Large-span whole-span dismantling method for prestressed continuous cast-in-place box girder

Abstract

The invention belongs to the technical field of bridge demolition, and particularly relates to a large-span whole-span demolition method for a prestressed continuous cast-in-place box girder, which comprises the following steps of: 1, foundation treatment: lofting a steel pipe support position on an expanded foundation, leveling the foundation at a mounting position by using epoxy mortar, and ensuring that the horizontal position error is not greater than 1cm and the elevation error is not greater than 3mm; according to the large-span whole-span dismantling method for the prestressed continuous cast-in-place box girder, by arranging the fixing device, the cutting device can be stably fixed, after a drill bit is driven by a fixing sleeve to rotate and descend at the same time, box girders at the two ends of the box girder needing to be cut can be drilled, and after drilling is conducted to the set depth, through deflection of a pushing block, the cutting device is driven to rotate. When the drill bit rotates, the hole diameter of the position where the drill bit is located can be enlarged, the drill bit is fixed through opening of the pushing block, the drill bit cannot leave the formed hole, and the supporting frame is fixed to the ground or the surface of the box girder.

Description

Technical Field

[0001] The invention relates to the technical field of bridge demolition, and in particular to a method for dismantling a large-span prestressed continuous cast-in-situ box girder. Background Art

[0002] With the rapid development of the economy and society, some bridges have structural problems due to their inability to meet the requirements of existing traffic use or due to backward technology, materials and management levels in their previous construction, and it is necessary to demolish them. To achieve the safe, adaptable, fast, environmentally friendly and economical demolition of box girder bridges under "complex conditions", there are major technical difficulties in "disassembly, lifting and safety control".

[0003] Common demolition methods include blasting demolition and non-blasting demolition. As for the existing non-blasting methods, the better means of concrete decomposition is the hydraulic cutting method. This method is mature, but limited by the suspension and lowering technology, it can only cut the abandoned bridge into small pieces and then lower them. This will incur high cutting costs and is not conducive to saving production. In order to improve economic benefits, it is necessary to cut the concrete bridge into larger demolition units as much as possible. In addition, the existing cutting equipment needs to be manually installed and debugged, which increases the demolition steps and reduces work efficiency. Summary of the invention

[0004] Based on the technical problem that existing cutting equipment requires manual installation and debugging, increases dismantling steps and reduces work efficiency, the present invention proposes a method for dismantling the entire span of a prestressed continuous cast-in-place box girder with a large span.

[0005] The present invention proposes a method for dismantling the entire span of a prestressed continuous cast-in-place box girder with a large span, comprising the following steps: foundation treatment: staking out the steel pipe support position on an enlarged foundation, leveling the foundation of the installation position with epoxy mortar, with a horizontal position error of no more than 1 cm and an elevation error of no more than 3 mm, assembling the lowered steel pipe support segments into place according to the staking out position, adjusting the verticality and the top surface elevation, planting screws on the foundation to fix the steel pipe support segments, tightening the flange nuts, with a top surface elevation difference of less than 10 mm at four points, and a top and bottom verticality of less than 5 mm, hoisting the processed steel main beam to the top of the support, locking the main beam and the distribution beam with high-strength bolts, with a top surface elevation difference of less than 5 mm.

[0006] Step 2: Installation of the lower system: hoist the spliced ​​Bailey longitudinal beam to the top of the main beam, lock the longitudinal beam and the main beam with angle steel and high-strength bolts, the elevation difference between the top surfaces at both ends of the same longitudinal beam should be less than 5mm, hoist the jack and distribution beam to the main beam and the longitudinal beam, fix them with high-strength bolts, thread the steel strands, number the steel strands before threading, and thread them in sequence to avoid twisting. The steel strands are threaded from bottom to top in the order of the shoulder beam anchor plate, shoulder beam and the lifting hole at the bottom of the box beam, the lifting hole at the top of the box beam, the lower anchor plate of the jack, and the upper anchor plate. Pretighten a single steel strand to 30% of the designed lifting force.

[0007] Step 3: Cut the box girder wing panels and guardrails, and use a long-handled oxygen cutting saw to cut off the steel strands.

[0008] Step 4: After installing the cutting equipment, cut the box girder.

[0009] Step 5: When lowering the large section box girder in the middle of the span, use continuous jacks on the main beams at both ends of the box girder to lift the beam section and slowly and continuously lower it to the bottom of the bridge.

[0010] Preferably, the cutting equipment in step 4 comprises a supporting frame, a fixing device, an adjusting device and a cutting device.

[0011] The fixing device is located on the outer surface of the support frame and automatically fixes the support frame to the box beam. The fixing device includes a lifting mechanism, a fixing mechanism, a driving mechanism and a self-locking mechanism. The lifting mechanism includes a lifting frame. The lifting and lowering of the lifting frame drives the fixing mechanism, the driving mechanism and the automatic mechanism to lift and lower. The fixing mechanism includes a fixing block. The deflection of the fixing block fixes the support frame to the box beam. The driving mechanism includes a transmission gear. The rotation of the transmission gear drives the fixing mechanism to rotate. The self-locking mechanism includes a friction block. The movement of the friction block self-locks the fixing mechanism.

