guide cylinder 5, the central rod 3 moves down, and the central rod 3 drives the connecting rod 4 and the valve 2. At the same time, the movement of the connecting rod 4 also drives the transmission plate 10, which is hinged to it. The transmission plate 10 pulls the transmission plate 19, and the transmission plate 19 drives the sealing plate 2. The rotation of plate 8 releases the seal on grouting hole 7, thus simultaneously opening the flap 2 and rotating the sealing plate 8. This allows for the expansion of the pile tip and opening of the grouting channel, ensuring that grouting can proceed after the anchoring end is formed. This ensures the accuracy of the construction process and avoids grouting failure due to incorrect operation sequence, such as grouting before the hole is opened, improving the continuity of construction and the reliability of the final pile foundation quality. After the grouting operation begins, high-pressure grout is transported to one-way valve 6 through the grouting pipe. Under pressure, it smoothly passes through grouting hole 7 and is injected into the cavity formed by the expansion and the surrounding strata. The grout quickly fills the gap between the pile tip and the strata and permeates and diffuses into the surrounding cracks, effectively improving the pile tip resistance and side friction resistance. The mechanical linkage allows the flap 2 to open and the sealing plate 8 to open simultaneously, simplifying the construction steps, reducing errors from manual intervention, and shortening the construction cycle. At the same time, the synchronous rotation of the sealing plate 8 ensures that the timing of the grouting channel opening matches the expansion action, preventing the grouting channel from being blocked at an unexpected stage and ensuring the stability of the grouting.

[0031] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 An embodiment of the present invention provides a pile tip for traversing complex strata, comprising a pipe pile 1 and a flap 2. The pipe pile 1 is circumferentially hinged with the flap 2. A guide cylinder 5 is provided inside the pipe pile 1. A central rod 3 is fixedly connected to the center of the guide cylinder 5. A connecting plate 18 is circumferentially fixedly connected to the outer wall of the central rod 3. A connecting rod 4 is hinged to the side wall of the connecting plate 18. The flap 2 is hinged to the side wall of the connecting rod 4. A connecting plate 29 is circumferentially movably installed on the central rod 3. An adjusting arm 20 is hinged to the side wall of the connecting plate 29. An extension plate 21 is hinged to the side wall of the adjusting arm 20. The flap 2 is slidably connected to the side wall of the extension plate 21. A long rod 17 is fixedly connected to the top of the connecting plate 29. The long rod 17 passes through the guide cylinder 5. A connecting ring plate 23 is fixedly connected to the top of the long rod 17. The connecting ring plate 23 is movably fitted onto the outer wall of the central rod 3. A limiting plate 22 is fixedly connected to the side wall of the flap 2. The extension plate 21 is slidably connected to the inner wall of the limiting plate 22.

[0032] Furthermore, during the pile tip enlargement stage, downward pressure is applied to the guide cylinder 5. The connecting ring plate 23 is not individually pressured. As the guide cylinder 5 and center rod 3 move downwards, the center rod 3 abuts against the connecting plate 19, thus synchronously driving the connecting plate 19 downwards. This causes the adjusting arm 20 and connecting rod 4 to move downwards and deflect simultaneously. The extension plate 21, mainly constrained by the limiting plate 22, moves synchronously with the valve 2. Once the valve 2 is fully extended, the pressure from the guide cylinder 5 is no longer applied; instead, pressure is applied solely to the connecting ring plate 23, thereby... The connecting ring plate 23 slides further downward relative to the central rod 3, causing the long rod 17 to move downward. The long rod 17 then causes the connecting plate 19 to move downward. The connecting plate 19 pushes the adjusting arm 20, which is hinged to it, to move. When the adjusting arm 20 moves, the other end of the adjusting arm 20 drives the extension plate 21 to move outward relative to the wall of the valve 2 along the inner wall of the limiting plate 22 fixed on the valve 2, so that the extension plate 21 extends further from the edge of the valve 2 and penetrates further into the bearing soil layer. When the valve 2 closes, the hollow conical structure must be maintained. This limitation on the length of the flap 2 prevents simply increasing its length from improving the enlarged base diameter and the penetration effect into the bearing stratum. However, by adding a sliding extension plate 21, which extends after the flap 2 is fully deployed, the structural conflict during flap 2 retraction is avoided. This effectively extends the radius of the enlarged base mechanism, resulting in a larger pile end diameter and a significantly increased contact area with the bearing stratum soil. This significantly improves the pile foundation's end bearing capacity and pull-out resistance, making it particularly suitable for pile foundations in complex geological conditions with high bearing capacity requirements. For complex construction scenarios, the extension plate 21 allows the base expansion mechanism to maintain a compact conical structure in the retracted state to smoothly traverse complex strata. When extended, the extension plate 21 can extend the base expansion operation to a wider range, improving construction convenience and load-bearing capacity. Furthermore, the secondary extension of the extension plate 21 increases the effective diameter of the base expansion head and the contact area with the soil, enabling the base expansion effect to affect deeper bearing layers and extend the anchoring force from shallow to deeper layers. This makes it suitable for complex engineering scenarios with extremely high requirements for foundation anchoring performance.

