Precast concrete threaded pipe pile twisting breaking and separating construction technology

Abstract

The invention relates to a precast concrete threaded pipe pile twist breaking separation construction process, which belongs to the technical field of concrete prestressed piles, and comprises the following steps: a grooving step: a threaded pipe pile is provided with a cavity along the axial direction in a penetrating manner, the side wall of the cavity is provided with at least one groove along the circumferential direction, and the groove extends along the axial direction of the threaded pipe pile and penetrates through the threaded pipe pile; the torsion bar is inserted from the cavity of the threaded pipe pile, the interior of the torsion bar is hollow, protrusions corresponding to the grooves are arranged on the exterior of the torsion bar, and the protrusions penetrate into the corresponding grooves; a drill rod penetrates through the torsion bar and does not make contact with the inner side wall of the torsion bar, and a drill bit is installed at the bottom end of the drill rod; the pile machine drives a drill rod and a torsion bar to twist into soil, and the torsion bar drives a threaded pipe pile knob to penetrate into soil; and a rod lifting step: when the threaded pipe pile is screwed into a designed pile end bearing layer, a pile machine stops working, the drill rod and the torsion rod are lifted upwards, and soil-penetrating construction of one threaded pipe pile is completed. And the effect of reducing the frictional resistance moment when the threaded pipe pile is screwed in is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of concrete prestressed piles, and in particular to a construction process for twisting, breaking and separating precast concrete threaded pipe piles. Background Art

[0002] Traditional pile driving methods involve static pressure, hammering, or burrowing. Static pressure is heavy, hammering is environmentally unfriendly, and burrowing is complex and costly. To address these issues, a screw-in method has been adopted. This screw-in method, with its threaded tubular piles, changes the traditional method of loading and driving, where the direction of force is aligned with the direction of burial. Instead, it applies a horizontal torsional force to the pile, leveraging the action of the pile's threaded blades to force the pile downward into the soil.

[0003] Currently, due to the low torsional (shear) strength of the concrete in the pile body, the torque required to penetrate the threaded pile to the target bearing depth in the soil far exceeds the concrete's allowable value, which can easily lead to cracking and damage in the pile body. Therefore, the goal of our construction technology is undoubtedly to ensure that the torque applied to the pile during penetration does not exceed the allowable torsional strength of the pile body concrete. Summary of the Invention

[0004] The purpose of the present invention is to provide a precast concrete threaded pipe pile twisting and separation construction process to solve the problem in the prior art that the torque required to penetrate the threaded pipe pile to the target bearing layer depth of the soil far exceeds the allowable value of concrete, which easily leads to cracking and damage of the pile body.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A construction process for twisting, breaking and separating precast concrete threaded pipe piles comprises the following steps: Grooving step: the threaded pipe pile is penetrated along the axial direction to form a cavity, and the side wall of the cavity is provided with at least one groove along the circumferential direction, and the groove extends along the axial direction of the threaded pipe pile and penetrates the threaded pipe pile; Pile and rod twisting assembly step: the torsion rod is inserted into the cavity of the threaded pipe pile, the torsion rod is hollow inside and has a protrusion on the outside corresponding to the groove, and the protrusion is inserted into the corresponding groove; Rod penetration step: the drill rod penetrates the torsion rod without contacting the inner wall of the torsion rod, and a drill bit is installed at the bottom end of the drill rod; Screwing steps: The pile driver drives the drill rod and the torsion rod to twist into the soil, and the torsion rod drives the threaded pile knob into the soil; Rod lifting steps: When the threaded pipe pile is screwed into the designed pile end bearing layer, the pile driver stops working, and the drill rod and torsion rod are lifted to complete the construction of a threaded pipe pile into the ground.

[0006] Furthermore, in the groove forming step, the cross-sectional shape of the groove is any one of a U-shape, a trapezoidal shape and a V-shape.

[0007] Furthermore, the axis of the drill rod, the axis of the torsion rod and the axis of the threaded tubular pile are collinear.

[0008] Furthermore, the torsion bar is made of steel.

[0009] Furthermore, the drill rod is provided with a soil discharge mechanism.

[0010] Furthermore, in the screwing step, when the pile driver torque reaches or exceeds a preset torque value of the threaded tubular pile, an axial top pressure is applied to the pile top.

