1. A shield tunnel segment repairing process is characterized by comprising the following steps:

1) evaluating the deformation of the duct piece; scanning, detecting and collecting evaluation parameters of the inner wall of the tunnel according to a laser scanner and an industrial vision system; the evaluation parameters comprise ovality of the inner wall of the tunnel, dislocation and damaged crack gap measurement;

2) pre-treating; changing pipelines, cutting and chiseling a ballast bed, leveling annular seams, longitudinal seams and hand hole plugging of the segments, keeping the leakage-free surfaces of the segment seams dry, and then polishing and napping;

3) assembling steel plates by a reinforcing device, welding, grouting and spraying;

the reinforcing device comprises an assembling system, a punching system, a welding system, a bottom system, an auxiliary operation platform system, a steel plate ring bracket and an epoxy resin glue barrel; after the steel plate ring is grabbed and installed at a preset position by the assembling system, drilling and installing anchor bolts by the punching system, wherein the screwing depth is more than 125mm, the drilling is reserved as a grouting hole and an exhaust hole from bottom to top in sequence; the welding system welds the seams among a plurality of steel plate rings; the bottom system is integrally moved; after the auxiliary operation platform assists workers to perform pressure injection between the steel plate and the duct piece from the grouting hole, the anchor bolts are installed from the grouting hole and the exhaust hole, and finally the auxiliary operation platform assists the workers to perform spraying of antirust, anticorrosion and fireproof coatings;

4) recovering pipelines and a track bed;

5) and (5) returning and checking.

2. The repair process according to claim 1, wherein the assembling system comprises an assembling robot, one end of the assembling robot is provided with an electric permanent magnetic chuck, an installation scanning and positioning module is fixedly arranged above the electric permanent magnetic chuck, and the bottom of the assembling robot is slidably connected with an assembling robot sliding table.

3. The repair process according to claim 1, wherein the punching system comprises a punching robot, a punching module, an installation module and a screwing module are arranged at one end of the punching robot, a punching robot sliding table is connected to the bottom of the punching robot in a sliding mode, and a punching robot lifting platform is arranged at the bottom of the punching robot sliding table.

4. The repair process according to claim 1, wherein the welding system comprises a welding robot, and one end of the welding robot is provided with a weld scanning and positioning module, a robot arc welding gun and a weld detection module.

5. The repair process of claim 1 wherein the bottom system comprises a multi-track bogie having a bi-directional traction flatbed disposed on top of the multi-track bogie and a balance leg disposed on the bottom of the multi-track bogie.

6. The repair process according to claim 1, wherein the auxiliary work platform system comprises an auxiliary work platform, wherein an equipment control cabinet is arranged at the bottom of the auxiliary work platform, and a welding module power supply is arranged on one side of the equipment control cabinet.

7. The repair process of claim 1 wherein one side of said erector robot secures said steel plate ring support for storing said steel plate rings; and an air compressor is arranged on one side of the epoxy resin glue barrel.

8. Repair process according to claim 1, characterized in that the ovality of the inner wall of the tunnel is such thatAnd when the a is more than 20 per thousand, reinforcing the tunnel.

9. The repair process according to claim 1, wherein in the step 2), the ring and the longitudinal seam are drilled obliquely with elastic epoxy slurry under the grouting pressure of not more than 0.2 Mpa.

10. The repair process according to claim 1, wherein in step 3), the joints between the two sides of the steel plate and the segment are sealed by epoxy cement, and epoxy resin is injected between the segment and the injection hole, wherein the pressure is controlled to be 0.1-0.15 Mpa.

Background

The space range of human activities is continuously enlarged, and along with the continuous development of underground space, the subway construction of large and medium-sized cities in China needs to construct a plurality of shield tunnels. In shield construction, shield segments are main assembly members of shield construction, are outermost barriers of a tunnel and play a role in resisting soil layer pressure, underground water pressure and some special loads. As a typical tunnel supporting technology, the assembled reinforced concrete segment is widely applied to the field of shield tunnel supporting due to the advantages of convenient material obtaining, simple manufacturing process, low manufacturing cost, high construction speed, high strength and the like. However, the phenomenon of cracking and damage of the segment lining on the tunnel site sometimes happens, the cracking and damage of the segment can weaken the overall supporting strength of the tunnel lining, and once the control is unfavorable, if the phenomenon of block falling is generated, the fatal threat can be brought to subway operation trains. How to carry out on-site segment lining rapid repair is an important task for guaranteeing tunnel construction and operation safety.

