Construction method for dismantling pile foundation of urban interchange ramp with full casing and full rotation drilling rig

Abstract

The present invention relates to the field of building construction technology, specifically to a method for dismantling a pile foundation of a city overpass ramp with a full-casing and full-rotation drilling rig, comprising the following steps: stakeout of pile positions; laying of a working platform; positioning of the drilling rig after the working platform is laid; pressing down the steel casing; embedding the wedge hammer; rotating and twisting off the old pile; pulling out the twisted-off old pile; grabbing and exposing the lower pile head with a grab bucket; ensuring thorough obstacle removal by grabbing; backfilling and pulling out the pipes to complete the removal of the old pile; the beneficial effect is as follows: the method for dismantling a pile foundation of a city overpass ramp with a full-casing and full-rotation drilling rig uses steel casing and a full-rotation casing drilling rig to pull out the concrete cast-in-place piles. The steel casing has two functions: on the one hand, it transmits the torque and pressing force provided by the top drive device to the cutter head; and on the other hand, it supports the hole wall and prevents the hole wall from collapsing during the drilling process. The steel casing is 26 meters long and is equipped with a 100t crawler crane for construction.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, in particular to a method for dismantling a city interchange ramp pile foundation with a full-casing and full-rotation drilling rig. Background Art

[0002] During the construction of roads and bridges, there is the work of demolishing old bridges. During the demolition process, isolation measures are taken to guide the traffic of vehicles and pedestrians. According to the traffic diversion plan of this project, the demolition of the bridge superstructure is divided into two stages. The first stage is to demolish the guide rails and sidewalks on both sides, and the second stage is to demolish the middle main lane.

[0003] In existing technology, the bridge deck's ancillary facilities are first removed, followed by the bridge structure, and finally the bridge's central T-beam structure. This process is carried out layer by layer, with non-load-bearing structures first removed, followed by load-bearing structures. During demolition, the machinery and equipment and lifting plan selected in the construction organization design are followed, and overloading or arbitrary expansion of the applicable range is strictly prohibited. The site for machinery and equipment must provide sufficient bearing capacity. However, the traditional method of dismantling old bridge piles is cumbersome and slow. Summary of the Invention

[0004] The purpose of the present invention is to provide a construction method for dismantling a pile foundation of an urban interchange ramp using a full-casing and full-rotation drilling rig, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for dismantling a pile foundation of an urban interchange ramp using a full-casing, full-rotation drilling rig, the method comprising the following steps:

[0006] Pile position setting out;

[0007] Laying the working platform;

[0008] After the working platform is laid, the drilling equipment is put into place;

[0009] Steel casing is pressed down;

[0010] Wedge hammer embedment;

[0011] Turn and twist off the old pile;

[0012] Remove and twist off old piles;

[0013] Use the grab bucket to grab and expose the lower pile head;

[0014] Rushing and grabbing to ensure thorough clearance;

[0015] Backfill and pull out the pipes to complete the removal of old piles.

[0016] Preferably, based on the survey control network that has been measured and set up on site, the positions of the old piles are laid out using a total station and marked with obvious objects, 1.5 cm thick steel plates are laid at the construction pile positions, and a working platform is set up on the steel plates.

[0017] Preferably, the specific operations for placing the drilling rig equipment in place are as follows:

[0018] Use the cross positioning method to lift the base plate to the pile center position, and use a crawler crane to lift the full-casing full-rotation drilling rig directly above the base plate. The center position point of the drilling rig's main clamp and the center point of the cross positioning must be on a vertical line. After the drilling rig is in place, connect the reaction fork, reaction frame, and counterweight auxiliary equipment to the drilling rig. After connection, the crawler crane will support the reaction frame, and use the crawler crane's own weight and the friction with the surface to assist the drilling rig operation.

[0019] Preferably, the specific operation of pressing the steel casing down is as follows:

[0020] Before the drilling rig starts working, the drilling rig itself is adjusted to a horizontal position using the drilling rig's horizontal adjustment function, and the crawler crane is used to lift the first section of steel casing. The drilling rig starts to rotate and press the steel casing into the soil, and the first section of steel casing is pressed in. According to the rotation torque and downward pressure parameters, it is determined whether the second section of steel casing should be connected or the wedge hammer should be used to embed and remove the casing in sections. The verticality of the first section of steel casing has a great influence on the vertical accuracy of the subsequent sections of steel casing. Therefore, during the downward pressing of the first section of steel casing, it is necessary to frequently check whether the steel casing is vertical from the X and Y axis directions using a hammer or theodolite. If any deviation occurs, it must be corrected in time. When the steel casing is pressed into place, the hoisted wedge hammer falls freely along the inner wall of the steel casing. The wedge hammer is embedded in the gap between the old pile body and the steel casing by the impact force generated by its own weight, ensuring that it is embedded and then enters the next step.

