A full-rotation full-casing drilling machine pile pulling and backfill integrated construction equipment and process

Abstract

The present application relates to a kind of full-rotation full-casing drilling rig pulling pile backfill integrated construction equipment and process, the equipment used includes full-rotation full-casing drilling rig, steel casing, fluid backfill material stirring pumping machine, crawler crane.Compared with prior art, based on the traditional full-rotation full-casing drilling rig, cooperate with high-pressure jetting system to reduce drilling and pulling pile resistance, and can recycle and utilize the waste mud generated in the process of pulling pile, through fluid backfill material stirring pumping machine to carry out in-situ preparation of backfill material, realize pulling pile backfill integrated construction, in addition, new fluid backfill material is applied to backfill, optimize construction process, reduce construction cost, greatly improve construction efficiency, especially suitable for group old pile pulling backfill engineering.

Description

Technical Field

[0001] This invention belongs to the field of pile foundation construction technology, and relates to an integrated construction process and equipment for pile extraction and backfilling using a full-rotation full-casing drilling rig. Background Technology

[0002] In the process of urban engineering construction, the problem of clearing underground obstacles is often encountered, especially in urban renovation and underground space construction projects. Among them, the pile foundations of existing buildings are common underground obstacles. When it is determined that the existence of existing pile foundations will have an adverse impact on subsequent construction, and it is impossible to reinforce and reuse them or the reuse plan is more expensive than the removal plan, the old piles should be cleared and removed in a timely manner to avoid affecting the subsequent work.

[0003] The existing methods for handling old piles in construction projects are mainly divided into two categories: the breaking and clearing method and the overall removal method. For old piles or other underground obstacles with shallow burial depth, the breaking and clearing method, which involves directly breaking, digging, or removing them, is often used. This method uses impact equipment such as picks, hammers, pneumatic picks, and rotary drills to dynamically break up the old piles and other obstacles before clearing them. This traditional breaking and clearing method generates a lot of noise during construction, and the vibration caused by the impact equipment can damage pipelines and existing buildings in the vicinity. In addition, the impact of breaking old piles and clearing debris can also cause the old piles to collapse, leading to ground subsidence and affecting the safety of the surrounding environment. This method is mostly used in projects where the old piles to be removed are shallow, few in number, and have a construction work surface.

[0004] When encountering deeply buried old piles, the process is complex and costly due to the difficulty in detecting the condition of the pile body, numerous site constraints, and the need to consider the impact of construction on the surrounding strata and buildings. Currently, most pile extraction projects employ the overall extraction method. This method, known as the "universal construction method," utilizes full-rotation casing drilling rigs. It boasts high precision, minimal disturbance, and reliability, and can be used in situations with fragile and sensitive geological conditions, limited working surfaces, and dense and complex surrounding buildings and facilities. However, its efficiency is limited by the torque and downforce provided by the full-rotation equipment, and it requires numerous supporting devices. Improving its efficiency is crucial for saving time and reducing costs.

[0005] With the continuous development and progress of science and technology, fluid backfill materials such as fluidized solidified soil and foamed lightweight soil are widely used in roadbed filling, pipe gallery backfilling and other fields due to their high fluidity, convenient construction and adjustable strength. These characteristics make them potential to be used as pile hole backfill materials after pile extraction, and there is no precedent for their application in the field of pile foundation extraction backfill construction.

[0006] Chinese patent application CN119083433A discloses a method, device, electronic equipment, and storage medium for pile extraction using a hydraulic full-sleeve full-rotation drilling rig. The method includes the following steps: construction preparation, pipeline exploration and excavation, pile extraction pipeline protection, pile location layout and platform laying, drilling rig positioning, sleeve installation and drilling, obstacle removal, removal of abandoned piles, pile hole inspection, pile hole backfilling, and sleeve removal. This patent only achieves the basic functions of sleeve drilling and pile extraction; it does not specifically address the treatment and backfilling of waste soil that may be generated during the pile extraction process. Further improvements are needed in terms of construction efficiency and environmental impact. Summary of the Invention

[0007] The purpose of this invention is to provide an integrated construction equipment and process for pile extraction and backfilling using a full-rotation casing drilling rig. By combining it with fluid backfill material, the construction efficiency of pile extraction and backfilling using the full-rotation casing method is greatly improved, the construction process is optimized, the connection between pile extraction and backfilling is accelerated, the disturbance to the strata and the impact on the environment are reduced, and construction safety, construction speed and construction quality are ensured.

[0008] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides an integrated construction equipment for pile extraction and backfilling using a full-rotation, full-casing drilling rig, comprising: A full-rotation full-casing drilling system includes a full-rotation full-casing drilling rig and a bidirectional high-pressure jetting subsystem, which can perform jetting operations along the axial and radial directions during drilling. The steel casing includes a drill pipe at the bottom, an intermediate connecting pipe connecting the drill pipe to the full-rotation full-casing drilling rig, and several slurry pipes arranged axially on the inner side. The slurry pipes are divided into pumping pipes and pumping pipes. The pumping pipes are used to pump mud to the ground, and the pumping pipes are used to pump fluid backfill material to the bottom of the pile hole. And a fluidized backfill material mixing pump, used for mixing, preparing and pumping fluidized backfill materials.