[0033] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 7An embodiment of the present invention provides: a pile tip for traversing complex strata, wherein a connecting plate 29 is movably installed around the center rod 3, an adjusting arm 20 is hinged to the side wall of the connecting plate 29, an extension plate 21 is hinged to the side wall of the adjusting arm 20, a valve 2 is slidably connected to the side wall of the extension plate 21, and a long rod 17 is fixedly connected to the top of the connecting plate 29; a connecting frame 26 is fixedly connected to the outer wall of the connecting ring plate 23, a spring 27 is fixedly connected to the inner wall of the connecting frame 26, a weight 28 is fixedly connected to the end of the spring 27, an arc-shaped block 29 is fixedly connected to the side wall of the weight 28, the arc-shaped block 29 has a bottom arc surface and a top plane, the arc-shaped block 29 penetrates the connecting ring plate 23, and an arc-shaped ring body 25 is axially fixedly connected to the outer wall of the center rod 3, the arc-shaped ring body 25 has a bottom plane and a top arc surface; an annular groove 30 is opened in the connecting ring plate 23, and the arc-shaped ring body 25 is located in the annular groove 30.

[0034] Furthermore, as the connecting ring plate 23 moves downward relative to the center rod 3 and the extension plate 21 extends further relative to the valve 2, the connecting ring plate 23 drives the connecting frame 26 to move downward. The connecting frame 26 drives the second spring 27, the weight 28, and the arc-shaped block 29 to move downward. The arc-shaped block 29 gradually approaches the uppermost arc-shaped ring 25. When the arc-shaped ring 25 contacts the arc-shaped block 29, the top arc surface of the arc-shaped ring 25 contacts the bottom arc surface of the arc-shaped block 29, allowing the arc-shaped block 29 to pass through the surface of the arc-shaped ring 25. The arc-shaped ring 25 drives the arc-shaped block 29, and the arc-shaped block 29 drives the weight 28 to compress the second spring 27. When the arc-shaped block 29 passes the surface of the arc-shaped ring 25, the second spring 27 releases its elastic potential energy. The second spring 27 drives the weight 28, which has a certain mass, to drive the arc-shaped block 29 to impact the central rod 3. Under the combined action of the weight 28 and the second spring 27, the resulting impact force is transmitted through the central rod 3 to the second connecting plate 19 and then to the adjusting arm 20 and the extension plate 21. This causes the extension plate 21 to generate micro-vibrations when it extends. These micro-vibrations can effectively break up loose sand, cohesive soil, or small gravel that the front end of the extension plate 21 contacts, reducing the resistance of the stratum to the extension action of the extension plate 21 and ensuring the extension is completed. The extension of plate 21 increases the contact area between the pile tip and the ground. Simultaneously, high-frequency micro-vibration reduces friction between the extension plate 21 and the flap 2, preventing wear caused by jamming. As the connecting ring plate 23 continues to move downwards, the arc-shaped block 29 passes sequentially through the arc-shaped ring 25 within the annular groove 30, continuously generating intermittent micro-vibrations to provide continuous assistance for the extension of the extension plate 21. When the extension plate 21 is fully extended, the arc-shaped block 29 passes through the lowest arc-shaped ring 25. At this point, the bottom plane of the arc-shaped ring 25 abuts against the top plane of the arc-shaped block 29, thus locking the arc-shaped block 29 and preventing it from extending. The upward movement of 29 prevents the upward movement of the connecting ring plate 23, the long rod 17, and the connecting plate 29, thereby preventing the adjustment arm 20 and the extension plate 21 from resetting. This ensures that the extension plate 21 always remains in the extended state to maintain the maximum contact area between the pile tip and the stratum. During operation, even if subjected to reverse extrusion or friction from the stratum, the extension plate 21 will not shrink back due to the force, effectively ensuring the bearing capacity of the pile foundation and the stability of the construction process. In addition, this locking mechanism relies on the mechanical cooperation between the arc-shaped block 29 and the arc-shaped ring 25, eliminating the need for additional locking devices and simplifying the overall structural design of the pile tip.

