Disassembling method for small-diameter screw machine direct-discharge type slurry shield tunneling machine under gravel stratum

Abstract

The invention discloses a dismounting method for a small-diameter screw machine direct-discharge type slurry shield tunneling machine under a gravel stratum, which comprises the following steps of: firstly, carrying out geological reinforcement, then dismounting the shield tunneling machine, transforming a flat car into a movable lifting point in the dismounting process, conveniently dismounting the shield tunneling machine in a narrow space, reserving a shell and a cutter head of the shield tunneling machine after the shield tunneling machine is dismounted, and blocking the shield tunneling machine. The technical problem that when a small-diameter screw machine direct discharge type slurry shield carries out in-hole shell abandoning and machine dismounting in a gravel unstable stratum, safe and efficient machine dismounting is difficult to achieve due to factors such as stratum instability and underground water invasion is solved. The shield tunneling machine shell and the cutter head serve as permanent supports, the technical problem that in the prior art, potential safety hazards are generated due to the fact that the stratum is not supported for a long time is effectively solved, and then the technical effect of safe and efficient construction is achieved. By installing the hoisting frame on the flat car, the problems that the space in a hole is small and hoisting is difficult are effectively solved, and then efficient construction in a narrow environment is achieved.

Description

Technical Field

[0001] This application relates to the field of tunnel construction technology, specifically to a method for dismantling a small-diameter screw conveyor direct-discharge slurry shield tunneling machine in gravel strata. Background Technology

[0002] Small-diameter screw-type direct-discharge slurry shield tunneling machines are widely used in tunnel construction. Gravelly strata are characterized by loose structure, high permeability, strong fluidity, and low stability. After the shield machine completes its excavation under complex geological conditions, the tunnel face and surrounding soil are highly susceptible to instability and collapse, directly threatening operational safety. Simultaneously, rapid groundwater infiltration, if not properly controlled, can easily lead to water and sand inrush accidents, exacerbating stratum instability. Therefore, the difficulty and risk of dismantling the shield machine inside the tunnel in gravelly strata far exceed those in conventional strata.

[0003] Currently, traditional dismantling techniques in the industry have significant limitations in application to such geological formations. For example, the open-cut method requires excavating large foundation pits, which is costly, time-consuming, and cannot be used in tunnels with great depth or in special areas. While the enlarged-chamber dismantling method avoids surface excavation, it is difficult to control the stability of the underlying layer when excavating in gravel layers, and the grout used for pre-support is easily lost in the loose gravel, resulting in poor reinforcement. In addition, precision excavation is prone to disturbing the shield shell, causing shell deformation or jamming, which poses an extremely high risk.

[0004] Furthermore, the operating space for small-diameter tunnel boring machines (TBMs) is relatively narrow, making it impossible for large equipment to enter. Currently, dismantling operations mainly rely on manual labor and small tools, which is inefficient and prone to component damage. In addition, after the TBM has been excavating through gravel layers, the cutters and shield body suffer severe wear and deformation, making it difficult to conduct accurate condition assessments in harsh environments, thus posing significant safety hazards for dismantling.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the background technology of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] In view of at least one of the above technical problems, this disclosure provides a method for dismantling a small-diameter screw-driven slurry shield tunneling machine in gravel strata, aiming to solve the technical problems of low dismantling efficiency and poor safety of small-diameter screw-driven slurry shield tunneling machines in unstable gravel strata.