[0012] The adjusting device is located on the outer surface of the supporting frame and moves the cutting device. The adjusting device includes an adjusting mechanism and a moving mechanism. The adjusting mechanism includes an adjusting screw. The rotation of the adjusting screw drives the moving mechanism to move. The moving mechanism includes a moving screw. The rotation of the moving screw drives the cutting device to rise and fall.

[0013] The cutting device is located on the outer surface of the adjusting device, and the cutting device comprises a wire saw, and the saw wire of the wire saw moves back and forth to cut the box beam.

[0014] Preferably, the lifting mechanism further comprises a fixing frame, the fixing frame is fixedly mounted on the outer surface of the supporting frame, a lifting hydraulic cylinder is fixedly mounted on the outer surface of the fixing frame, and one end of the piston rod of the lifting hydraulic cylinder is fixedly mounted on the outer surface of the lifting frame.

[0015] Through the above technical solution, the lifting frame can be pushed up and down by the lifting hydraulic cylinder, which is convenient for pushing the fixing device to be lifted up and down, thereby achieving fixation between the support frame and the ground or the box beam.

[0016] Preferably, the fixing mechanism also includes a fixing sleeve with a gear, the fixing sleeve is rotatably connected to the outer surface of the lifting frame through a bearing, the outer surface of the lifting frame is rotatably connected to a transmission gear through a bearing, the transmission gear is meshed with a gear of the fixing sleeve, a drill bit is fixedly installed on the lower end of the fixing sleeve, the inner wall of the drill bit is hinged to one end of the fixing block through a pin shaft, a fixing connecting rod is hinged to the outer surface of the fixing block through a pin shaft, one end of the fixing connecting rod is hinged to a pushing block through a pin shaft, the upper surface of the pushing block is rotatably connected to a pushing rod with a rack through a bearing, and one end of the pushing rod is slidably plugged into the outer surface of the lifting frame.

[0017] Through the above technical scheme, after the drill bit is driven to rotate and descend by the fixed casing, holes can be drilled on the box beams at both ends of the box beam that need to be cut. After drilling to the set depth, the aperture of the drill bit position can be expanded when the drill bit rotates by deflecting the push block. The drill bit is fixed by expanding the push block, and the drill bit cannot leave the opened hole, so the support frame is fixed to the ground or the surface of the box beam.

[0018] Preferably, the driving mechanism includes a driving motor, the driving motor is fixedly mounted on the outer surface of the lifting frame, one end of the output shaft of the driving motor is fixedly mounted on the inner wall of the transmission gear, the transmission gear is meshed with the gear of the fixed sleeve, and a driving electromagnet is fixedly mounted on one end of the output shaft of the driving motor, and the outer surface of the driving electromagnet is magnetically connected to the outer surface of the transmission gear.

[0019] Through the above technical solution, the driving motor can drive the transmission gear to rotate, and the transmission gear drives the gear of the fixed sleeve to rotate. Through the transmission of multiple transmission gears, multiple fixed sleeves can be driven to rotate synchronously in the same direction. After the driving electromagnet is energized, the transmission gear and the gear of the fixed sleeve can be released from meshing.

[0020] Preferably, the outer surface of the lifting frame is rotatably connected to a transmission rod with a gear through a bearing, the gear of the transmission rod is meshed with the rack of the pushing rod, the outer surface of the lifting frame is rotatably connected to a worm with a bevel gear through a bearing seat, a worm wheel is fixedly mounted on one end of the output shaft of the driving motor, the worm wheel is meshed with the worm, a switching electromagnet is fixedly mounted on one end of the transmission rod, a switching bevel gear with a spring is slidably inserted on one end of the transmission rod, the switching bevel gear is meshed with the bevel gear of the worm, and the outer surface of the switching electromagnet is meshed with the outer surface of the switching bevel gear.

[0021] Through the above technical solution, the transmission rod is rotated to push the rod to rise and fall, the worm can be rotated under the drive of the driving motor, and the transmission rod can be driven to rotate by the bevel gear of the transmission rod. After the switching electromagnet on the transmission rod is energized, the engagement between the switching bevel gear and the bevel gear of the worm can be released.

[0022] Preferably, a fixed clamp block is fixedly installed on the outer surface of the lifting frame, the outer surface of the transmission rod contacts the inner wall of the fixed clamp block, the outer surface of the fixed clamp block is hinged with a self-locking link through a pin shaft, one end of the self-locking link is hinged to one end of the friction block through an intermediate end, one end of the self-locking link is hinged to a connecting push handle through a pin shaft, one end of the connecting push handle is hinged to a connecting rod through a pin shaft, one end of the connecting link is hinged to one end of the fixed clamp block through a pin shaft, and one end of the connecting push handle is rotatably connected to the outer surface of the switching bevel gear through a bearing.