[0035] Please see Figure 1 , Figure 2 , Figure 3 and Figure 8The present invention provides an embodiment of a pile foundation construction method for traversing complex strata. The pile foundation construction method includes the following steps: S1, pile driving: pressure is applied to the top of the pipe pile 1 by a static pile driver, and the closed valve 2 and the pipe pile 1 are pressed into the strata. The conical valve 2 squeezes part of the complex strata material to the surrounding area through the inclined surface, and the other part enters the pipe pile 1 through the connecting groove 16 at the bottom of the guide cylinder 5 through the hollow area formed by the valve 2; S2, pile end expansion: when the pipe pile 1 has penetrated to a predetermined depth, the pressure on the top of the pipe pile 1 is stopped, and the independent auxiliary pressure device on the pile driver is activated to apply pressure to the top of the guide cylinder 5 inside the pipe pile 1. The guide cylinder 5 and the central rod 3 move down synchronously. The central rod 3 drives the connecting rod 4, and the connecting rod 4 drives the valve 2 to rotate outward and expand. The high-pressure grouting pump injects cement grout through the grouting pipe embedded in the pipe pile 1. The cement grout is sprayed out from the opened grouting hole 7 through the one-way valve 6; The pile driving penetration stage also includes the following steps: During the process of the static pile driver applying pressure to the top of the pipe pile 1, the pressure sensor continuously measures the working oil pressure of the hydraulic system of the static pile driver, the displacement sensor continuously measures the sinking displacement of the top of the pipe pile 1 relative to the fixed reference point, and the dual-axis digital inclinometer continuously measures the tilt angle of the pipe pile 1 in two orthogonal directions; Based on the collected working oil pressure, sinking displacement, and tilt angle, the pile driving force, penetration speed, and pile verticality data are identified, and the three sets of data are displayed synchronously on the same monitoring interface. When the pile driving force curve reaches a peak, the pile driving force curve drops slightly and then fluctuates within a narrow range and tends to stabilize. At the same time, the penetration speed curve shows that the sinking speed recovers and remains at a stable and slow value, and the changes in the pile verticality data stop. The pressure on the top of the pipe pile 1 is stopped, and the current penetration stage is determined to be completed. Furthermore, in stage S1, three core data points—pile driving force, penetration speed, and pile verticality—are continuously collected using pressure sensors, displacement sensors, and a biaxial inclinometer. These data are displayed in real-time as synchronous curves on the monitoring interface. Construction personnel observe the curve's changing characteristics and, based on preset criteria such as stable peak pressure, stable speed, and fixed verticality, determine whether the penetration stage is complete, thus triggering the start of stage S2. By monitoring the data curve characteristics, the key geological interface from the pile tip's passage through complex strata to its entry into the bearing layer is identified. Therefore, the initiation timing of stage S2 is no longer a fixed depth value but is determined by actual ground feedback. The retracted flap 2 of the pile tip must unfold in the correct soil layer to achieve maximum effectiveness. This is achieved through monitoring the pile driving force, penetration speed, and verticality. Monitoring the insertion speed and pile verticality ensures that the deployment action is triggered at the most appropriate soil layer and depth, avoiding ineffective deployment in weak layers or failure to deploy in excessively hard rock layers. This ensures the realization of the designed bearing capacity and pull-out resistance of the pile foundation, and avoids construction risks and quality defects caused by relying solely on experience or estimated depth for the valve 2 state transition. For example, the pile foundation expansion effect may not meet expectations, the bearing capacity may not meet design standards, or the pile structure may be damaged due to valve 2 misoperation, leading to problems such as excessive settlement and