Construction method for removing cast-in-place pile in shield tunneling area under viaduct and protecting bridge foundation

Abstract

The application relates to the technical field of pile removal, and discloses a construction method for removing piles and protecting bridge foundations in a shield crossing area under a viaduct, wherein a plurality of retaining piles are formed between a shield route and a bridge foundation; the positions of old piles are determined; a full-casing full-rotation drill machine is positioned, a low-crouching short-arm crawler crane is used to hoist a casing, the casing is rotated downward and cut until the casing surrounds the outer periphery of an old pile cap; a micro wedge-shaped drill hammer is hoisted and embedded between the old pile cap and the inner side wall of the casing, the casing is driven to rotate until the old pile cap is twisted off, and the old pile cap is taken out; the casing is continuously driven to press down and cut the soil layer until the lower part of the casing surrounds the upper part of the old pile; the micro wedge-shaped drill hammer is embedded between the old pile and the inner side wall of the casing, the casing is driven to rotate until the inserted section is twisted off, and the inserted section is taken out; the above steps are repeated until the length of a residual pile section is less than a set length, the residual pile section is broken by using a micro cross-shaped impact hammer, the hole is cleaned, cement mortar is backfilled, and the casing is pulled up.

Description

TECHNICAL FIELD

[0001] The application relates to a technical field of bored pile removal, in particular to a construction method for bored pile removal and bridge foundation protection in a shield tunneling area under an elevated bridge. BACKGROUND

[0002] In order to meet the demand of urban traffic, subway lines in various cities are continuously expanded, and underground tunnel construction is becoming more and more common. During the tunnel shield construction process, the shield line often conflicts with the existing building waste pile foundation. In order to ensure the smooth development of the project shield tunnel excavation, the old pile needs to be removed before the shield construction without affecting the safety of the surrounding infrastructure.

[0003] Taking the Guangzhou Metro New Line 18 south extension as an example, the project tunnel design diameter is 8 m, the top buried depth is about 24 m from the ground, and according to the planning, the shield line will pass under the elevated bridge section of Nansha Port Expressway located in the Shiliu River area. The Nansha Port Expressway (bridge) is located in the Nansha District of Guangzhou City and was completed and opened to traffic in 2004. The bridge carries a large number of freight vehicles passing through the Nansha Port, with a daily vehicle flow of 140,000 times. There is a Lingxin Avenue under the elevated bridge with a height of 7 m. The factory buildings in this road section were removed when the Lingxin Avenue was built. The shield line conflicts with the old bored pile foundation of the original factory building of Lingxin Avenue. The number of conflicts between the new shield tunneling area and the old pile is 83, of which 55 old piles are distributed in the low clearance range under the bridge. The old piles are concrete bored piles with a design pile diameter of 800 mm and an average pile length of 34 m. The concrete strength of the old pile foundation is C35, and it is difficult for the shield machine to pass through.

[0004] In the prior art, the underground old pile removal is usually performed by impact breaking, rotary excavation, full casing full rotation pile pulling and other methods. Since the Nansha site is a fishpond backfill, if the impact hammer is used to crush the old pile, the impact process is easy to cause hole collapse. In addition, the original old pile end enters the rock, and it is located under the elevated bridge. The vibration and hole collapse caused by the impact will have adverse effects on the upper bridge foundation. If a rotary drilling rig is used for construction, the torque of the low-clearance rotary drilling rig is small, and the old pile is deep. The performance of the low-clearance rotary drilling rig is slow in removing the old pile and consumes a lot of materials. If a full casing full rotation drilling machine is used to remove the old pile, it is also limited by the low-clearance environment, and the conventional pile pulling operation cannot be normally performed on site. SUMMARY

[0005] The application aims to provide a construction method for bored pile removal and bridge foundation protection in a shield tunneling area under an elevated bridge, and aims to solve the problem of difficult underground old pile removal under an elevated bridge in the prior art.

[0006] The application is implemented as follows. The construction method for bored pile removal and bridge foundation protection in a shield tunneling area under an elevated bridge comprises the following construction steps:

[0007] 1) Determine the blocking area between the shield tunnel route and the bridge foundation, and perform MJS method pile construction in the blocking area to form a plurality of blocking piles, and the plurality of blocking piles are arranged along the length direction of the blocking area;

[0008] 2) According to the shield tunnel route, measure the line and determine the old pile position;

[0009] 3) The crawler type full casing full rotary drilling machine is in place, the middle part of the crawler type full casing full rotary drilling machine has a central hole, a casing is hoisted by a low crouching short arm crawler crane, the casing passes through the central hole, and the bottom of the casing abuts against the old pile position; the casing is driven to rotate downward by the crawler type full casing full rotary drilling machine, and cutting is performed until the casing embraces the outer periphery of the old pile pile cap, and the outer periphery of the old pile cap and the inner side wall of the casing have a pile cap interval;

[0010] 4) A micro wedge-shaped drill hammer is hoisted by a low crouching short arm crawler crane, the micro wedge-shaped drill hammer is embedded into the pile cap interval from top to bottom, and the micro wedge-shaped drill hammer is clamped and fixed between the old pile cap and the casing; the casing is driven to rotate by the crawler type full casing full rotary drilling machine until the old pile cap is twisted off, and the old pile cap is taken out of the casing;

[0011] 5) The casing is continuously driven to cut the soil layer by the crawler type full casing full rotary drilling machine until the bottom of the casing is pressed to a set distance, the casing is stopped from rotating, and the lower part of the casing embraces the upper part of the old pile; the old pile has an inserted section inserted into the casing and a residual pile section below the casing, and a pile interval is formed between the outer periphery of the inserted section and the inner side wall of the casing;