[0009] Furthermore, the bidirectional high-pressure jetting subsystem includes a high-pressure nozzle disposed at the bottom of the drilling pipe, the high-pressure nozzle comprising an axial nozzle and a radial nozzle disposed along the axial and radial directions of the steel casing, respectively.

[0010] Furthermore, the high-pressure nozzle is also connected to the high-pressure pump group and air compressor on the ground through a high-pressure connecting pipe located on the inner wall of the steel casing, and can alternately spray high-pressure water jets and high-pressure air jets.

[0011] Furthermore, when connecting the drilling pipe to the connecting pipe, and connecting the connecting pipe to the connecting pipe, the slurry pipe is first aligned and stacked before being fixed.

[0012] Furthermore, a one-way valve is provided at the bottom of the slurry pipe, and the one-way valves on the suction pipe and the pump pipe are in opposite directions.

[0013] Furthermore, the fluidized backfill material mixing and pumping machine includes a slurry mixing mechanism, a feeding mechanism, a fluidized material mixing mechanism, and a pumping mechanism, wherein... The mud mixing mechanism includes a mud tank, an excavator, and an automated mud mixer. The feeding mechanism includes a hopper, a screw feeder, and a crane; The fluid material mixing mechanism includes a mixing tank, a storage tank, a pumping mechanism, and a foaming mechanism.

[0014] In a second aspect, the present invention provides an integrated construction process for pile extraction and backfilling using a full-rotation, full-casing drilling rig. This construction process is implemented based on the construction equipment described in the first aspect above, and includes the following steps: S1. Locate the old pile position and remove the pile cap foundation above the top of the old pile to be removed, so that the pile head of the old pile is exposed. S2. Construct a working platform around the old piles to be removed and complete the installation of construction equipment; S3. Install the drilling pipe onto the full-rotation full-casing drilling rig, align it with the center of the old pile to be removed, start rotary drilling, and simultaneously perform jetting operation of the bidirectional high-pressure jetting subsystem to reduce drilling resistance. S4. After the steel casing is pressed down into place, shut down the bidirectional high-pressure jetting subsystem and begin the old pile removal work. S5. During the removal of the old pile body in S4, after the steel sleeve is pressed down into place, the mud at the bottom of the pile hole is extracted using the internal pumping pipe simultaneously for the preparation of fluid backfill material. S6. After the obstacles inside the steel casing are cleared, the steel casing is lifted. At the same time, the grouting of the fluid backfill material is carried out using the pump pipe. S7. After the old pile is removed and backfilled, repeat S1 to S6 above to carry out the removal and backfilling work of the next old pile.

[0015] Furthermore, in S4, when removing old piles, if the pile length is less than the set value, a static removal method is adopted. The pile is directly lifted after being connected and fixed to the old pile by a steel wire rope or a grab bucket. When the pile length exceeds the set value, the segmented cutting method is adopted. A wedge hammer or inverted triangular hammer is used to cut the pile body into segments. Then, the broken pile inside the steel casing is lifted to the ground using a wire rope or grab bucket. The above operation is repeated until the old pile is completely removed. When the old pile body expands in diameter, bulges appear, or the strength is too high, the impact crushing method is adopted. After the obstacle is broken by equipment including hammer or auger, the grab bucket is replaced to remove the debris inside the steel casing. This process is repeated several times until the debris is completely removed before construction can proceed.

[0016] Furthermore, in S4, the fluidized backfill material is selected from fluidized solidified soil or foamed lightweight soil, and when foamed lightweight soil is selected, the foaming gas includes air or carbon dioxide.

[0017] Furthermore, in S6, during the lifting process of the steel casing, the grouting of the fluid backfill material meets the following requirements: the liquid level of the injected fluid backfill material is maintained at 0.5~1m above the bottom of the steel casing until the steel casing is completely removed.

[0018] The key innovations of this invention are reflected in the following aspects: In conventional pile extraction and backfilling schemes, pile extraction and backfilling are usually independent operations carried out separately. This invention utilizes a bidirectional high-pressure jetting subsystem to convert the engineering waste soil generated during pile extraction into lubricating mud. This reduces the resistance of casing drilling and pile extraction, and uses the waste drilling mud as one of the raw materials for in-situ preparation of backfilling materials, linking the two processes of pile extraction and backfilling, thus greatly improving construction efficiency. 2. In-situ preparation of pile hole backfill materials using waste drilling mud as raw material, including but not limited to fluidized solidified soil and foamed lightweight soil, breaks through the limitations of conventional cement-soil backfill materials, and pile hole backfill can be completed by pouring, eliminating conventional procedures such as filling and compaction, and optimizing the construction process; Third, two construction modules are set up at the construction site: a mobile integrated pile extraction and backfilling construction unit and a fixed backfill material supply unit. These two modules are connected by a pumping pipe. The former is responsible for pile extraction, and the latter for backfilling. The former extracts old piles in batches through a streamlined operation, while the latter acts as an in-situ mixing plant, continuously supplying backfill materials in real time. The two modules work together to greatly improve the efficiency of integrated pile extraction and backfilling construction, with even more significant advantages when dealing with group pile extraction operations. Compared with existing technologies, this invention has the following advantages: (1) The present invention adds a bidirectional high-pressure jetting subsystem to the traditional full-rotation full-casing drilling rig, which reduces drilling resistance, removes soil debris between the casing and the pile body, and forms a mud lubrication layer to reduce frictional resistance and viscous resistance during construction, thereby effectively improving construction efficiency.