[0023] Through the above technical scheme, the switching bevel gear moves after the switching bevel gear is energized, and the connecting push handle can be pulled to move synchronously. After that, the friction block can be pulled to move through the connecting rod and the self-locking connecting rod, the friction block contacts the transmission rod and self-locks the transmission rod to prevent the transmission rod from rotating and affecting the stability of the fixed block.

[0024] The transmission gear of the present invention is a gear selected from the group consisting of a gearbox and a gearbox, wherein the gearbox has two ends connected to the inner wall of the gearbox and a gearbox is connected to the gearbox at two ends respectively.

[0025] Through the above technical scheme, by adjusting the movement of the screw rod, the movable block can be driven to move in the limit groove body, so that the position of the cutting device can be adjusted accordingly according to the width of the box beam to be cut. An adjusting motor can drive the rotation of the limit rod and the adjusting screw rod. The adjusting gear can move under the magnetic connection of the adjusting electromagnet to change the position of the adjusting gear, realize the engagement with the gears at different positions on the adjusting screw rod or the limit rod, and complete the switching of the drive of the adjusting screw rod and the limit rod. At the same time, the limit rod can limit the movable block.

[0026] Preferably, the moving mechanism also includes a moving trough body, which is fixedly mounted on one end of the moving block, and both ends of the moving screw rod are rotatably connected to the inner wall of the moving trough body through bearings, and the lower surface of the moving block is rotatably connected to a transmission shaft through a bearing, and one end of the transmission shaft drives the rotation of the moving screw rod through the cooperation of a synchronous belt and a synchronous wheel, and the outer surface of the transmission shaft is rotatably connected to a connecting frame with a bevel gear through a bearing, and a moving bevel gear is fixedly mounted on the outer surface of the transmission shaft, and the bevel gear of the connecting frame is meshed with the moving bevel gear.

[0027] Through the above technical scheme, the rotation of the limiting rod can drive the rotation of the movable screw rod, and one end of the transmission shaft can mesh with the bevel gear on the connecting frame through the movable bevel gear. The bevel gear on the connecting frame and the limiting rod are slidably connected, thereby driving the bevel gear on the connecting frame to rotate, thereby driving the rotation of the transmission shaft, thereby driving the rotation of the movable screw rod. The bevel gear on the connecting frame and the limiting rod are connected, which does not affect the movement of the movable trough body. The position of the cutting device can be adjusted by rotating the movable screw rod, which is convenient for adjusting the tension of the cutting device during the cutting process.

[0028] Preferably, the cutting device further comprises a movable frame, the movable frame is slidably inserted into the inner wall of the movable trough body, the inner wall of the movable frame is threadedly connected to the outer surface of the movable screw rod, and the wire saw is fixedly mounted on the outer surface of the movable frame.

[0029] Through the above technical solution, the box beam can be cut by driving the saw wire back and forth through the driving components of the wire saw on the movable frames on both sides.

[0030] The beneficial effects of the present invention are:

[0031] 1. By setting a fixing device, the cutting device can be stably fixed. By driving the drill bit to rotate and descend through the fixing casing, holes can be drilled on the box beams at both ends of the box beam to be cut. After drilling to a set depth, the aperture of the drill bit can be expanded when the drill bit rotates by deflecting the push block. The drill bit is fixed by expanding the push block so that the drill bit cannot leave the opened hole. The support frame is fixed to the ground or the surface of the box beam, so that the cutting equipment can be automatically fixed, reducing labor input and solving the technical problems that the existing cutting equipment needs to be manually installed, increasing the dismantling steps and reducing the work efficiency.

[0032] 2. By setting a self-locking mechanism, the stability of the push rod can be increased. The bevel gear is switched and moved after the switching bevel gear is energized. The connecting push handle can be pulled to move synchronously. The friction block can be pulled to move by the connecting rod and the self-locking rod. The friction block contacts the transmission rod and self-locks the transmission rod to prevent the transmission rod from rotating and affecting the stability of the fixed block, thereby facilitating the stability of the support frame and the ground or box beam.

[0033] 3. By setting an adjusting device, the position of the cutting device can be quickly adjusted. By adjusting the movement of the screw rod, the moving block can be driven to move in the limiting groove body, so that the position of the cutting device can be adjusted accordingly according to the width of the box beam to be cut. An adjusting motor can drive the rotation of the limiting rod and the adjusting screw rod. The adjusting gear can move under the magnetic connection of the adjusting electromagnet to change the position of the adjusting gear, so as to achieve meshing with the gears at different positions on the adjusting screw rod or the limiting rod. The rotation of the limiting rod can drive the rotation of the moving screw rod, and one end of the transmission shaft can mesh with the bevel gear on the connecting frame through the moving bevel gear to drive the rotation of the transmission shaft, thereby driving the rotation of the moving screw rod. The position of the cutting device can be adjusted by rotating the moving screw rod, which is convenient for adjusting the tension of the cutting device during the cutting process, and solves the technical problems that the existing cutting equipment needs to be manually debugged, increases the dismantling steps, and reduces the work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of a method for dismantling a large-span prestressed continuous cast-in-situ box girder provided by the present invention;