[0012] 6) The micro wedge-shaped drill hammer is embedded into the pile interval from top to bottom, the micro wedge-shaped drill hammer is clamped and fixed between the old pile and the casing, and the casing is driven to rotate by the crawler type full casing full rotary drilling machine until the inserted section is twisted off, and the inserted section is taken out of the casing;

[0013] 7) The above construction steps 5) to 6) are repeated until the length of the residual pile section is less than a set length, the residual pile section is broken into slag by a micro cross-shaped drill hammer, and the slag is taken out of the casing by a micro grab bucket, and a to-be-filled hole is formed in the casing;

[0014] 8) A pouring frame and a grouting pipe are installed, and cement mortar is backfilled into the to-be-filled hole through the grouting pipe;

[0015] 9) The casing is pulled out.

[0016] Optionally, in the construction step 1), an infrared displacement monitoring device for monitoring the displacement of the bridge deck is arranged.

[0017] Optionally, in the construction step 3), a positioning base plate is hoisted and positioned on the old pile site, and then the caterpillar full casing full-rotation drilling machine is moved, a middle part of the positioning base plate is formed with a positioning hole penetrating up and down, and the positioning hole is arranged in alignment with the central hole up and down.

[0018] Optionally, a top part of the positioning base plate is formed with a plurality of positioning grooves, and the caterpillar full casing full-rotation drilling machine is provided with a plurality of supporting legs moving up and down in an extending mode.

[0019] In the construction step 3), after the caterpillar full casing full-rotation drilling machine is moved to the set position, the plurality of supporting legs are moved in an extending mode downward until the bottom part of the supporting leg is pressed on the positioning groove.

[0020] Optionally, in the construction step 5), the casing comprises a plurality of joint pipes connected up and down, and the adjacent joint pipes are connected with each other through the connecting structure.

[0021] In the construction step 5), in the process that the caterpillar full casing full-rotation drilling machine drives the casing to continue to press down and cut the soil layer, the casing has an upper extending section extending above the central hole, when the length of the upper extending section is less than 50 cm, the driving of the casing is stopped, the waterproof film is coiled and laid on the outer periphery of the upper extending section to form a waterproof layer, and then butter is coated on the waterproof layer to form a lubricating layer; the joint pipe is hoisted by the low-crouching short-arm caterpillar crane, and the hoisted joint pipe is connected with the top part of the upper extending section through the connecting structure, and the waterproof layer is clamped and fixed between the upper extending section and the hoisted joint pipe.

[0022] Optionally, the bottom part of the casing is provided with a plurality of cutting shoes, and the plurality of cutting shoes are arranged in an interval along the circumferential direction of the casing; an inner side wall of the bottom part of the casing is provided with a plurality of inner cutting heads, an inner end of the inner cutting head is connected to the inner side wall of the casing, and an outer end of the inner cutting head extends and is arranged toward the center of the casing; a convex strip is welded on the outer periphery of the bottom part of the casing, and a plurality of convex strips form a convex grid on the outer periphery of the casing.

[0023] In the construction step 3), in the process that the caterpillar full casing full-rotation drilling machine drives the casing to rotate downward for cutting, under the action of the inner cutting head, an annular pile interval is formed on the old pile site.

[0024] In the construction step 5), in the process that the caterpillar full casing full-rotation drilling machine drives the casing to rotate downward for cutting, under the action of the inner cutting head, an annular pile interval is formed on the old pile site.

[0025] Optionally, the outer side of the micro wedge-shaped drill hammer is formed with an arc-shaped outer side surface, the inner side of the micro wedge-shaped drill hammer is formed with a concave-convex inner side surface, the two sides of the outer side surface are connected with the two sides of the inner side surface respectively, and the outer side surface is arranged to extend obliquely towards the inner side surface along the direction from top to bottom;

[0026] In the construction step 3), when the micro wedge-shaped drill hammer is embedded into the pile interval, the outer side surface abuts against the inner side wall of the sleeve pipe, and the inner side surface abuts against the outer periphery of the old pile cap;

[0027] In the construction step 6), when the micro wedge-shaped drill hammer is embedded into the pile interval, the outer side surface abuts against the inner side wall of the sleeve pipe, and the inner side surface abuts against the outer periphery of the inserted section.

[0028] Optionally, the top of the micro wedge-shaped drill hammer is provided with a hanging ear for connecting with a steel wire rope, in the construction step 3), the micro wedge-shaped drill hammer is hoisted to above the pile interval by the steel wire rope, and after the outer side surface is tightly fitted with the inner side wall of the sleeve pipe, the steel wire rope is released, and under the action of gravity, the micro wedge-shaped drill hammer is embedded into the pile interval from top to bottom;

[0029] In the construction step 6), the micro wedge-shaped drill hammer is hoisted to above the pile interval by the steel wire rope, and after the outer side surface is tightly fitted with the inner side wall of the sleeve pipe, the steel wire rope is released, and under the action of gravity, the micro wedge-shaped drill hammer is embedded into the pile interval from top to bottom.