[0019] (2) The present invention provides a suction pipe and a pumping pipe on the inner wall of the steel casing. The suction pipe allows the drilling mud to be recycled in situ for the preparation of backfill material, which solves the adverse effects of the mud at the bottom of the pile hole on the backfilling work, greatly reduces environmental pollution, and realizes the recycling of waste mud. The pumping pipe inputs the backfill material prepared in situ to the bottom of the pile hole, and the pile hole is backfilled simultaneously with the lifting of the casing, which optimizes the construction process of pile extraction and backfilling and improves construction efficiency.

[0020] (3) This invention proposes an integrated construction equipment for pile extraction and backfilling using a full-rotation full-casing drilling rig, including a full-rotation full-casing drilling rig, a steel casing, a fluidized backfill material mixing pump, and a crawler crane. The full-rotation full-casing drilling rig and the steel casing move dynamically on the old pile to be extracted under the scheduling of the crawler crane, achieving precise extraction of the old pile. The fluidized backfill material mixing pump is fixed in the site and connected to the casing through a pumping pipe to recover mud from the bottom of the pile hole and prepare backfill material. It provides sufficient backfill material when the casing is lifted. The combination of dynamic and static operation realizes integrated construction of pile extraction and backfilling, optimizes existing construction methods, and significantly improves construction efficiency.

[0021] (4) This invention applies new fluid backfill materials such as fluidized solidified soil and foamed lightweight soil to the backfilling of pile holes after the removal of old piles. Compared with traditional backfill materials, the new fluid backfill materials have controllable strength, lower cost, convenient construction and guaranteed safety. The pumping method is used for construction, which optimizes the backfilling construction process and can be carried out simultaneously with pile extraction, which greatly improves the construction efficiency.

[0022] (5) This invention can effectively handle various types of old pile removal work, with high precision, low disturbance and strong safety. It can be carried out in complex geological conditions or sensitive areas, and is especially suitable for group old pile removal work. It greatly improves the construction efficiency of old pile removal work while ensuring project safety and minimizing the impact on the strata and surrounding environment. It is especially suitable for group old pile removal projects. Attached Figure Description

[0023] Figure 1 A structural schematic diagram of an integrated construction equipment for full-rotation, full-casing pile extraction and backfilling; Figure 2 This is a schematic diagram of the steel casing structure; Figure 3 A schematic diagram of the integrated construction process of full-rotation full-casing pile extraction and backfilling; Explanation of markings in the diagram: 1-Full-rotation full-casing drilling rig; 2-Two-way high-pressure jetting subsystem; 3-Steel casing; 31-Drilling pipe; 32-Connecting pipe; 4-Slurry pipe; 41-Suction pipe; 42-Pumping pipe; 5-Fluid backfill material mixing and pumping machine; 6-Crawler crane; 7-Storage tank; 8-Screw feeder. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0025] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Unless otherwise specified, the functional components or structures in the following embodiments or examples are conventional components or structures used in the art to achieve the corresponding functions.

[0028] To achieve integrated pile extraction and backfilling construction, this invention provides a fully rotary, full-casing drilling rig integrated pile extraction and backfilling construction equipment, the structure of which is described below. Figure 1 , Figure 2 As shown, including: A full-rotation full-casing drilling system includes a full-rotation full-casing drilling rig 1 and a bidirectional high-pressure jetting subsystem 2, wherein the bidirectional high-pressure jetting subsystem 2 can perform jetting operations along the axial and radial directions during the drilling process; The steel casing 3 includes a drilling pipe 31 at the bottom, an intermediate connecting pipe 32 connecting the drilling pipe 31 to the full-rotation full-casing drilling rig 1, and several slurry pipes 4 arranged axially on the inner side. The slurry pipes 4 are divided into a pumping pipe 41 and a pumping pipe 42. The pumping pipe 41 is used to pump mud to the ground, and the pumping pipe 42 is used to pump fluid backfill material to the bottom of the pile hole. Specifically, during the drilling process, the pumping pipe 42 is kept closed, and the pumping pipe 41 continuously and passively delivers a small amount of mud to the ground. During the pile extraction process, when the steel casing 3 is lifted, the pumping pipe 41 actively pumps mud from the bottom of the pile hole to the ground, and the pumping pipe 42 pumps the mixed fluid backfill material to the bottom of the pile hole. And a fluidized backfill material mixing and pumping machine 5, used for mixing, preparing and pumping fluidized backfill material.