In the prior art, a steel plate ring reinforcing method is mainly adopted for repairing and reinforcing damaged segments of an external shield subway tunnel, steel plate rings are grabbed and installed, seams among a plurality of steel plate rings are welded, a plurality of links such as epoxy resin glue injection and steel plate ring anti-corrosion treatment after segment pretreatment and steel plate ring installation further need manual intervention, and the rapid repair of on-site segment lining cannot be effectively realized.

Therefore, how to provide a shield tunnel segment repair process reduces the manual intervention link, and the processes of once-through steel plate ring installation, positioning and anchoring, integral welding, steel plate glue injection, anti-corrosion treatment and the like reduce the error rate, improve the shield tunnel segment repair efficiency, and shorten the repair time is a technical problem that needs to be solved urgently by technical personnel in the field.

Disclosure of Invention

The invention aims to solve one of the technical problems in the related technology at least to a certain extent, provides a shield tunnel segment repairing process, aims at solving the problems of long construction period, high construction cost, low construction efficiency and great construction difficulty in the prior art, improves the intelligent level and construction efficiency of tunnel construction, and reduces the labor intensity of operators.

In view of the above, a shield tunnel segment repair process is characterized by comprising the following steps:

1) evaluating the deformation of the duct piece; scanning, detecting and collecting evaluation parameters of the inner wall of the tunnel according to a laser scanner and an industrial vision system; the evaluation parameters comprise ovality of the inner wall of the tunnel, dislocation and measurement of damaged crack gaps; determining a reinforcement position according to the scanning result, drawing up a reinforcement scheme, and preparing reinforcement equipment and materials;

2) pre-treating; changing pipelines, cutting and chiseling a ballast bed, plugging and leveling ring, longitudinal joints and hand holes of the pipe pieces, keeping the surfaces of the joints of the pipe pieces free of leakage dry, and then polishing and napping;

3) assembling steel plates by a reinforcing device, welding, grouting and spraying;

the reinforcing device comprises an assembling system, a punching system, a welding system, a bottom system, an auxiliary operation platform system, a steel plate ring bracket and an epoxy resin glue barrel; after the steel plate ring is grabbed and installed at a preset position by the assembling system, drilling holes by the punching system and installing anchor bolts, wherein the screwing depth is more than 125mm, the drilling holes are reserved as a grouting hole and an exhaust hole from bottom to top in sequence; for the duct piece with the bolts as the penetrating bolts due to overlarge staggered joints, the steel plates are installed in a riding joint mode, the joints among a plurality of steel plate rings are welded by a welding system, and the bottom system moves integrally; the joints between the two sides of the steel plate and the segment are plugged by epoxy cement paste, then an auxiliary operation platform assists workers to perform epoxy resin pressure injection between the steel plate and the segment from the grouting hole, anchor bolts are installed at the original grouting hole and the exhaust hole, and finally the auxiliary operation platform assists the workers to perform spraying of antirust, anticorrosive and fireproof coatings;

fixing a steel plate ring in the inner wall of the duct piece in a manner of screwing an anchor bolt through a punching system;

4) recovering pipelines and a track bed;

5) and (5) returning and checking.

The assembly, drilling, anchoring and welding are all operated by robots, and positioning, obstacle detection and path planning are carried out by an intelligent vision system, so that efficient and accurate assembly actions are realized. Hole site recognition is carried out by adopting a visual positioning system in the drilling process, the hole site can be accurately positioned, automatic drilling, material taking, filling and screwing actions are realized, and the operation efficiency is high. Replace manual welding through welding robot, can effectively improve welding efficiency, shorten the activity duration, in addition, the problem of the long time keeping overhead welding posture when also having solved manual welding tunnel top steel sheet welding seam. The whole operation process only needs 2 people to cooperate to accomplish can, personnel's input is reduced by a wide margin, personnel's cost greatly reduced.