[0030] Optionally, the micro wedge-shaped drill hammer comprises a plurality of steel plates, the steel plates are connected with each other by welding, the outer end surface of the steel plate is formed with an abutting surface for abutting against the inner side wall of the sleeve pipe, the abutting surfaces of the steel plates combine to form the outer side surface, and the abutting surface is provided with an elastic counter-pressure convex strip;

[0031] In the construction step 3), when the micro wedge-shaped drill hammer is embedded into the pile interval under the action of gravity, the micro wedge-shaped drill hammer is pressed by the old pile cap, the counter-pressure convex strip is compressed under stress, and under the action of elasticity, the inner side surface of the micro wedge-shaped drill hammer is pressed against the outer periphery of the old pile cap;

[0032] In the construction step 6), when the micro wedge-shaped drill hammer is embedded into the pile interval under the action of gravity, the micro wedge-shaped drill hammer is pressed by the old pile, the counter-pressure convex strip is compressed under stress, and under the action of elasticity, the inner side surface of the micro wedge-shaped drill hammer is pressed against the outer periphery of the old pile.

[0033] Optionally, the inner end face of the steel plate is formed with an inclined face, which is arranged to extend obliquely towards the abutting face along a top-down direction, and a plurality of the inclined faces of the steel plates combine to form the inner side face; a through hole extending through the steel plate from front to back is arranged in the middle part of the steel plate, and the outer end of the through hole extends through the abutting face, and the inner end of the steel plate extends through the inclined face;

[0034] The reverse pressure convex strip has a telescopic section embedded into the through hole; the through hole is provided with a moving block, the inner end of the moving block is connected with the outer end of the telescopic section, the outer end of the moving block is provided with a pressure abutting head arranged towards the inclined face, and the upper and lower ends of the moving block are provided with convex blocks protruding outwardly; two guide rails are arranged in the through hole, springs for driving the moving block to reset are arranged in the guide rails, the inner end of the spring is fixedly arranged, and the outer end of the spring is pressed on the convex block;

[0035] In the construction step 3), after the micro wedge-shaped drill hammer is embedded into the pile interval under the action of gravity, the reverse pressure convex strip is extruded by the inner side wall of the sleeve pipe, the reverse pressure convex strip is compressed under stress, the telescopic section deforms and extends towards the inclined face, the moving block is driven to move towards the inclined face, and the convex block extrudes the spring to deform, until the pressure abutting head is pressed on the old pile cap;

[0036] In the construction step 6), after the micro wedge-shaped drill hammer is embedded into the pile interval under the action of gravity, the reverse pressure convex strip is extruded by the inner side wall of the sleeve pipe, the reverse pressure convex strip is compressed under stress, the telescopic section deforms and extends towards the inclined face, the moving block is driven to move towards the inclined face, and the convex block extrudes the spring to deform, until the pressure abutting head is pressed on the old pile;

[0037] When the micro wedge-shaped drill hammer is taken out from the pile interval or the pile interval, under the action of elasticity, the spring presses the convex block to move towards the abutting face, the moving block extrudes the telescopic section to deform and shorten, the pressure abutting head moves into the through hole, and the reverse pressure convex strip expands and deforms outwardly.

[0038] Compared with the prior art, the high bridge under shield crossing area cast-in-place pile removal and bridge foundation protection construction method provided by the application adopts a caterpillar type full sleeve full rotation drilling machine, which can be accurately positioned and freely moved without the cooperation of a large crane through a caterpillar self-propelled mechanism, and the old pile removal process adopts a low-crouching caterpillar crane and modified micro grab bucket, micro cross rammer, micro wedge-shaped drill hammer, realizes barrier-free construction under low clearance conditions, and ensures normal construction. Moreover, the caterpillar type full sleeve full rotation drilling machine is quick and efficient in positioning; the sleeve is sunk to cover the old pile by using the full sleeve full rotation drilling machine, the micro wedge-shaped drill hammer is clamped into the gap between the pile caps and the pile intervals, the caterpillar type full sleeve full rotation drilling machine is rotated to twist and break the old pile cap and the inserted section, and the broken pile is pulled out with the help of the micro grab bucket or the low-crouching short-arm caterpillar crane, so that the overall obstacle removal efficiency is high.

[0039] Next, the whole process of old pile removal adopts casing following, by measuring the length of the inserted section, the length of the residual pile section in the casing is determined, when the length of the residual pile section is short, the micro cross hammer and the micro grab bucket repeatedly hit and grab in the casing to take the slag, and the obstacle is completely removed to clear the obstacle for the subsequent shield crossing. Moreover, before the construction of the old pile removal, the MJS reinforcement is carried out on the bridge pier, the bridge foundation and the intermediate area of the shield outer line. During the construction process, the casing is advanced and drilled to cover the old pile by the full casing full rotation drill, and the hole operation is isolated to prevent excessive disturbance to the bridge foundation. After the old pile is removed, the ultra slow setting cement mortar is immediately filled in the hole to reinforce the site again, and the safety and stability of the bridge foundation are ensured. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a flowchart of the construction method for removing cast-in-place piles and protecting bridge foundations in a shield crossing area under an elevated bridge provided by the present application;

[0041] Figure 2 is a structural schematic diagram of a cast-in-place pile and a bridge foundation in a shield crossing area under an elevated bridge provided by the present application;

[0042] Figure 3 is a structural schematic diagram of a low-slung short-arm crawler crane provided by the present application;

[0043] Figure 4 is a structural schematic diagram of a positioning base plate provided by the present application;

[0044] Figure 5 is a structural schematic diagram of a micro wedge-shaped hammer provided by the present application;

[0045] Figure 6 is a front view schematic diagram of the bottom of the casing provided by the present application;

[0046] Figure 7 is a cross-sectional schematic diagram of a steel plate provided by the present application. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0048] The implementation of the present application will be described in detail below in combination with specific examples.

[0049] The same or similar reference numerals in the drawings of the embodiments correspond to the same or similar components; in the description of the present application, it is understood that if the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right" and the like is based on the orientation or positional relationship shown in the drawings, it is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the positional relationship described in the drawings is only for exemplary illustration, and cannot be understood as a limitation of the present patent, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0050] Referring to Figures 1-7 The preferred embodiment provided by the present application is shown.