[0035] Figure 2 A three-dimensional diagram of a lifting frame structure for a method for dismantling a large-span prestressed continuous cast-in-situ box girder provided by the present invention;

[0036] Figure 3 A three-dimensional diagram of a fixed sleeve structure for a method for dismantling a large-span prestressed continuous cast-in-situ box girder provided by the present invention;

[0037] Figure 4 A three-dimensional diagram of a drill structure for a method for dismantling a large-span prestressed continuous cast-in-situ box girder provided by the present invention;

[0038] Figure 5 A three-dimensional diagram of a push rod structure for a method for dismantling a large-span prestressed continuous cast-in-situ box girder provided by the present invention;

[0039] Figure 6 A three-dimensional diagram of a fixed block structure of a method for dismantling a large-span prestressed continuous cast-in-situ box girder provided by the present invention;

[0040] Figure 7 A three-dimensional diagram of a driving motor structure for a method for dismantling a large-span prestressed continuous cast-in-situ box girder provided by the present invention;

[0041] Figure 8 A three-dimensional diagram of a friction block structure of a method for dismantling a large-span prestressed continuous cast-in-situ box girder provided by the present invention;

[0042] Fig. 9 A three-dimensional diagram of a movable block structure of a method for dismantling a large-span entire-span prestressed continuous cast-in-situ box girder proposed by the present invention;

[0043] Fig.10 A three-dimensional diagram of an adjusting gear structure for a method for dismantling a large-span prestressed continuous cast-in-situ box girder provided by the present invention;

[0044] Fig.11 A three-dimensional diagram of a mobile frame structure for a method for dismantling a large-span prestressed continuous cast-in-situ box girder provided by the present invention;

[0045] Fig.12 A stereoscopic diagram of a movable bevel gear structure for a method for dismantling a large-span entire prestressed continuous cast-in-situ box girder proposed by the present invention.

[0046] In the figure: 1, support frame; 2, fixed frame; 21, lifting hydraulic cylinder; 22, lifting frame; 3, fixed casing; 31, transmission gear; 32, drill bit; 33, fixed block; 34, fixed connecting rod; 35, push block; 36, push rod; 4, drive motor; 41, transmission gear; 42, drive electromagnet; 43, transmission rod; 44, worm; 45, worm wheel; 46, switching electromagnet; 47, switching bevel gear; 5, fixed Clamping block; 51. Self-locking connecting rod; 52. Friction block; 53. Connecting push handle; 54. Connecting connecting rod; 6. Limiting slot; 61. Adjusting screw rod; 62. Moving block; 63. Limiting rod; 64. Adjusting motor; 65. Adjusting gear; 66. Reset spring; 67. Adjusting electromagnet; 7. Moving slot; 71. Moving screw rod; 72. Transmission shaft; 73. Connecting frame; 74. Moving bevel gear; 8. Moving frame; 81. Wire saw. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0048] A method for dismantling the entire span of a prestressed continuous cast-in-place box girder with a large span comprises the following steps: foundation treatment: staking out a steel pipe support position on an enlarged foundation, leveling the foundation of the installation position with epoxy mortar, with a horizontal position error of no more than 1 cm and an elevation error of no more than 3 mm, assembling the lowered steel pipe support segments in place according to the staking out position, adjusting the verticality and the top surface elevation, planting screws on the foundation to fix the steel pipe support segments, tightening flange nuts, with a top surface elevation difference of less than 10 mm at four points and a verticality of less than 5 mm up and down, hoisting the processed steel main beam to the top of the support, locking the main beam and the distribution beam with high-strength bolts, with a top surface elevation difference of less than 5 mm.

[0049] Step 2: Installation of the lower system: hoist the spliced ​​Bailey longitudinal beam to the top of the main beam, lock the longitudinal beam and the main beam with angle steel and high-strength bolts, the elevation difference between the top surfaces at both ends of the same longitudinal beam should be less than 5mm, hoist the jack and distribution beam to the main beam and the longitudinal beam, fix them with high-strength bolts, thread the steel strands, number the steel strands before threading, and thread them in sequence to avoid twisting. The steel strands are threaded from bottom to top in the order of the shoulder beam anchor plate, shoulder beam and the lifting hole at the bottom of the box beam, the lifting hole at the top of the box beam, the lower anchor plate of the jack, and the upper anchor plate. Pretighten a single steel strand to 30% of the designed lifting force.

[0050] Step 3: Cut the box girder wing panels and guardrails, and use a long-handled oxygen cutting saw to cut off the steel strands.

[0051] Step 4: After installing the cutting equipment, cut the box girder.

[0052] Step 5: When lowering the large section box girder in the middle of the span, use continuous jacks on the main beams at both ends of the box girder to lift the beam section and slowly and continuously lower it to the bottom of the bridge.

[0053] Reference Figure 1-Figure 12 The cutting equipment in step 4 includes a support frame 1, a fixing device, an adjusting device and a cutting device.