[0011] Furthermore, in the rod lifting step, the drill rod is first pulled upward from the torsion rod, the pile driver continues to drive the torsion rod to twist, and the torsion rod drives the threaded pipe pile to twist, and the pile end is screwed into the bearing layer required by the design.

[0012] Furthermore, a blocking block is provided at the bottom end of the drill rod, and a slot is provided at the bottom end of the torsion bar. During the screwing step, when the torsional resistance torque of the torsion bar increases to the point where the stiffness coordinated deformation of the outer torsion bar and the pile body concrete is close to the critical value of the deformation of the concrete, the pile driver stops, the drill rod is lifted upward, and the blocking block at the bottom end of the drill rod is inserted into the slot of the torsion bar.

[0013] Furthermore, the clamping block is fixedly connected to the drill rod, and in the rod lifting step, the drill rod and the torsion rod are pulled upward together.

[0014] Furthermore, a mounting rod is coaxially fixed to the bottom end of the drill rod, the diameter of the mounting rod is larger than the diameter of the drill rod and smaller than the inner diameter of the torsion rod, the clamping block is movably pressed on the mounting rod, and the upper and lower ends of the clamping block are provided with extrusion inclined surfaces. In the rod lifting step, the drill rod is first pulled upward from the inside of the torsion rod, and the pile driver continues to drive the torsion rod to twist, and the torsion rod drives the threaded pipe pile to twist, and the pile end is screwed into the bearing layer required by the design.

[0015] Beneficial effects of the present invention: A drill rod is inserted into the torsion rod. The drill rod is extended to extend out of the pile bottom. The end of the drill rod is equipped with a drill bit. The soil at the pile end is mixed and cut and squeezed to the side. The drill rod and the pile body are not in contact with each other. That is, the drill rod breaks and squeezes the soil and the torsion rod twists the pile separately. The torsion rod penetrates the groove through the protrusion to twist the pile to overcome the torque generated by the frictional resistance of the soil on the side of the pile. The drill rod breaks and squeezes the soil with the pile end. When the soil at the bottom of the pile has been mixed and squeezed by the drill rod and has been pre-guided to open the threaded blade trajectory, the friction torque of the subsequent pile body has been greatly reduced. The threaded pipe pile penetrates into the target bearing layer of the soil without cracking or damage.

[0016] By setting a full-length groove on the side wall of the cavity of the threaded pipe pile, the purpose and function is to form a combination with the torsion bar of the pile driver, so as to distribute the torsional torque exerted on the pile body to the entire length of the pile body and the torsion bar inserted into the inner cavity to jointly bear the torsional torque, balance the resistance exerted on the entire length of the outer side of the pile, and avoid stress concentration at the same time.

[0017] The protrusion of the torsion bar fits in with the full-length groove in the pile to bear the force. The combination of two materials with different stiffness results in a superposition of stiffness, forming a coordinated stiffness (i.e., stiffness distribution), which makes the combined stiffness exceed the individual stiffness of the two materials. In addition, the superposition and coordination of the stiffness of the concrete and steel materials make it possible to achieve a process in which the torque and the corresponding torsional deformation angle of the pile body are less than their limit values.

[0018] By applying downward pressure on the pile top when the threaded pipe pile rotates, the threaded pipe pile is assisted in its downward rotation and the tensile strength of the pile concrete is improved.

[0019] When the torsional resistance torque of the torsion bar increases to the point where the stiffness cooperative deformation of the torsion bar and the pile body concrete is close to the critical value of the deformation of the concrete, the drill rod is lifted upward and the end block of the drill rod is inserted into the slot of the torsion bar. At this time, when the drill rod continues to twist, it will push the end of the torsion bar at the bottom in the same torsional direction through the small slot. Since the torsional deformation of the bottom end section of the torsion bar is opposite to the torsional direction of the drill rod, the common positioning and twisting of the inner and outer rods at this time will offset the deformation of the torsion bar by the drill rod, and the deformation of the pile will be reduced or even zero. At the same time, the pile's rotational resistance will also be reduced, and the construction operation can be mastered and controlled.