[0051] The high-level bridge under shield crossing area cast-in-place pile cleaning and bridge foundation protection construction method provided by the present application comprises the following construction steps:

[0052] 1) Determine the blocking area between the shield route 30 and the bridge foundation 10, and perform MJS method pile construction in the blocking area to form a plurality of blocking piles, which are arranged along the length direction of the blocking area;

[0053] 2) According to the shield route 30, measure and lay out the line to determine the pile position of the old pile 20;

[0054] 3) Position the crawler type full casing full rotation drill machine, the middle part of which has a central hole, use the low crouching short arm crawler crane 100 to hoist the casing 400, the casing 400 passes through the central hole, and the bottom of the casing 400 is pressed on the pile position of the old pile 20; the crawler type full casing full rotation drill machine drives the casing 400 to rotate downward for cutting until the casing 400 embraces the outer periphery of the old pile pile cap, and the outer periphery of the old pile pile cap and the inner side wall of the casing 400 have a pile cap interval;

[0055] 4) Use the low crouching short arm crawler crane 100 to hoist the micro wedge-shaped drill hammer 300, which is embedded into the pile cap interval from top to bottom, and the micro wedge-shaped drill hammer 300 is clamped and fixed between the old pile pile cap and the casing 400; use the crawler type full casing full rotation drill machine to drive the casing 400 to rotate until the old pile pile cap is twisted off, and the old pile pile cap is taken out of the casing 400;

[0056] 5) Use the crawler type full casing full rotation drill machine to drive the casing 400 to continue to press down and cut the soil layer until the bottom of the casing 400 is pressed to a set distance, stop driving the casing 400 to rotate, and the lower part of the casing 400 embraces the upper part of the old pile 20; the old pile 20 has an inserted segment inserted into the casing 400 and a residual pile segment below the casing 400, and a pile interval is formed between the outer periphery of the inserted segment and the inner side wall of the casing 400;

[0057] 6), the micro wedge drill hammer 300 is embedded into the pile interval from top to bottom, the micro wedge drill hammer 300 is clamped and fixed between the old pile 20 and the casing 400, the casing 400 is driven to rotate by the crawler type full casing full rotary drilling machine, until the inserted section is twisted off, and the inserted section is taken out of the casing 400;

[0058] 7), the above construction steps 5) to 6) are repeated until the length of the residual pile section is less than the set length, the residual pile section is broken into slag by the micro cross hammer, and the slag is taken out of the casing 400 by the micro grab bucket, and the casing 400 forms a hole to be filled;

[0059] 8), install the pouring frame and the grouting pipe, and backfill the cement mortar into the hole to be filled through the grouting pipe;

[0060] 9), the casing 400 is pulled out.

[0061] The construction method for removing the bored pile in the shield crossing area under the viaduct and protecting the bridge foundation provided above adopts the crawler type full casing full rotary drilling machine, which can move freely and accurately in place through the crawler self-propelled mechanism without the cooperation of a large crane. The low-crawling crawler crane 100 and the modified micro grab bucket, micro cross hammer and micro wedge drill hammer 300 are used in the process of removing the old pile 20 to realize barrier-free construction under low clearance conditions and ensure normal construction. Moreover, the crawler type full casing full rotary drilling machine is quick and efficient in positioning. The casing 400 is sunk to cover the old pile 20 by the full casing full rotary drilling machine, the micro wedge drill hammer 300 is clamped into the gap between the pile interval and the pile interval, the crawler type full casing full rotary drilling machine is rotated to twist off the old pile cap and the inserted section, and the broken pile is pulled out with the help of the micro grab bucket or the low-crawling short-arm crawler crane 100, so that the overall obstacle removal efficiency is high.

[0062] Then, the casing 400 is followed throughout the process of removing the old pile 20, the length of the inserted section is measured to determine the condition of the residual pile section in the casing 400, when the length of the residual pile section is short, the micro cross hammer and the micro grab bucket are repeatedly hammered and grabbed in the casing 400 to take out the slag, so that the obstacle removal is completely thorough, and the obstacle is cleared for the subsequent shield crossing. Moreover, before the construction of removing the old pile 20, the MJS reinforcement is carried out on the intermediate area between the bridge pier and bridge foundation 10 and the shield line. In the construction process, the casing 400 is sunk to cover the old pile 20 by the full casing full rotary drilling machine, and the hole operation is completely isolated to prevent excessive disturbance to the bridge foundation 10. After the old pile 20 is removed, the super slow setting cement mortar is immediately filled in the hole to reinforce the site again, so that the safety and stability of the bridge foundation 10 are ensured.

[0063] Specifically, the JAR-210H full casing full-rotation drilling machine is modified, a track walking mechanism is added to the base thereof to form a full casing full-rotation drilling machine, the overall height of the machine is 4 m, and the machine can be self-walked to the pile hole to be positioned without the assistance of a large crane, thereby meeting the construction requirements in a low-clearance environment.

[0064] Specifically, the YTQU100HD track crane 100 arm support 110 is disassembled and reduced, and is adjusted to a low-crouching state to form a low-crouching short-arm track crane 100, the maximum lifting load of which is 100 t, and the overall height thereof is only 3.5 m, thereby meeting the lifting operation requirements in a low-clearance environment.

[0065] Specifically, the conventional impact grab bucket has a length of 5 m, and cannot meet the construction requirements in a low-clearance environment. Therefore, a micro impact grab bucket for a low-clearance environment is specially developed, and the length of the bucket body is 2 m.