[0054] like Figure 2-Figure 8 As shown, in order to quickly fix the support frame 1, the fixing device is located on the outer surface of the support frame 1, and automatically fixes the support frame 1 to the box beam. The fixing device includes a lifting mechanism, a fixing mechanism, a driving mechanism and a self-locking mechanism. The lifting mechanism includes a lifting frame 22. The lifting and lowering of the lifting frame 22 drives the fixing mechanism, the driving mechanism and the automatic mechanism to lift and lower. The fixing mechanism includes a fixing block 33. The deflection of the fixing block 33 fixes the support frame 1 to the box beam. The driving mechanism includes a transmission gear 41. The rotation of the transmission gear 41 drives the fixing mechanism to rotate. The self-locking mechanism includes a friction block 52. The movement of the friction block 52 self-locks the fixing mechanism.

[0055] Specifically, in order to drive the fixing mechanism to automatically descend, the lifting mechanism also includes a fixing frame 2, which is fixedly installed on the outer surface of the supporting frame 1. A lifting hydraulic cylinder 21 is fixedly installed on the outer surface of the fixing frame 2, and one end of the piston rod of the lifting hydraulic cylinder 21 is fixedly installed on the outer surface of the lifting frame 22.

[0056] Specifically, in order to drive the fixing block 33 to fix the support frame 1, the fixing mechanism also includes a fixing sleeve 3 with a gear, the fixing sleeve 3 is rotatably connected to the outer surface of the lifting frame 22 through a bearing, the outer surface of the lifting frame 22 is rotatably connected to a transmission gear 31 through a bearing, the transmission gear 31 is meshed with the gear of the fixing sleeve 3, a drill bit 32 is fixedly installed on the lower end of the fixing sleeve 3, the inner wall of the drill bit 32 is hinged to one end of the fixing block 33 through a pin shaft, the outer surface of the fixing block 33 is hinged to a fixing connecting rod 34 through a pin shaft, one end of the fixing connecting rod 34 is hinged to a pushing block 35 through a pin shaft, the upper surface of the pushing block 35 is rotatably connected to a pushing rod 36 with a rack through a bearing, one end of the pushing rod 36 is slidably plugged into the outer surface of the lifting frame 22.

[0057] Specifically, in order to drive the fixed sleeve 3 to rotate, the driving mechanism includes a driving motor 4, which is fixedly installed on the outer surface of the lifting frame 22, and one end of the output shaft of the driving motor 4 is fixedly installed on the inner wall of the transmission gear 41, and the transmission gear 41 is meshed with the gear of the fixed sleeve 3. A driving electromagnet 42 is fixedly installed on one end of the output shaft of the driving motor 4, and the outer surface of the driving electromagnet 42 is magnetically connected to the outer surface of the transmission gear 41.

[0058] Specifically, in order to drive the push rod 36 to rise and fall, the outer surface of the lifting frame 22 is rotatably connected to a transmission rod 43 with a gear through a bearing, the gear of the transmission rod 43 is meshed with the rack of the push rod 36, and the outer surface of the lifting frame 22 is rotatably connected to a worm 44 with a bevel gear through a bearing seat. A worm gear 45 is fixedly installed on one end of the output shaft of the drive motor 4, and the worm gear 45 is meshed with the worm 44. A switching electromagnet 46 is fixedly installed on one end of the transmission rod 43, and a switching bevel gear 47 with a spring is slidably inserted at one end of the transmission rod 43. The switching bevel gear 47 is meshed with the bevel gear of the worm 44, and the outer surface of the switching electromagnet 46 is meshed with the outer surface of the switching bevel gear 47.

[0059] Specifically, in order to self-lock the transmission rod 43, a fixed clamping block 5 is fixedly installed on the outer surface of the lifting frame 22, the outer surface of the transmission rod 43 contacts the inner wall of the fixed clamping block 5, and the outer surface of the fixed clamping block 5 is hinged with a self-locking connecting rod 51 through a pin shaft, one end of the self-locking connecting rod 51 is hinged to one end of the friction block 52 through the middle end, one end of the self-locking connecting rod 51 is hinged to a connecting push handle 53 through a pin shaft, one end of the connecting push handle 53 is hinged to a connecting connecting rod 54 through a pin shaft, one end of the connecting connecting rod 54 is hinged to one end of the fixed clamping block 5 through a pin shaft, and one end of the connecting push handle 53 is rotatably connected to the outer surface of the switching bevel gear 47 through a bearing.

[0060] like Figure 9-12 As shown, in order to adjust the position of the cutting device, the adjusting device is located on the outer surface of the support frame 1 and moves the cutting device. The adjusting device includes an adjusting mechanism and a moving mechanism. The adjusting mechanism includes an adjusting screw rod 61. The rotation of the adjusting screw rod 61 drives the moving mechanism to move. The moving mechanism includes a moving screw rod 71. The rotation of the moving screw rod 71 drives the cutting device to rise and fall.