Furthermore, the assembling system comprises an assembling robot, an electric permanent magnetic chuck is arranged at one end of the assembling robot, an installation scanning and positioning module is fixedly arranged above the electric permanent magnetic chuck, and an assembling robot sliding table is connected to the bottom of the assembling robot in a sliding mode.

Further, the system of punching includes the punching machine people, and the one end of punching machine people is provided with punching module, installation module, screws up the module, and punching machine people's bottom sliding connection has the punching machine people slip table, and punching machine people slip table's bottom is provided with punching machine people lift platform.

Furthermore, the welding system comprises a welding robot, and one end of the welding robot is provided with a welding seam scanning and positioning module, a robot arc welding gun and a welding seam detection module.

Further, the bottom system comprises a multi-track bogie, a bidirectional traction flat car is arranged at the top of the multi-track bogie, and balance support legs are arranged at the bottom of the multi-track bogie.

Furthermore, the auxiliary operation platform system comprises an auxiliary operation platform, an equipment control cabinet is arranged at the bottom of the auxiliary operation platform, and a welding module power supply is arranged on one side of the equipment control cabinet.

Further, a steel plate ring support is fixed on one side of the assembling robot and used for storing steel plate rings; and an air compressor is arranged on one side of the epoxy resin glue barrel.

Further, the ovality of the inner wall of the tunnel isWhen a is more than 20 per mill or the unidirectional deformation rate is 12 per mill<a1<And reinforcing the tunnel by 20 per mill.

Wherein D_maxIs the maximum outer diameter; d_minIs the minimum outer diameter; d is the nominal outer diameter; a1 is the vertical deformation ratio.

When a is less than 6 per mill, the standard requirement is met, and reinforcement is not performed; 6 per mill < a <12 per mill, if the surrounding rock conditions are good, the structure is stable and can not be reinforced; 12 per mill < a <20 per mill or 9 per mill < a1<12 per mill of unidirectional deformation rate, and no obvious longitudinal crack and serious breakage; and in the elastic stress stage, the influence of the assembling quality of the duct pieces is considered, and weak reinforcement is adopted.

Further, in the step 2), the elastic epoxy grout is injected into the annular and longitudinal seams in an inclined drilling mode under the condition that the grouting pressure is not more than 0.2 Mpa.

Furthermore, in the step 3), the joints between the two sides of the steel plate and the segment are sealed by epoxy cement, epoxy resin is injected between the segment and the grouting holes, and the pressure is controlled to be 0.1-0.15 MPa.

According to the technical scheme, the steel plate rings can be grabbed and installed at the preset positions through the assembling system, after the steel plate rings are initially installed in place, the steel plate rings are fixed through the punching system through punching and installing anchor bolts, the welding system can weld joints among a plurality of steel plate rings, so that the steel plate rings in the tunnel are integrally fixed, the bottom system can ensure the overall operation and working stability of the device, the auxiliary operation platform can assist workers, the assembling system can realize automation and intellectualization of grabbing and installing processes of the steel plate rings, the installation positions and the steel plate rings are scanned firstly, the electric permanent magnetic chucks are aligned to the pre-installation positions after the electric permanent magnetic chucks are grabbed through the electric permanent magnetic discs, the initial installation of the steel plate rings is completed, and by adopting the device, the grabbing and installing processes of the steel plate rings in the shield tunnel can be realized, and the punching system punches holes, The anchor bolt is installed and tightened, and the welding system welds the seam between the steel plate rings, so that automation and intellectualization can be realized, and the labor cost is reduced.

Drawings

The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic structural view of a reinforcing apparatus provided in the present invention.

Figure 2 is an isometric view of a reinforcement device provided by the present invention.

Fig. 3 is a schematic structural diagram of the splicing system provided by the present invention.

Fig. 4 is a schematic structural diagram of a welding system provided by the present invention.

Fig. 5 is a schematic structural diagram of the punching system provided by the present invention.

Fig. 6 is a schematic structural view of the anchor bolt continuous feeding assembly provided by the invention.

Fig. 7 is a schematic structural view of a feeding gripper assembly provided by the present invention.

Fig. 8 is a schematic structural view of a steel plate ring support provided by the present invention.