insufficient pull-out resistance in the later stage. In addition, the data-driven state transition method effectively reduces the subjective error of human judgment, ensuring that the valve 2 deployment action is accurately matched with the stratum conditions, providing a solid guarantee for the long-term stability of the pile foundation.Working principle: At the start of construction, the hinge 2 at the pile tip is in a closed state, forming a hollow acute-angled cone. After the static pile driver applies pressure to the top of the pipe pile 1, the hinge 2 converts the frontal resistance into oblique extrusion force, squeezing the gravel and pebbles towards the pile periphery. At the same time, some soil and rock enter the pipe pile 1 through the hollow area of ​​the hinge 2 cone tip and the connecting groove 16, realizing direct driving without pre-drilling. During the penetration process, pressure sensors, displacement sensors, and biaxial inclinometers continuously collect data on pile driving force, penetration speed, and pile verticality, and display the three sets of curves in real time. When the pile tip penetrates complex strata and reaches a stable bearing layer such as moderately weathered rock, the monitoring data will show stable characteristics: the pile driving force curve falls back after reaching a peak and fluctuates stably, the penetration speed becomes slow and uniform, and the pile verticality no longer changes. It is determined that the pile driving penetration stage is completed, and pressure is stopped on the top of the pipe pile 1. The auxiliary pressurization device is activated to apply pressure to the top of the guide cylinder 5 inside the pipe pile 1. The guide cylinder 5 drives the central rod 3 to move downward, and pushes the valve 2 to rotate outward through the connecting rod 4, forming an expanded anchoring end. At the same time, the movement of the connecting rod 4 is transmitted through the transmission plate 10 and the transmission plate 9, pulling the closing plate 8 to rotate and opening the grouting hole 7 to prepare for grouting. When the valve 2 is expanded to the maximum design angle, the contact block 14 is locked into the contact groove 13. After the central rod 3 has moved downward, the connecting ring plate 23 moves downward, and the long rod 17 and the connecting plate 19 move downward, pushing the adjusting arm 20 so that the extension plate 21 extends further outward relative to the valve 2 and is deeply inserted into the bearing layer. After the grouting hole 7 has been opened in conjunction, cement grout is injected into the grouting pipe embedded in the pipe pile 1 through the grouting pump. The cement grout passes through the one-way valve 6. Grout is ejected from the injection hole 7. A one-way valve 6 prevents backflow of the grout. The high-pressure grout penetrates and fills the surrounding soil within the space created by the valve 2 and extension plate 21 at the pile end. After solidification, the grout tightly bonds with the original bearing layer soil. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for constructing pile foundations through complex geological formations, characterized in that: The pile foundation construction method includes the following steps: S1, Pile driving: Pressure is applied to the top of the pipe pile (1) by a static pile driver, and the closed valve (2) and the pipe pile (1) are pressed into the stratum. The conical valve (2) pushes some of the complex stratum material to the surrounding area through the inclined surface, and the other part enters the pipe pile (1) through the hollow area formed by the valve (2) and the connecting groove (16) at the bottom of the guide tube (5). S2, pile end expansion: When the pipe pile (1) penetrates to the predetermined depth, stop pressurizing the top of the pipe pile (1), activate the independent auxiliary pressurizing device on the pile driver, apply pressure to the top of the guide cylinder (5) inside the pipe pile (1), the guide cylinder (5) and the central rod (3) move down synchronously, the central rod (3) drives the connecting rod (4), the connecting rod (4) drives the valve (2) to rotate outward and expand, the high pressure grouting pump presses in cement grout through the grouting pipe embedded in the pipe pile (1), the cement grout passes through the one-way valve (6) and sprays out from the opened grouting hole (7).