[0061] In order to adjust the position of the cutting device, the adjusting mechanism includes a limit groove body 6, which is fixedly installed on the outer surface of the support frame 1, and a moving block 62 is slidably inserted into the inner wall of the limit groove body 6. The inner wall of the limit groove body 6 is rotatably connected to an adjusting screw rod 61 with a gear through a bearing, and the two ends of the adjusting screw rod 61 are respectively threadedly connected to the inner walls of the two moving blocks 62. The inner wall of the limit groove body 6 is rotatably connected to a limit rod 63 with a gear through a bearing, and the two ends of the limit rod 63 are respectively slidably inserted into the inner walls of the two moving blocks 62. An adjusting motor 64 is fixedly installed on the inner wall of the body 6, and an adjusting gear 65 is slidably inserted at one end of the output shaft of the adjusting motor 64. After moving, the adjusting gear 65 meshes with the gear of the limit rod 63 and the gear of the adjusting screw rod 61 respectively. A return spring 66 is fixedly installed on the outer surface of the adjusting gear 65, and one end of the return spring 66 is fixedly installed on one end of the output shaft of the adjusting motor 64. An adjusting electromagnet 67 is fixedly installed on one end of the output shaft of the adjusting motor 64, and the outer surface of the adjusting electromagnet 67 is magnetically connected to the outer surface of the adjusting gear 65.

[0062] Specifically, in order to drive the cutting device to rise and fall, the moving mechanism also includes a moving trough body 7, which is fixedly mounted at one end of the moving block 62, and both ends of the moving screw rod 71 are rotatably connected to the inner wall of the moving trough body 7 through bearings. The lower surface of the moving block 62 is rotatably connected to a transmission shaft 72 through a bearing, and one end of the transmission shaft 72 drives the rotation of the moving screw rod 71 through the cooperation of a synchronous belt and a synchronous wheel. The outer surface of the transmission shaft 72 is rotatably connected to a connecting frame 73 with a bevel gear through a bearing, and a moving bevel gear 74 is fixedly mounted on the outer surface of the transmission shaft 72, and the bevel gear of the connecting frame 73 is meshed with the moving bevel gear 74.

[0063] like Fig. 9 As shown, in order to cut the box beam, a cutting device is located on the outer surface of the adjusting device, and the cutting device includes a wire saw 81, and the saw wire of the wire saw 81 moves back and forth to cut the box beam.

[0064] Specifically, in order to drive the wire saw 81 to rise and fall, the cutting device also includes a moving frame 8, which is slidably inserted into the inner wall of the moving trough 7, the inner wall of the moving frame 8 is threadedly connected to the outer surface of the moving screw rod 71, and the wire saw 81 is fixedly installed on the outer surface of the moving frame 8.

[0065] Working principle: In order to cut the box beam, the support frame 1 is moved to the two ends of the uncut box beam of the cutting box beam, and the lifting frame 22 is pushed down by the lifting hydraulic cylinder 21. At the same time, the driving motor 4 is started to drive the transmission gear 41 to rotate. After the transmission gear 41 drives the gear of the fixed sleeve 3 to rotate, it can drive the fixed sleeve 3 to rotate through the transmission of the transmission gear 31. The fixed sleeve 3 drives the drill bit 32 to rotate and then descends to drill the ground. After drilling a certain depth, the switching electromagnet 46 is powered off to release the adsorption of the switching bevel gear 47. After the switching bevel gear 47 is reset under the action of the spring, it and the worm 44 After the bevel gear of the drill bit 32 is meshed, the switching bevel gear 47 is driven to rotate, thereby driving the transmission rod 43 to rotate. After the gear on the transmission rod 43 is meshed with the rack of the push rod 36, the push rod 36 is driven to descend, and the push block 35 is lowered. After the fixed link 34 is driven to deflect, the fixed link 34 pushes the fixed block 33 to move out of the drill bit 32. The rotation of the drill bit 32 drives the fixed block 33 to rotate, so that the fixed block 33 can grind the concrete around the drill bit 32 and expand the hole opened by the drill bit 32, so that the drill bit 32 is fixed in the concrete through the expanded fixed block 33, and the support frame 1 is fixed;

[0066] At the same time, after the switching electromagnet 46 is powered off, the adsorption of the switching bevel gear 47 is released, and the movement of the switching bevel gear 47 pushes the connecting push handle 53, and the connecting push pushes the friction block 52 to move through the connecting rod 54 and the self-locking connecting rod 51, and the self-locking of the transmission rod 43 is released, and the transmission rod 43 can rotate;

[0067] The adjusting screw rod 61 in the limit groove body 6 is driven by the adjusting motor 64 to drive the adjusting gear 65 to rotate, and the adjusting gear 65 drives the adjusting screw rod 61 to rotate, and drives the moving block 62 which is slidably plugged with the limit groove body 6 to move. After the moving block 62 drives the wire saw 81 to move to a suitable position, the power is cut off by adjusting the electromagnet 67 so that the adjusting motor 64 can mesh with the gear on the limit rod 63, and drive the limit rod 63 to rotate. The limit rod 63 drives the bevel gear on the connecting frame 73 to rotate, drives the moving bevel gear 74 to rotate, and drives the transmission shaft 72 to rotate. The rotating shaft can drive the moving screw rod 71 in the moving groove body 7 to rotate through the transmission of the synchronous belt and the synchronous wheel, and adjust the position of the moving frame 8, thereby adjusting the position of the wire saw 81. The wire saw 81 is started to cut the box beam, and the cut box beam is fixed by the lower system and then moved down.