[0007] According to one aspect of this disclosure, a method for dismantling a small-diameter screw conveyor direct-discharge slurry shield tunneling machine under gravel strata is provided, comprising the following steps: (1) The tunnel boring machine advances with all articulated cylinders fully extended. When only one ring of segments remains inside the tail of the shield, the machine stops, all the advance cylinders are retracted, and each articulated cylinder is retracted accordingly, and the cutterhead is kept at a certain distance from the front face. (2) Weld anti-reverse steel plates at 6° intervals along the circumferential direction between the segment annular surface and the shield shell, and weld sealing steel plates parallel to the segment annular surface between two adjacent anti-reverse steel plates to seal the gap between the segment and the shield tail. (3) The shield tunneling synchronous grouting is adopted. Cement mortar is used to seal the cutterhead and the front shield, and the shield tail is compacted by grouting through the top advanced grouting hole. At the same time, the connecting valve between the mud-water chamber and the air cushion chamber is opened to fill the mud-water chamber and the air cushion chamber with mortar. (4) Secondary grouting is carried out through the grouting hole of the segment. The grouting material is cement single liquid grout. If necessary, cement-water glass double liquid grout is used for construction. (5) Clean the bottom of the main unit and remove the pipes, walkway slabs, relay pumps, crushers and rear trailers in the tunnel; remove the segment trolley and mud and water pipelines, collect the hydraulic oil after removing the propulsion cylinder and seal it with a plug; (6) Build a mobile hoisting frame and dismantle the screw conveyor using the mobile hoisting frame; fix the lifting lugs at the shield body, and apply prestress to the segment installation machine with the corresponding hand chain hoist before dismantling the segment assembly machine; (7) Set up lifting points and hand-operated hoists at the corresponding positions of the middle shield and the tail shield, stabilize the cross beam in its original position, remove the connecting bolts between the cross beam and the upper and lower bases of the middle shield, and after setting up support plates and flip hinge points at the bottom of the cross beam, tilt and dismantle the cross beam, and then remove the valve group and electrical components inside the shield. (8) Use manual hoists suspended at the lifting points inside the middle shield and tail shield respectively to remove the main drive motor, reducer and slewing center; (9) After stabilizing the personnel chamber, material chamber and air cushion chamber by using the lifting points and hand-operated hoists at the corresponding positions of the shield body, remove the corresponding bolts and nuts, and then gradually pull out the personnel chamber, material chamber and air cushion chamber in sequence by using multiple hand-operated hoists to change hooks. (10) After the main unit’s detachable parts are removed, concrete is used to seal the tail cylinder position. The end segment has a pre-embedded steel plate. After the concrete wall is filled, steel bars are welded from the pre-embedded steel plate position of the segment to the concrete wall. The sealed block is completed by pouring concrete, and the shield machine shell and cutterhead are used as permanent support for the tunnel.

[0008] In some embodiments of this disclosure, in step (3), before reinforcement and grouting, the mud and water pipeline is shut off after the soil inside the chamber is completely cleaned.

[0009] In some embodiments of this disclosure, in step (6), the mobile hoisting frame includes a flatbed truck whose bottom is connected to the locomotive head and an isosceles triangular hoisting frame fixed on the flatbed truck.

[0010] In some embodiments of this disclosure, in step (6), before the segment assembly machine is dismantled, the segment assembly machine is adjusted so that all cylinders are fully retracted and the grabbing head is at its lowest position.

[0011] In some embodiments of this disclosure, in step (8), the main drive motor, reducer, and rotary center are removed sequentially from top to bottom.

[0012] In some embodiments of this disclosure, during step (10), the cutter head and main bearing are retained during disassembly.

[0013] One or more technical solutions provided in the embodiments of this application have at least one of the following technical effects or advantages: 1. By using the shield machine shell and cutterhead as permanent supports, the technical problem of safety hazards caused by the lack of ground support during the time in the existing technology is effectively solved, thereby achieving the technical effect of safe and efficient construction.

[0014] 2. By installing a hoisting frame on a flatbed truck, the problem of limited space inside the tunnel and difficulty in hoisting was effectively solved, thus enabling efficient construction in a confined environment.

[0015] 3. Welding anti-reverse steel plates between the segment annular surface and the shield shell, and welding sealing steel plates between two adjacent anti-reverse steel plates, effectively solves the problem of accidental movement of segments and tunnel boring machines in traditional technology, while sealing the tail gap, thus creating a safer construction environment. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the dismantling method of a small-diameter screw conveyor direct-discharge slurry shield tunneling machine under gravel strata in one embodiment of this application.

[0017] Figure 2 This is a schematic diagram of the installation of the anti-reverse steel plate in one embodiment of this application. Figure 1 .

[0018] Figure 3 This is a schematic diagram of the installation of the anti-reverse steel plate in one embodiment of this application. Figure 2 .