[0020] The soil discharge mechanism is provided to eliminate the large soil squeezing effect caused by the threaded pipe piles as prefabricated piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the construction structure of a first embodiment of a construction process for twisting and breaking a precast concrete threaded pipe pile according to the present invention; Figure 2 This is a structural diagram of the combination of a threaded pipe pile, a torsion rod and a drill rod in Example 1 of a construction process for twisting, breaking and separating precast concrete threaded pipe piles according to the present invention; Figure 3 for Figure 1 Schematic diagram of the enlarged structure at A in the middle; Figure 4 Schematic diagram of the cross-sectional structure of the threaded pipe pile in the first embodiment of the construction process for twisting and breaking precast concrete threaded pipe piles of the present invention Figure 1 ; Figure 5 Schematic diagram of the cross-sectional structure of the threaded pipe pile in the first embodiment of the construction process for twisting and breaking precast concrete threaded pipe piles of the present invention Figure 2 ; Figure 6 Schematic diagram of the cross-sectional structure of the threaded pipe pile in the first embodiment of the construction process for twisting and breaking precast concrete threaded pipe piles of the present invention Figure 3 ; Figure 7Schematic diagram of the cross-sectional structure of the threaded pipe pile and the torsion rod in the first embodiment of the construction process for twisting and breaking precast concrete threaded pipe piles of the present invention Figure 1 ; Figure 8 Schematic diagram of the cross-sectional structure of the threaded pipe pile and the torsion rod in the first embodiment of the construction process for twisting and breaking the precast concrete threaded pipe pile of the present invention Figure 2 ; Figure 9 Schematic diagram of the cross-sectional structure of the threaded pipe pile and the torsion rod in the first embodiment of the construction process for twisting and breaking precast concrete threaded pipe piles of the present invention Figure 3 ; Figure 10 This is a partial structural diagram of the combination of a threaded pipe pile, a torsion rod and a drill rod in Example 2 of a construction process for twisting, breaking and separating precast concrete threaded pipe piles according to the present invention; Figure 11 This is a structural diagram of a drill rod in a second embodiment of a construction process for twisting, breaking and separating precast concrete threaded pipe piles according to the present invention; Figure 12 This is a partial structural diagram of the combination of a threaded pipe pile, a torsion rod and a drill rod in Example 3 of a construction process for twisting, breaking and separating precast concrete threaded pipe piles according to the present invention.

[0022] Among them, there are threaded pipe pile 1, cavity 11, groove 12, torsion bar 2, protrusion 21, clamping groove 22, drill rod 3, clamping block 31, drill bit 4, soil discharge mechanism 5, installation rod 6, and pile driver 7. DETAILED DESCRIPTION

[0023] The following describes the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the various details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0024] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0025] Example 1 When the threaded pipe pile 1 is screwed into the soil under the torsional torque, the stress state between the pile and the soil is different from that of the traditional pipe pile construction process. The resistance state of the pile body is: ① The corresponding vertical resistance of the soil mass compressed by the pile tip is small.

[0026] ② The corresponding "soil breaking" resistance of the soil mass directly sheared by the rotation of the pile tip is small.

[0027] ③ The corresponding horizontal resistance of the soil mass squeezed by the pile tip when penetrating into the soil mass is large.

[0028] ④ The corresponding resistance of the soil mass compressed and sheared by the first thread blade of the pile body is small.

[0029] ⑤ The horizontal frictional resistance of the pile body and the thread blade during the rotation in the soil mass is large.

[0030] ⑥ The internal stress of the pile body is formed by a pair of torsional stress couples of the pile machine 7 power and the soil resistance.

[0031] The test results show that the soil breaking and squeezing resistance of the pile tip of the threaded pipe pile 1 is lower than the ultimate torsional torque of the concrete of the pile body, and the proportion of the pile peripheral frictional resistance gradually increases with the increase of the penetration depth of the pile body into the soil layer. The torsional bearing capacity of the concrete of the pile body and the corresponding allowable torsional angle are small, and the torsional torque required for the penetration of the threaded pipe pile 1 into the target bearing layer of the soil mass is far more than the allowable value of the concrete. Therefore, the target of the construction process of the present application must be to ensure that the torsional torque of the pile during the penetration process does not exceed the allowable value of the torsional strength of the concrete of the pile body.