[0068] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for dismantling a large-span prestressed continuous cast-in-place box girder, characterized in that: The process includes the following steps: foundation treatment: staking out the steel pipe support position on the expanded foundation, leveling the foundation of the installation position with epoxy mortar, with the horizontal position error not greater than 1cm and the elevation error not greater than 3mm, assembling the lowered steel pipe support segments in place according to the staking out position, adjusting the verticality and top surface elevation, planting screws on the foundation to fix the steel pipe support segments, tightening the flange nuts, with the top surface elevation difference of four points less than 10mm and the verticality less than 5mm, hoisting the processed steel main beam to the top of the support, locking the main beam and the distribution beam with high-strength bolts, with the top surface elevation difference of the main beam less than 5mm; Step 2: Installation of the lower system: hoist the spliced ​​Bailey longitudinal beam to the top of the main beam, and lock the longitudinal beam and the main beam with angle steel and high-strength bolts. The elevation difference between the top surfaces of the two ends of the same longitudinal beam should be less than 5mm. Hoist the jack and the distribution beam to the main beam and the longitudinal beam, fix them with high-strength bolts, and thread the steel strands. Number the steel strands before threading, and thread them in sequence to avoid twisting. The steel strands are threaded from bottom to top in the order of the shoulder beam anchor plate, shoulder beam, and the bottom lifting hole of the box beam, the top lifting hole of the box beam, the lower anchor plate of the jack, and the upper anchor plate. Pretighten the single steel strand to 30% of the designed lifting force; Step 3: Cut the box girder wing slab and guardrail, and use a long-handled oxygen-cutting saw to cut off the steel strands; Step 4: After installing the cutting equipment, cut the box beam; Step 5: When lowering the large section box girder in the middle of the span, use continuous jacks on the main beams at both ends of the box girder to lift the beam section and slowly and continuously lower it to the bottom of the bridge.

2. A method for dismantling a large-span prestressed continuous cast-in-situ box girder according to claim 1, characterized in that: The cutting device in step 4 comprises a support frame (1), a fixing device, an adjusting device and a cutting device; The fixing device is located on the outer surface of the support frame (1) and automatically fixes the support frame (1) and the box beam. The fixing device comprises a lifting mechanism, a fixing mechanism, a driving mechanism and a self-locking mechanism. The lifting mechanism comprises a lifting frame (22). The lifting and lowering of the lifting frame (22) drives the fixing mechanism, the driving mechanism and the automatic mechanism to lift and lower. The fixing mechanism comprises a fixing block (33). The deflection of the fixing block (33) fixes the support frame (1) and the box beam. The driving mechanism comprises a transmission gear (41). The rotation of the transmission gear (41) drives the fixing mechanism to rotate. The self-locking mechanism comprises a friction block (52). The movement of the friction block (52) self-locks the fixing mechanism. The adjusting device is located on the outer surface of the support frame (1) and moves the cutting device. The adjusting device comprises an adjusting mechanism and a moving mechanism. The adjusting mechanism comprises an adjusting screw rod (61). The rotation of the adjusting screw rod (61) drives the moving mechanism to move. The moving mechanism comprises a moving screw rod (71). The rotation of the moving screw rod (71) drives the cutting device to move up and down. The cutting device is located on the outer surface of the adjusting device, and the cutting device comprises a wire saw (81). The saw wire of the wire saw (81) moves back and forth to cut the box beam.

3. A method for dismantling a large-span prestressed continuous cast-in-situ box girder according to claim 2, characterized in that: The lifting mechanism further comprises a fixing frame (2), wherein the fixing frame (2) is fixedly mounted on the outer surface of the supporting frame (1), a lifting hydraulic cylinder (21) is fixedly mounted on the outer surface of the fixing frame (2), and one end of the piston rod of the lifting hydraulic cylinder (21) is fixedly mounted on the outer surface of the lifting frame (22).

4. A method for dismantling a large-span prestressed continuous cast-in-situ box girder according to claim 2, characterized in that: The fixing mechanism further comprises a fixing sleeve (3) with a gear, the fixing sleeve (3) is rotatably connected to the outer surface of the lifting frame (22) through a bearing, the outer surface of the lifting frame (22) is rotatably connected to a transmission gear (31) through a bearing, the transmission gear (31) is meshed with the gear of the fixing sleeve (3), a drill bit (32) is fixedly installed at the lower end of the fixing sleeve (3), the inner wall of the drill bit (32) is hinged to one end of the fixing block (33) through a pin shaft, the outer surface of the fixing block (33) is hinged to a fixing connecting rod (34) through a pin shaft, one end of the fixing connecting rod (34) is hinged to a pushing block (35) through a pin shaft, the upper surface of the pushing block (35) is rotatably connected to a pushing rod (36) with a rack through a bearing, one end of the pushing rod (36) is slidably plugged into the outer surface of the lifting frame (22).