[0019] Figure 4 This is a schematic diagram of the installation of the sealing steel plate in one embodiment of this application. Figure 1 .

[0020] Figure 5 This is a schematic diagram of the installation of the sealing steel plate in one embodiment of this application. Figure 2 .

[0021] Figure 6 This is a schematic diagram of the disassembly of the rear trailer in one embodiment of this application.

[0022] Figure 7 This is a schematic diagram of the structure of a movable hoisting frame in one embodiment of this application.

[0023] Figure 8 This is a schematic diagram of the disassembly of a screw conveyor in one embodiment of this application.

[0024] Figure 9 This is a schematic diagram of the fixed transportation of the segment installation machine in one embodiment of this application.

[0025] Figure 10 This is a schematic diagram of the disassembly of the cross beam in one embodiment of this application.

[0026] Figure 11 This is a schematic diagram showing the removal of the motor, reducer, and rotation center in one embodiment of this application.

[0027] Figure 12 This is a schematic diagram of the dismantling of the personnel compartment in one embodiment of this application.

[0028] 1 is the shield shell; 11 is the stop plate; 12 is the sealing plate; 2 is the tunnel segment; 21 is the gap between the tunnel segment and the shield tail; 3 is the rear-mounted trailer; 4 is the mobile hoisting frame; 41 is the flatbed trolley; 42 is the hoisting frame; 5 is the tunnel segment assembly machine; 6 is the screw conveyor; 61 is the No. 1 lifting lug; 62 is the No. 2 lifting lug; 63 is the No. 3 lifting lug; 64 is the No. 4 lifting lug; 65 is the No. 5 lifting lug; 66 is the No. 6 lifting lug; 7 is the crossbeam; 71 is the original installation position of the crossbeam; 72 is the jacking position of the crossbeam; 73 is the tilted position of the crossbeam; 74 is the laid-down position of the crossbeam. 81 is the main drive motor, 811 is the original installation position of the electrode, 812 is the position during electrode disassembly, 813 is the fixed position of the electrode, 82 is the rotation center, 821 is the original installation position of the rotation center, 822 is the position during rotation center disassembly, 823 is the fixed position of the rotation center, 9 is the human compartment, 91 is the original installation position of the human compartment, 92 is the position during human compartment disassembly, and 93 is the fixed position of the human compartment. Detailed Implementation

[0029] In the description of this application, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," "vertical," "horizontal," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "connection" and "linkage" in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0030] The programs involved or relied upon in the following embodiments are all conventional or simple programs in this technical field. Those skilled in the art can make conventional choices or adaptive adjustments according to specific application scenarios.

[0031] Unless otherwise specified, the unit modules (components, structures, mechanisms) or sensors involved in the following embodiments are all conventional commercially available products.

[0032] To better understand the technical solution of this application, the above technical solution will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] This example discloses a method for dismantling a small-diameter screw-type direct-discharge slurry shield tunneling machine in gravel strata. By using the shield machine's outer shell and cutterhead as permanent supports and installing a hoisting frame on a flatbed truck, it achieves safe and efficient construction in confined environments. See also Figure 1 The method includes the following steps: (1) Before the tunnel boring machine reaches the dismantling and stopping position, all articulated cylinders are in the fully extended state for propulsion. When stopping, only one ring of segments remains inside the tail shield, and all propulsion cylinders are in the retracted state. Then, the articulated cylinders are retracted to maintain a certain distance between the cutterhead and the front face. The cutterhead angle is set to 30°, and the cutter beam is stopped at the top. The segment installer retracts all cylinders and is in the front position, with the grab head at the bottom. The screw conveyor is in the extended state, and the rear door is closed. All devices are in the best dismantling state, with sufficient space.

[0034] (2) See Figures 2 to 5 A backlash steel plate 11 is welded between the annular surface of segment 2 and the shield shell 1 at a circumferential spacing of 6° along segment 2. A sealing steel plate 12 is welded between two adjacent backlash steel plates 11 parallel to the annular surface of segment 2 to seal the gap 21 between the segment and the shield tail.