[0021] Preferably, the specific operation of rotating and twisting off the old pile is as follows:

[0022] After the wedge hammer is firmly embedded in the gap between the old pile and the inner wall of the steel casing, the full-casing and full-rotation drilling rig is started to rotate. The powerful torque of the drilling rig is transmitted through the wedge hammer to twist the old pile body off. The old pile is twisted off in the form of the pile head of the old pile body rotating together with the steel casing. The maximum length of the old pile twisted off by rotation is 5m. After confirming that the old pile has been twisted off, personnel are arranged to enter the steel casing and connect the pile head part to the lifting equipment with a chain bolt. The lifting equipment is then put on the twisted-off old pile body, and then the crawler crane and the full-casing and full-rotation drilling rig are used to cooperate with each other to pull the twisted-off old pile out of the steel casing.

[0023] Preferably, the specific operation of grabbing and leaking the lower pile head with the grab bucket is:

[0024] After the old pile is twisted off and pulled out, the crawler crane lifts the grab bucket and relies on the large and small hooks of the crane to carry out the digging operation until the pile head of the old pile in the lower section is exposed and the digging operation is stopped. After the pile head of the old pile in the lower section is exposed, the steel casing is repeatedly pressed down to pull out the twisted old pile until the entire old pile is completely pulled out.

[0025] Preferably, the specific operations for backfilling and pulling out the pipe to complete the old pile removal construction are:

[0026] Determine whether there are any broken old piles underground based on the length of the pulled-out old piles, and continue to use the grab bucket to take soil to completely remove the obstacles and waste concrete structures inside the steel casing; after confirming that the interior of the steel casing has been completely cleared, backfill 10% cement soil into the steel casing to fill the original space of the old pile to prevent the collapse of the hole wall from affecting the surrounding soil environment. Use the grab bucket to tamp the cement soil during backfilling and pull out the steel casing section by section. It is required that the steel casing should always be about 2m lower than the backfill soil elevation until the backfill reaches the design elevation and the steel casing is completely pulled out, completing the pile removal and obstacle removal task at the pile site.

[0027] Preferably, the lifting equipment includes a lifting sleeve, a mounting groove is provided on the top surface of the lifting sleeve, an electric cylinder is plugged into the bottom surface of the mounting groove, a thread sleeve is fixed on the surface of the electric cylinder, the thread sleeve is screwed to the top of the limit frame, the limit frame is fixed to the surface of the mounting groove, a connecting ring is fixed to the top of the limit frame, a connecting block is movably plugged into the surface of the connecting ring, the connecting block is plugged into the slot, the slot is provided on the surface of the thread sleeve, the piston rod of the electric cylinder passes through the pressure plate, the pressure plate and the piston rod of the electric cylinder are connected by a positioning screw, a clamping block is movably plugged into the inner wall of the mounting groove, and after the electric cylinder pulls the pressure plate down, the pressure plate squeezes the clamping block to clamp the twisted old pile body.

[0028] Preferably, the bottom surface of the lifting sleeve is integrally formed with an introduction slope, the installation groove is an annular groove, and a plurality of positioning grooves are provided on the bottom surface of the installation groove. The electric cylinder and the positioning groove correspond one to one, and the bottom end of the electric cylinder is inserted into the positioning groove. A plurality of rubber gaskets are fixed on the surface of the positioning groove. The limit frame is a frame structure with a "convex" shaped circular opening in the inner ring mouth. The top notch of the limit frame is a screw hole, the wire sleeve is a "T" shaped round tube, the wire sleeve and the screw hole are screwed together, the card groove is an annular groove, and a plurality of through-openings are provided on the surface of the connecting ring. The connecting plug block and the through-opening correspond one to one, and the connecting plug block is inserted into the through-opening one. In the embodiment, the connecting plug is an arc-shaped plate, and the top surface of one end of the connecting plug facing the slot is provided with an inclined surface, and the other end of the connecting plug is provided with a notch, and an elastic rubber sheet is fixed on the surface of the notch, and the two ends of the elastic rubber sheet are respectively fixed on the top surface of the through-hole and the bottom surface of the through-hole, and the other end of the connecting plug is fixed with a traction rope, and one end of the traction rope is fixed on the top surface of the ring, and the ring is movably sleeved on the outside of the limit frame, and a reserved groove is provided on the top surface of the pressure plate, and a positioning screw is screwed on the surface of the reserved groove, and one end of the positioning screw is inserted in the ring groove, and the ring groove is provided on the surface of the piston rod of the electric cylinder.