5. A method for dismantling a large-span prestressed continuous cast-in-situ box girder according to claim 4, characterized in that: The driving mechanism comprises a driving motor (4), the driving motor (4) being fixedly mounted on the outer surface of the lifting frame (22), one end of the output shaft of the driving motor (4) being fixedly mounted on the inner wall of the transmission gear (41), the transmission gear (41) being meshed with the gear of the fixed sleeve (3), and a driving electromagnet (42) being fixedly mounted on one end of the output shaft of the driving motor (4), the outer surface of the driving electromagnet (42) being magnetically connected to the outer surface of the transmission gear (41).

6. A method for dismantling a large-span prestressed continuous cast-in-situ box girder according to claim 5, characterized in that: The outer surface of the lifting frame (22) is rotatably connected to a transmission rod (43) with a gear through a bearing, and the gear of the transmission rod (43) meshes with the rack of the pushing rod (36). The outer surface of the lifting frame (22) is rotatably connected to a worm (44) with a bevel gear through a bearing seat. A worm wheel (45) is fixedly installed at one end of the output shaft of the driving motor (4), and the worm wheel (45) meshes with the worm (44). A switching electromagnet (46) is fixedly installed at one end of the transmission rod (43). A switching bevel gear (47) with a spring is slidably inserted at one end of the transmission rod (43), and the switching bevel gear (47) meshes with the bevel gear of the worm (44). The outer surface of the switching electromagnet (46) meshes with the outer surface of the switching bevel gear (47).

7. A method for dismantling a large-span prestressed continuous cast-in-situ box girder according to claim 6, characterized in that: A fixed clamping block (5) is fixedly mounted on the outer surface of the lifting frame (22); the outer surface of the transmission rod (43) contacts the inner wall of the fixed clamping block (5); the outer surface of the fixed clamping block (5) is hinged with a self-locking connecting rod (51) via a pin shaft; one end of the self-locking connecting rod (51) is hinged with one end of the friction block (52) via an intermediate end; one end of the self-locking connecting rod (51) is hinged with a connecting push handle (53) via a pin shaft; one end of the connecting push handle (53) is hinged with a connecting connecting rod (54) via a pin shaft; one end of the connecting connecting rod (54) is hinged with one end of the fixed clamping block (5) via a pin shaft; one end of the connecting push handle (53) is rotatably connected to the outer surface of the switching bevel gear (47) via a bearing.

8. A method for dismantling a large-span prestressed continuous cast-in-situ box girder according to claim 2, characterized in that: The adjustment mechanism comprises a limit groove body (6), the limit groove body (6) is fixedly mounted on the outer surface of the support frame (1), the inner wall of the limit groove body (6) is slidably plugged with a moving block (62), the inner wall of the limit groove body (6) is rotatably connected to an adjusting screw rod (61) with a gear through a bearing, the two ends of the adjusting screw rod (61) are respectively threadedly connected to the inner walls of the two moving blocks (62), the inner wall of the limit groove body (6) is rotatably connected to a limit rod (63) with a gear through a bearing, the two ends of the limit rod (63) are respectively slidably plugged with the inner walls of the two moving blocks (62), the inner wall of the limit groove body (6) is An adjusting motor (64) is fixedly installed, and an adjusting gear (65) is slidably inserted at one end of the output shaft of the adjusting motor (64). After the adjusting gear (65) moves, it meshes with the gear of the limit rod (63) and the gear of the adjusting screw rod (61) respectively. A return spring (66) is fixedly installed on the outer surface of the adjusting gear (65), and one end of the return spring (66) is fixedly installed on one end of the output shaft of the adjusting motor (64). An adjusting electromagnet (67) is fixedly installed on one end of the output shaft of the adjusting motor (64), and the outer surface of the adjusting electromagnet (67) is magnetically connected to the outer surface of the adjusting gear (65).

9. A method for dismantling a large-span prestressed continuous cast-in-situ box girder according to claim 8, characterized in that: The moving mechanism further comprises a moving groove body (7), wherein the moving groove body (7) is fixedly mounted on one end of the moving block (62), and both ends of the moving screw rod (71) are rotatably connected to the inner wall of the moving groove body (7) via bearings; the lower surface of the moving block (62) is rotatably connected to a transmission shaft (72) via a bearing; one end of the transmission shaft (72) drives the rotation of the moving screw rod (71) via the cooperation of a synchronous belt and a synchronous wheel; the outer surface of the transmission shaft (72) is rotatably connected to a connecting frame (73) with a bevel gear via a bearing; a moving bevel gear (74) is fixedly mounted on the outer surface of the transmission shaft (72), and the bevel gear of the connecting frame (73) meshes with the moving bevel gear (74).

10. A method for dismantling a large-span prestressed continuous cast-in-situ box girder according to claim 9, characterized in that: The cutting device further comprises a movable frame (8), wherein the movable frame (8) is slidably inserted into the inner wall of the movable trough body (7), the inner wall of the movable frame (8) is threadedly connected to the outer surface of the movable lead screw (71), and the wire saw (81) is fixedly mounted on the outer surface of the movable frame (8).

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