[0029] In this invention, the difference between the drilling pipe 31 and the connecting pipe 32 is that the drilling pipe 31 is the lowest casing responsible for downward drilling, while the remaining casings are all connecting pipes 32. Compared with the connecting pipe 32, the drilling pipe 31 has an alloy cutter head added to the bottom of the casing for cutting the soil and drilling downward; a high-pressure nozzle is added to reduce drilling resistance and remove debris between the casing and the pile body during drilling, forming a mud lubrication layer.

[0030] In some specific embodiments, the bidirectional high-pressure jetting subsystem 2 includes a high-pressure nozzle disposed at the bottom of the drilling pipe 31. The high-pressure nozzle includes an axial nozzle and a radial nozzle whose jetting directions are respectively arranged along the axial and radial directions of the steel casing 3.

[0031] In a more specific embodiment, the high-pressure nozzle is also connected to the high-pressure pump group and air compressor on the ground through a high-pressure connecting pipe 32 located on the inner wall of the steel casing 3. It can alternately spray high-pressure water jets and high-pressure air jets. During drilling, it sprays along the axial direction to reduce the resistance when the bottom cutter head of the steel casing 3 drills downward. It also sprays along the radial direction to impact the soil between the casing and the pile body to form mud, effectively reducing the frictional resistance and viscous resistance during construction.

[0032] In some specific embodiments, when connecting the drilling pipe 31 to the connecting pipe 32, and connecting pipe 32 to connecting pipe 32, the slurry pipe 4 is first aligned and stacked before being fixed.

[0033] In some specific embodiments, the bottom of the slurry pipe 4 is provided with a one-way valve, and the one-way valve on the suction pipe 41 is opposite in direction to that on the pump pipe 42.

[0034] In some specific embodiments, the fluidized backfill material mixing and pumping machine 5 includes a slurry mixing mechanism, a feeding mechanism, a fluidized material mixing mechanism, and a pumping mechanism, wherein... The mud mixing mechanism includes a mud tank, an excavator and an automated mud mixer. The mud passively discharged by the pumping pipe 41 during drilling and the mud actively extracted by the pumping pipe 41 during pile extraction are both stored in the mud tank. At the same time, as needed, the excavator can cooperate with the automated mud mixer to supplement and produce a certain amount of mud for the preparation of fluid backfill material. The feeding mechanism includes a hopper, a screw feeder 8 and a crane, which can lift the solidified material onto the hopper via the crane and feed it into the fluid material mixing system via the screw feeder 8. The fluid material mixing mechanism includes a mixing tank, a storage tank 7, a pumping mechanism, and a foaming mechanism, which can realize the automated mixing and pumping functions of fluid soil or foamed lightweight soil according to the mixing ratio of different fluid backfill materials.

[0035] In another aspect, the present invention also provides an integrated construction process for pile extraction and backfilling using a full-rotation full-casing drilling rig 1. This construction process is implemented based on the construction equipment described in the first aspect above. Please refer to [link to relevant documentation]. Figure 3 As shown, the construction process includes the following steps: S1. The location of the old pile can be located using a total station or GPS, and the pile cap foundation above the top of the old pile to be removed can be cleared to expose the pile head. S2. Construct a working platform around the old piles to be removed. Specifically, construct a working platform around the old piles to be removed, level the land, lay steel plates, and establish a temporary working platform. At the same time, find a suitable location in the entire site, level the site, and use it as a working platform for the fluid backfill material mixing pump 5, and use it to complete the installation of related equipment. Determine the construction equipment parameters and the type of steel casing 3 according to the size, depth, and type of the piles to be removed. Use a crawler crane 6 to hoist the drilling rig onto the working platform, and then complete the assembly and connection of the remaining equipment to complete the installation of the construction equipment. S3. Install the drilling pipe 31 onto the full-rotation full-casing drilling rig 1, align it with the center of the old pile to be removed, clamp the steel casing 3, start rotary drilling, and simultaneously perform jetting operation of the bidirectional high-pressure jetting subsystem 2 to reduce drilling resistance. During the drilling process, pay attention to controlling the drilling rig speed and torque to ensure equipment stability and drilling verticality. S4. After the steel sleeve 3 is pressed down to the position, shut down the bidirectional high-pressure jetting subsystem 2, and select the pile body removal work according to the pile length and pile type of the old pile to be removed. S5. During the removal of the old pile body in S4, after the steel sleeve is pressed into place, the mud at the bottom of the pile hole is extracted simultaneously using the internal extraction pipe 41. This mud is used to prepare backfill materials such as fluidized solidified soil and foamed lightweight soil. The fluidized backfill material mixing pump 5 is used to automatically produce backfill materials after determining the mix ratio of the backfill material according to the required strength. This process can be carried out simultaneously with "S4". The mud generated during the casing drilling process is recycled and reused, which solves the adverse effects of the mud at the bottom of the pile hole on subsequent backfilling and improves construction efficiency. After the backfill material is prepared, it is stored in the storage tank 7 for use during backfilling. S6. After the obstacles inside the steel casing 3 are cleared, the steel casing 3 is lifted. At the same time, the grouting of the fluid backfill material is carried out using the pump pipe 42. S7. After the old pile is removed and backfilled, repeat S1 to S6 above to carry out the removal and backfilling work of the next old pile.

