Slurry shield tunneling machine de-trapping method in cement system grouting body

Abstract

The invention discloses a slurry shield tunneling machine de-trapping method in a cement system grouting body, which belongs to the technical field of shield tunneling, and comprises the following steps: preparing new bentonite slurry to replace thin slurry in a slurry bin of a shield tunneling machine; primarily increasing the pressure of the muddy water bin; the bentonite anti-drag slurry is pressed and injected to the outer sides of a middle shield shell and a shield tail shell of the shield tunneling machine; the pressure of the slurry bin is increased again, and thrust oil cylinders of the shield tunneling machine are sequentially jacked in a partitioned mode till the shield advances by a preset distance; then the thrust oil cylinder retracts by a preset distance, and a hinged oil cylinder between a middle shield shell and a shield tail shell of the shield tunneling machine extends by another preset distance; the shield tail shell and the shield tail rear segment are connected into a whole; the hinged oil cylinder stretches and retracts repeatedly; the cutterhead rotates until the torque reaches a stable value; the pressure of the muddy water bin is reduced, and the oil pressure of the thrust cylinder is increased, so that the shield tunneling machine recovers tunneling forwards. According to the method, the problem that the shield tunneling machine is trapped due to the fact that a cutterhead and a shield shell are wrapped by a cement system grouting body in an existing shield tunneling de-trapping method cannot be effectively solved is solved.

Description

Technical Field

[0001] The invention relates to the technical field of shield construction, and in particular to a method for escaping a slurry shield machine in a cement-based grouting body. Background Art

[0002] Shield machine jamming in soft-on-top, hard-on-bottom composite strata is a common technical challenge. Broadly speaking, shield machine jamming refers to a situation where the machine's capacity is nearing its limit, preventing normal advancement, resulting in decreased tunneling efficiency or even a complete stall. In a narrower sense, shield machine jamming refers to a situation where the machine is directly stuck, preventing normal tunneling. This typically manifests as an inability to start the cutterhead or excessive thrust. However, shield tunneling in soft-on-top, hard-on composite strata often requires additional bunker filling and ground cement reinforcement to assist with bunker opening operations. However, the circumstances surrounding shield machine jamming are somewhat different. On the one hand, cement grouting pressure is greater than the water and soil pressure. This disturbance releases and redistributes stress in the surrounding rock, allowing the cement grout to erode into the shield's perimeter, creating a certain bond strength. On the other hand, the loss of upper soil layers creates a back-soil effect. Prolonged downtime causes the surrounding rock to converge around the shield machine, squeezing the shield tail. During the bunker opening and water exchange process, unstable wedge-shaped rock masses below the surrounding rock may further collapse, and this jamming effect exacerbates the cutterhead jam. Therefore, the probability of the shield machine being trapped and the difficulty of escaping will be greatly increased in the cement grouting body.

[0003] Existing shield machine extrication methods generally include extreme torque extrication, chamber expansion and cleaning, auxiliary excavation and local decompression blasting, and the use of reverse jacks. For situations where the shield machine is trapped after the riverbed filling and grouting reinforcement is opened and cleaned under pressure, the cutterhead and shield shell are both wrapped in cement grouting, resulting in the shield machine being trapped. In existing situations, the shield machine is completely wrapped, and the torque required to roll the shield shell is greater than the cutterhead's extreme torque, meaning the shield body will not roll. In addition, the extreme torque load is entirely borne by the main drive and cutterhead flange connecting bolts, and stress concentration may cause damage to the main drive connecting bolts. In soft upper and hard lower fractured strata, the operating space for chamber expansion and cleaning is limited. In addition, the presence of hard rock blocks at the bottom greatly increases the chamber opening time, and the risk of excavation face instability is increased by prolonged exposure to atmospheric pressure. Local blasting is mostly used for full-section hard rock with good stability and is not suitable for soft upper and hard lower strata. Given the poor stability of the excavation face and the low bearing capacity of the soil, the use of reverse jacks is limited, and the operating space is narrow.

[0004] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0005] In order to overcome the defects of the existing technology, a method for escaping a slurry shield machine from a cement-based grouting body is provided to solve the problem that the existing shield escape method cannot effectively solve the situation where the cutter head and the shield shell are both wrapped by the cement-based grouting body, causing the shield machine to be trapped.