[0029] Preferably, the surface of the mounting groove is provided with a plurality of through-openings 2, the clamping block and the through-openings 2 correspond one to one, the clamping block is movably inserted in the through-opening 2, the top surface of one end of the clamping block facing the inside of the mounting groove is provided with a slope 2, and the other end of the clamping block is fixed with a plurality of protrusions, the top surface of the clamping block and the bottom surface of the clamping block are both provided with an embedding groove 1, the top surface of the through-opening 2 and the bottom surface of the through-opening 2 are both provided with an embedding groove 2, and an elastic support piece is fixed on the surfaces of the embedding groove 1 and the embedding groove 2, and the elastic support piece is a "U"-shaped strip, and the outer ring surface of the lifting sleeve is provided with a plurality of side grooves, and the surface of the side groove is fixed with a pull ring, and the top surface of the lifting sleeve is fixed with a flexible dust cover, and the flexible dust cover is an annular plate structure, and the outer ring surface of the flexible dust cover is fixed with a rubber band ring, and the rubber band ring is arranged in the hoop groove, and the hoop groove is opened on the top surface of the lifting sleeve.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention proposes a method for dismantling the pile foundation of an urban interchange ramp using a full-casing, full-rotation drilling rig. The method uses steel casing and a full-rotation casing drilling rig to extract the concrete cast-in-place piles. The steel casing has two functions. On the one hand, it transmits the torque and pressing force provided by the top drive device to the cutter head. At the same time, it also supports the hole wall and prevents the hole wall from collapsing during the drilling process. The steel casing is 26 meters long and is equipped with a 100t crawler crane for construction. The principle is to use the downward pressure and torque generated by the full-rotation equipment to drive the steel casing to rotate and drill the casing into the ground. The outer casing is rotated and drilled to serve as a retaining wall to isolate the pile from the outer soil. A wedge hammer (inverted triangle hammer) is inserted into the inside of the casing. After the pile is twisted off, a grab bucket is used to grab the broken pile (a dedicated person is arranged to be on duty during the operation to ensure an absolute safe distance between the crawler crane and the overhead power line to ensure construction safety). Backfill in time after the pile extraction operation is completed. The backfill material is 10% cement soil, which is a mixture of cement and clay. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the present invention;

[0033] Figure 2 This is a schematic diagram of a half-section structure of the present invention;

[0034] Figure 3 This is a structural diagram of the lifting sleeve of the present invention;

[0035] Figure 4 This is a schematic diagram of the connection structure between the electric cylinder and the limit frame of the present invention;

[0036] Figure 5 A half-section schematic diagram of the connection structure between the electric cylinder and the limit frame of the present invention;

[0037] Figure 6 This is a schematic diagram of the clamping block structure of the present invention;

[0038] Figure 7 This is a schematic diagram of the connecting plug structure of the present invention.

[0039] In the figure: lifting sleeve 1, introduction slope 2, installation groove 3, positioning groove 4, rubber gasket 5, electric cylinder 6, limit frame 7, silk sleeve 8, connecting ring 9, through-mouth 10, connecting plug 11, card slot 12, missing slot 13, elastic rubber sheet 14, collar 15, traction rope 16, reserved slot 18, positioning screw 19, ring groove 20, flexible dust cover 21, rubber band 22, hoop groove 23, side groove 24, pull ring 25, through-mouth 26, protrusion 27, embedded groove 1 28, embedded groove 2 29, elastic support piece 30, clamping block 31, pressure plate 32. DETAILED DESCRIPTION

[0040] In order to clearly and completely describe the objectives and technical solutions of the present invention and make the advantages more clearly understood, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are part of the embodiments of the present invention, rather than all of the embodiments, and are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] Example 1

[0042] The present invention provides a technical solution: a construction method for dismantling a pile foundation of an urban interchange ramp using a full-casing, full-rotation drilling rig, the method comprising the following steps:

[0043] 1. Construction preparation

[0044] Bridge Substructure Demolition: The existing bridge, with its pile foundation, should be completely demolished and backfilled with 10% cement soil (primarily to reserve space for the future westbound section of Metro Line 2). Demolition of the existing bridge must strictly adhere to the requirements of all parties involved, and no debris from the demolition should be left in the river. During the demolition process, close observation should be exercised to avoid disturbing adjacent buildings and temporary bridges, ensuring construction safety.