[0036] In some specific implementations, in S4, when the pile length is less than the set value, i.e., the pile length is short, a static extraction method is adopted. The pile is directly lifted after being connected and fixed to the old pile by a wire rope or a grab bucket. When the pile length exceeds the set value, i.e. the pile length is too long, the segmented cutting method is adopted. A wedge hammer or inverted triangular hammer is used to cut the pile body into segments. Then, the broken pile inside the steel casing 3 is hoisted to the ground using a wire rope or a grab bucket. The above operation is repeated until the old pile is completely removed. When the old pile body expands in diameter, bulges appear, or the strength is too high, the impact crushing method is adopted. After the obstacle is broken by equipment including hammer or auger, the grab bucket is replaced to remove the debris inside the steel casing 3. This is repeated several times until it is completely removed before construction can proceed.

[0037] In some specific implementations, in S4, the fluid backfill material can be selected from a variety of materials with high fluidity, adjustable strength, and convenient construction, such as fluidized solidified soil and foamed lightweight soil. The cementing materials used include, but are not limited to, cement, blast furnace slag, carbide slag, magnesium oxide, serpentine tailings, and other building materials or solid waste materials with cementing activity. If foamed lightweight soil is selected, the foaming gas includes, but is not limited to, air, carbon dioxide, and other gases with stable properties or recyclable value.

[0038] In some specific implementations, during the lifting process of the steel casing 3 in S6, the grouting of the fluid backfill material satisfies the following: the liquid level of the injected fluid backfill material is maintained at 0.5~1m above the bottom of the steel casing 3 until the steel casing 3 is completely removed.

[0039] Each of the above implementation methods can be implemented individually, or in any combination of two or more without violating logic.

[0040] The above implementation methods will be described in more detail below with reference to specific embodiments.

[0041] Example 1: like Figure 1 , Figure 2 As shown, the present invention provides an integrated construction equipment for pile extraction and backfilling using a full-rotation full-casing drilling rig 1, including a full-rotation full-casing drilling rig 1, a steel casing 3, a fluid backfill material mixing and pumping machine 5, and a crawler crane 6.

[0042] Compared with traditional equipment, the full-rotation full-casing drilling rig 1 used in this embodiment is equipped with a slurry pumping system and a high-pressure jetting system. It is connected to the fluid backfill material mixing and pumping machine 5, high-pressure pump set and air compressor through pipelines, motor and slurry pump to realize functions such as mud extraction at the bottom of the pile hole, pumping and backfilling of fluid backfill material, and high-pressure gas-liquid circulation jetting during drilling.

[0043] In this embodiment, the steel casing 3 is based on a traditional casing with multiple steel grout pipes 4 and high-pressure pipelines added to its inner wall. Based on functional differences, these are divided into drilling pipes 31 and connecting pipes 32. The grout pipes 4 are further divided into extraction pipes 41 and pumping pipes 42. When connecting adjacent steel casings 3, care must be taken to align and overlap the grout pipes 4 before connecting and fixing them. A one-way valve is installed at the bottom of the grout pipes 4 of the drilling pipe 31. The one-way valves of the extraction pipe 41 and the pumping pipe 42 have opposite directions. The extraction pipe 41 transports liquid from the bottom of the pile hole to the ground, while the pumping pipe 42 transports liquid from the ground to the bottom of the pile hole. During drilling, the pump... The liquid pipe 42 remains closed, and the liquid extraction pipe 41 continuously and passively delivers a small amount of mud to the ground. During the pile extraction process, when the steel casing 3 is lifted, the liquid extraction pipe 41 actively pumps the mud from the bottom of the pile hole to the ground. The mud is directly pumped to the fluidized backfill material mixing pump 5 for the preparation of fluidized backfill material. The prepared fluidized backfill material is pumped to the bottom of the pile hole through the liquid pump pipe 42. The fluidized backfill material is pumped and backfilled while the casing is lifted upward. The high-pressure pipeline is made of high-pressure resistant material and is used to connect the high-pressure pump set and the air compressor to realize the transportation of high-pressure gas and liquid. The above devices are installed on the inner wall of each section of steel casing 3. Compared with the connecting pipe 32, the drilling pipe 31 has a bidirectional high-pressure nozzle (including axial nozzle and radial nozzle) and an alloy cutter head with the injection direction in both axial and radial directions added to the bottom of the casing. The bidirectional high-pressure nozzle realizes bidirectional gas-liquid circulation injection along the axial and radial directions during drilling by high-pressure gas and liquid transported through high-pressure pipeline. This can greatly reduce drilling resistance, remove broken soil between the casing and the pile body to be extracted, and prepare mud at the same time to form a mud lubrication layer, reducing the side friction and viscous resistance during drilling and pile extraction. The alloy cutter head is used to rotate and cut the soil to realize casing drilling.