[0035] A backlash steel plate 11 is welded between the circumferential surface of segment 2 and the shield shell 1. The backlash steel plate 11 is 400mm long, 381.4mm wide, and 30mm thick. The two sides of the plate that are not connected to the shield shell 1 or segment 2 are chamfered with 150mm*150mm. The plates are welded evenly along the circumference of segment 2. The angle between two adjacent backlash steel plates 11 is 6°. By physically blocking the backlash, the most uncontrollable risk of recoil during dismantling is eliminated, which is one of the key guarantees for the safe conduct of the entire dismantling operation.

[0036] Simultaneously, a sealing steel plate 12 is welded parallel to the annular surface of the tunnel segment 2 between two adjacent anti-reverse steel plates 11. The sealing steel plate 12 is a quadrilateral with one side being an arc, in which the arc is tightly fitted and welded to the shield shell 1. The two right-angled sides adjacent to the arc are tightly fitted and welded to the two adjacent anti-reverse steel plates 11. Its fourth side extends beyond the position of the tunnel segment 2 in the gap 21 between the tunnel segment and the shield tail, thereby sealing the gap 21 between the tunnel segment and the shield tail, providing a closed area for grouting, and strengthening the rigidity of the anti-reverse steel plate 11. Through the anti-reverse steel plate 11 and the sealing steel plate 12, the stability of the tunnel boring machine area is enhanced, facilitating subsequent grouting in this area.

[0037] (3) The shield tunneling synchronous grouting is adopted. Cement mortar is used to seal the cutterhead and the front shield, and the shield tail is compacted by grouting through the top advanced grouting hole. At the same time, the connecting valve between the mud-water chamber and the air cushion chamber is opened to fill the mud-water chamber and the air cushion chamber with mortar.

[0038] After the tunnel boring machine (TBM) reaches the stopping point, it first performs a circulating flushing process to ensure that the mud slurry ratio in the chamber is no greater than 1:1. The screw conveyor gate is closed, and grouting is performed to consolidate the soil in front of the cutterhead through the grouting holes (also known as advance drilling holes or pre-drilled holes) on the cutterhead. Radial grouting is also performed through the pre-drilled holes on the front shield to seal the cutterhead and the front shield, blocking water from entering the tunnel face. Cement mortar is then injected to fill the gaps between the inner wall of the TBM and the outer wall of the segments, as well as the voids between the shield and the surrounding rock, through the pre-drilled holes on the shield.

[0039] During mortar filling, the chamber pressure must be reasonably controlled using the chamber pressure data on the control panel to achieve stability at the working face. An advanced drilling rig is used to grout the top holes. The drilling rig must be stopped when the grouting pressure inside the chamber exceeds 1.5 times the water and soil pressure. If necessary, emergency polyurethane material can be used for sealing.

[0040] (4) Secondary grouting is carried out through the grouting hole of the segment. The grouting material is cement single liquid grout. If necessary, cement-water glass double liquid grout is used for construction.

[0041] Secondary grouting is performed on the ring segment just after it exits the shield tail to block water from coming in from behind, filling the gap between the shield body and the segment to achieve water stoppage and ensure that the shield tail does not leak. After grouting is completed, the secondary grouting hole of the last ring segment is opened as an observation hole. If no water flows out, it means that the grouting was successful and that the shield tail does not leak. Three days after the cutterhead and front shield are sealed, the ball valves at the corresponding points on the pressure diaphragm are opened to check the effect. Before the screw conveyor is removed, the observation hole in front of the screw conveyor should be opened to check if there is any water flowing out. If so, pure cement grout is injected using a secondary grouting machine until the filling effect is achieved.

[0042] The core purpose of grouting at this stage is not for temporary stability during dismantling, but for permanent engineering safety. Its function is to fill the "structural void" between the shield and the ground. As the tunnel boring machine advances, its outer diameter is larger than the outer diameter of the tunnel segments, leaving a ring-shaped gap between the segments and the soil. This gap must be filled to prevent later ground settlement; and to form permanent support. Injecting grout into this gap and allowing it to solidify, the shield, the solidified grout, and the tunnel segments together form a complete and permanent tunnel support structure.