[0032] Based on the stress state of the pile during the rotation into the soil, the following influencing factors exist: ① The main tensile stress and longitudinal tensile stress of the concrete caused by the torsional torque are reduced when the concrete component is subjected to axial pressure, thereby improving the cracking torque Tcr and the ultimate torque Tu of the component.

[0033] ② The full-length combined contact stress of the concrete of the pile body and the steel torsional rod 2 can avoid local stress concentration and produce good effects of stiffness superposition and collaborative stiffness (stiffness distribution).

[0034] ③ The resistance of the soil mass horizontally squeezed by the pile tip when encountering sand, gravel layer and other hard soil layers with high shear strength is large.

[0035] ④ The soil is an elastic body. Even if the bottom soil mass is squeezed by the pile tip and the "edge" of the first thread blade of the pile body has cut and squeezed the soil mass, the frictional resistance of the pile side and the blade will gradually increase with the increase of the penetration depth of the pile body into the soil layer. On the other hand, due to the construction stoppage of the welding of the pile segment, the cohesion of the soil mass to the pile body quickly recovers. At the moment of the continuous torsion after the stoppage, the increase value of the frictional resistance is large, which exceeds the torsional bearing capacity of the concrete.

[0036] According to the above-mentioned resistance factors, the embodiment of the present invention proposes a precast concrete threaded pipe pile twisting and breaking separation construction process, such as Figures 1 to 9 As shown, the following steps are included: Grooving steps: The threaded pipe pile 1 is axially penetrated to form a cavity 11, and the side wall of the cavity 11 is circumferentially provided with at least one groove 12, and the groove 12 extends axially along the threaded pipe pile 1 and penetrates the threaded pipe pile 1. In this embodiment, the cross-section of the cavity 11 is circular. If there are multiple grooves 12, the multiple grooves 12 are evenly distributed along the circumference of the threaded pipe pile 1. In this embodiment, the preferred number of grooves is 2-4.

[0037] Pile and rod twisting assembly steps: the torsion rod 2 is inserted into the cavity 11 of the threaded pipe pile 1. The interior of the torsion rod 2 is hollow, and a protrusion 21 is fixedly provided on the outside corresponding to each groove 12. The protrusion 21 penetrates into the corresponding groove 12. In this embodiment, the protrusion 21 and the groove 12 form a sliding key connection. Since the pile body surface of the threaded pipe pile 1 is provided with spiral blades throughout its length, its power output is transmitted through the torsion rod 2. The top end of the torsion rod 2 protrudes outside the top end of the threaded pipe pile 1 and is connected to the pile driver 7.

[0038] Rod penetration steps: The drill rod 3 penetrates the torsion rod 2 and does not touch the inner wall of the torsion rod 2. The bottom end of the drill rod 3 extends out of the bottom end of the torsion rod 2 and the bottom end of the threaded pipe pile 1. The bottom end of the drill rod 3 is installed with a drill bit 4 for easy rotation and breaking the soil.

[0039] Lifting rod step: When the threaded pipe pile 1 is screwed into the designed pile end bearing layer, the pile driver 7 stops working, and the drill rod 3 and the torsion rod 2 are lifted up to complete the construction of the threaded pipe pile 1 into the soil.

[0040] In the grooving step, the cross-sectional shape of the groove 12 is any one of U-shape, trapezoidal and V-shape. In this embodiment, the groove 12 is preferably U-shaped. It should be noted that if the groove 12 is trapezoidal, it is preferably an isosceles trapezoid.

[0041] The axis of the drill rod 3, the axis of the torsion bar 2 and the axis of the threaded tubular pile 1 are collinear.

[0042] The torsion bar 2 is made of steel.

[0043] The drill rod 3 is provided with a soil discharge mechanism 5. In this embodiment, different soil discharge mechanisms 5 are prepared according to different strata, such as adding spiral blades to the outside of the drill rod 3 or making the drill rod 3 into a twist drill bit 4 type drill rod 3.