Wherein 1-epoxy resin glue barrel; 2-an air compressor; 3-a perforating robot sliding table; 4-a punching robot; 5-assembling the robot; 6-welding a robot sliding table; 7-a welding robot; 8-an auxiliary work platform; 9-equipment control cabinet; 10-welding module power supply; 11-a welding robot lifting platform; 12-steel plate ring support; 1201-support base, 1202-storage rack bottom plate, 1203-limiting block and 13-assembling robot sliding table; 14-a balance leg; 15-a punching robot lifting platform; 16-a multi-track bogie; 17-bidirectional traction flatbed; 18-installing a scanning positioning module; 19-electric permanent magnetic chuck; 20-a welding seam scanning and positioning module; 21-a robotic arc welding torch; 22-a punching module; 23-installing a module; 24-screwing the module; 25-anchor bolt continuous feeding assembly, 2501-socket, 2502-backing plate, 2503-anchor bolt fixing frame, 2504-socket plate, 2505-anchor bolt, 26-feeding gripper assembly, 2601-first air cylinder, 2602-first air cylinder mounting seat, 2603-second air cylinder, 2604-second air cylinder mounting seat, 2605-third air cylinder, 2606-third air cylinder mounting seat and 2607-gripper assembly.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

Example 1

A shield tunnel segment repairing process is characterized by comprising the following steps:

1) evaluating the deformation of the duct piece; scanning, detecting and collecting evaluation parameters of the inner wall of the tunnel according to a laser scanner and an industrial vision system; the evaluation parameters comprise ovality of the inner wall of the tunnel, dislocation and measurement of damaged crack gaps; determining a reinforcement position according to the scanning result, drawing up a reinforcement scheme, and preparing reinforcement equipment and materials;

ovality of tunnel inner wall ofWhen a is more than 20 per mill or the unidirectional deformation rate is 12 per mill<a1<Reinforcing the tunnel by 20 per mill;

wherein D_maxIs the maximum outer diameter; d_minIs the minimum outer diameter; d is the nominal outer diameter; a1 is the vertical deformation ratio.

When a is less than 6 per mill, the standard requirement is met, and reinforcement is not performed; 6 per mill < a <12 per mill, if the surrounding rock conditions are good, the structure is stable and can not be reinforced; 12 per mill < a <20 per mill or 9 per mill < a1<12 per mill of unidirectional deformation rate, and no obvious longitudinal crack and serious breakage; and in the elastic stress stage, the influence of the assembling quality of the duct pieces is considered, and weak reinforcement is adopted.

2) Pre-treating; and (3) changing the pipeline, cutting and chiseling the ballast bed, leveling the ring, the longitudinal joint and the hand hole plugging of the pipe piece, keeping the leakage-free surface of the pipe piece joint dry, polishing and roughening, wherein the elastic epoxy grout is obliquely drilled and injected into the middle ring and the longitudinal joint under the condition that the grouting pressure is not more than 0.2 Mpa.

In the pretreatment, pipeline changing is firstly carried out, a ballast bed is cut and chiseled, then, the oblique drilling holes of the pipe piece rings and the longitudinal joints are injected with elastic epoxy slurry, then, the pipe piece damage repair and the staggered repair are carried out, the post-grouting of the pipe piece walls is carried out to fill the holes and stop water, then, the bolt hand holes and the longitudinal joints of the pipe pieces are plugged by anti-crack mortar, and finally, after the surface of the joints of the pipe pieces is kept to be free of leakage and dry, the inner walls are polished and napped by a grinding machine.

The method comprises the following steps of:

first water-impermeable fracture: injecting elastic epoxy resin slurry and epoxy adhesive by adopting the pressure in the crack;

second type infiltration crack: firstly, pouring double-liquid slurry into a secondary grouting hole, then using oil polyurethane to perform local leakage stoppage, and finally sealing by using elastic epoxy resin slurry and epoxy adhesive;

the third one is not more than 0.2m²Partial breakage of (2): when the steel bar does not exceed the steel bar protective layer, high-strength epoxy mortar is used for repairing and sealing;

fourth is greater than 0.2m²Partial breakage of (2): and (4) repairing by using high-strength epoxy mortar, embedding a grouting pipe, and injecting elastic epoxy slurry into the grouting pipe.