[0045] The pile positions were determined based on the basic information provided by the construction company regarding the existing bridge piles. The appropriate steel casing and full-casing, full-rotation drilling rig were selected based on the existing pile diameters, depth, and other parameters. The existing piles for this project had diameters of 1000mm, 1300mm, and 1200mm, respectively. Based on past construction experience and the specific conditions of the project site, 1500mm / 1800mm diameter steel casing was ultimately selected for the removal of the old piles.

[0046] 2. Pile position setting out

[0047] Based on the survey control network established on-site, the positions of the old piles were staked out using a total station and marked with visible objects. The old piles in this project were bridge piles, and their tops were exposed, allowing for direct pile location determination.

[0048] 3. Lay the working platform

[0049] Because the project's construction site is a riverbed, surface silt and other debris must be cleared in advance and backfilled (to road level) with gravel to level the surface. A 1.5cm thick steel plate will be laid at the construction pile location, and a working platform will be erected on top of the plate to reduce pressure at the center of the drilling rig and prevent sinking or ground collapse caused by weak foundations.

[0050] 4. Drilling rig in place

[0051] After the work platform is laid, the drilling rig is positioned. First, the baseplate is hoisted to the pile center using the cross positioning method. Next, the fully casing, fully rotary drilling rig is hoisted directly above the baseplate using a crawler crane. The center point of the drilling rig's main fixture must be aligned with the center point of the cross positioning method. Once the drilling rig is in place, auxiliary equipment such as the reaction fork, reaction frame, and counterweight are connected to the drilling rig. After connection, the crawler crane is pressed against the reaction frame, using its own weight and friction with the ground to assist the drilling rig operation.

[0052] 5. Press down the steel casing

[0053] Before drilling, the drill rig is first adjusted to a horizontal position using its horizontal adjustment function. The crawler crane is then used to lift the first section of steel casing. The drill rig then begins its rotation and downward pressure, pressing the casing into the soil. Once the first section is inserted, parameters such as rotational torque and downward pressure are used to determine whether to continue with the second section or proceed with the wedge hammer insertion and segmented removal process. The verticality of the first section significantly impacts the vertical accuracy of subsequent sections. Therefore, during the downward pressure of the first section, the verticality of the casing must be frequently checked from both the X and Y axes using a plummet or theodolite. Any deviation must be corrected promptly.

[0054] 6. Wedge hammer embedment

[0055] When the steel casing is pressed down into place, the hoisted wedge hammer falls freely along the inner wall of the steel casing. The wedge hammer is embedded in the gap between the old pile body and the steel casing by the impact force generated by its own weight, ensuring that it is embedded and plugged before entering the next step.

[0056] 7. Rotate and break the old pile

[0057] After the wedge hammer has firmly penetrated the gap between the old pile and the inner wall of the steel casing, the fully casing, fully rotary drill is activated. The powerful torque of the drill is transmitted through the wedge hammer, breaking the old pile. The breaking of the old pile occurs when the pile head rotates along with the steel casing. The maximum length of the old pile broken by the rotation is 5 meters.

[0058] 8. Remove and twist off old piles

[0059] After confirming that the old pile has been twisted off, arrange personnel to enter the steel casing and use chains to tie up the pile head and hang the twisted old pile body. Then use the crawler crane and the full-casing full-rotation drilling rig to cooperate with each other to pull the twisted old pile out of the steel casing.

[0060] Before personnel enter the steel casing, a rope ladder must be installed in advance. After the rope ladder is installed, ventilation equipment must be installed immediately to ventilate the steel casing, and then harmful gases in the casing must be monitored. If the harmful gases exceed the standard, the next step can only be carried out after the harmful gases reach the qualified standard.

[0061] 9. Grab the grab bucket and expose the lower pile head

[0062] After the old pile is twisted off and pulled out, the crawler crane lifts the grab bucket and relies on the large and small hooks of the crane to carry out the digging operation until the pile head of the old pile in the lower section is exposed and the digging is stopped.

[0063] 10. Repeated steel casing pressing down to remove broken old piles

[0064] After the old pile heads of the lower section are exposed, repeat the above steps until the old piles are completely removed.

[0065] 11. Ensure thorough clearance by rushing and grabbing

[0066] Determine whether there are any broken old piles underground based on the length of the old piles pulled out, and continue to use the grab bucket to take soil to completely remove obstacles and waste concrete structures inside the steel casing.