[0044] In the screwing step, when the torque of the pile driver 7 reaches or exceeds the preset torque value of the threaded pipe pile 1, an axial top pressure is applied to the pile top to realize the knob and downward pressing function of the threaded pipe pile 1. In this embodiment, the preset torque values ​​for different on-site construction conditions are different and are selected according to the actual on-site conditions. The preset torque value range of the threaded pipe pile 1 is usually 1-80 tons·m, depending on the pile diameter, soil quality and pitch design.

[0045] In the rod lifting step, the drill rod 3 is first pulled upward from the torsion rod 2, and the pile driver 7 continues to drive the torsion rod 2 to twist, and the torsion rod 2 drives the threaded pipe pile 1 to twist, and the pile end is screwed into the bearing layer required by the design, so that the position of the threaded pipe pile 1 is more accurate.

[0046] During on-site construction, the actual operation of this embodiment is as follows: Two to four continuous grooves 12 are formed in the inner cavity 11 of the threaded tubular pile 1. These grooves 12 can be created in a variety of ways, including sawed concrete grooves 12, embedded U-shaped channels or other metal materials, or prefabricated concrete grooves. Their purpose and function is to combine with the torsion bar 2 of the pile driver 7 to distribute the torsional torque applied to the pile shaft over the entire length of the pile shaft and the torsion bar 2 inserted into the cavity, thereby balancing the resistance applied to the entire outer length of the pile and avoiding stress concentration.

[0047] The pile driver 7 uses a circular tubular torsion bar 2 with a protrusion 21 on the outer edge of the torsion bar 2. The protrusion 21 corresponds one-to-one with the groove 12. The protrusion 21 matches the inner wall groove 12 of the threaded pipe pile 1. The torsion bar 2 is inserted from the cavity 11 of the threaded pipe pile 1, and the protrusion 21 penetrates into the corresponding groove 12 on the inner wall of the pile. When twisting, the entire length of one side of the protrusion 21 is pressed against the groove 12. On the pressed side, the size of the processing surface of the protrusion 21 is calculated according to the same curvature of the torsion bar 2 and the groove 12 on the inner wall of the pile, and the angle of the arc radius is different. During processing, the inclination angle of the side surface of the protrusion 21 is calculated to ensure that it fully matches the inner surface of the groove 12 and is in contact with the force.

[0048] In this embodiment, the use of double grooves → triple grooves → four grooves or more grooves corresponds to different pile diameters and different strata.

[0049] In this embodiment, the protrusion 21 of the torsion bar 2 and the groove 12 of the threaded tubular pile 1 are aligned and force-bearing. The combination of two materials with different stiffnesses creates a superimposed stiffness, forming a coordinated stiffness (i.e., stiffness distribution), which makes the combined stiffness exceed the individual stiffness of the two materials. Furthermore, the superimposed and coordinated stiffness of the concrete and steel materials makes it possible to achieve a process in which the torque and corresponding torsional deformation angle of the pile body concrete are less than their limit values. The torque experienced by the threaded tubular pile 1 is a pair of torsional moments formed by the torsional force of the pile driver 7 and the resistance of the soil to the pile. Therefore, the target direction of the process setting is to ensure that the torsional deformation of the torsion bar 2 with the protrusion 21 does not exceed the maximum allowable torsional angle of the pile body concrete, thereby preventing the pile body from cracking and damage. This combination ensures that the torsional strength of the threaded tubular pile 1 remains within the limit value even when the pile body is subjected to a torque far exceeding the design value of the torsional strength.

[0050] Twisting and breaking separation: The resistance of the soil at the bottom of the pile is separated and not transmitted to the pile body to bear the resistance of the soil at the end of the pile. A round tube drill rod 3 is inserted into the torsion bar 2. The drill rod 3 is extended to the bottom of the pile. The end of the drill rod 3 is equipped with a drill bit 4. The soil at the pile end is stirred and cut and squeezed to the side. The drill rod 3 is not in contact with the pile body. That is, the inner and outer rods are twisted, broken and squeezed to separate. The torsion bar 2 penetrates the groove 12 through the protrusion 21 to twist the pile to overcome the torque generated by the friction resistance of the soil on the side of the pile. The drill rod 3 breaks and squeezes the soil with the pile end. When the soil at the bottom of the pile has been stirred, cut and squeezed by the drill rod 3 and has been pre-guided to open the threaded blade trajectory, the friction torque of the pile body that follows has been greatly reduced, making the threaded pipe pile 1 less likely to be damaged or cracked. When the threaded pipe pile 1 is screwed into the designed pile end bearing layer, the pile driver 7 stops rotating, lifts the drill rod 3 upward, and the drill rod 3 is pulled upward from the inside of the torsion bar 2. Then the pile driver 7 continues to drive the torsion bar 2 to twist, and the torsion bar 2 drives the threaded pipe pile 1 to twist, so that the pile end is screwed into the designed bearing layer.