In the pretreatment process, if the slab staggering is not more than 2cm, high-strength epoxy resin mortar is adopted for flattening, if the slab staggering is more than 2cm, quincunx bar planting is firstly carried out, and then the high-strength epoxy resin mortar is adopted for flattening.

3) Assembling steel plates by a reinforcing device, welding, grouting and spraying;

the reinforcing device comprises an assembling system, a punching system, a welding system, a bottom system, an auxiliary operation platform system and a steel plate ring support 12.

The system of assembling is including assembling robot 5, the one end of assembling robot 5 is provided with electric permanent magnetism sucking disc 19, the fixed installation scanning orientation module 18 that is provided with in top of electric permanent magnetism sucking disc 19, the bottom sliding connection who assembles robot 5 has and assembles robot slip table 13, the system of assembling is including assembling robot 5, the one end of assembling robot 5 is provided with electric permanent magnetism sucking disc 19, the fixed installation scanning orientation module 18 that is provided with in top of electric permanent magnetism sucking disc 19, the bottom sliding connection who assembles robot 5 has and assembles robot slip table 13. One side of the assembling robot 5 is fixedly provided with a steel plate ring bracket 12 for storing steel plate rings. The plate ring storage rack comprises a support base 1201, a storage rack bottom plate 1202 is arranged above the support base 1201, two limiting blocks 1203 are symmetrically arranged on the storage rack bottom plate 1202, each limiting block 1203 comprises four limiting blocks 1203, arc-shaped structures are arranged on the four limiting blocks 1203, the radian of the arc-shaped structures of the four limiting blocks 1203 is identical to the radian of a placed steel plate ring, the steel plate rings are limited in cooperation, overlapping placement of the steel plate rings can be achieved, and the steel plate rings are prevented from moving along with the bidirectional traction flat car 17 to generate displacement. One side that the robot 4 that punches kept away from and assembles robot 5 is provided with epoxy and glues bucket 1, and one side that epoxy glued bucket 1 is provided with air compressor 2, and air compressor 2 provides atmospheric pressure when being used for section of jurisdiction preliminary treatment, section of jurisdiction injecting glue and the clear hole of commentaries on classics hole, contains epoxy in the epoxy bucket for the welding seam injecting glue after the section of jurisdiction installation welding provides the raw materials.

The auxiliary operation platform system comprises an auxiliary operation platform 8, an equipment control cabinet 9 is arranged at the bottom of the auxiliary operation platform 8, and a welding module power supply 10 is arranged on one side of the equipment control cabinet 9.

The welding system comprises a welding robot 7, a welding robot sliding table 6, a welding robot lifting platform 11, a welding seam scanning and positioning module 20, a robot arc welding gun 21 and a welding seam detection module.

The punching system comprises a punching robot 4, a punching module 22, an installation module 23 and a screwing module 24 are arranged at one end of the punching robot 4, the bottom of the punching robot 4 is connected with a punching robot sliding table 3 in a sliding mode, and a punching robot lifting platform 15 is arranged at the bottom of the punching robot sliding table 3.

The punching system further comprises an anchor bolt continuous feeding assembly 25 and a feeding gripper assembly 26, wherein the anchor bolt continuous feeding assembly 25 comprises a socket 2501, a backing plate 2502, an anchor bolt fixing frame 2503, a socket plate 2504 and a plurality of anchor bolts 2505; wherein, two ends of the backing plate 2502 can be inserted and movably connected below the socket 2501; the anchor bolt fixing frame 2503 is arranged below the backing plate 2502; a plurality of the anchor bolts 2505 are provided on the anchor bolt fixing bracket 2503. The plurality of socket plates 2504 are vertically connected above the socket plate 2501 at one end and are arranged in parallel with the anchor bolts 2505; the anchor bolt fixing frame 2503 is a buckle or a clamping groove in which an electric permanent magnet block is arranged.