[0006] To achieve the above object, a method for freeing a slurry shield machine from a cement-based grouting body is provided, comprising the following steps: The following steps are involved: Prepare new bentonite slurry to replace the thin slurry in the slurry bin of the shield machine, wherein the viscosity and specific gravity of the new bentonite slurry are greater than the viscosity and specific gravity of the thin slurry; Initially increasing the pressure of the mud and water tank so that the pressure value of the mud and water tank is greater than the pressure value of the ground water pressure at the excavation surface; hydraulically injecting bentonite drag-reducing slurry onto the outer sides of the middle shield shell and the tail shield shell of the shield machine; The shield machine's cutter head and the shield machine's propulsion cylinder are rotated at low speeds to generate eccentric force in an attempt to escape the predicament. After the escape attempt fails, the pressure in the mud and water tank is increased again and the thrust cylinder of the shield machine is retracted a preset distance, so that the thrust cylinder is separated from the assembled segments; The articulated oil cylinder between the middle shield shell and the tail shield shell of the shield machine extends to the preset distance, so that the propulsion oil cylinder abuts against the pipe segment to free the tail shield shell; After the tail shield shell is freed, the tail shield shell is connected to the 10 ring segments behind the tail shield through a connecting piece; The articulated oil cylinder repeatedly extends and retracts, causing the cutterhead, front shield and middle shield of the shield machine to retreat as a whole; The cutter disc rotates and is successfully freed; Disassembling the coupling and reducing the pressure of the mud and water tank so that the pressure value of the mud and water tank reaches the pressure value of the stratum water pressure of the excavation surface; The cutter head rotates, increasing the oil pressure of the propulsion cylinder, so that the shield machine resumes tunneling forward.

[0007] Furthermore, the pressure value of the mud and water tank is initially increased to 1.2 times the pressure value of the stratum water pressure of the excavation surface.

[0008] Furthermore, the pressure value of the mud and water tank is increased again to 1.3 times the pressure value of the stratum water pressure of the excavation surface.

[0009] Furthermore, the preset distance is 20 mm.

[0010] Furthermore, before the pressure of the mud and water bin is initially increased, the hinge sealing grease of the shield machine is supplementally injected.

[0011] Furthermore, a monitoring point is set at the tail of the shield machine to observe the cutter head mileage, shield posture, shield tail and segment displacement during the escape period.

[0012] Furthermore, the step of attempting to escape by rotating the cutterhead of the shield machine at a low speed includes: Starting the cutter disc at a low speed and rotating the cutter disc left and right once; Divide the thrust cylinder of the shield machine into four sections: upper, lower, left, and right; retract the thrust cylinders of the upper and lower sections and then rotate the cutterhead; After the propulsion cylinders of the left and right partitions are retracted, the cutter disc is rotated.

[0013] Furthermore, the shield machine's propulsion cylinder generates eccentric force to try to escape the jam, including: Retract all the propulsion cylinders, and then extend the propulsion cylinders corresponding to each segment other than the capping block of the segment in a clockwise or counterclockwise direction to push the segment; The cutter head is rotated.

[0014] Furthermore, the propulsion cylinder extends in a clockwise or counterclockwise direction to push the pipe segment through multiple rounds, and the propulsion oil pressure is increased step by step according to the rounds.

[0015] The beneficial effect of the present invention is that the method for freeing a slurry shield machine from a cement-based grouting body of the present invention is a method for freeing a slurry shield machine from a cement-based grouting body. It utilizes the existing equipment system of the shield machine to solve the problem that the cutter head and the shield shell are both wrapped by the cement-based grouting body under complex working conditions, causing the shield machine to be trapped. It can be quickly and safely freed through convenient operation in the tunnel, and has the characteristics of programmed operation, safety, convenience and cost savings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 The present invention is a flow chart of a method for escaping a slurry shield machine from a cement-based grouting body according to an embodiment of the present invention.

[0017] Figure 2 Schematic diagram of a trapped working condition of a slurry shield machine according to an embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the preparation work for the escape of a slurry shield machine according to an embodiment of the present invention.