[0044] The fluidized backfill material mixing and pumping machine 5 used here includes a mud mixing mechanism, a feeding mechanism, a fluidized material mixing mechanism, and a pumping mechanism. This embodiment takes backfill fluidized solidified soil as an example. The solidified material uses a solid waste cementitious material formed by the compounding of slag and carbide slag, combined with mud and waste soil generated during the project. This mixture is then processed by the fluidized backfill material mixing and pumping machine 5 to form solid waste-based fluidized solidified soil. The compressive strength (3d) can be adjusted within the range of 0.2~0.8MPa. The mud mixing mechanism used here includes a mud tank, an excavator, and an automated mud mixer. Mud passively discharged by the extraction pipe 41 during drilling and mud actively extracted by the extraction pipe 41 during pile extraction are both stored in the mud tank. Simultaneously, the excavator uses the excavated soil from the project to extract a certain amount of mud through the automated mud mixer for the preparation of the fluidized solidified soil. The feeding mechanism includes a hopper, a screw feeder 8, and a crane. The ton-bag packaged solid waste materials such as slag and carbide slag are hoisted onto the screw feeder 8 by the crane, and then fed into the fluid material mixing mechanism by the screw feeder 8. The fluid material mixing mechanism used here is an automated fluid solidified soil equipment, including a mixing tank, a storage tank 7, and a pumping mechanism. The mixing tank mixes the solid waste cementitious materials such as slag and carbide slag with the mud evenly, and then transports them to the storage tank 7 for storage. The storage tank 7 is equipped with a stirring blade to continuously stir and prevent the fluid solidified soil from solidifying. The prepared fluid solidified soil can be directly pumped to the bottom of the pile hole through the pumping system along the pumping pipe 42 on the inner wall of the steel casing 3. Backfilling work is carried out simultaneously when the casing is lifted.

[0045] The crawler crane 6 used here, together with the full-rotation full-casing drilling rig 1 and the steel casing 3, achieves precise positioning, extraction and backfilling of the old piles to be removed.

[0046] like Figure 3 As shown in the figure, this embodiment also provides an integrated construction method for pile extraction and backfilling using a full-rotation full-casing drilling rig. The overall concept is introduced in conjunction with the embodiment, including the following steps: S1. Construction site preparation: Use a total station or GPS to locate the old piles, remove the foundation above the top of the old piles to be removed, and expose the pile heads; at the same time, use a combination of manual excavation and survey data to locate and mark any underground pipelines that may exist within the construction site area, record pipeline information and set up warning signs.

[0047] S2. Construction of the working platform: Construct a working platform around the old piles to be removed, level the land, and lay steel plates under the full-rotation, all-steel casing drilling rig to increase the stress area and prevent accidents such as drilling rig subsidence or surface collapse. This will reduce pressure on shallow ground and shallow underground facilities and pipelines. Establish a temporary working platform and simultaneously search for an area of ​​approximately 100m² within the entire site. 2In areas where there are no piles to be removed and where the construction of existing piles to be removed is not affected, the ground is leveled and hardened to serve as a fixed working platform for the fluid backfill material mixing and pumping machine 5, and the installation and connection of the fluid backfill material mixing and pumping equipment are completed.

[0048] S3. Construction Equipment Installation: Determine the construction equipment parameters and steel casing type 3 according to the size, depth, and type of the pile to be extracted. Ensure that the rotation torque and maximum extraction force of the full-rotation steel casing 3 drilling rig can overcome the frictional resistance of the soil. The diameter range of the drilling rig and steel casing 3 should match the diameter of the pile to be extracted. Generally, it is more appropriate to select a steel casing 3 with a diameter 700mm~1000mm larger than the diameter of the pile to be extracted. If there are special circumstances such as pile diameter change or bulge, the diameter of the steel casing 3 should be adjusted in time according to the actual situation. Use the cross positioning method to lift the base plate to the pile core position, and then use the crawler crane 6 to lift the drilling rig to the top of the working platform. Then complete the installation of auxiliary facilities such as hydraulic clamp system, hydraulic jacking system, anti-torque lock, and diameter changing pad, as well as the connection of the selected steel casing 3 with the high-pressure pump set, air compressor, and fluid backfill material pumping system, and prepare to carry out the integrated pile extraction and backfilling construction.

[0049] S4. Casing Rotary Drilling: Install the drill pipe 31 onto the full-rotation drilling rig, align it with the center of the pile to be extracted, and start the hydraulic power system. Clamp the steel casing 3 using the hydraulic clamping system, and then start the rotary drive system. Simultaneously start the bidirectional high-pressure jetting system to reduce the drilling resistance of the drill pipe 31. Once the drill pipe 31 is fully pressed in, align it with the fixed connecting pipe 32 and continue drilling. During drilling, pay attention to controlling the drilling rig speed and torque to ensure equipment stability and drilling verticality. At the same time, during the process, pay attention to the parameters such as rotary torque, downward pressure, and downward pressure depth to determine the next step of the work.