[0067] 12. Backfill and remove pipes to complete the removal of old piles

[0068] After confirming that the internal obstacles of the steel casing are completely cleared, it is necessary to backfill 10% of the steel casing with cement soil to fill the original space of the old pile to prevent the hole wall from collapsing and affecting the surrounding soil environment. During the backfill, the cement soil is compacted with a grab bucket while the steel casing is pulled out section by section. The steel casing is required to always be about 2m below the backfill soil elevation until the backfill reaches the design elevation and the steel casing is completely pulled out, completing the pile removal and obstacle removal task at the pile site.

[0069] 13. Construction guarantee measures

[0070] 13.1 Local expansion and verticality difference

[0071] During the project construction period or after construction, bored piles may shift in position due to geological, hydrological, age and other reasons. For example, if the pile body is tilted too much or the pile body is inevitably broken during the pile extraction process, the old pile or residual pile body must be thoroughly removed with a grab bucket.

[0072] 13.2 Pile body quality problems, such as local breakage and fracture

[0073] Construction experience shows that pile removal and clearing often results in localized breakage and fracture of old piles due to factors such as pile body quality issues. Furthermore, the length of the old piles in this project ranges from 16 to 23 meters, and the main reinforcement of the excavated pile heads and pile bodies is 25 to 22 mm in diameter. This makes pile removal more difficult and risky. After separating the piles from the surrounding soil, the old piles are removed using a grabbing method. Specialized grabbing methods allow for repeated grabbing with a high cycle speed, making them unaffected by short piles.

[0074] After the steel casing is sunk into the pile bottom to cut, separate, and reduce friction, the pile body is then grabbed out by a dedicated grabbing device and pulled out from the top. Even if the pile body is partially broken or fractured, it will not be affected, and the goal of pile removal and obstacle removal can be achieved.

[0075] 14 Safety Monitoring and Early Warning

[0076] During demolition operations, monitor road surface settlement at the road-bridge junction when removing auxiliary structures, bridge surface layers, and the bridge's main T-beam. If pavement settlement or uplift exceeds 1 cm, monitor the frequency of settlement monitoring. If settlement or uplift exceeds 2 cm, immediately suspend demolition operations and investigate the cause of the settlement.

[0077] Demolition construction traffic guidance installation guarantee measures:

[0078] 1. All construction workers entering the construction site must wear safety helmets, and those working on the road must wear reflective vests. Construction workers are strictly prohibited from crossing the left lane.

[0079] 2. Container storage, machinery and equipment, materials, etc. at the construction site should be placed on the side close to the emergency parking lane to ensure that they do not affect traffic on the other side.

[0080] 3. Use reflective cones and warning lines to enclose the construction area, and set up warning lights in conspicuous locations at both ends of the construction area. Set up "Construction ahead, slow down" warning signs 50 meters before and after the construction section. Safety officers will supervise on-site construction safety to ensure smooth traffic.

[0081] 5. During lifting operations, a certified operator must be in charge and a designated person must be in charge. The boom, hook, and materials are not allowed to move over the fast lane and the left lane, which will affect the normal passage of vehicles. It is strictly prohibited to occupy the traffic lane. Strictly abide by the safety operating procedures of the crane.

[0082] 6. There will be personnel on duty at the ramp opening 24 hours a day to strictly control vehicle entry and exit registration.