[0066] Specifically, the micro wedge-shaped hammer 300 has a total length of only 2 m, is composed of a plurality of trapezoidal steel plates 310, and the curvature thereof fits the inner wall of the casing 400.

[0067] Specifically, the conventional impact hammer has a length of 5 m, and cannot meet the construction requirements in a low-clearance environment. Therefore, the length of the cross impact hammer is reduced in the method, the micro cross impact hammer has a diameter of 1.2 m and a length of 2 m, and the hammer body is designed by using a plurality of steel plates 310 to add weight, thereby offsetting the influence of the too light weight due to the length reduction.

[0068] Specifically, the fender piles are arranged in rows, have a pile diameter of 1.5 m, a pile spacing of 1.3 m, and a pile length of 34 m, and are used to surround and reinforce the bridge pier to reduce the adverse effects of pile pulling on the existing bridge.

[0069] In the construction step 1), an infrared displacement monitoring device for monitoring the displacement of the bridge deck is laid out. In this way, the deformation is automatically monitored for 24 hours.

[0070] In the construction step 3), the positioning base plate 200 is hoisted and placed at the pile position of the old pile 20, and then the track-type full-casing full-rotation drilling machine is moved. The middle part of the positioning base plate 200 is formed with a positioning hole 201 that penetrates up and down, and the positioning hole 201 is arranged in alignment with the central hole up and down. In this way, the axis of the casing 400 can be ensured to be on the same straight line as the axis of the old pile 20 through the action of the positioning base plate 200, the track-type full-casing full-rotation drilling machine can be positioned, and the track-type full-casing full-rotation drilling machine is conveniently moved to the set position.

[0071] The top of the positioning base plate 200 is formed with a plurality of positioning grooves 202, and the track-type full-casing full-rotation drilling machine has a plurality of up-and-down telescopic supporting legs;

[0072] In the construction step 3), after the caterpillar full casing 400 is moved to the set position, the plurality of legs are extended downwards until the bottom of the legs abut against the positioning groove 202. In this way, the caterpillar full casing full-rotation drilling machine is prevented from being easily moved.

[0073] In the construction step 5), the casing 400 includes a plurality of connected segment casings, and the adjacent segment casings are connected to each other through the connecting structure.

[0074] In the construction step 5), in the process of driving the casing 400 to continue to cut the soil layer by the caterpillar full casing full-rotation drilling machine, the casing 400 has an upper extension segment extending above the central hole. When the length of the upper extension segment is less than 50 cm, the driving of the casing 400 is stopped, the waterproof membrane is wound on the outer periphery of the upper extension segment, the waterproof layer is formed, the butter is coated on the waterproof layer, the lubricating layer is formed, the segment casing is hoisted by the low-slung short-arm caterpillar crane 100, and the hoisted segment casing is connected to the top of the upper extension segment through the connecting structure. The waterproof layer is clamped and fixed between the upper extension segment and the hoisted segment casing. In this way, through the design of the waterproof layer, the sealing is ensured, and through the design of the lubricating layer, the segment casing of the upper segment is smoothly embedded in the lengthening process.

[0075] The bottom of the casing 400 is provided with a plurality of cutting shoes 410, and the plurality of cutting shoes 410 are arranged at intervals along the circumference of the casing 400. The inner side wall of the bottom of the casing 400 is provided with a plurality of inner cutting heads 420, the inner ends of the inner cutting heads 420 are connected to the inner side wall of the casing 400, and the outer ends of the inner cutting heads 420 extend towards the center of the casing 400. The outer periphery of the bottom of the casing 400 is welded with a plurality of protruding strips, and the plurality of protruding strips form a protruding grid on the outer periphery of the casing 400.

[0076] In the construction step 3), in the process of driving the casing 400 to rotate downwards for cutting by the caterpillar full casing full-rotation drilling machine, under the action of the inner cutting heads 420, the annular pile interval is formed on the pile position of the old pile 20.

[0077] In the construction step 5), in the process of driving the casing 400 to rotate downwards for cutting by the caterpillar full casing full-rotation drilling machine, under the action of the inner cutting heads 420, the annular pile interval is formed on the pile position of the old pile 20. In this way, through the action of the inner cutting heads 420, the space is broken in the casing 400, which is convenient for the micro wedge-shaped pile hammer 300 to be embedded, and the cutting body to be grabbed and hoisted out. And through the design of the protruding grid, the casing 400 is facilitated to be lowered.

[0078] The width of the inner cutting head 420 is greater than 12 cm.

[0079] The outer side of the micro wedge-shaped drill hammer 300 is formed with an arc-shaped outer side surface 301, and the inner side of the micro wedge-shaped drill hammer 300 is formed with a concave-convex inner side surface 302. The two sides of the outer side surface 301 are respectively connected to the two sides of the inner side surface 302. Along the direction from top to bottom, the outer side surface 301 extends and is arranged obliquely towards the inner side surface 302;

[0080] In the construction step 3), when the micro wedge-shaped drill hammer 300 is embedded into the pile interval, the outer side surface 301 abuts against the inner side wall of the sleeve pipe 400, and the inner side surface 302 abuts against the outer periphery of the old pile cap.

[0081] In the construction step 6), when the micro wedge-shaped drill hammer 300 is embedded into the pile interval, the outer side surface 301 abuts against the inner side wall of the sleeve pipe 400, and the inner side surface 302 abuts against the outer periphery of the inserted section. In this way, the design of the outer side surface 301 facilitates the determination of the last position of the micro wedge-shaped drill hammer 300 before lowering, and facilitates the accurate placement of the micro wedge-shaped drill hammer 300.

