Recyclable precast pile

Abstract

The utility model belongs to the technical field of underground building construction, and particularly relates to a recyclable precast pile. The precast pile comprises a pipe pile body, a recoverable prestressed steel assembly and a connecting assembly, the recoverable prestressed steel assembly is arranged on the pipe pile body in a penetrating mode in the axis direction of the pipe pile body, and the recoverable prestressed steel assembly comprises an isolation sleeve and at least one prestressed tendon; the two ends of the prestressed tendons are detachably connected with the pipe pile body through connecting assemblies. According to the precast pile, the prestressed tendons are detachably connected with the pipe pile body through the connecting assemblies, it is ensured that the prestressed tendons can be separated from the connecting assemblies after construction is completed, that is, the prestressed tendons can be released from the pipe pile body through simple operation, material waste in the building industry is reduced, carbon emission is reduced, and the construction efficiency is improved. And the construction industry is promoted to develop in a more sustainable direction.

Description

TECHNICAL FIELD

[0001] The utility model belongs to underground building construction technical field, more particularly to recyclable precast pile. BACKGROUND

[0002] Under the background of the current rapid urbanization, efficient use of urban space has become an urgent task. As an important part of underground building structure, foundation pit engineering has made significant progress in design theory, construction method and management technology, but still faces many problems. Especially in the aspects of resource conservation and environmental protection, the existing foundation pit support engineering often causes resource waste and environmental damage due to the use of a large number of disposable materials. In particular, the internal reinforcement of traditional reinforced concrete piles is difficult to recycle after construction, not only leading to resource waste, but also possibly causing long-term pollution to the underground environment. In addition, although the detachable steel cage technology provides a partial solution, the on-site processing requirements, slow construction progress, and environmental problems of electric welding operation still limit its application. SUMMARY

[0003] The utility model aims at solving the problem that the main reinforcement of precast pile cannot be recycled. The purpose is realized by the following technical scheme:

[0004] The utility model provides a recyclable precast pile, which is characterized by comprising:

[0005] A pipe pile body;

[0006] A recyclable prestressed steel assembly, which is arranged along the axial direction of the pipe pile body, the recyclable prestressed steel assembly comprising an isolation sleeve and at least one prestressed reinforcement, the isolation sleeve being arranged on the outer side of the prestressed reinforcement in the circumferential direction, at least one end of the prestressed reinforcement being located outside the top of the pipe pile body along the axial direction, and the top being directed towards the slope top of the foundation pit;

[0007] A connecting assembly, both ends of the prestressed reinforcement being connected with the pipe pile body in a detachable manner through the connecting assembly.

[0008] According to the recyclable precast pile of the utility model, by being arranged at the outside of the top of the pipe pile body at least one end of the prestressed tendon, and the prestressed tendon is connected with the pipe pile body in a detachable mode through the connecting assembly, it is ensured that the prestressed tendon can be separated from the connecting assembly after construction is completed. After the foundation pit support of the precast pile is completed, the prestressed tendon (referring to the main tendon) can be released from the pipe pile body through simple operation, and the pipe pile body or the prestressed tendon itself will not be damaged. Through the above analysis, it can be seen that the recyclable precast pile of the utility model not only solves the technical problem that the main tendon of the traditional precast pile cannot be recycled, but also provides a more environmentally friendly and economical building solution. The application of the utility model is expected to greatly reduce the material waste of the building industry and promote the development of the building industry in a more sustainable direction. In addition, the implementation of the utility model will also reduce the long-term maintenance and replacement cost, providing actual economic benefits for users and builders.

[0009] In addition, the recyclable precast pile according to the utility model can also have the following additional technical features:

[0010] In some embodiments of the utility model, the recyclable prestressed steel assembly includes a prestressed tendon and an anchoring tendon, one end of the prestressed tendon is arranged in the isolation sleeve from the axial end of the isolation sleeve, the anchoring tendon is fixedly connected with the pipe pile body, and the connecting assembly includes a connector, the connector abuts against the other axial end of the isolation sleeve, and the prestressed tendon is connected with the anchoring tendon through the connector.

[0011] In some embodiments of the utility model, one end of the prestressed tendon located outside the top of the isolation sleeve is a first end, and the connecting assembly further includes a first nut, and the first end is connected with the pipe pile body through the first nut.

[0012] In some embodiments of the utility model, the anchoring tendon and the pipe pile body are integrally formed and poured.

[0013] In some embodiments of the utility model, the number of prestressed tendons is one, and the prestressed tendon penetrates the isolation sleeve, the prestressed tendon has a first end and a second end, the first end is located outside the top of the isolation sleeve, and the second end is located outside the bottom of the isolation sleeve, the connecting assembly includes a first nut and a second nut, the first end is connected with one end of the pipe pile body through the first nut, and the second end is connected with the other end of the pipe pile body through the second nut.

[0014] In some embodiments of the utility model, lubricating grease and / or slow adhesive are filled between the isolation sleeve and the prestressed tendon.

[0015] In some embodiments of the utility model, the number of the recyclable pre-stressed steel assembly is multiple, and the multiple recyclable pre-stressed steel assemblies are uniformly and symmetrically arranged along the circumference of the pipe pile body.