[0051] In this embodiment, during the twisting construction process of the pile driver 7, when the torque of the pile driver 7 reaches above the preset torque value of the threaded pipe pile 1, axial top pressure is applied to the pile top to assist the threaded pipe pile 1 in rotating downward and improve the tensile strength of the pile body concrete.

[0052] A soil discharge mechanism 5 is provided on the surface of the drill rod 3. During engineering applications, the pile end often needs to penetrate dense layers of sand and gravel. However, the resistance to shearing and horizontally squeezing the sand and gravel layers is very large. It is still very difficult for the drill rod 3 and the drill bit 4 to squeeze them apart. Moreover, even after the aforementioned twisting and separating measures of the drill rod 3, torsion bar 2, and threaded pipe pile 1 have been adopted, the resistance may still exceed the torsional yield strength of the drill rod 3 material. To ensure that the deformation of the pile concrete during the process does not exceed the critical value, a pile bottom soil discharge device is further provided on the surface of the drill rod 3. Different soil discharge devices are prepared according to different strata. Spiral blades are added to the outside of the drill rod 3, or the drill rod 3 is made into a twist drill bit-shaped drill rod 3. Another function of the soil discharge measure is to eliminate the large soil squeezing effect caused by the threaded pipe pile 1 as a prefabricated pile. There are two main aspects of engineering damage caused by the soil squeezing effect: on the one hand, it squeezes the surrounding piles upward and deflects them; on the other hand, it is easy to squeeze or displace nearby buildings and underground pipelines around the site. This hazard is particularly common in coastal soft soil areas due to the fluid plasticity of the soil. Soil drainage measures can effectively eliminate this engineering hazard.

[0053] The connection method of the drill rod 3, torsion rod 2 and threaded pipe pile 1: The connection method of the various segments of the threaded pipe pile 1 still adopts the traditional electric welding connection or mechanical connection method. The connection of the various segments of the torsion rod 2 has very high requirements for connection accuracy, stiffness and deformation. The torsion rod 2 needs a high-precision connection. The closer the gap between the upper and lower sections is to zero, the better, to avoid excessive gaps causing torsional displacement at the joint and driving torsional cracking of the pile concrete. For the drill rod 3, the main construction method is the connection method, and no requirements are made on the deformation amount. Specifically, the torsion rod 2 and the drill rod 3 adopt two methods: "spline connection" and "thread connection". Considering the order of the construction process of the drill rod 3 and the torsion rod 2 and the convenience of operation, and the fact that the torsion rod 2 requires the alignment of the upper and lower keyways to be correct, considering these factors, the torsion rod 2 adopts "spline connection" and the drill rod 3 adopts "thread connection". During the connection operation, the drill rod 3 is connected first, and after observing that the connection is complete, the "spline connection" of the torsion bar 2 is lowered.

[0054] Example 2 like Figures 10 to 11As shown, this embodiment differs from the first embodiment in that a block 31 is fixedly provided at the bottom end of the drill rod 3, and a slot 22 is provided at the bottom end of the torsion bar 2. In this embodiment, the block 31 and the slot 22 also form a sliding key connection. At least one block 31 is provided along the circumference of the drill rod 3. If there are multiple blocks 31, they are evenly distributed along the circumference of the drill rod 3, with each slot 22 corresponding to each block 31. During the screwing step, when the torsional resistance torque of the torsion bar 2 increases to a point where the stiffness-coordinated deformation of the outer torsion bar 2 and the pile concrete approaches the critical deformation value of the concrete, the pile driver 7 stops, and the drill rod 3, torsion bar 2, and threaded tubular pile 1 cease rotating or moving downward. The pile driver 7 lifts the drill rod 3 upward, and the block 31 at the bottom end of the drill rod 3 engages the slot 22 of the torsion bar 2. During the lifting step of this embodiment, the pile driver 7 withdraws the drill rod 3 and torsion bar 2 upward together.