[0083] Example 2

[0084] On the basis of embodiment 1, when a lifting device is used to clamp the twisted old pile body, the lifting device includes a lifting sleeve 1, the top surface of the lifting sleeve 1 is provided with a mounting groove 3, the bottom surface of the mounting groove 3 is plugged with an electric cylinder 6, the surface of the electric cylinder 6 is sleeved with a wire sleeve 8, the wire sleeve 8 is screwed to the top of the limit frame 7, the limit frame 7 is fixed to the surface of the mounting groove 3, the top of the limit frame 7 is fixed with a connecting ring 9, the surface of the connecting ring 9 is movably plugged with a connecting plug 11, the connecting plug 11 is plugged into the card slot 12, and the card slot 12 is provided on the surface of the wire sleeve 8. The piston rod of the electric cylinder 6 passes through the pressure plate 32, and the pressure plate 32 and the piston rod of the electric cylinder 6 are connected by a positioning screw 19. The inner wall of the mounting groove 3 is movably plugged with a clamping block 31. After the electric cylinder 6 pulls the pressure plate 32 down, the pressure plate 32 squeezes the clamping block 31 to clamp the twisted old pile body; the bottom surface of the lifting sleeve 1 is integrally formed with an introduction slope 2, the mounting groove 3 is an annular groove, and the bottom surface of the mounting groove 3 is provided with a plurality of positioning grooves 4, the electric cylinder 6 and the positioning groove 4 correspond one to one, the bottom end of the electric cylinder 6 is plugged into the positioning groove 4, and the surface of the positioning groove 4 is fixed There are multiple rubber gaskets 5, the limit frame 7 is a frame structure with a "convex" shaped circular opening in the inner ring, the top notch of the limit frame 7 is a screw hole, the wire sleeve 8 is a "T" shaped round tube, the wire sleeve 8 is screwed to the screw hole, the card slot 12 is a circular ring groove, the surface of the connecting ring 9 is provided with multiple through-holes 10, the connecting plug 11 and the through-hole 10 correspond one to one, the connecting plug 11 is inserted in the through-hole 10, the connecting plug 11 is an arc-shaped plate, the top surface of the connecting plug 11 facing the card slot 12 is provided with an inclined surface, and the other end of the connecting plug 11 is provided with a notch 13 , an elastic rubber sheet 14 is fixed to the surface of the notch 13, and the two ends of the elastic rubber sheet 14 are respectively fixed to the top surface of the through-hole 10 and the bottom surface of the through-hole 10, and the other end of the connecting plug 11 is fixed with a traction rope 16, one end of the traction rope 16 is fixed to the top surface of the collar 15, and the collar 15 is movably sleeved on the outer side of the limit frame 7, and a reserved groove 18 is provided on the top surface of the pressure plate 32, and a positioning screw 19 is screwed on the surface of the reserved groove 18, and one end of the positioning screw 19 is inserted in the annular groove 20, and the annular groove 20 is provided on the surface of the piston rod of the electric cylinder 6;The surface of the mounting groove 3 is provided with a plurality of through-openings 26, the clamping blocks 31 and the through-openings 26 correspond one to one, the clamping blocks 31 are movably inserted in the through-openings 26, the top surface of the clamping block 31 facing the inside of the mounting groove 3 is provided with an inclined surface 2, the other end of the clamping block 31 is fixed with a plurality of protrusions 27, the top surface of the clamping block 31 and the bottom surface of the clamping block 31 are both provided with an embedded groove 28, the top surface of the through-opening 26 and the bottom surface of the through-opening 26 are both provided with an embedded groove 29, the embedded groove 2 8 and the surface of the second insertion groove 29 are fixed with an elastic support piece 30. The elastic support piece 30 is a "U"-shaped strip. The outer ring surface of the lifting sleeve 1 is provided with multiple side grooves 24. The surface of the side grooves 24 is fixed with a pull ring 25. The top surface of the lifting sleeve 1 is fixed with a flexible dust cover 21. The flexible dust cover 21 is an annular plate structure. The outer ring surface of the flexible dust cover 21 is fixed with a rubber band 22. The rubber band 22 is mounted in a hoop groove 23. The hoop groove 23 is provided on the top surface of the lifting sleeve 1.

[0085] When the lifting device is used, the chain is tied to the pull ring 25 in advance, and the lifting sleeve 1 is installed on the top of the twisted old pile body, triggering the switch of the electric cylinder 6, the piston rod of the electric cylinder 6 is retracted, and the pressure plate 32 is pulled down along the installation groove 3. During the descending process of the pressure plate 32, the clamping block 31 is squeezed along the inclined surface 21, and the clamping block 31 is pressed and slides along the through-hole 26, squeezing the elastic support piece 30 when the clamping block 31 slides, and the clamping block 31 presses the protrusion 27 against the surface of the twisted old pile body. At this time, the pressure plate 32 blocks the other end of the clamping block 31 to prevent the clamping block 31 from moving back. In this way, multiple groups of clamping blocks 31 clamp the twisted old pile body together, and the lifting sleeve 1 is lifted up together with the twisted old pile body by the lifting equipment. When the screw thread 8 is screwed to the screw hole of the limit frame 7, the connecting block 11 is plugged into the card slot 12, thereby achieving the anti-loosening reinforcement effect of the screw thread 8.