[0016] In some embodiments of the utility model, the prefabricated pile comprises an end plate, the end plate is located at the top of the pipe pile body and is clamped between the first nut and the top of the pipe pile body. BRIEF DESCRIPTION OF DRAWINGS

[0017] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments with reference made to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to be limiting in any respect. Throughout the drawings, the same reference numerals are used for the same parts throughout the several views. In the drawings:

[0018] Figure 1 A structural schematic view of a prefabricated pile according to an embodiment of the utility model is schematically shown;

[0019] Figure 2 A first perspective view of a prefabricated pile according to an embodiment of the utility model is schematically shown;

[0020] Figure 3 A cross-sectional structural schematic view of a prefabricated pile according to a first embodiment of the utility model without an expander is schematically shown;

[0021] Figure 4 A first perspective view of a prefabricated pile according to a first embodiment of the utility model without an expander is schematically shown, and three pile types a, b and c are given;

[0022] Figure 5 A partial enlarged view of A in FIG. 1 is shown; Figure 3

[0023] A partial enlarged view of B in FIG. 1 is shown; Figure 6 Figure 3 A cross-sectional structural schematic view of a prefabricated pile according to a second embodiment of the utility model without an expander is schematically shown;

[0024] Figure 7 A partial enlarged view of C in FIG. 2 is shown;

[0025] Figure 8 A structural schematic view of a prefabricated pile according to the utility model when arranged in a foundation pit is schematically shown; Figure 7

[0026] Figure 9 A structural schematic view of a prefabricated pile according to the utility model when arranged in a foundation pit is schematically shown;

[0027] Figure 10 ​​The structure schematic diagram of prefabricated pile using triaxial cement soil mixing construction according to the utility model is shown schematically.

[0028] Reference signs are as follows:

[0029] 100, prefabricated pile;

[0030] 10, pipe pile body; hole, 101; 20, prestressed tendon 20; 21, anchoring tendon; 30, connecting assembly; 31, first nut; 32, second nut; 33, anchoring piece; 34, connector; 40, expanding body; 50, isolation sleeve;

[0031] 201, foundation pit slope top; 202, foundation pit groove bottom; 203, triaxial cement soil mixing pile; 300, anchor rod. DETAILED DESCRIPTION

[0032] Exemplary embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. While example embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0033] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically identified as an order dependent step. It is also to be understood that additional or alternative steps can be employed.

[0034] Although the terms first, second, third, and the like can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to differentiate one element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second", and the like are used herein to describe a variety of elements, components, regions, layers and / or sections, and do not imply an order or sequence unless the context clearly indicates otherwise. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of example embodiments.

[0035] For ease of description, spatial relative terms can be used herein to describe a relationship of one element or feature to another element or feature as shown in the drawings, such as "inner", "outer", "inside", "outside", "lower", "below", "upper", "above", and the like. Such spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawings is turned over, an element described as "below" or "beneath" the other element or feature would then be oriented "above" or "over" the other element or feature. Thus, the example term "below" can encompass both an orientation of above and below. The embodiments of the device can be implemented in any of a variety of ways, some of which are specifically set forth herein.

[0036] As shown in the drawings, Figures 1 to 8 According to the embodiments of the present application, a recyclable precast pile 100 is provided, which comprises a pipe pile body 10, a recyclable prestressed steel assembly and a connecting assembly 30. Along the axial direction of the pipe pile body 10, the recyclable prestressed steel assembly comprises an isolation sleeve 50 and at least one prestressed tendon 20. The isolation sleeve 50 is sleeved on the outer side of the prestressed tendon 20 in the circumferential direction. At least one end of the prestressed tendon 20 is located outside the top of the pipe pile body 10 along the axial direction, which is used to face the slope top of the foundation pit. Both ends of the prestressed tendon 20 are connected with the pipe pile body 10 in a detachable manner through the connecting assembly 30.

[0037] According to the precast pile 100 of the present application, by arranging at least one end of the prestressed tendon 20 outside the top of the pipe pile body 10 and exposed on the slope top of the foundation pit, and connecting the prestressed tendon 20 with the pipe pile body 10 in a detachable manner through the connecting assembly 30, it is ensured that the prestressed tendon 20 can be separated from the connecting assembly 30 after the construction is completed. This design not only simplifies the disassembly process of the prestressed tendon 20, but also ensures the flexibility and maintainability of the construction. After the foundation pit support of the precast pile is completed, the main tendon can be released from the pipe pile body 10 through simple operation, without damaging the pipe pile body 10 or the prestressed tendon 20 itself. Through the above analysis, it can be seen that the recyclable precast pile 100 of the present application not only solves the technical problem that the main tendon of the traditional precast pile cannot be recycled, but also provides a more environmentally friendly and economical building solution. The application of the present application is expected to greatly reduce the material waste in the construction industry, reduce carbon emissions, and promote the development of the construction industry in a more sustainable direction. In addition, the implementation of the present application will also reduce the long-term maintenance and replacement cost, providing actual economic benefits for users and builders. The design idea and implementation strategy of this precast pile 100 will have a positive impact on the material utilization and construction method of the entire construction industry.

[0038] In some embodiments, the precast pile 100 also includes an enlarged portion 40, in which the pile body 10 is housed.

[0039] like Figure 3 As shown, in some embodiments, the recyclable prestressed steel assembly includes only one prestressing tendon 20. The prestressing tendon 20 completely penetrates the isolation sleeve 50, which in turn completely penetrates the pipe pile body 10. The two ends of the prestressing tendon 20 are respectively located at the top and bottom of the pipe pile body; the end at the top is the first end, and the end at the bottom is the second end. Both ends are connected to the pipe pile body via a connecting assembly, which includes a first nut 31 and a second nut 32. The first end is connected to the top of the pipe pile body 10 via the first nut 31, and the second end is connected to the bottom of the pipe pile body 10 via the second nut 32. After the precast pile 100 is supported, the nut at the top of the prestressing tendon 20 is first unscrewed, and then the prestressing tendon 20 is rotated to separate the nut at the bottom from the prestressing tendon 20, allowing the prestressing tendon 20 to be removed and recycled.