[0055] In this embodiment, the drill rod 3 and torsion bar 2 are counteracted: the torsional engagement of the drill rod 3 and torsion bar 2 partially or completely offsets the torsional deformation of the external torsion bar 2. Even with the drill rod 3 and torsion bar 2, and the separate torsion and crushing process, the torque applied to the pile shaft has been significantly reduced. However, for large-diameter pipe piles, such as those with a diameter of 600 mm or greater, or in hard soil, where the resistance to driving the pile is high, as the pile shaft penetrates deeper into the soil, the soil is elastic. Even after the drill rod 3 has squeezed the soil at the bottom of the pile and the blades have guided the blades into a rotational trajectory, the frictional resistance of the surrounding soil on the pile side quickly recovers. However, the frictional resistance of the pile shaft during the driving process will still gradually increase. In this situation, to further reduce the torsional deformation of the external torsion bar 2 on the pile shaft, a combined reverse torsioning method of the drill rod 3 and torsion bar 2 at the bottom is initiated when the resistance (torque) reaches a critical value. The specific process operation is as follows: at the initial stage when the combination of the threaded pipe pile 1, the drill rod 3 and the torsion bar 2 begins to be screwed into the soil, the deformation of the torsion bar 2 and the pile is very small due to the small friction torque on the pile side, and the pile body is safe. At this time, the drill rod 3 and the torsion bar 2 are separated at the bottom and do not contact the force. As the pile goes deeper into the soil, when the torsion resistance torque of the torsion bar 2 increases to the point where the stiffness of the outer torsion bar 2 and the pile body concrete cooperates to deform the pile body close to the critical value of the concrete deformation, the pile driver 7 stops working and the drill rod 3 is moved upward. Lifting, the end block 31 of the drill rod 3 is stuck in the slot 22 of the torsion bar 2. At this time, when the drill rod 3 continues to twist, the small block 31 will push the end of the torsion bar 2 at the bottom to twist in the same torsion direction. Since the torsional deformation of the bottom end section of the torsion bar 2 is opposite to the torsion direction of the drill rod 3, the inner and outer rods are twisted together at this time, and the drill rod 3 offsets the deformation of the torsion bar 2, so the deformation of the pile is also reduced or even zero, or reverse twisting occurs, which is controlled in the construction operation.

[0056] Example 3 like Figure 12As shown, the difference between this embodiment and the second embodiment is that a mounting rod 6 is coaxially fixed to the bottom end of the drill rod 3. The diameter of the mounting rod 6 is larger than the diameter of the drill rod 3 and smaller than the inner diameter of the torsion bar 2. A clamping block 31 is movably pressed on the mounting rod 6. The upper and lower ends of the clamping block 31 are provided with extrusion inclined surfaces. In the rod lifting step, after the pile driver 7 is stopped, the drill rod 3 is first pulled upward from the inside of the torsion bar 2. Then the pile driver 7 drives the torsion bar 2 to twist again. The torsion bar 2 drives the threaded pipe pile 1 to twist, and the pile end is screwed into the bearing layer required by the design.

[0057] In this embodiment, a mounting slot is defined on the mounting rod 6, and a block 31 is slidably disposed within the slot. The block 31 can slide radially along the mounting rod 6. A spring is disposed between the block 31 and the inner sidewall of the slot, with one end of the spring fixedly connected to the block 31 and the other end fixedly connected to the inner sidewall of the slot. The top and bottom of the outer side of the block 31 are respectively provided with extrusion slopes. During the screwing step, when the torsional resistance torque of the torsion bar 2 increases to a point where the stiffness-coordinated deformation of the outer torsion bar 2 and the pile concrete approaches a critical value for the deformation of the concrete, the pile driver 7 is stopped, the drill rod 3 is lifted upward, and the block 31 at the bottom end of the drill rod 3 engages with the slot 22 of the torsion bar 2. In the rod lifting step, the drill rod 3 is first pulled out upward from the torsion rod 2, and the extrusion slope on the top of the clamping block 31 is squeezed with the inner wall of the clamping groove 22, so that the clamping block 31 is retracted into the installation groove, so that the drill rod 3 can be pulled out upward. Then, the pile driver 7 continues to drive the torsion rod 2 to twist, and the torsion rod 2 drives the threaded pipe pile 1 to twist, and the pile end is screwed into the bearing layer required by the design, so that the position of the threaded pipe pile 1 is more accurate.