[0086] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. The method for dismantling the pile foundation of an urban interchange ramp using a full-casing, full-rotation drilling rig is characterized by: The method comprises the following steps: Pile position setting out; Laying the working platform; After the working platform is laid, the drilling equipment is put into place; Steel casing is pressed down; Wedge hammer embedment; Turn around and twist off the old pile; Remove and twist off old piles; the specific operations are as follows: After the wedge hammer is firmly embedded in the gap between the old pile and the inner wall of the steel casing, the full-casing full-rotation drilling rig is started to rotate. The powerful torque of the drilling rig is transmitted through the wedge hammer to twist off the old pile body. The twisting off of the old pile is manifested in that the pile head of the old pile body rotates together with the steel casing. The maximum length of the old pile twisted off by rotation is 5m. After confirming that the old pile has been twisted off, personnel are arranged to enter the steel casing and connect the pile head part with a chain bolt to the lifting equipment. The lifting equipment is then placed on the twisted-off old pile body. Subsequently, the crawler crane and the full-casing full-rotation drilling rig are used to cooperate with each other to pull the twisted-off old pile out of the steel casing. The lifting equipment includes a lifting sleeve (1), the top surface of the lifting sleeve (1) is provided with an installation groove (3), the installation groove ( The bottom surface of the electric cylinder (3) is plugged with an electric cylinder (6), the surface of the electric cylinder (6) is fixed with a threaded sleeve (8), the threaded sleeve (8) is screwed to the top of the limit frame (7), the limit frame (7) is fixed to the surface of the mounting groove (3), the top of the limit frame (7) is fixed with a connecting ring (9), the surface of the connecting ring (9) is movably plugged with a connecting plug (11), the connecting plug (11) is plugged into the card slot (12), the card slot (12) is opened on the surface of the threaded sleeve (8), the piston rod of the electric cylinder (6) passes through the pressure plate (32), the pressure plate (32) and the piston rod of the electric cylinder (6) are connected by a positioning screw (19), and the inner wall of the mounting groove (3) is movably plugged with a connecting plug (11). A clamping block (31) is connected, and a plurality of through-holes (26) are provided on the surface of the mounting groove (3). The clamping block (31) and the through-holes (26) correspond to each other one by one. The clamping block (31) is movably inserted into the through-holes (26). The top surface of one end of the clamping block (31) facing the inside of the mounting groove (3) is provided with a second inclined surface. The other end of the clamping block (31) is fixed with a plurality of protrusions (27). The top surface of the clamping block (31) and the bottom surface of the clamping block (31) are both provided with an embedded groove (28). The top surface of the through-hole (26) and the bottom surface of the through-hole (26) are both provided with an embedded groove (29). The surfaces of the embedded groove (28) and the embedded groove (29) are fixed together. There is a fixed elastic support piece (30), the elastic support piece (30) is in the shape of a "U" shape, the outer ring surface of the lifting sleeve (1) is provided with a plurality of side grooves (24), the surface of the side groove (24) is fixed with a pull ring (25), the top surface of the lifting sleeve (1) is fixed with a flexible dust cover (21), the flexible dust cover (21) is in the shape of an annular plate, the outer ring surface of the flexible dust cover (21) is fixed with a rubber band (22), the rubber band (22) is sleeved in the hoop groove (23), and the hoop groove (23) is provided on the top surface of the lifting sleeve (1); after the electric cylinder (6) pulls the pressing plate (32) down, the pressing plate (32) squeezes the clamping block (31) to clamp the twisted old pile body; Use the grab bucket to grab and expose the lower pile head; Rushing and grabbing to ensure thorough clearance; Backfill and pull out the pipe to complete the removal of old piles.

2. The method for dismantling a pile foundation of an urban interchange ramp using a full-casing, full-rotation drilling rig according to claim 1 is characterized in that: According to the survey control network that has been measured and set up on site, the positions of the old piles are marked out using a total station and marked with obvious objects. 1.5cm thick steel plates are laid at the construction pile positions and a working platform is set up on the steel plates.

3. The method for dismantling a pile foundation of an urban interchange ramp using a full-casing, full-rotation drilling rig according to claim 2 is characterized in that: The specific operations for positioning the drilling rig are as follows: Use the cross positioning method to lift the base plate to the pile center position, and use a crawler crane to lift the full-casing full-rotation drilling rig directly above the base plate. The center position point of the drilling rig's main clamp and the center point of the cross positioning must be on a vertical line. After the drilling rig is in place, connect the reaction fork, reaction frame, and counterweight auxiliary equipment to the drilling rig. After connection, the crawler crane will support the reaction frame, and use the crawler crane's own weight and the friction with the surface to assist the drilling rig operation.