[0040] In other embodiments, the recyclable prestressed steel assembly includes prestressed tendons 20 and anchor bars 21. One end of the prestressed tendon 20 passes through the axial end of the isolation sleeve 50 and is inserted into the isolation sleeve 50. The anchor bar 21 is fixedly connected to the pipe pile body 10. The connecting assembly 30 includes a connector 34, which abuts against the other axial end of the isolation sleeve 50 (i.e., the connector 34 does not enter the isolation sleeve 50). The prestressed tendon 20 located in the isolation sleeve 50 is connected to the anchor bar 21 through the connector 34.

[0041] Understandably, the prestressing tendon 20 is the main reinforcement, and the anchoring tendon 21 is the auxiliary reinforcement. The prestressing tendon 20 protrudes from the top of the pit slope, while the anchoring tendon 21 faces towards the bottom of the pit. As the main reinforcement, the prestressing tendon 20 typically has a larger diameter and higher strength because it needs to withstand greater tensile forces and ground loads. The portion protruding from the top of the pit slope is usually used for connection with other structures, such as capping beams or ground structures, providing the main load-bearing capacity of the entire pit support system. The location and protrusion of the main reinforcement allow for the recovery of the prestressing tendon 20 after the pit work is completed, facilitating its removal from the connection point for subsequent processing or reuse. The anchoring tendon 21, as the auxiliary reinforcement, is mainly positioned towards the bottom of the pit. This configuration helps provide bottom-up support, enhancing the stability of the entire pit, especially effective in deeper pits. The auxiliary reinforcement helps distribute earth pressure, reducing pressure and deformation on the pit sidewalls. By extending towards the bottom of the pit, the auxiliary reinforcement also helps provide additional anchorage in softer or unstable strata, thus ensuring the safety of the pit.

[0042] Specifically, the prestressed tendon 20 is located at one end of the outer side of the top of the isolation sleeve 50 as a first end, and the connecting assembly 30 includes a first nut 31, and the first end is connected to one end of the pipe pile body 10 through the first nut 31. The first nut 31 is located at the first end of the prestressed tendon 20 and is fastened to one end of the pipe pile body 10. The first nut 31 is used to adjust the initial tension of the prestressed tendon 20 during the installation process of the prefabricated pile 100, and maintain the tension during operation.

[0043] As shown in Figure 1 , it can be understood that the anchoring tendon 21 is integrally formed with the pipe pile body 10, and the pipe pile body 10 directly provides anchoring force for the anchoring tendon 21.

[0044] As shown in Figure 7 and Figure 8 , it can be understood that the following implementation can also be provided, the anchoring tendon 21 is located at one end of the bottom of the isolation sleeve 50 as a second end, and the connecting assembly 30 further includes an anchoring piece 33, and the second end is connected to the pipe pile body 10 through the anchoring piece 33. In combination with the first nut 31 in the above-mentioned implementation, a complete embodiment is constituted, the anchoring tendon 21 has one end connected to the connector 34 and the second end, the one end connected to the connector 34 is connected to the prestressed tendon 20 through the connector 34, and the second end is connected to the pipe pile body 10 through the anchoring piece 33. The second end of the anchoring tendon 21 is stably connected to the other end of the pipe pile body 10 through the anchoring piece 33. The anchoring piece 33 is designed to provide strong anchoring function, so as to ensure that the anchoring tendon 21 will not loosen or shift even in the case of long-term or high load.

[0045] In particular, the anchor 33 is a concrete block or a concrete footing, which is formed at the end of the anchor tendon 21 where it connects to the pile body 10. The main purpose of this design is to utilize the strength and structural stability of concrete to carry the tension force exerted by the prestressed tendon 20. The concrete anchor 33 can be made by prefabrication. Prefabricated concrete anchors 33 are manufactured in a controlled environment to ensure that the quality and strength meet the engineering requirements. The steps of prefabricating the anchor 33 can be as follows: first, design the size, shape, and strength of the anchor 33 according to the engineering requirements and load demands. This usually involves calculations and simulations by structural engineers to ensure that the anchor 33 can withstand the expected forces and environmental influences; second, make appropriate molds; then, place the pile body 10 into the mold in a way that the second end of the anchor tendon 21 is exposed, prepare the concrete according to the design requirements to ensure that it reaches the required strength and durability, and pour the concrete into the mold, using a vibrator to ensure that the concrete fills the mold and forms a seamless connection around the second end. The high compressive strength of the concrete provides a solid anchoring point for the anchor tendon 21, which helps to carry larger tension forces, thereby improving the stability and uplift resistance of the entire pile. The durability of the concrete ensures that the anchor 33 can resist environmental factors such as humidity, temperature changes, and chemical corrosion over a long period of service, maintaining the structural integrity and functionality. Using prefabricated concrete anchors 33 can complete most of the manufacturing and quality control work in the factory in advance, shortening the on-site construction time, reducing the complexity and cost of on-site construction. By using concrete as the material for the anchor 33, its structural properties can be effectively utilized to support the high-tension anchor tendon 21, providing a solid and reliable anchoring solution for the prefabricated pile 100. This solution is suitable for various geological conditions and environments, especially for heavy-load engineering projects that require long-term stable support.