[0043] (5) First, clean the slag at the bottom of the main unit, and then wash it with high-pressure water to facilitate track laying and transportation. Remove the pipes, walkway slabs, relay pumps, crushers and rear trailers in the tunnel in advance to facilitate trailer transportation. Remove the segment trolley, dismantle the propulsion cylinder and mud-water pipeline and collect the hydraulic oil, and seal it with plugs.

[0044] The rear-mounted trailer 3 was dismantled, and the connecting bridge and the lifting frame of the fan and ventilation duct on the top of the trailer were removed and transported to the outside of the tunnel by battery-powered vehicle; the equipment bridge and the trailer tie rods and connecting pins were removed, and the water, gas, hydraulic and other pipelines between the trailers were disconnected, and protective measures were taken for the joints; the three flatbed trolleys 41 were sent to the middle position of the rear trailer frame, and the trailer was lifted with four 20T jacks. The 175mm H-beams were placed in the appropriate position on the flatbed trolleys 41, and the jacks were slowly removed. The trailer was then smoothly lowered onto the flatbed trolleys, and the trailer wheels were removed. Figure 6 As shown, it was transported outside the tunnel.

[0045] Remove the segment trolley and move it backward using an electric cart. Remove the propulsion cylinder, dismantle the mud and water pipeline, disconnect the propulsion cylinder oil pipe, collect the hydraulic oil, and seal it with a plug. Install a special cylinder dismantling tool on the segment installation machine, remove the cylinder base, use the segment assembly machine and special tool to grip the propulsion cylinder, and then move the assembly machine backward to drag the cylinder for dismantling.

[0046] (6) Set up a mobile hoisting frame 4. After the screw conveyor 6 is lifted by the mobile hoisting frame 4, it is placed horizontally on the flat trolley 41 and fixed to complete the disassembly of the screw conveyor 6. By using the lifting lugs fixed on the shield body and the hand hoist, the segment assembly machine is pre-tightened to facilitate the removal of bolts, thereby disassembling the segment assembly machine 5.

[0047] The flatbed trolley 41 is made into a mobile hoisting frame 4, such as... Figure 7As shown, the mobile hoisting frame 4 includes a flatbed trolley 41 at the bottom connected to the motor locomotive head, and two isosceles triangular hoisting frames 42 fixed on the flatbed trolley 41 with their top ends connected, used for hoisting disassembled main unit components. To facilitate construction operations and reduce operational risks, two mobile hoisting frames 4 need to be fabricated. The hoisting frames 42 are erected on the flatbed trolley 41 and can move back and forth along the track. The flatbed trolley 41 is connected to the motor locomotive head. The battery-powered vehicle is turned off and braked. In addition, an anti-slip device is deployed, and iron shoes are used to secure the wheels of the battery-powered vehicle and the wheels of the flatbed trolley 41.

[0048] Dismantle the pipelines of screw conveyor 6. Before dismantling the equipment pipelines, retract the screw of the screw conveyor and close the gates of the front and rear compartments. Completely retract the screw of screw conveyor 6, then disconnect all electrical, fluid, and hydraulic lines between the equipment bridge and the main unit, and securely tie them together. After clearly marking the pipelines, remove the connecting pipelines between the main unit and the downstream equipment, and protect the pipeline connections, placing them properly in a suitable location. Stop the segment assembler at its foremost position, and remove the V-beam and walkway of the segment assembler to avoid friction and collision during the dismantling of screw conveyor 6.