The feeding gripper assembly 26 is arranged at one end of the punching robot 4 and comprises a first cylinder mounting seat 2602 provided with a first cylinder 2601, a second cylinder mounting seat 2604 provided with a second cylinder 2603, a third cylinder mounting seat 2606 provided with a third cylinder 2605 and a gripper assembly 2607; wherein the first cylinder mount 2602 is connected with the mobile module; the first cylinder 2601 is connected with the second cylinder mounting block 2604; the second cylinder 2603 is connected to a third cylinder mount 2606; the third cylinder 2605 is connected with the gripper assembly 2607 through a gripper support; the gripper assembly 2607 grips the anchor bolt 2505 on the anchor bolt continuous feeder assembly 25 and aligns the anchor bolt 2505 to the installation module 23. After the gripper assembly 2607 grips the anchor bolt 2505, the third cylinder 2605 retracts to extend the gripper gripping anchor bolt 2505, the second cylinder 2603 and the third cylinder 2605 a suitable distance to avoid collision with other parts when the gripper rotates, the gripper assembly 2607 rotates 180 ° to move the gripper downward, the first cylinder 2601, the second cylinder 2603 and the third cylinder 2605 retract to an adjusted position to align the anchor bolt 2505 on the gripper to the installation module 23, the anchor bolt 2505 is installed in the borehole in cooperation with the installation module 23, and then the nut on the anchor bolt 2505 is tightened by the tightening module 24 to complete the installation of the anchor bolt 2505.

When the anchor bolt 2505 is used for feeding, the base plate 2502 which is movably connected below the socket 2501 in an inserting manner is drawn out, a buckle is fixed on the base plate 2502 in time, and the anchor bolt 2505 is clamped in the bayonet to feed the socket anchor bolt 2505.

The bottom system comprises a multi-track bogie 16, a bidirectional traction flat car 17 is arranged on the top of the multi-track bogie 16, and a balance leg 14 is arranged on the bottom of the multi-track bogie 16.

Wherein the bottom system comprises a bidirectional traction platform 17, a multi-track bogie 16, a balance leg 14 and a brake section. The double-traction flat car 17 is reserved with a bidirectional traction joint so as to ensure that when one end of the traction locomotive breaks down, equipment can be pulled away from the subway rail from the traction joint at the other end in time, and normal subway operation is not influenced. The multi-track bogie 16 can be operated on an operated subway tunnel and can also be operated on a built subway tunnel. The balance supporting legs 14 can be unfolded after the double-traction flat car is in place, so that the anti-overturning capacity of the equipment can be increased, and the stability of the equipment during operation can be ensured; the balance legs 14 can also be aligned with the subway tunnel axis during operation.

The assembling robot 5 positions a steel plate ring mounting position and a steel plate ring position through a mounting scanning positioning module 18, calculates a moving path of the assembling robot 5 through a computer, moves an electric permanent magnetic chuck 19 to one side of a steel plate ring storage rack, grabs the steel plate ring from the steel plate ring storage rack through the electric permanent magnetic chuck 19, adjusts the posture of the steel plate ring through rotation, pitching and other actions of the assembling robot 5, assembles the steel plate ring to a shield tunnel, the punching robot 4 scans and positions a punching position in a scanning mode in cooperation with a vision system, the punching robot 4 punching module 22 punches holes, the mounting module 23 mounts M16 anchor bolts 2505, the screwing module 24 screws the anchor bolts 2505, fixes the steel plate ring on the inner wall of a subway tunnel segment, the screwing depth is more than 125mm, the sequence is from bottom to top, the anchor bolt holes are reserved as a grouting hole and an exhaust hole, and after the mounting operation of the whole ring steel plate ring is completed, the welding robot 7 passes through a robot lifting platform 11, The 7 gestures of welding robot are adjusted to robot slip table 6, and the seam of welding robot 7 scanning orientation module 20 positioning weld position, seam between the welding steel sheet ring, functions such as welding seam searching location, welding seam pursuit, welding seam detection can be realized to the welding system of robot. The bottom system is moved integrally, the auxiliary operation platform 8 assists workers in grouting and steel plate ring corrosion prevention spraying, joints between two sides of a steel plate and a duct piece are plugged by epoxy cement, epoxy resin is injected between a grouting hole and the duct piece in a pressing mode, the pressure is controlled to be 0.1-0.15 Mpa, and finally the auxiliary operation platform assists workers in spraying rust prevention, corrosion prevention and fire-resistant coatings.

4) Recovering pipelines and track beds.

5) And (5) returning and checking.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.