[0046] It is understood that the isolation sleeve 50 is a tubular component that is sleeved on the prestressed tendon 20. Its role is to protect the prestressed tendon 20 from direct contact with the soil or other corrosive substances, while allowing the prestressed tendon 20 to slide freely therein when applying prestress, so as to uniformly transmit the prestress. The isolation sleeve 50 is usually made of corrosion-resistant materials such as plastic, stainless steel or metal coated with a corrosion-resistant layer. Before inserting the prestressed tendon 20 into the isolation sleeve 50 of the tubular pile body 10, the prestressed tendon 20 is first threaded into the isolation sleeve 50. The length of the isolation sleeve 50 usually matches the length of the prestressed tendon 20 in the tubular pile body 10. The isolation sleeve 50 provides a protective layer for the prestressed tendon 20, which isolates the contact of moisture and corrosive chemicals, thereby significantly prolonging the service life and maintenance period of the prestressed tendon 20. Since the prestressed tendon 20 can slide freely in the isolation sleeve 50, it allows the tension to be more uniformly transmitted along the prestressed tendon 20, improving the stability and load-bearing capacity of the overall structure. By preloading the isolation sleeve 50 and pre-filling the concrete, the on-site construction process is simplified, the complex operation during construction is reduced, and the consistency and controllability of construction quality are ensured.

[0047] It is understood that the isolation sleeve 50 and the prestressed tendon 20 (including the prestressed tendon 2021) are filled with lubricating grease and / or a slow-setting adhesive, and the isolation sleeve 50 and the prestressed tendon 20 can be filled with lubricating grease. Lubricating grease is mainly used to reduce the friction of the prestressed tendon 20 during tensioning, allowing the prestressed tendon 20 to slide freely in the isolation sleeve 50, thereby more uniformly transmitting the prestress. The lubricating grease should be selected to be high-performance and long-acting to ensure its lubricity in long-term application. The slow-setting adhesive is used to control the adhesion between the prestressed tendon 2021 and the isolation sleeve 50, which usually has the characteristic of slow hardening, allowing the prestressed tendon 2021 and the anchor tendon 21 to slide in the isolation sleeve 50 for a certain period of time, and then gradually solidifying, which helps to control the long-term stability of the prestress. Before the prestressed tendon 20 is implanted in the isolation sleeve 50, lubricating grease is first applied. After the prestressed tendon 20 is installed, the filling material can be supplemented through the injection port of the isolation sleeve 50 to ensure that there is no gap and the distribution is uniform. The use of lubricating grease can significantly reduce the frictional resistance of the prestressed tendon 20 during tensioning, allowing the tension to be more uniformly distributed along the tendon body, improving the overall performance of the structure.

[0048] In some embodiments, the precast pile 100 further comprises an end plate, which is located at the top of the tubular pile body 10 and sandwiched between the first nut 31 and the top of the tubular pile body 10. The end plate is designed as a solid metal plate, which is located between the first end of the prestressed tendon 20 and the first nut 31. The main function of the end plate is to act as a pressure distribution plate between the prestressed tendon 20 and the tubular pile body 10, which helps to distribute the force transmitted by the prestressed tendon 20 to the tubular pile body 10, avoiding local stress concentration. The shape of the end plate matches the shape of the end of the tubular pile body 10. The end plate is usually made of high-strength steel material to ensure sufficient strength and rigidity to withstand the high tension of the prestressed tendon 20. The thickness and size of the end plate are determined according to the diameter of the prestressed tendon 20 and the expected tension, ensuring that it can work effectively. In addition, the end plate is sandwiched between the first end of the prestressed tendon 20 and the first nut 31 during installation. This configuration allows the end plate to directly bear the tension from the prestressed tendon 20, while being fixed by the nut to ensure the stability of the connection. There can also be the use of gaskets or other cushioning materials between the end plate and the tubular pile body 10, which are used to further reduce wear and protect the contact surface of the end plate and the tubular pile body 10. The end plate can effectively distribute the tension of the prestressed tendon 20, avoiding excessive stress concentration at the connection point, which helps to improve the structural stability and durability of the entire uplift pile.

[0049] In some embodiments, the volume of the enlarged body portion 40 is greater than the volume of the tubular pile body 10. The enlarged body portion 40 is usually designed as an enlarged structure at the bottom of the tubular pile, which can adopt different shapes such as circular, square or structures with specific profiles, aiming to increase the contact area with the soil layer and thus improve the uplift capacity. The material of the enlarged body portion 40 can be concrete, reinforced concrete or other suitable structural materials, selected according to the geological conditions and structural requirements. Specifically, the enlarged body portion 40 is cast in situ. The enlarged body portion 40 greatly increases the bearing area and friction area of the pile foundation due to its larger volume than the tubular pile body 10, significantly improving the uplift capacity. This is particularly important in soft soil layers or underwater engineering, effectively preventing the structure from moving or overturning due to buoyancy. The enlarged enlarged body portion 40 can more effectively distribute loads and stresses, reduce local instability of the soil layer and uneven settlement of the structure, and increase the stability of the entire uplift pile. In summary, through the large-volume enlarged body portion 40, the uplift pile can provide reliable support in demanding environments such as marine engineering, bridge foundations and high-rise buildings, etc. important structures, ensuring their stability and safety during long-term operation.