[0019] Figure 4 Schematic diagram of the installation position of the observation device according to an embodiment of the present invention.

[0020] Figure 5for Figure 4 A local enlarged schematic diagram of point B in FIG.

[0021] Figure 6 2 is a top view of an observation device according to an embodiment of the present invention.

[0022] Figure 7 2 is a side view of an observation device according to an embodiment of the present invention.

[0023] Figure 8 This is a schematic diagram of the eccentric force escape of the propulsion cylinder according to an embodiment of the present invention.

[0024] Figure 9 Schematic diagram of the position correspondence between the pipe segments and the thrust cylinders according to an embodiment of the present invention.

[0025] Figure 10 Schematic diagram comparing the articulated oil cylinder before and after the first extension of an embodiment of the present invention.

[0026] Figure 11 This is a schematic diagram of the longitudinal section of the pipe segment after the connecting piece according to an embodiment of the present invention is installed.

[0027] Figure 12 This is a schematic diagram of the cross section of the pipe segment after the connecting piece according to an embodiment of the present invention is installed.

[0028] Figure 13 This is a schematic diagram of the cutter disc and housing being freed after articulation and retraction according to an embodiment of the present invention.

[0029] Reference numerals: Cutter head 1, front shield shell 2, middle shield shell 3, shield tail shell 4, cement grouting body 5, pipe segment 6, bottom reserved hole 7, mud and water bin 8, top ball valve 9, hinged seal grease injection port 10, grease pump 11, pressure gauge 12, middle shield radial hole 13, observation device 14, marking scale 15, ink line 16, propulsion cylinder 17, air cushion bin 18, hinged cylinder 19, connecting piece 20, channel steel end 21. DETAILED DESCRIPTION

[0030] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the invention are shown in the accompanying drawings.

[0031] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] Reference Figures 1 to 13As shown, the present invention provides a method for escaping a slurry shield machine in a cement-based grouting body, comprising the following steps: S1. Prepare new bentonite slurry to replace the thin slurry in the mud and water tank of the shield machine. The viscosity and specific gravity of the new bentonite slurry are greater than the viscosity and specific gravity of the thin slurry.

[0033] See Figure 2 As shown, the cutter head 1, front shield shell 2, middle shield shell 3, and tail shield shell 4 of the shield machine are all wrapped by the cement grouting body 5 and trapped, and the tail shield contains the formed tunnel segment 6.

[0034] Before the slurry shield machine is rescued, the following preparatory work should be carried out.

[0035] S11 replaces the slurry in the mud and water tank with new bentonite slurry.

[0036] Mix new bentonite slurry on the ground to increase the viscosity and specific gravity of the new bentonite slurry, then transport it into the tunnel and inject it into the mud and water tank for replacement.

[0037] Specifically, new bentonite slurry is mixed on the ground to increase the viscosity and specific gravity of the new bentonite slurry, which is then transported to the tunnel and injected into the mud and water bin 8 through the reserved hole 7 at the bottom of the mud and water bin. The slurry is then discharged from the top ball valve 9 of the mud and water bin to the bottom of the shield tail and pumped out of the tunnel for slurry replacement.

[0038] Bentonite new slurry is added with polymer materials, the ratio is: 1m 3 15kg of HS-1, 5kg of HS-3 and 40kg of bentonite are mixed with water. The viscosity of the slurry discharged from the top after displacement is required to reach 60s.

[0039] Replace the bentonite with new slurry to fill the pores in the excavation surface to prevent leakage of slurry from the excavation surface.

[0040] S12 uses radial holes in the shield to inject bentonite drag reduction slurry.

[0041] Bentonite drag reduction slurry is injected into the radial holes 13 of the middle shield around the middle shield shell 3 and the tail shield shell 4 to lubricate and reduce friction of the shells.

[0042] The mass ratio of the drag reducing slurry is: composite bentonite: water = 1:1, and the grouting pressure does not exceed 0.4MPa.

[0043] S13 increases the pressure in the mud and water tank.

[0044] Increase the pressure setting value of the mud and water tank 8 to 1.2 times the stratum water pressure of the excavation surface and infiltrate for more than 3 hours.