[0049] The screw conveyor 6 can be disassembled using a mobile lifting frame, such as... Figure 8As shown. First, push the two flatbed trolleys 41 to the front end. Assemble the No. 1 moving support on the flatbed trolleys and install the lifting points. Use two 10t hand-operated hoists to connect the No. 1 lifting lug 61 and No. 2 lifting lug 62 on the screw conveyor. Utilize the articulated hydraulic cylinder lifting lugs and weld lifting lugs at appropriate positions at the bottom of the personnel compartment, the middle shield, and the tail shield to serve as lifting points No. 3 lifting lug 63, No. 4 lifting lug 64, No. 5 lifting lug 65, and No. 6 lifting lug 66, providing stable front-end lifting points. After each lifting point is under load, remove the bolts connecting the front flange of the screw conveyor to the front shield. When disassembling the connecting bolts, loosen all bolts by 1-2mm first, then leave 4 to 6 bolts symmetrically on the upper left and upper right, and remove all the remaining bolts. During the process of disassembling the connecting bolts, constantly observe the stress condition of each lifting point and make timely adjustments to avoid sudden swinging or displacement of the screw conveyor 6 or overloading of the hand-operated hoists. Gradually tighten the hoists at lifting lugs 62 (2), 65 (5), and 66 (6), while simultaneously releasing the hoists at lifting lugs 61 (1) and 63 (3), causing the screw conveyor 6 to gradually move outward and flatten, advancing approximately 1 meter. After the screw conveyor 6 has moved forward, connect the rear flatbed trolley's No. 2 moving bracket to lifting lugs 61 and 62, and connect the front flatbed trolley's No. 1 moving bracket to lifting lugs 63 and 64. Continue moving lifting lugs 65 and 66 via the shield body lifting lugs, causing the screw conveyor 6 to gradually move outward, flatten, and advance. Then, by replacing lifting points 4, 5, and 6 and moving the rear flatbed trolley's No. 2 moving bracket, the screw conveyor is gradually moved outward, flattened, and advanced. Finally, the screw conveyor 6 is suspended by two movable supports, and the flatbed trolley 41 is moved forward to a suitable position using an electric vehicle. The hand-operated hoist on the movable supports is then released, allowing the screw conveyor 6 to be lowered onto the flatbed trolley 41 and secured. This hoisting device, installed inside the tunnel boring machine and on the transport equipment, not only facilitates the disassembly of components in confined spaces but also speeds up the disassembly and transportation process.

[0050] Stop the segment assembler 5 with all cylinders fully retracted and the grab head at its lowest position. Extend the track to below the assembler to drain the oil, disconnect the high pressure and equipment bridge, extend the track, and weld the connecting bridge with steel to prevent tipping. Remove the segment assembler's mounting bolts and transport it to the wellhead for hoisting. Before disassembly, the segment assembler's cylinders must be retracted and fixed with welded baffles to prevent movement during disassembly. First, extend the battery-powered locomotive track to below the shield tail segment assembler. Using the lifting lugs fixed to the shield body, and in conjunction with a hand-operated hoist, disassemble the segment assembler 5 platform. Before disassembly, the segment assembler 5 must be pre-tensioned using a suspended hand-operated hoist to facilitate bolt removal. Use the special bracket on the flatbed trolley to support and fix the segment assembler 5 from below. Figure 9 As shown, ensure that it will not shake or tip over during transport on the flatbed cart.

[0051] (7) Set up lifting points and hand-operated hoists on the middle shield and the tail shield to stabilize the cross beam 7 in its original position and remove the connecting bolts between the cross beam 7 and the upper and lower bases of the middle shield. Set up support plates and flip hinge points at the lower part of the cross beam 7 to facilitate the tilting and falling of the cross beam 7 and complete the dismantling. Then remove the valve group and electrical components inside the shield.

[0052] like Figure 10 As shown, the dismantling of the cross beam 7 specifically includes: setting up multiple lifting points and hand-operated hoists on the middle shield, shield tail, and cross beam to stabilize the cross beam 7 in its original installation position 71; to prevent the cross beam from swaying, welding two lifting lugs to the front of the cross beam 7 and one lifting lug to the front of the shield body; using hand-operated hoists to stabilize the cross beam 7 in its original installation position 71; removing the connecting bolts between the cross beam 7 and the upper and lower bases of the middle shield; after removing the four pairs of flange bolts of the cross beam 7, using "L"-shaped plates to provide support reaction force, jacks are placed at the four flanges to push the cross beam 7 horizontally to the rear in the direction of excavation. Before jacking, support plates and flip hinge points are set on the two flanges at the bottom of the cross beam. Two lifting lugs are set on the top ring plate of the cross beam. The cross beam is pulled by a hand hoist until it reaches the jacking position 72. With the cooperation of jacks and multiple hand hoists, the cross beam 7 is gradually tilted. After passing the tilt position 73, it is laid down and placed on the flatbed trolley 41 at the laid-down position 74. After being fixed, it is transported to the starting wellhead and lifted out of the ground.