[0050] It can be understood that the material of the expansion body 40 can be a pre-mixed fluidized cement soil mixture, a cement mortar mixture, a fine stone concrete, or a jet mixing cement soil. Among them, the pre-mixed fluidized cement soil mixture is suitable for occasions that require rapid construction and initial strength. This material has good fluidity and is easy to pour, and is suitable for complex or narrow foundation conditions; the cement mortar mixture can provide better compactness and bearing capacity, and is suitable for structural foundations that bear medium loads; the fine stone concrete, due to its smaller aggregate size, is suitable for expansion body 40 that requires higher surface quality and structural tightness; the jet mixing cement soil is suitable for uneven foundation conditions or soil improvement. Jet mixing can ensure that the material is fully mixed with the original foundation soil. The selected expansion material combined with the construction method can significantly improve the bearing capacity and stability of the uplift pile foundation, especially in soft soil, by increasing the bottom area to increase the uplift capacity.

[0051] It can be understood that the construction process of the expansion body 40 can be a long spiral pressure pouring method, a rotary drilling and pouring method, or a jet mixing cement soil method, etc. Among them, the long spiral pressure pouring method is suitable for expansion construction that needs to penetrate deep into the foundation. Continuous pouring is carried out through a long spiral drill, effectively controlling the pouring process and reducing material stratification and voids; the rotary drilling and pouring method is suitable for the construction of large-diameter expansion body 40. After the hole is formed by a rotary drilling machine, concrete is poured, which is suitable for hard geological conditions. The jet mixing cement soil method improves the soil quality by high-pressure jet mixing technology, and forms an expansion body. It is suitable for foundation reinforcement and environmental remediation projects. The diversity of material selection and construction technology makes the uplift pile system adaptable to various geological and environmental conditions, providing targeted solutions to meet the specific needs of different projects.

[0052] It can be understood that the method of implanting the pipe pile body 10 can be a static pressure method or a hammering method. The static pressure method is suitable for areas with strict noise and vibration requirements. The pipe pile is pressed in by static force, reducing the impact on the surrounding environment. The hammering method is suitable for hard foundation conditions. The pipe pile penetrates the hard layer by hammering, which is fast but may produce a lot of noise and vibration.

[0053] In some embodiments, the number of recyclable prestressed steel assemblies is multiple, and the multiple recyclable prestressed steel assemblies are uniformly and symmetrically arranged along the circumference of the pipe pile body 10. In this embodiment, only recyclable prestressed steel assemblies are provided in the pipe pile body 10. The multiple recyclable prestressed steel assemblies are uniformly and symmetrically arranged along the circumference, which can effectively disperse the uplift force and enhance the overall uplift performance of the uplift pile. The uniform and symmetrical arrangement makes the pipe pile body 10 more uniform in stress, reduces local stress concentration, and prolongs the service life.

[0054] In other embodiments, multiple recyclable prestressed steel assemblies are arranged symmetrically and uniformly along the circumference of the pipe pile body 10. However, in this embodiment, not only are recyclable prestressed steel assemblies inserted into the pipe pile body 10, but also prestressed steel bars from the prior art are inserted. The recyclable prestressed steel assemblies and prestressed steel bars are arranged in a one-to-one correspondence and at intervals. The combined use of recyclable prestressed steel assemblies and prestressed steel bars from the prior art significantly enhances the pull-out resistance of the precast pile 100, enabling it to withstand higher pull-out forces. The one-to-one correspondence and interval arrangement of prestressed steel bars and recyclable prestressed steel assemblies provide multiple reinforcements, further improving the overall strength and stiffness of the pipe pile body 10.

[0055] Understandably, the first nut 31 and the second nut 32 have a self-locking function, which can be achieved by designing specific thread shapes, such as sawtooth or wedge threads. These self-locking threads effectively prevent the nuts from loosening under load. Alternatively, additional locking devices, such as reverse-locking nuts or locking pins, can be introduced to ensure that the nuts are reliably locked in place after the required prestress is reached. Nylon inserts or other anti-loosening devices can be considered; these devices generate additional friction between the threads to prevent the nuts from loosening automatically under vibration or prolonged load.

[0056] Understandably, the first nut 31 and the second nut 32 are convex in design, which will bring additional structural advantages and functionality to the tensioning and locking of the prestressing tendons 20 and anchoring tendons 21, respectively. Convex nuts typically have a larger contact area and improved mechanical properties; this design helps to more effectively transmit and distribute pressure while improving the stability of the connection. Convex nuts typically have a protruding dome-shaped or hemispherical head, which provides a larger contact area and reduces material fatigue or damage caused by tension concentration. The protruding portion of the nut can effectively disperse the forces generated by the prestressing tendons 20 and anchoring tendons 21 during tensioning, helping to uniformly transmit these forces to the pipe pile structure.

[0057] It is understandable that, such as Figure 4 As shown, there are three types of precast piles, namely a, b, and c, with different pile types to be selected according to different construction scenarios.

[0058] Furthermore, such as Figure 4 The precast pile 100 shown in a figure has a hole 101 in the center of the pipe pile body 10 of the precast pile 100, which penetrates the top and bottom of the precast pile 100. The hole 101 is coaxially arranged with the pipe pile body 10.

[0059] like Figures 9 to 10As shown, the embodiment also provides a construction method of the recyclable precast pile 100, for construction according to the precast pile 100 described above, comprising the following steps:

[0060] The precast pile 100 is processed in the factory, and the prestressed tendon 20 is tensioned and locked;

[0061] The precast pile 100 is lowered to the design elevation according to the static pressure method or the hammering method;

[0062] The crown beam construction is carried out, and the exposed prestressed tendon 20 is isolated and protected;

[0063] The soil excavation and anchor rod construction are carried out layer by layer until the designed slot bottom is reached;

[0064] After the construction of the main structure reaches or exceeds the ground elevation, the fat groove backfilling is carried out;

[0065] The prestressed tendon 20 is recycled.