[0082] The top of the micro wedge-shaped drill hammer 300 is provided with a hanging ear for connecting with a steel wire rope. In the construction step 3), the micro wedge-shaped drill hammer 300 is hoisted to the upper side of the pile interval through the steel wire rope, and after the outer side surface 301 is tightly fitted with the inner side wall of the sleeve pipe 400, the steel wire rope is released. Under the action of gravity, the micro wedge-shaped drill hammer 300 is embedded into the pile interval from top to bottom.

[0083] In the construction step 6), the micro wedge-shaped drill hammer 300 is hoisted to the upper side of the pile interval through the steel wire rope, and after the outer side surface 301 is tightly fitted with the inner side wall of the sleeve pipe 400, the steel wire rope is released. Under the action of gravity, the micro wedge-shaped drill hammer 300 is embedded into the pile interval from top to bottom. In this way, the self-gravity of the micro wedge-shaped drill hammer 300 is utilized to realize the advanced embedding of the micro wedge-shaped drill hammer 300, so that the micro wedge-shaped drill hammer 300 is stably clamped in the pile interval. When the sleeve pipe 400 rotates, the torsion can be better transmitted to the cut body.

[0084] When the micro wedge-shaped drill hammer 300 does not achieve the effect once, the operation can be repeated multiple times until the micro wedge-shaped drill hammer 300 is clamped.

[0085] The micro wedge-shaped drill hammer 300 includes a plurality of steel plates 310, which are connected to each other by welding. The outer end surface of the steel plate 310 is formed with an abutting surface 311 for abutting against the inner side wall of the sleeve pipe 400. The abutting surfaces 311 of the plurality of steel plates 310 combine to form the outer side surface 301. The abutting surface 311 is provided with a reverse pressure convex strip 320 having elasticity.

[0086] In the construction step 3), when the micro wedge-shaped drill hammer 300 is embedded into the pile interval under the action of gravity, the micro wedge-shaped drill hammer 300 is pressed by the old pile cap, and the counter-pressure convex strip 320 is compressed under the action of force. Under the action of the elastic force, the inner side surface 302 of the micro wedge-shaped drill hammer 300 is pressed on the outer periphery of the old pile cap;

[0087] In the construction step 6), when the micro wedge-shaped drill hammer 300 is embedded into the pile interval under the action of gravity, the micro wedge-shaped drill hammer 300 is pressed by the old pile 20, and the counter-pressure convex strip 320 is compressed under the action of force. Under the action of the elastic force, the inner side surface 302 of the micro wedge-shaped drill hammer 300 is pressed on the outer periphery of the old pile 20. In this way, under the action of the acceleration of gravity, the counter-pressure convex strip 320 is extruded to be compressed after falling, and the extrusion force on the micro wedge-shaped drill hammer 300 is absorbed. Under the action of the elastic force, the micro wedge-shaped drill hammer 300 is pressed on the cutting body, the insertion effect of the micro wedge-shaped drill hammer 300 is improved, and the probability of being stuck is improved.

[0088] As a preferred embodiment, the inner end surface of the steel plate 310 is formed with an inclined surface 312, which is arranged to extend obliquely towards the abutting surface 311 along the upward direction, and the inclined surfaces 312 of the plurality of steel plates 310 are combined to form the inner side surface 302. The middle part of the steel plate 310 is provided with a through hole penetrating through the steel plate 310 in front and back directions, the outer end of the through hole penetrates through the abutting surface 311, and the inner end of the steel plate 310 penetrates through the inclined surface 312;

[0089] The counter-pressure convex strip 320 has an extension section 321 embedded in the through hole. The through hole is provided with a moving block 330, the inner end of the moving block 330 is connected with the outer end of the extension section 321, the outer end of the moving block 330 is provided with a pressing cutter head 331 arranged towards the inclined surface 312, and the upper and lower ends of the moving block 330 are provided with outwardly protruding lugs 332. The through hole is provided with two guide rails, the guide rails are provided with springs 333 for driving the moving block 330 to reset, the inner end of the spring 333 is fixedly arranged, and the outer end of the spring 333 is pressed on the lugs 332;

[0090] In the construction step 3), when the micro wedge-shaped drill hammer 300 is embedded into the pile interval under the action of gravity, the micro wedge-shaped drill hammer 300 is pressed by the old pile cap, and the counter-pressure convex strip 320 is compressed under the action of force. Under the action of the elastic force, the inner side surface 302 of the micro wedge-shaped drill hammer 300 is pressed on the outer periphery of the old pile cap;

[0091] In the construction step 6), after the micro wedge-shaped drill hammer 300 is embedded into the pile interval under the action of gravity, the reverse pressure convex strip 320 is extruded by the inner wall of the sleeve 400, the reverse pressure convex strip 320 is forced to compress, the telescopic section 321 deforms and extends towards the inclined surface 312, the moving block 330 moves towards the inclined surface 312, the convex block 332 extrudes the spring 333 to deform, until the pressing cutter head 331 is pressed on the old pile 20;

[0092] When the micro wedge-shaped drill hammer 300 is taken out from the pile interval or the pile interval, under the action of the elastic force, the spring 333 moves the convex block 332 towards the abutting surface 311, the moving block 330 extrudes the telescopic section 321 to deform and shorten, the pressing cutter head 331 moves into the through hole, and the reverse pressure convex strip 320 expands and deforms outwardly. In this way, by designing the telescopic section 321, the movement of the pressing cutter head 331 is controlled, so that it is hidden in the through hole in the natural state, and the pressing cutter head 331 abuts on the cut body in the embedded state, ensuring that the surface part is broken, so that the internal steel bar is exposed, and the lifting is facilitated. Moreover, the connection between the micro wedge-shaped drill hammer 300 and the cut body is increased, and the transmission of the torsion force is ensured.