[0053] Electrical component disassembly steps: Main unit to control room → Main unit to distribution cabinet → Control room to distribution cabinet → Distribution cabinet to trolley. Power outage steps: After confirming that the main unit equipment is no longer working, disconnect the control power, leaving only the lighting and socket box circuits in the distribution cabinet and the air compressor circuit powered. High-voltage power will be disconnected during the subsequent assembly. The specific disassembly sequence will be arranged according to the disassembly sequence of the mechanical parts.

[0054] (8) Use manual hoists suspended on the lifting points inside the middle shield and tail shield respectively to remove the main drive motor 81, reducer and slewing center 82.

[0055] like Figure 11 As shown, after draining the gear oil from the main bearing, use the hand-operated hoists suspended from the lifting points inside the middle and tail shields to dismantle the central rotary joint, pipelines, motor, and reducer in a top-to-bottom order. The dismantling order for the motor and reducer is to first remove the topmost part, and then remove them one by one from top to bottom, left and right. The main drive motor 81 is hoisted from the original electrode installation position 811 to the electrode fixing position 813 via the electrode dismantling position 812. After dismantling the main drive motor 81 and reducer one by one, they are hoisted onto the segment trolley 41 and transported out. Following the same steps, the rotary center 82 is dismantled.

[0056] (9) Use the lifting points and hand-operated hoists inside the shield to stabilize the personnel chamber, material chamber and air cushion chamber, remove the bolts and nuts, and gradually pull out the personnel chamber, material chamber and air cushion chamber slowly by changing the hooks with multiple hand-operated hoists.

[0057] like Figure 12 As shown, after stabilizing the personnel compartment 9 using multiple lifting points and hand-operated hoists inside the shield, the fixing bolts and nuts are removed. Multiple hand-operated hoists are used in conjunction with hook replacement to gradually and slowly pull the personnel compartment 9 out from its original installation position 91. After passing the personnel compartment dismantling position 92, it is lowered and placed on the personnel compartment fixing position 93 on the flatbed trolley 41. After being fixed, it is transported out. The air cushion compartment is cut into sections and transported to the wellhead for hoisting out of the well. Before cutting into sections, lifting lugs need to be set on the top of the middle shield. A lifting lug is cut at the air cushion compartment section that is about to be cut to facilitate the suspension of the lifting slings. Finally, the lifting slings are used to smoothly place the personnel compartment 9 onto the flatbed transport trolley through the lifting lugs on the top of the middle shield.

[0058] (10) After the detachable parts of the main machine are removed, concrete is used to seal the tail cylinder position. The end segment has a pre-embedded steel plate. After the concrete wall is filled, steel bars are welded from the pre-embedded steel plate position of the segment to the concrete wall. The sealed position is completed by pouring concrete, and the shield machine shell and cutterhead are used as permanent support for the tunnel. The main strata at the machine stop position face and tunnel top are gravel-gravel, silt layer and sand layer, which have poor self-stability. In order to ensure safety, the cutterhead and main bearing are not removed during the machine dismantling and abandonment of the shell inside the tunnel.

[0059] This example breaks with the traditional "outside-in" dismantling approach. It uses the tunnel boring machine (TBM) shell and cutterhead as permanent supports, first reinforcing and sealing the tail of the shield and the area in front of the cutterhead through grouting inside the tunnel, then dismantling the TBM equipment. Finally, the cutterhead, shield shell, and ground are integrated into a single unit by pouring concrete into the shield body and constructing a sealing wall at the end. This process has a short construction cycle and eliminates the time spent without ground support. By using the TBM shell and cutterhead as permanent supports and installing a hoisting frame on a flatbed trolley, it effectively solves the technical problems of safety hazards caused by unsupported ground time and the difficulty of hoisting in confined tunnels. This achieves efficient and safe dismantling of the TBM in a confined construction environment.

[0060] Although some preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0061] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and variations.