[0066] In addition, the embodiment also provides a construction method of the recyclable precast pile 100, for construction according to the precast pile 100 described above, comprising the following steps:

[0067] The water stop curtain is constructed according to the mixing method or the high-pressure rotary jet grouting method;

[0068] The precast pile 100 is lowered to the design elevation according to the static pressure method or the hammering method;

[0069] The prestressed tendon 20 is tensioned and locked;

[0070] The crown beam construction is carried out, and the exposed prestressed tendon 20 is isolated and protected;

[0071] The soil excavation and anchor rod construction are carried out layer by layer until the designed slot bottom is reached;

[0072] After the construction of the main structure reaches or exceeds the ground elevation, the fat groove backfilling is carried out;

[0073] The prestressed tendon 20 is recycled.

[0074] As shown, Figure 9 The precast pile 100 has been completely inserted into the foundation pit, the top of the precast pile 100 is flush with the slope top 201 of the foundation pit, and part of the precast pile 100 is inserted below the slot bottom 202 of the foundation pit.

[0075] Specifically, the method for constructing the water stop curtain according to the mixing method is to use a drill rod with mixing blades for mixing. The drill rod can be single-shaft, double-shaft or multi-shaft (such as three-shaft, such as Figure 10The tri-axial cement-soil mixing pile 203) is shown to improve the uniformity and efficiency of mixing. A cement slurry is typically used as the mixing additive, which hardens after thorough mixing with the soil layer to form a solidified soil mass with waterproof function. The construction process involves driving the drill pipe into the ground to the designed depth, and then rotating and mixing while pulling up the drill pipe to ensure uniform distribution of the additive in the soil layer. The method for constructing a waterproof curtain according to the high-pressure jet grouting method involves using a high-pressure jet grouting machine to inject cement slurry into the soil layer through a rotating nozzle. The direction and intensity of the high-pressure water flow can be adjusted as needed. The construction process involves first drilling the jet grouting drill pipe to the predetermined depth, and then starting the high-pressure pump to inject cement slurry in all directions through the rotating nozzle. During the injection process, the drill pipe is slowly lifted while rotating to form a solidified soil column with a larger diameter. In addition, other chemical additives may be added in addition to cement to improve the performance of the soil column.

[0076] Specifically, the static pressure method uses static force to push the precast pile 100 into the ground. This method is particularly suitable for areas sensitive to environmental disturbance, such as city centers, residential areas, or sites near sensitive facilities. The hammering method uses a heavy hammer (diesel hammer, air hammer, or hydraulic hammer) to periodically strike the top of the pile, driving the pile into the ground. This method is suitable for a variety of soil conditions, particularly harder ground layers.

[0077] Specifically, the step of tensioning and locking the prestressed tendon 20 includes, first, ensuring that the prestressed tendon 20 is correctly placed in the precast pile 100 according to design requirements, and fixed in place in the pile body through the isolation sleeve 50 or directly. Specialized tensioning equipment, such as hydraulic tensioners, is used to connect to the first end of the prestressed tendon 20. These devices can accurately control the tension applied to the tendon. The tension is gradually increased according to design requirements until the desired force value is reached. This process requires strict monitoring to ensure uniform tension and compliance with technical specifications. During tensioning, monitoring equipment such as stress sensors or strain gauges is used to detect the stress state of the prestressed tendon 20 to ensure that it does not exceed the elastic limit of the prestressed tendon 20, avoiding permanent deformation or damage. After reaching the desired tension, a fastening device (such as the first nut 31) is used to fix the position of the prestressed tendon 20. The fastening device must be able to reliably withstand long-term tension without slipping. After anchoring is complete, the tension of the prestressed tendon 20 is checked again to ensure its stability and consistency. If necessary, fine-tuning is performed to accommodate changes that may occur during construction. To prevent corrosion or damage to the anchoring point, the anchoring system should be properly protected, such as by applying a corrosion-resistant coating or installing a protective cover.

[0078] It is understood that in order to avoid uneven tensioning causing deformation or cracking of the pile body of the precast pile 100, the correct tensioning sequence should be adopted to prevent structural cracks or uneven settlement caused by uneven loading. First, according to the structural design requirements, the layout and position of the prestressed tendon 20 and the predetermined tension of each prestressed tendon 20 are determined. The prestressed tendon 20 is grouped according to its position and function in the structure, and each group of prestressed tendon 20 will be tensioned within a certain time period. Based on the symmetry of the structure, construction convenience and structural balance, the tensioning sequence is determined. Generally, tensioning is carried out from the center to the outside of the structure or from one end to the other end to maintain the balance of the structure. The tensioning of the prestressed tendon 20 usually needs to be carried out in several stages, and each stage tensioning a group or more groups of prestressed tendon 20. After each tensioning, the response of the structure needs to be evaluated, such as monitoring the displacement and stress. In order to avoid causing asymmetry and possible deviation of the structure, the tensioning of the tendons in the relative position should be carried out alternately. For example, in a bridge project, the prestressed tendon 20 on the left side can be tensioned first, then the prestressed tendon 20 on the right side is tensioned, and so on. The applied tension should be strictly controlled to ensure that it reaches but does not exceed the design required tension value. High-precision tensioning equipment and real-time monitoring system are used to ensure the accuracy of the tensioning force. The correct tensioning sequence is particularly important for prestressed concrete structures, as it relates to the final performance and safety of the structure.