[0093] The pressing cutter head 331 can be a diamond bead or the like.

[0094] As a preferred embodiment, in the process of backfilling the cement mortar, the guide pipe is pulled out according to the pouring surface of the cement mortar formed in the hole to be filled. The bottom of the pouring guide pipe in the hole always maintains more than 2m above the height of the cement mortar backfill surface, in order to ensure that the guide pipe and the sleeve 400 are smoothly pulled out, when the cement mortar is backfilled to half the volume of the hole, the pouring hopper is removed, and the pulling out of the sleeve 400 is started.

[0095] The above only describes the preferred embodiments of the present application and does not limit the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A construction method for removing cast-in-place piles and protecting bridge foundations in the shield tunneling area under a viaduct, characterized in that: The construction steps include: 1) Determine a blocking area between the shield route and the bridge foundation, perform MJS pile construction in the blocking area to form multiple blocking piles, and arrange the multiple blocking piles at intervals along the length direction of the blocking area; 2) According to the shield route, measure and lay out the lines to determine the positions of the old piles; 3) The crawler-type full-casing, full-rotation drilling rig is in place. The crawler-type full-casing, full-rotation drilling rig has a center hole in the middle. The casing is hoisted by a low-lying, short-arm crawler crane. The casing passes through the center hole, and the bottom of the casing is pressed against the position of the old pile. The crawler-type full-casing, full-rotation drilling rig drives the casing to rotate and cut downward until the casing encircles the outer periphery of the old pile cap, and a cap gap is formed between the outer periphery of the old pile cap and the inner side wall of the casing. 4) Using a low-lying short-arm crawler crane to hoist a miniature wedge-shaped drill hammer, the miniature wedge-shaped drill hammer is inserted into the pile cap gap from top to bottom. The miniature wedge-shaped drill hammer is clamped and fixed between the old pile cap and the casing. Using a crawler-type full-casing full-rotation drill rig, the casing is driven to rotate until the old pile cap is twisted off, and the old pile cap is removed from the casing. 5) Using a crawler-type fully-cased, fully-rotating drill rig, the casing is driven downward to continue cutting the soil layer until the bottom of the casing is pressed down to a set distance, and the casing is stopped from rotating. The lower portion of the casing is wrapped around the upper portion of the old pile; the old pile has an insertion section inserted into the casing and a residual pile section located below the casing, and a pile gap is formed between the outer periphery of the insertion section and the inner side wall of the casing; 6) Use a micro wedge drill hammer to insert into the pile interval from top to bottom. The micro wedge drill hammer is clamped and fixed between the old pile and the casing. Use a crawler-type full-casing full-rotation drill rig to drive the casing to rotate until the inserted section is twisted off and the inserted section is removed from the casing. 7) Repeat the above construction steps 5) to 6) until the length of the residual pile segment is less than the set length, use a micro cross hammer to crush the residual pile segment into debris, and then use a micro grab to remove the debris from the casing, forming a hole to be filled in the casing; 8) Installing a grouting frame and a grouting conduit, and backfilling cement mortar into the hole to be filled through the grouting conduit; 9) Pull out the casing.

2. The method for removing bored piles and protecting bridge foundations in the shield tunneling area under a viaduct as claimed in claim 1, characterized in that: In the construction step 1), an infrared displacement monitoring device for monitoring bridge deck displacement is deployed.

3. The method for removing bored piles and protecting bridge foundations in the shield tunneling area under a viaduct as claimed in claim 1, characterized in that: In the construction step 3), a positioning base plate is hung on the old pile position, and then the crawler-type full-casing full-rotation drilling rig is moved. A positioning hole is formed in the middle of the positioning base plate and is aligned with the center hole.

4. The method for removing bored piles and protecting bridge foundations in the shield tunneling area under a viaduct as claimed in claim 3, characterized in that: A plurality of positioning grooves are formed on the top of the positioning base plate, and the crawler-type full-casing full-rotation drilling rig has a plurality of legs that can be telescopically moved up and down; In the construction step 3), after the crawler-type full-casing full-rotation drilling rig is moved to a set position, the plurality of legs are extended and moved downward until the bottoms of the legs are pressed against the positioning grooves.

5. The method for removing bored piles and protecting bridge foundations in the shield tunneling area under a viaduct as claimed in claim 1, characterized in that: The sleeve comprises a plurality of vertically connected section tubes, and adjacent section tubes are connected to each other via a connecting structure; In the construction step 5), during the process of using a crawler-type full-casing full-rotation drilling rig to drive the casing to continue pressing down to cut the soil layer, the casing has an upper extension section extending above the center hole. When the length of the upper extension section is less than 50 cm, the casing rotation is stopped, and a waterproof membrane is rolled on the outer periphery of the upper extension section to form a waterproof layer, and then butter is applied on the waterproof layer to form a lubricating layer; a low-lying short-arm crawler crane is used to lift the joint pipe, and the lifted joint pipe is connected to the top of the upper extension section through a connecting structure, and the waterproof layer is clamped and fixed between the upper extension section and the lifted joint pipe.