2. The pile foundation construction method for traversing complex strata according to claim 1, characterized in that: The pile driving penetration stage also includes the following steps: During the process of applying pressure to the top of the pipe pile (1) by the static pile driver, the pressure sensor continuously measures the working oil pressure of the hydraulic system of the static pile driver, the displacement sensor continuously measures the sinking displacement of the top of the pipe pile (1) relative to the fixed reference point, and the dual-axis digital inclinometer continuously measures the tilt angle of the pipe pile (1) in two orthogonal directions. Based on the collected working oil pressure, sinking displacement, and tilt angle, identify the data of pile driving force, penetration speed, and pile verticality. Display the three sets of data synchronously on the same monitoring interface. When the pile driving force curve reaches a peak, the pile driving force curve drops slightly and then fluctuates within a narrow range to stabilize. At the same time, the penetration speed curve shows that the sinking speed recovers and remains at a stable and slow value. The changes in the pile verticality data stop. Stop pressurizing the top of the pipe pile (1) and determine that the current penetration stage is completed.

3. The pile foundation construction method for traversing complex strata according to claim 1, characterized in that: The pile end enlargement stage also includes the following steps: When the valve (2) is extended to the maximum design angle, the locking block (12) fixed on the valve (2) moves to a specific position, and the abutment block (14) is inserted into the abutment groove (13) on the side of the locking block (12) to lock the position of the valve (2) and maintain the expanded state of the valve (2).

4. The pile foundation construction method for traversing complex strata according to claim 1, characterized in that: The steps for opening the grouting hole (7) inside the pile end enlargement are as follows: While the connecting rod (4) drives the valve (2), the connecting rod (4) drives the transmission plate two (10) and the transmission plate one (9) to move synchronously. The transmission plate one (9) drives the sealing plate (8) to release the seal on the grouting hole (7).

5. The pile foundation construction method for traversing complex strata according to claim 1, characterized in that: The steps for opening the grouting hole (7) inside the pile end enlargement are as follows: While the connecting rod (4) drives the valve (2), the connecting rod (4) drives the transmission plate two (10) and the transmission plate one (9) to move synchronously. The transmission plate one (9) drives the sealing plate (8) to release the seal on the grouting hole (7).

6. A pile tip for penetrating complex strata according to claim 5, characterized in that: The valve (2) is fixedly connected to a locking block (12) on its side wall, and the pipe pile (1) is fixedly connected to an arc sleeve (11). The arc sleeve (11) is movably fitted onto the outer wall of the locking block (12). The inner wall of the locking block (12) is fixedly connected to a spring (15). The end of the spring (15) is fixedly connected to an abutment block (14). The side wall of the locking block (12) is provided with an arc groove (24). The arc groove (24) is movably fitted onto the outer wall of the abutment block (14). The side wall of the locking block (12) is provided with an abutment groove (13).

7. A pile tip for penetrating complex strata according to claim 5, characterized in that: The bottom of the guide cylinder (5) is rotatably connected to a transmission plate (9), and a sealing plate (8) is fixedly connected to the side wall of the transmission plate (9). The sealing plate (8) is located below the grouting hole (7). A transmission plate (10) is hinged to the side wall of the transmission plate (9), and a connecting rod (4) is hinged to the side wall of the transmission plate (10).

8. A pile tip for penetrating complex strata according to claim 5, characterized in that: The central rod (3) is circumferentially mounted with a connecting plate two (19). The side wall of the connecting plate two (19) is hinged with an adjusting arm (20). The side wall of the adjusting arm (20) is hinged with an extension plate (21). The side wall of the extension plate (21) is slidably connected with a valve (2). The top of the connecting plate two (19) is fixedly connected with a long rod (17). The long rod (17) passes through the guide cylinder (5). The top of the long rod (17) is fixedly connected with a connecting ring plate (23). The connecting ring plate (23) is movably fitted on the outer wall of the central rod (3). The side wall of the valve (2) is fixedly connected with a limiting plate (22). The inner wall of the limiting plate (22) is slidably connected with an extension plate (21).

9. A pile tip for penetrating complex strata according to claim 5, characterized in that: The central rod (3) is circumferentially mounted with a connecting plate two (19). The side wall of the connecting plate two (19) is hinged with an adjusting arm (20). The side wall of the adjusting arm (20) is hinged with an extension plate (21). The side wall of the extension plate (21) is slidably connected with a valve (2). The top of the connecting plate two (19) is fixedly connected with a long rod (17). The long rod (17) passes through the guide cylinder (5). The top of the long rod (17) is fixedly connected with a connecting ring plate (23). The connecting ring plate (23) is movably fitted on the outer wall of the central rod (3). The side wall of the valve (2) is fixedly connected with a limiting plate (22). The inner wall of the limiting plate (22) is slidably connected with an extension plate (21).

10. A pile tip for penetrating complex strata according to claim 9, characterized in that: The connecting ring plate (23) has an annular groove (30) inside, and the arc-shaped ring (25) is located inside the annular groove (30).

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