[0079] Specifically, the method for carrying out the corbel construction is as follows: first, before pouring the corbel, the steel bar mesh of the corbel, including longitudinal and transverse steel bars, is bound. The position of the steel bars is ensured to be correct and consistent with the design drawings to ensure the load-bearing capacity and crack resistance of the corbel. Spacers and supports are used to ensure that the cover depth of the steel bars meets the specification requirements. The corbel formwork is installed, and the stability and tightness of the formwork are checked to ensure that there is no slurry leakage or formwork deformation during pouring. The horizontal and vertical degrees of the formwork are checked to ensure the accuracy of the geometric dimensions and position of the corbel. Finally, the appropriate concrete mix is selected, which usually needs to have high strength and good fluidity to fill the entire formwork and bypass the steel bars and prestressed tendons 20. The concrete is thoroughly vibrated using a vibrating rod to eliminate air bubbles and ensure good adhesion between the concrete and the steel bars.

[0080] Specifically, the isolation and protection of the exposed prestressed tendons 20 include the installation of isolation sleeves 50. These isolation sleeves 50 not only protect the prestressed tendons 20 from external environmental erosion, but also prevent them from bonding with the corbel concrete, ensuring that the length and diameter of the isolation sleeves 50 are suitable for the prestressed tendons 20 and remain stable during the entire construction and use period. In addition, the ports of the isolation sleeves 50 are sealed, and non-shrinkage grouting materials or special sealants are used for sealing treatment to prevent moisture and other corrosive substances from entering the interior of the isolation sleeves 50. Waterproof paint or other protective layers are applied to the parts of the isolation sleeves 50 that are in contact with the corbel to further enhance the protection effect.

[0081] Specifically, the earth excavation and anchor rod construction are carried out step by step until the designed slot bottom is reached. The earth excavation is carried out by layer or zone, gradually deepening from top to bottom, and stabilizing the soil body after each excavation to a certain depth. This method can reduce the impact on the surrounding environment and prevent the foundation pit from collapsing. The anchor rod construction designs the length, diameter, layout and inclination angle of the anchor rod 300 according to the structure and geological conditions. The position of each anchor rod 300 should be accurately calculated to ensure the maximum support effect.

[0082] It can be understood that the inclination angle of the anchor rod construction is selected between 10° and 15°. The inclination angle of 10° to 15° during anchor rod construction can more effectively resist the sliding force along the side wall of the foundation pit. This angle setting helps to disperse the shear force of the soil or rock layer and reduce the impact of vertical pressure on the anchoring point, thereby enhancing the overall stability of the foundation pit or slope.

[0083] Specifically, after the construction of the main structure reaches or exceeds the ground level, the trench backfill is carried out. The steps of the trench backfill are as follows: first, before starting the backfill, a detailed structural and geological assessment is carried out to ensure that all supporting structures (such as supporting walls, anchor rods 300, etc.) are stable and have no obvious damage or deformation. Clean up the trench area and remove any construction waste, debris or accumulated water to ensure that the backfill material can be evenly laid. Second, the excavated soil layer is usually used, but it must be ensured that the soil layer is suitable for backfilling and is not contaminated. Sometimes it may be necessary to use screened and treated soil or specific engineering fill to ensure compaction and drainage. In some cases, a certain proportion of sand, gravel or other improvement materials may also be added to improve the bearing capacity and stability of the soil layer. Then, the backfill process is carried out in layers, and the thickness of each layer is usually controlled at 20 to 30 centimeters. After each layer is laid, it is compacted to ensure that the soil layer is dense and to reduce future settlement. A road roller or vibrating plate is used to compact each layer of soil. In water-sensitive areas, the moisture content of the backfill soil needs to be controlled to avoid excessive wetness or dryness. Finally, after all the backfill work is completed, the final ground leveling is carried out to ensure that the site reaches the expected elevation and slope. If necessary, further treatment of the ground surface can be carried out, such as laying turf, installing drainage systems or landscaping.

[0084] In some embodiments, the prestressed tendon 20 can be recycled after the trench backfill, the steps including:

[0085] Releasing the prestress on the prestressed tendon 20 one by one and dismounting the connecting assembly 30;

[0086] Reversely rotating the prestressed tendon 20 to make the prestressed tendon 20 disengage from the connector 34;

[0087] Passing the upper portion of the prestressed tendon 20 through the rectangular crossbeam in the basket, and locking the upper portion of the prestressed tendon 20 with the basket;

[0088] Hoisting the basket and the prestressed tendon 20 together and recycling.

[0089] It can be understood that the step of disengaging the prestressed tendon 20 from the connector 34 is to select a pipe wrench of appropriate size and model to match the diameter and material of the main tendon. The pipe wrench should be able to firmly grasp the main tendon without causing damage. Fix the pipe wrench on the main tendon, and after confirming that it is firmly fixed, start slowly reversing the rotation. Reversing rotation refers to the opposite direction of installation, usually counterclockwise. Once the bottom of the main tendon is successfully separated from the connector 34, slowly rotate the main tendon out completely. Ensure smooth throughout the process, avoid fast pull or sharp action, which may cause damage to the main tendon or surrounding structure.

[0090] It can be understood that recycling the prestressed tendon 20 is a key step in the construction or maintenance of the precast pile 100. First, select a suitable basket that is designed to carry the prestressed tendon 20 and its own weight, and is suitable for safe operation in the working environment. Second, pass the upper portion of the prestressed tendon 20 through the rectangular crossbeam in the basket. Ensure that the position of the prestressed tendon 20 passing through the crossbeam is correct to maintain balance and avoid unnecessary tension or torsion during hoisting. Then, use the locking mechanism inside the basket (such as bolts, clamps or other fixing devices) to fix the upper portion of the prestressed tendon 20 with the basket. Ensure that all locking devices are firmly installed in place and checked to confirm their load capacity. Then, use a crane or other suitable hoisting equipment to slowly hoist the basket and the prestressed tendon 20 together. The hoisting speed should be uniform to avoid sudden movements to prevent swinging or impact forces. Finally, safely transfer the hoisted prestressed tendon 20 and the basket to the designated recycling or storage area. During placement, ensure that the ground is flat and can withstand heavy loads. Once safely placed, gradually release the load of the hoisting equipment and carefully release all locking mechanisms to separate the prestressed tendon 20 for recycling.