4. The method for dismantling a pile foundation of an urban interchange ramp using a full-casing, full-rotation drilling rig according to claim 1 is characterized in that: The specific operation of pressing the steel casing down is as follows: Before the drilling rig starts working, the drilling rig itself is adjusted to a horizontal position using the drilling rig's horizontal adjustment function, and the crawler crane is used to lift the first section of steel casing. The drilling rig starts to rotate and press the steel casing into the soil, and the first section of steel casing is pressed in. According to the rotation torque and downward pressure parameters, it is determined whether the second section of steel casing should be connected or the wedge hammer should be used to embed and remove the casing in sections. The verticality of the first section of steel casing has a great influence on the vertical accuracy of the subsequent sections of steel casing. Therefore, during the downward pressing of the first section of steel casing, it is necessary to frequently check whether the steel casing is vertical from the X and Y axis directions using a hammer or theodolite. If any deviation occurs, it must be corrected in time. When the steel casing is pressed into place, the hoisted wedge hammer falls freely along the inner wall of the steel casing. The wedge hammer is embedded in the gap between the old pile body and the steel casing by the impact force generated by its own weight, ensuring that it is embedded and then enters the next step.

5. The method for dismantling a pile foundation of an urban interchange ramp using a full-casing, full-rotation drilling rig according to claim 1 is characterized in that: The specific operation of grabbing and leaking the lower pile head with the grab bucket is as follows: After the old pile is twisted off and pulled out, the crawler crane lifts the grab bucket and relies on the large and small hooks of the crane to carry out the digging operation until the pile head of the old pile in the lower section is exposed and the digging operation is stopped. After the pile head of the old pile in the lower section is exposed, the steel casing is repeatedly pressed down to pull out the twisted old pile until the entire old pile is completely pulled out.

6. The method for dismantling a pile foundation of an urban interchange ramp using a full-casing, full-rotation drilling rig according to claim 5 is characterized in that: The specific operations of backfilling and pulling out the pipe to complete the removal of old piles are as follows: Determine whether there are any broken old piles underground based on the length of the pulled-out old piles, and continue to use the grab bucket to take soil to completely remove the obstacles and waste concrete structures inside the steel casing; after confirming that the internal obstacles of the steel casing have been completely cleared, backfill 10% cement soil into the steel casing to fill the original space of the old pile to prevent the collapse of the hole wall from affecting the surrounding soil environment. Use the grab bucket to compact the cement soil during backfilling and pull out the steel casing section by section. It is required that the steel casing should always be about 2m lower than the backfill soil elevation until the backfill reaches the design elevation and the steel casing is completely pulled out, completing the pile removal and obstacle removal task at the pile site.

7. The method for dismantling a pile foundation of an urban interchange ramp using a full-casing, full-rotation drilling rig according to claim 1 is characterized in that: The bottom surface of the hoisting sleeve (1) is integrally formed with an introduction slope (2), the installation groove (3) is an annular groove, and the bottom surface of the installation groove (3) is provided with a plurality of positioning grooves (4), the electric cylinder (6) and the positioning groove (4) correspond one to one, the bottom end of the electric cylinder (6) is plugged into the positioning groove (4), and a plurality of rubber gaskets (5) are fixed on the surface of the positioning groove (4), the limiting frame (7) is a frame structure with an inner ring opening of a "convex"-shaped circular opening, the top notch of the limiting frame (7) is a screw hole, the thread sleeve (8) is a "T"-shaped round tube, the thread sleeve (8) and the screw hole are screwed together, the clamping groove (12) is a circular annular groove, the surface of the connecting ring (9) is provided with a plurality of through-openings (10), the connecting plug (11) and the through-opening (10) correspond one to one, the connecting plug (11) is plugged into the through-opening (10), and the connecting plug (11) is an arc. The connecting plug (11) is provided with an inclined surface on the top surface of one end facing the slot (12), and the other end of the connecting plug (11) is provided with a notch (13). An elastic rubber sheet (14) is fixed on the surface of the notch (13), and the two ends of the elastic rubber sheet (14) are respectively fixed on the top surface of the through-opening (10) and the bottom surface of the through-opening (10). A traction rope (16) is fixed on the other end of the connecting plug (11), and one end of the traction rope (16) is fixed on the top surface of the collar (15). The collar (15) is movably sleeved on the outer side of the limit frame (7). A reserved groove (18) is provided on the top surface of the pressure plate (32), and a positioning screw (19) is screwed on the surface of the reserved groove (18). One end of the positioning screw (19) is inserted into the annular groove (20), and the annular groove (20) is provided on the surface of the piston rod of the electric cylinder (6).

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