[0045] Increase the pressure setting value of the mud and water tank 8 to 1.2 times the water pressure of the excavation surface formation and infiltrate for 3 hours to achieve a stable pressure maintenance effect. Increasing the mud and water tank pressure can increase the slurry penetration distance and achieve a stable pressure maintenance effect.

[0046] S14 replenishes sealing grease.

[0047] Replenishing the injection-molded shield machine's hinged seal grease can protect the seal.

[0048] Specifically, the hinged seal grease injection port 10 on the center shield is connected to a grease pump 11 and an external pressure gauge 12 to facilitate inspection and verification of the hinged seal grease pressure. The pressure is required to be no less than 0.45 MPa, and grease is replenished promptly if the pressure is low. Bentonite drag-reducing slurry is then pressure-injected through the center shield's radial holes. The mass ratio of the drag-reducing slurry is 1:1 composite bentonite: water, and the injection pressure does not exceed 0.4 MPa.

[0049] S15 sets a monitoring point at the tail of the shield.

[0050] After re-tightening the shield tail, nearly 10 rings of segment connecting bolts are set up at the shield tail of the shield machine to observe the displacement of the shield tail and segments during the escape period.

[0051] Specifically, after measuring the gap between the tail shell 4 and the tube segment 6, eight observation devices 14 are welded at equal intervals around the inner side of the tail shell 4. The observation devices are used to indicate the relative displacement between the tail shell and the tube segment in the axial direction, as well as the relative displacement in the circumferential and radial directions.

[0052] Specifically, the observation device includes a base plate, a radial plate, and an axial plate. The base plate is installed on the inner side of the tail shield shell. The radial plate is installed vertically on the base plate. The radial plate is arranged in the radial direction of the tail shield shell. The axial plate is connected to the radial plate. The axial plate abuts the outer wall of the tube segment. The axial plate is arranged in the axial direction of the tail shield shell. The axial plate is marked with 15 scales, with a total length of 100 mm and a single scale of 2 mm. There are 25 scales inside and outside the tube segment coverage area, allowing observation of the relative displacement of the tail shield shell 4 and tube segment 6 along the propulsion direction.

[0053] Two ink lines 16 are marked on the side of the segment in the radial direction at the corresponding position of the observation device at the initial position, so that the relative rotation angle between the shield tail shell and the segment can be observed; at the same time, the gap change value at each point between the shield tail shell and the segment can be obtained by observing the deformation of the device in the radial direction.

[0054] In addition, the shield control room can constantly monitor cutterhead mileage and shield attitude data, allowing accurate judgment of whether the shield is moving forward, backward, rotating, bowing, or raising its head.

[0055] S2, try to escape by rotating the cutter head of the shield machine and the thrust cylinder of the shield machine at a low speed to generate eccentric force.

[0056] In this embodiment, the cutterhead 1 was first rotated at a low speed to attempt an escape. Specifically, the cutterhead 1 was started at a low speed and, under the escape torque, attempted to rotate left and right once each. The upper and lower propulsion cylinders were then retracted 20 mm and the cutterhead was restarted twice. Finally, the propulsion cylinders were fully retracted 20 mm and the cutterhead was restarted twice. The cutterhead 1 then tripped at high torque and stopped rotating. The observation device and measurement system revealed a slight fluctuation of 0.02 degrees in the roll angles of the front and middle shields 2 and 3 before recovering. Inspection of the tail shield's specialized observation device 14 revealed no changes in the tail shield shell 4 or segments 6. Escape under the extreme torque condition failed, and the process proceeded to the next step.

[0057] Specifically, the step of attempting to escape by rotating the cutter head of the shield machine at a low speed in S4 includes the following steps: S21, start the cutter disc at a low speed and rotate it left and right once; S22, dividing the thrust cylinder of the shield machine into four sections: upper, lower, left, and right; retracting the thrust cylinders of the upper and lower sections and rotating the cutterhead; S23. Retract the thrust cylinders of the left and right partitions and rotate the cutter disc.