[0091] In addition, the present embodiment also provides another construction method of the recyclable precast pile 100, which is used for constructing the precast pile 100 according to the above, comprising the following steps:

[0092] Processing the precast pile 100 in the factory, and tensioning and locking the prestressed tendon 20 or constructing a waterproof curtain according to the mixing method or high-pressure rotary jet method

[0093] Lowering the precast pile 100 to the design elevation according to the static pressure method or hammering method;

[0094] Performing the crown beam construction, and isolating and protecting the exposed prestressed tendon 20;

[0095] The earthwork excavation and anchor rod construction are performed layer by layer until the designed slot bottom is reached;

[0096] After the construction of the main structure reaches or exceeds the ground elevation, the backfilling of the fat groove is performed;

[0097] The precast pile 100 is recovered.

[0098] Further, the precast pile 100 is recovered by tensioning the upper part of the prestressed tendon 20, and the step of recovering the precast pile 100 includes:

[0099] The precast pile 100 is slowly pulled out together with the prestressed tendon 20 and gradually forms a pile hole;

[0100] The backfilling material is injected into the pile hole through the hole 101 in the center of the precast pile 100 to fill the pile hole until the precast pile 100 is completely removed.

[0101] It can be understood that during the pulling out of the precast pile 100, the backfilling material such as solidified soil and cement slurry is injected into the pile hole by connecting a pumping pipe to the top of the precast pile 100. This design can ensure that the pile hole is gradually filled with backfilling material while the precast pile 100 is pulled out. Using solidified soil and cement slurry as backfilling material has good consolidation effect and bearing capacity, which can effectively support the sidewall of the pile hole and prevent the pile hole from collapsing.

[0102] It can be understood that the embodiment emphasizes that the pulling speed of the precast pile 100 should not be too fast, so that the backfilling material can timely fill the pile hole. If the pulling speed of the precast pile is too fast, the backfilling material may not be able to fill the bottom of the pile hole in time, thereby forming a gap in the pile hole. Such a gap may cause the soil around the pile hole to lose stability and be damaged when subjected to lateral load in the later stage.

[0103] It can be understood that the key technical point of the embodiment is to prevent the pile hole from losing stability and being damaged due to the action of lateral load (such as foundation soil or other structural load) by controlling the pulling speed and timely filling the backfilling material. Reasonable construction sequence and process help to ensure the stability of the whole process.

[0104] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements easily thought of by those skilled in the art within the technical range disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A recyclable precast pile, characterized by, The utility model relates to a prefabricated pile, which comprises: a pipe pile body; a recyclable prestressed steel assembly, which is arranged along the axial direction of the pipe pile body, the recyclable prestressed steel assembly comprising an isolation sleeve and at least one prestressed tendon, the isolation sleeve being arranged on the outer side of the prestressed tendon in the circumferential direction, at least one end of the prestressed tendon being located outside the top of the pipe pile body along the axial direction, the top being directed towards the slope top of the foundation pit; a connecting assembly, both ends of the prestressed tendon being connected to the pipe pile body in a detachable manner through the connecting assembly.

2. A recyclable precast pile according to claim 1, characterised in that, The recyclable prestressed steel assembly comprises a prestressed tendon and an anchoring tendon, one end of the prestressed tendon being arranged in the isolation sleeve from one axial end of the isolation sleeve, the anchoring tendon being fixedly connected to the pipe pile body, the connecting assembly comprising a connector, the connector being in abutment with the other axial end of the isolation sleeve, the prestressed tendon being connected to the anchoring tendon through the connector.

3. A recyclable precast pile according to claim 2, characterised in that, The end of the prestressed tendon located outside the top of the isolation sleeve is a first end, the connecting assembly further comprising a first nut, the first end being connected to the pipe pile body through the first nut.

4. A recyclable precast pile according to claim 3, characterised in that, The anchoring tendon and the pipe pile body are integrally formed in a pouring structure.

5. The recyclable precast pile of claim 1, wherein, The number of the prestressed tendons is one, and the prestressed tendon penetrates the isolation sleeve, the prestressed tendon having a first end and a second end, the first end being located outside the top of the isolation sleeve, the second end being located outside the bottom of the isolation sleeve, the connecting assembly comprising a first nut and a second nut, the first end being connected to one end of the pipe pile body through the first nut, the second end being connected to the other end of the pipe pile body through the second nut.

6. A recyclable precast pile according to any one of claims 1 to 5, characterised in that, Lubricating grease and / or a retarder are filled between the isolation sleeve and the prestressed tendon.

7. A recyclable precast pile according to any one of claims 1 to 5, characterised in that, The number of the recyclable prestressed steel assemblies is multiple, and the multiple recyclable prestressed steel assemblies are uniformly and symmetrically arranged along the circumferential direction of the pipe pile body.

8. A recyclable precast pile according to any one of claims 3 to 5, characterised in that, The prefabricated pile further comprises an end plate, the end plate being located at the top of the pipe pile body and being clamped between the first nut and the top of the pipe pile body.

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