Claims

1. A method for dismantling a small-diameter screw conveyor direct-discharge slurry shield tunneling machine in gravel strata, characterized in that, Includes the following steps: (1) The tunnel boring machine advances with all articulated cylinders fully extended. When only one ring of segments remains inside the tail of the shield, the machine stops, all the advance cylinders are retracted, and each articulated cylinder is retracted accordingly, and the cutterhead is kept at a certain distance from the front face. (2) Weld anti-reverse steel plates at 6° intervals along the circumferential direction between the segment annular surface and the shield shell, and weld sealing steel plates parallel to the segment annular surface between two adjacent anti-reverse steel plates to seal the gap between the segment and the shield tail. (3) The shield tunneling synchronous grouting is adopted. Cement mortar is used to seal the cutterhead and the front shield, and the shield tail is compacted by grouting through the top advanced grouting hole. At the same time, the connecting valve between the mud-water chamber and the air cushion chamber is opened to fill the mud-water chamber and the air cushion chamber with mortar. (4) Secondary grouting is carried out through the grouting hole of the segment. The grouting material is cement single liquid grout. If necessary, cement-water glass double liquid grout is used for construction. (5) Clean the bottom of the main unit and remove the pipes, walkway slabs, relay pumps, crushers and rear trailers in the tunnel; Remove the segment trolley and mud-water pipelines, collect the hydraulic oil after removing the propulsion cylinder, and seal it with a plug. (6) Build a mobile hoisting frame and dismantle the screw conveyor using the mobile hoisting frame; fix the lifting lugs at the shield body, and apply prestress to the segment installation machine with the corresponding hand chain hoist before dismantling the segment assembly machine; (7) Set up lifting points and hand-operated hoists at the corresponding positions of the middle shield and the tail shield, stabilize the cross beam in its original position, remove the connecting bolts between the cross beam and the upper and lower bases of the middle shield, and after setting up support plates and flip hinge points at the bottom of the cross beam, tilt and dismantle the cross beam, and then remove the valve group and electrical components inside the shield. (8) Use manual hoists suspended at the lifting points inside the middle shield and tail shield respectively to remove the main drive motor, reducer and slewing center; (9) After stabilizing the personnel chamber, material chamber and air cushion chamber by using the lifting points and hand-operated hoists at the corresponding positions of the shield body, remove the corresponding bolts and nuts, and then gradually pull out the personnel chamber, material chamber and air cushion chamber in sequence by using multiple hand-operated hoists to change hooks. (10) After the main unit’s detachable parts are removed, concrete is used to seal the tail cylinder position. The end segment has a pre-embedded steel plate. After the concrete wall is filled, steel bars are welded from the pre-embedded steel plate position of the segment to the concrete wall. The sealed block is completed by pouring concrete, and the shield machine shell and cutterhead are used as permanent support for the tunnel.

2. The method for dismantling a small-diameter screw conveyor direct-discharge slurry shield tunneling machine under gravel strata according to claim 1, characterized in that, In step (3), before reinforcement and grouting, the mud inside the chamber is completely cleaned and the mud and water pipeline is shut off.

3. The method for dismantling a small-diameter screw conveyor direct-discharge slurry shield tunneling machine under gravel strata according to claim 1, characterized in that, In step (6), the mobile hoisting frame includes a flatbed truck whose bottom is connected to the motor locomotive head and an isosceles triangular hoisting frame fixed on the flatbed truck.

4. The method for dismantling a small-diameter screw conveyor direct-discharge slurry shield tunneling machine under gravel strata according to claim 1, characterized in that, In step (6), before dismantling the segment assembly machine, the segment assembly machine is adjusted so that all cylinders are fully retracted and the grab head is at its lowest position.

5. The method for dismantling a small-diameter screw conveyor direct-discharge slurry shield tunneling machine under gravel strata according to claim 1, characterized in that, In step (8), the main drive motor, reducer and rotary center are removed in order from top to bottom.

6. The method for dismantling a small-diameter screw conveyor direct-discharge slurry shield tunneling machine under gravel strata according to claim 1, characterized in that, In step (10), the cutter head and main bearing are retained during disassembly.

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