[0050] S5. Removal of Old Pile: After the steel casing 3 is pressed into place, shut down the bidirectional high-pressure jetting subsystem 2. Select the appropriate method for removing the old pile based on its length and type. If the pile is short, a static removal method can be used, where the pile is directly lifted after being connected and fixed to the old pile with a wire rope or grab bucket. If the pile is too long, a segmented cutting method can be used. When the steel casing 3 is pressed to a certain depth, a wedge hammer or inverted triangular hammer is used to break the pile into segments. Then, the broken pile inside the steel casing 3 is lifted to the ground using a wire rope or grab bucket. The pressing of the steel casing 3 is then continued, and the above operations are repeated until the old pile is completely removed. When encountering situations such as pile diameter expansion, bulging, or excessive strength, an impact crushing method can be used. After breaking the obstacle with a hammer or auger, the grab bucket is used to remove the debris inside the steel casing 3. This process is repeated several times until the debris is completely removed before continuing construction.

[0051] S6. Preparation of backfill material: During the removal of the old pile body, after the last section of steel casing 3 is pressed into place, the mud at the bottom of the pile hole can be extracted using the liquid extraction pipe 41 on the inner wall of the steel casing 3 for the preparation of fluidized solidified soil. This process can be carried out simultaneously with "S5. Removal of old pile body". In this embodiment, the recycled drilling mud, slag and carbide slag are mixed evenly by the fluidized backfill material mixing pump 5 to form solid waste base fluidized solidified soil, which is then transported to the storage tank for backfilling.

[0052] S7. Lifting and Backfilling of Steel Casing 3: After the old pile body, abandoned concrete structure and other obstacles inside the steel casing 3 are cleared, the lifting of the steel casing 3 will be carried out. While the full-rotation steel casing 3 drilling rig is rotating and lifting the steel casing 3, the pumping system of the fluidized backfill material mixing pump 5 will be used to pump the prepared fluidized solidified soil in the storage tank 7 through the pumping pipe 42 on the inner wall of the steel casing 3 to the bottom of the steel casing 3 for grouting. During this process, the bottom of the steel casing 3 must always be kept 1-2m below the fluidized solidified soil backfill material liquid surface. If a confined aquifer is encountered, grouting can be carried out first. After the fluidized solidified soil has solidified rapidly and gained strength, the lifting of the steel casing 3 can be carried out to prevent groundwater leakage and pile hole collapse and other dangerous accidents. This process continues until the last section of the steel casing 3 is lifted, completing the integrated construction of pile extraction and backfilling for the pile to be extracted.

[0053] S8. Equipment relocation: After the old piles at this location have been removed and backfilled, the crawler crane 6 will be used to lift the full-rotation drilling rig to the next pile to be removed, establish a temporary working platform, and reconnect it with the fluid backfill material mixing pump 5 and other equipment to prepare for the removal and backfilling of the next old pile.

[0054] S9. Repeat steps S2 to S8 until all old piles that need to be removed are removed and backfilling is completed.

[0055] A full-rotation full-casing drilling rig 1, in conjunction with a crawler crane 6, forms a mobile integrated pile extraction and backfilling construction unit. A temporary working platform is erected, and steps S2 to S8 are implemented for single piles to be extracted or single piles in a group of piles to be extracted, carrying out integrated pile extraction and backfilling construction operations. A fluidized backfill material mixing pump 5, supplemented by a screw feeder 8, storage tank 7, and other supporting facilities, forms a fixed backfill material supply unit. A fixed working platform is erected, and the unit is connected to the aforementioned mobile integrated pile extraction and backfilling construction unit via pipelines. The process flow of drilling mud extraction—backfill material preparation—pumping material backfilling is designed. This technology enables the recycling of drilling mud and the in-situ preparation of fluid backfill materials. The integrated construction unit for pile extraction and backfilling works in conjunction with the fixed backfill material supply unit, combining dynamic and static approaches. This optimizes the traditional pile extraction and backfilling process, simplifies construction procedures, solves the environmental problem of unmanageable drilling mud, incorporates green new materials into the backfilling application system, and improves the stability of pile holes. The integrated construction of pile extraction and backfilling greatly improves the construction efficiency of old pile extraction, ensures construction safety, saves construction time, creates environmental benefits, and is especially suitable for group pile extraction operations.

[0056] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A fully rotary, full-casing drilling rig integrated construction equipment for pile extraction and backfilling, characterized in that, include: A full-rotation full-casing drilling system includes a full-rotation full-casing drilling rig and a bidirectional high-pressure jetting subsystem, which can perform jetting operations along the axial and radial directions during drilling. The steel casing includes a drill pipe at the bottom, an intermediate connecting pipe connecting the drill pipe to the full-rotation full-casing drilling rig, and several slurry pipes arranged axially on the inner side. The slurry pipes are divided into pumping pipes and pumping pipes. The pumping pipes are used to pump mud to the ground, and the pumping pipes are used to pump fluid backfill material to the bottom of the pile hole. And a fluidized backfill material mixing pump, used for mixing, preparing and pumping fluidized backfill materials.