[0058] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A construction process for twisting and breaking precast concrete threaded pipe piles, characterized by: The method includes the following steps: a slotting step: a cavity is formed through the threaded pipe pile along the axial direction, and at least one groove is formed on the side wall of the cavity along the circumferential direction, and the groove extends along the axial direction of the threaded pipe pile and penetrates the threaded pipe pile; a pile and rod twisting combination step: a torsion rod is inserted into the cavity of the threaded pipe pile, the interior of the torsion rod is hollow, and a protrusion is provided on the outside corresponding to the groove, and the protrusion penetrates into the corresponding groove; a rod penetration step: the drill rod penetrates the torsion rod and does not contact the inner wall of the torsion rod, and a drill bit is installed at the bottom end of the drill rod; a screwing step: the pile driver drives the drill rod and the torsion rod to twist into the soil, and the torsion rod drives the threaded pipe pile knob into the soil; a rod lifting step: when the threaded pipe pile is screwed into the designed pile end bearing layer, the pile driver stops working, lifts the drill rod and the torsion rod, and completes the construction of a threaded pipe pile into the soil.

2. The precast concrete threaded pipe pile twisting and breaking separation construction process according to claim 1 is characterized by: In the groove forming step, the cross-sectional shape of the groove is any one of a U-shape, a trapezoidal shape and a V-shape.

3. The precast concrete threaded pipe pile twisting and breaking separation construction process according to claim 1 is characterized by: The axis of the drill rod, the axis of the torsion rod and the axis of the threaded pipe pile are collinear.

4. The precast concrete threaded pipe pile twisting and breaking separation construction process according to claim 1 is characterized in that: The torsion bar is made of steel material.

5. The precast concrete threaded pipe pile twisting and separation construction process according to claim 1 is characterized in that: A soil discharge mechanism is provided on the drill rod.

6. The precast concrete threaded pipe pile twisting and breaking separation construction process according to claim 1 is characterized by: In the screwing step, when the pile driver torque reaches or exceeds a preset torque value of the threaded tubular pile, an axial top pressure is applied to the pile top.

7. The precast concrete threaded pipe pile twisting and separation construction process according to claim 1 is characterized by: In the rod lifting step, the drill rod is first pulled upward from the inside of the torsion rod, and the pile driver continues to drive the torsion rod to twist, and the torsion rod drives the threaded pipe pile to twist, and the pile end is screwed into the bearing layer required by the design.

8. The precast concrete threaded pipe pile twisting and separation construction process according to any one of claims 1 to 6, characterized in that: The bottom end of the drill rod is provided with a block, and the bottom end of the torsion bar is provided with a slot. During the screwing step, when the torsional resistance torque of the torsion bar increases to the point where the stiffness cooperative deformation of the outer torsion bar and the pile body concrete is close to the critical value of the deformation of the concrete, the pile driver stops, the drill rod is lifted upward, and the block at the bottom end of the drill rod is inserted into the slot of the torsion bar.

9. The construction process for twisting and breaking precast concrete threaded pipe piles according to claim 8 is characterized in that: The clamping block is fixedly connected to the drill rod, and in the rod lifting step, the drill rod and the torsion rod are pulled upward together.

10. The construction process for twisting and breaking precast concrete threaded pipe piles according to claim 8, characterized in that: A mounting rod is coaxially fixed to the bottom end of the drill rod, the diameter of the mounting rod is larger than the diameter of the drill rod and smaller than the inner diameter of the torsion rod, the clamping block is movably pressed on the mounting rod, and extrusion inclined surfaces are provided at the upper and lower ends of the clamping block. In the rod lifting step, the drill rod is first pulled upward from the inside of the torsion rod, and the pile driver continues to drive the torsion rod to twist, and the torsion rod drives the threaded pipe pile to twist, and the pile end is screwed into the bearing layer required by the design.

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