[0058] In this embodiment, the shield machine has a total of 16 groups of thrust cylinders in the entire circle, divided into four sections: upper, lower, left, and right, each containing 3, 4, 5, and 4 groups of thrust cylinders, respectively. First, the cutterhead is started at a low speed. Under the escape torque, it is attempted to turn left and right once each. Then, the upper and lower section thrust cylinders are retracted 20 mm, and the cutterhead is restarted twice. Finally, all the thrust cylinders are retracted 20 mm, and the cutterhead is restarted twice. The cutterhead 1 stops at high torque and does not rotate. Through the observation device and measurement system, the rolling angles of the front shield 2 and the middle shield 3 fluctuate slightly by 0.02 degrees and then recover. Through the observation device 14 and the measurement system, no changes are found in the shield tail 4, the tube 6, and the cutterhead 1 during the process, indicating that the escape under the extreme torque state has failed, and the eccentric force escape attempt step is entered.

[0059] The eccentric force generated by the thrust cylinder of the shield machine in S2 to try to break free includes the following steps: S24, retract all the thrust cylinders, and then extend the thrust cylinders corresponding to the segments other than the capping block of the segment in a clockwise or counterclockwise direction to push the segment forward; S25: Rotate the cutter disc.

[0060] The thrust cylinder extends the push pipe segment in a clockwise or counterclockwise direction through multiple rounds, and increases the thrust oil pressure step by step according to the rounds.

[0061] By utilizing eccentric thrust to shear and squeeze the reinforcement surrounding the shell, localized shear failure causes the reinforcement to crack and fall off, facilitating shield extrication. All thrust cylinders 17 are retracted 50mm, and then three groups of thrust cylinders corresponding to each segment other than the capping block are rotated out to press against the segments. Before extending the cylinders, the pressure in the slurry tank 8 is lowered to the set value, increasing it to the ground water pressure at the excavation surface to increase the effective eccentric force. This operation is repeated multiple times, with the thrust cylinders extending and retracting in groups, first clockwise and then counterclockwise, in a single cycle.

[0062] After repeating each cycle three times, increase the oil pressure by stages, with each stage increasing by no more than 3 MPa. The maximum setting for the assembly oil pressure is 70% of the maximum propulsion oil pressure, or the operation stops when the cutter head moves forward 5 mm.

[0063] In this embodiment, all thrust cylinders are retracted 50mm. In assembly mode, three groups of thrust cylinders corresponding to each segment other than the capping block (F) are extended in turn to press against the segment, in the order L2, B2, B3, B1, and L1. Before extending the thrust cylinders, the slurry tank pressure is lowered to the set value, increasing it to the ground water pressure at the excavation face. This reduces the slurry reaction force and increases the effective eccentric force. The thrust cylinders are extended and retracted in groups, first clockwise and then counterclockwise, in a single cycle. This operation is repeated three times, and then the oil pressure is increased in stages, by 2.5 to 3.0 MPa. When the oil pressure reached 10 MPa, after repeating the second cycle and the three propulsion cylinders were at position B3, the cutterhead mileage of cutterhead 1 began to change by 1 mm, and the shield began to move forward. The oil pressure was further increased to 17 MPa. After repeating the second cycle, the cutterhead mileage changed by 5 mm, and the entire machine moved forward by 5 mm. Operation was stopped, and the shield tail observation device 14 was observed to move forward by a total of 5 mm. The segments remained unchanged, and no rotation or radial displacement of the observation device 14 was observed. During this period, the pressure in the mud and water tank 8 fluctuated slightly, increasing by a total of 0.02 bar, and the liquid level in the air cushion tank 18 rose significantly by 60 mm.

[0064] After the cutterhead moved forward 5mm and stopped, we tried to start the cutterhead and turned it left and right twice each. We observed again that the special observation device at the tail of the shield did not rotate, the shield rolling angle did not change, the pipe segment and the tail of the shield did not rotate or move relative to each other, the cutterhead still could not be started, and the eccentric force of the thrust cylinder failed to escape.

[0065] S3. After the escape attempt fails, the pressure in the mud and water bin is increased again and the thrust cylinder 10 of the shield machine is retracted a preset distance so that the thrust cylinder 10 is separated from the assembled segments.