2. The integrated construction equipment for pile extraction and backfilling using a full-rotation, full-casing drilling rig according to claim 1, characterized in that, The bidirectional high-pressure jetting subsystem includes a high-pressure nozzle installed at the bottom of the drilling pipe. The high-pressure nozzle comprises an axial nozzle and a radial nozzle, with the jetting directions respectively arranged along the axial and radial directions of the steel casing.

3. The integrated construction equipment for pile extraction and backfilling using a full-rotation, full-casing drilling rig according to claim 2, characterized in that, The high-pressure nozzle is also connected to the high-pressure pump group and air compressor on the ground through a high-pressure connecting pipe located on the inner wall of the steel casing, and can alternately spray high-pressure water jets and high-pressure air jets.

4. The integrated construction equipment for pile extraction and backfilling using a full-rotation, full-casing drilling rig according to claim 1, characterized in that, When connecting the drilling pipe to the connecting pipe, or connecting pipe to connecting pipe, the slurry pipes should be aligned and stacked before being fixed.

5. The integrated construction equipment for pile extraction and backfilling using a full-rotation, full-casing drilling rig according to claim 1, characterized in that, The bottom of the slurry pipe is equipped with a one-way valve, and the one-way valves on the suction pipe and the pump pipe are in opposite directions.

6. The integrated construction equipment for pile extraction and backfilling using a full-rotation, full-casing drilling rig according to claim 1, characterized in that, The fluidized backfill material mixing and pumping machine includes a slurry mixing mechanism, a feeding mechanism, a fluidized material mixing mechanism, and a pumping mechanism, wherein... The mud mixing mechanism includes a mud tank, an excavator, and an automated mud mixer. The feeding mechanism includes a hopper, a screw feeder, and a crane; The fluid material mixing mechanism includes a mixing tank, a storage tank, a pumping mechanism, and a foaming mechanism.

7. A construction process integrating pile extraction and backfilling using a full-rotation, full-casing drilling rig, characterized in that... This construction process is implemented using the construction equipment described in any one of claims 1-6, and the construction process includes the following steps: S1. Locate the old pile position and remove the pile cap foundation above the top of the old pile to be removed, so that the pile head of the old pile is exposed. S2. Construct a working platform around the old piles to be removed and complete the installation of construction equipment; S3. Install the drilling pipe onto the full-rotation full-casing drilling rig, align it with the center of the old pile to be removed, start rotary drilling, and simultaneously perform jetting operation of the bidirectional high-pressure jetting subsystem to reduce drilling resistance. S4. After the steel casing is pressed down into place, shut down the bidirectional high-pressure jetting subsystem and begin the old pile removal work. S5. During the removal of the old pile body in S4, after the steel sleeve is pressed down into place, the mud at the bottom of the pile hole is extracted using the internal pumping pipe simultaneously for the preparation of fluid backfill material. S6. After the obstacles inside the steel casing are cleared, the steel casing is lifted. At the same time, the grouting of the fluid backfill material is carried out using the pump pipe. S7. After the old pile is removed and backfilled, repeat S1 to S6 above to carry out the removal and backfilling work of the next old pile.

8. The integrated construction process for pile extraction and backfilling using a full-rotation, full-casing drilling rig according to claim 7, characterized in that, In S4, when removing old piles, if the pile length is less than the set value, the static removal method is adopted. The pile is directly lifted after being connected and fixed to the old pile by steel wire rope or grab bucket. When the pile length exceeds the set value, the segmented cutting method is adopted. A wedge hammer or inverted triangular hammer is used to cut the pile body into segments. Then, the broken pile inside the steel casing is lifted to the ground using a wire rope or grab bucket. The above operation is repeated until the old pile is completely removed. When the old pile body expands in diameter, bulges appear, or the strength is too high, the impact crushing method is adopted. After the obstacle is broken by equipment including hammer or auger, the grab bucket is replaced to remove the debris inside the steel casing. This process is repeated several times until the debris is completely removed before construction can proceed.

9. The integrated construction process for pile extraction and backfilling using a full-rotation, full-casing drilling rig according to claim 7, characterized in that, In S4, the fluidized backfill material is selected from fluidized solidified soil or foamed lightweight soil, and when foamed lightweight soil is selected, the foaming gas includes air or carbon dioxide.

10. The integrated construction process for pile extraction and backfilling using a full-rotation, full-casing drilling rig according to claim 7, characterized in that, In S6, during the lifting of the steel casing, the grouting of the fluid backfill material must meet the following requirements: the liquid level of the injected fluid backfill material must be maintained at 0.5~1m above the bottom of the steel casing until the steel casing is completely removed.

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