6. The method for removing bored piles and protecting bridge foundations in the shield tunneling area under a viaduct as claimed in claim 1, characterized in that: The bottom of the casing is provided with a plurality of cutting shoes, which are arranged at intervals along the circumference of the casing; the inner side wall of the bottom of the casing is provided with a plurality of inner cutting heads, the inner ends of the inner cutting heads are connected to the inner side wall of the casing, and the outer ends of the inner cutting heads extend toward the center of the casing; the outer periphery of the bottom of the casing is welded with protruding strips, and the plurality of protruding strips form a protruding grid on the outer periphery of the casing; In the construction step 3), during the process of the crawler-type full-casing full-rotation drilling rig driving the casing to rotate and cut downward, an annular cap gap is formed on the old pile position under the action of the inner cutter head; In the construction step 5), during the process of the crawler-type full-casing full-rotation drilling rig driving the casing to rotate and cut downward, an annular pile gap is formed on the old pile position under the action of the inner cutter head.

7. The method for removing bored piles and protecting bridge foundations in the shield tunneling area under an elevated bridge according to any one of claims 1 to 6, characterized in that: The outer side of the micro wedge-shaped drill hammer is formed with an arc-shaped outer side surface, and the inner side of the micro wedge-shaped drill hammer is formed with a concave-convex inner side surface, the two sides of the outer side surface are respectively connected to the two sides of the inner side surface, and along the direction from top to bottom, the outer side surface is inclined and extended toward the inner side surface; In the construction step 4), after the miniature wedge-shaped drill hammer is inserted into the pile cap gap, the outer side surface abuts against the inner side wall of the casing, and the inner side surface abuts against the outer periphery of the old pile cap; In the construction step 6), after the miniature wedge-shaped drill hammer is embedded in the pile interval, the outer side surface abuts against the inner side wall of the casing, and the inner side surface abuts against the outer periphery of the insertion section.

8. The method for removing bored piles and protecting bridge foundations in the shield tunneling area under a viaduct as claimed in claim 7, characterized in that: The top of the miniature wedge drill hammer is provided with a hanging ear for connecting to a wire rope. In the construction step 4), the miniature wedge drill hammer is hoisted to the top of the base gap by the wire rope, and after the outer side surface is tightly fitted with the inner side wall of the casing, the wire rope is released. Under the action of gravity, the miniature wedge drill hammer is embedded in the base gap from top to bottom; In the construction step 6), the miniature wedge-shaped drill hammer is hoisted to the top of the pile interval by a steel wire rope, and after the outer side surface is tightly fitted with the inner wall of the casing, the steel wire rope is released. Under the action of gravity, the miniature wedge-shaped drill hammer is embedded into the pile interval from top to bottom.

9. The method for removing bored piles and protecting bridge foundations in the shield tunneling area under a viaduct as claimed in claim 8, characterized in that: The miniature wedge drill hammer comprises a plurality of steel plates, the plurality of steel plates being welded to each other, the outer end surfaces of the steel plates being formed with abutment surfaces for abutting against the inner side wall of the casing, the abutment surfaces of the plurality of steel plates being combined to form the outer side surface, and the abutment surfaces being provided with elastic counter-pressure ridges; In the construction step 4), when the micro-wedge drill hammer is embedded into the pile cap gap under the action of gravity, the micro-wedge drill hammer is pressed by the old pile cap, the counter-pressure rib is compressed, and under the action of elastic force, the inner surface of the micro-wedge drill hammer is pressed against the outer periphery of the old pile cap; In the construction step 6), when the micro wedge-shaped drill hammer is embedded into the pile interval under the action of gravity, the micro wedge-shaped drill hammer is pressed by the old pile, the counter-pressure rib is compressed, and under the action of elastic force, the inner surface of the micro wedge-shaped drill hammer is pressed against the outer periphery of the old pile.

10. The method for removing bored piles and protecting bridge foundations in the shield tunneling area under an elevated bridge as claimed in claim 9, characterized in that: The inner end surface of the steel plate is formed with an inclined surface, and along the direction from top to bottom, the inclined surface is arranged to extend obliquely toward the abutting surface, and a plurality of the inclined surfaces of the steel plate are combined to form the inner side surface; a through hole is provided in the middle portion of the steel plate, which passes through the steel plate front and back, and the outer end of the through hole passes through the abutting surface, and the inner end of the steel plate passes through the inclined surface; The counter-pressure convex strip has a telescopic section embedded in the through hole; a moving block is provided in the through hole, the inner end of the moving block is connected to the outer end of the telescopic section, the outer end of the moving block is provided with a pressing cutter head arranged toward the inclined surface, and the upper and lower ends of the moving block are provided with outwardly protruding protrusions; two guide rails are provided in the through hole, and a spring for driving the moving block to return is provided in the guide rail, the inner end of the spring is fixedly arranged, and the outer end of the spring presses against the protrusion; In the construction step 4), after the miniature wedge-shaped drill hammer is embedded into the pile cap gap under the action of gravity, the counter-pressure convex strip is squeezed by the inner side wall of the casing, the counter-pressure convex strip is compressed, and the telescopic section deforms and extends toward the inclined surface, driving the moving block to move toward the inclined surface, and the convex block compresses the spring until the pressing cutter head presses against the old pile cap; In the construction step 6), after the miniature wedge-shaped drill hammer is embedded into the pile interval under the action of gravity, the counter-pressure convex strip is squeezed by the inner side wall of the casing, the counter-pressure convex strip is compressed, and the telescopic section deforms and extends toward the inclined surface, driving the moving block to move toward the inclined surface, and the convex block compresses the spring until the pressing cutter head presses against the old pile; When the miniature wedge-shaped drill hammer is taken out from the base gap or pile gap, under the action of elastic force, the spring pressing protrusion moves toward the abutment surface, the moving block squeezes the telescopic section to deform and shorten, the pressing cutter head moves into the through hole, and the counter-pressure protrusion expands and deforms outward.

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