[0066] Increasing the mud and water tank pressure again can provide a backward reaction force after retracting the thrust cylinder, which is beneficial for the shield to retreat.

[0067] Specifically, the pressure in the mud tank is increased to 1.3 times the ground water pressure at the excavation surface. Increasing the pressure in the mud tank can provide a backward reaction force after the thrust cylinder is retracted, facilitating the shield machine to retreat.

[0068] As a preferred embodiment, the preset distance is 20 mm.

[0069] Specifically, when retracting the propulsion cylinders, all the propulsion cylinders are retracted symmetrically one by one from top to bottom, so that all the propulsion cylinders are 20 mm away from the pipe segment.

[0070] S4. The articulated oil cylinder between the middle shield shell 3 and the tail shield shell 4 of the shield machine extends out a preset distance, so that the propulsion oil cylinder 17 abuts against the pipe segment 6 to free the tail shield shell 4.

[0071] Active articulation is activated, and the thrust from the extension of the articulation cylinder 19 pushes the rear of the center shield and the tail shield backward until the propulsion cylinders are fully in contact with the pipe segments. Specifically, the articulation cylinders are opened and extended uniformly by 20 mm, with a single extension controlled at 4 mm per stroke, until the propulsion cylinders are fully in contact with the pipe segments.

[0072] Under the premise of maintaining the pressure of the front mud and water tank, the thrust of the articulated cylinder when it is extended is used to push the rear part of the middle shield and the shield tail to move backward.

[0073] The observation device at the tail shield observed that the entire tail shield shell had retreated 20mm. There was no relative rotation between the segments and the tail shield shell, and the movable segments remained unchanged, effectively freeing the tail shield shell. During this period, the cutterhead 1 mileage, the mud and water tank 8 pressure, and the air cushion tank 18 fluid level remained unchanged. After the active articulation was activated, a dedicated person observed the articulation grease pressure gauge 12, which slowly decreased from 0.50 MPa to 0.45 MPa. The grease pump 11 was immediately activated to replenish grease until the grease pressure reached 0.50 MPa.

[0074] S5. After the shield tail shell 4 is freed, the shield tail shell 4 is connected to the 10 ring segments behind the shield tail 4 through the connecting piece 20.

[0075] In this embodiment, the connecting member 20 is a channel steel. A channel steel 21 is set in the gap of the propulsion cylinder 17 to connect the 10 ring segments 6 behind the shield tail into a whole. The end of the channel steel 21 is welded to the shield tail 4, which can effectively restrain the relative displacement of the segments and the shield tail shell.

[0076] S6. The articulated cylinder repeatedly extends and retracts, causing the cutter head 1, front shield 2 and middle shield 3 of the shield machine to retreat as a whole.

[0077] Specifically, the pressure in the mud and water tank 8 was raised to 1.35 times the ground water pressure at the excavation face. The thrust cylinder was first retracted 10 mm, then the articulated cylinder was retracted 10 mm. The cutterhead travel was observed to change by 10 mm, and the cutterhead retreated 10 mm until the thrust cylinder was completely against the segment. The observation device 14 at the tail shield and the segment 6 remained unchanged. The articulated cylinder was then repeatedly extended and retracted 10 to 20 mm three times, achieving a 10 mm back and forth movement of the cutterhead, middle shield, and front shield without moving the tail shield shell. This completely freed the front and middle shield shells. Simultaneously, the mud and water tank pressure fluctuated slightly, decreasing by a cumulative 0.09 mm, and the air cushion tank fluid level dropped significantly, by a cumulative 150 mm. During this period, a dedicated person monitored the articulated grease pressure gauge 12 and refilled it promptly to maintain the grease pressure at 0.50 MPa.

[0078] Retract within the extended stroke range of the articulated cylinder to maintain the pressure in the front mud and water tank, extend and retract back and forth within the extended stroke range of 10~20mm of the articulated cylinder, and realize the 10mm movement of the cutter disc and the front shield without moving the shield tail, so that the cutter disc, front shield and middle shield retreat as a whole, and break away from the surrounding cement slurry, so as to free the front shield and middle shield shells, and then continue to extend and retract the articulated cylinder back and forth 3 times to ensure that the shells are completely freed.

[0079] S7. Remove the connecting parts and reduce the pressure of the mud and water tank so that the pressure value of the mud and water tank reaches the pressure value of the ground water pressure at the excavation surface.

[0080] The articulated cylinder stops at the 10mm extended state, locks the active articulation, starts the cutter disc 1, first turns right at 0.3rpm, and when started for the second time, the torque reaches a peak of 2640kN·m. Continue to turn 3 circles until the torque is stable at around 550kN·m, then turn left at 0.3rpm, the peak reaches 1280kN·m, and continue to turn 2 circles until the torque is stable at around 500kN·m, which is close to the propulsion torque, and the cutter disc is completely freed.

[0081] After the cutterhead is freed, the observation device on the shield tail is cut off, and the connecting parts between the shield tail and the pipe segment are cut off. The pressure of the front mud water tank is reduced to the original set excavation surface formation water pressure.

[0082] S8. The cutterhead rotates, increasing the oil pressure in the thrust cylinder to allow the shield machine to resume forward excavation.

[0083] Specifically, the cutterhead is rotated and the thrust cylinder oil pressure is gradually increased to resume shield tunneling. After the total thrust reaches a certain peak, the thrust cylinder stroke and thrust distance change significantly. Continue pushing for 1-2 meters until the total thrust reaches a stable level, allowing the shield to resume normal tunneling.

[0084] In this example, the cutterhead 1 speed was set to 0.5 rpm, the thrust rate to 1 mm / min, and the thrust cylinder oil pressure was gradually increased to resume shield tunneling. The shield machine's thrust limit was 41,600 kN. After the thrust reached 35,000 kN, the thrust cylinder stroke and cutterhead mileage changed significantly, allowing smooth resumption of tunneling and normal slurry circulation. After advancing another 0.5 m, the cutterhead speed was set to 1.0 rpm and the thrust rate to 3 mm / min. After advancing another 1.5 m, the total thrust dropped to a plateau, maintaining at 25,000 kN, and normal shield tunneling was achieved.

[0085] The method for freeing a slurry shield machine from a cement-based grouting body of the present invention is a method for freeing a slurry shield machine from a cement-based grouting body. It utilizes the existing equipment system of the shield machine to solve the problem that the cutter head and the shield shell are both wrapped by the cement-based grouting body under complex working conditions, causing the shield machine to be trapped. The method can be easily operated in the tunnel to quickly and safely achieve freeing, and has the characteristics of programmed operation, safety, convenience and cost savings.

[0086] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features having similar functions disclosed in this application.

Claims

1. A method for escaping a slurry shield machine from a cement-based grouting body, characterized in that: The following steps are involved: Prepare new bentonite slurry to replace the thin slurry in the slurry bin of the shield machine, wherein the viscosity and specific gravity of the new bentonite slurry are greater than the viscosity and specific gravity of the thin slurry; Initially increasing the pressure of the mud and water tank so that the pressure value of the mud and water tank is greater than the pressure value of the ground water pressure at the excavation surface; hydraulically injecting bentonite drag-reducing slurry onto the outer sides of the middle shield shell and the tail shield shell of the shield machine; Trying to escape by rotating the cutter head of the shield machine at a low speed and using the eccentric force of the propulsion cylinder of the shield machine; After the escape attempt fails, the pressure in the mud and water tank is increased again and the thrust cylinder of the shield machine is retracted a preset distance, so that the thrust cylinder is separated from the assembled segments; The articulated oil cylinder between the middle shield shell and the tail shield shell of the shield machine extends to the preset distance, so that the propulsion oil cylinder abuts against the pipe segment to free the tail shield shell; After the tail shield shell is freed, the tail shield shell is connected to the 10 ring segments behind the tail shield through a connecting piece; The articulated oil cylinder repeatedly extends and retracts, causing the cutterhead, front shield and middle shield of the shield machine to retreat as a whole; The cutter disc rotates and is successfully freed; Disassembling the coupling and reducing the pressure of the mud and water tank so that the pressure value of the mud and water tank reaches the pressure value of the stratum water pressure of the excavation surface; The cutter head rotates, increasing the oil pressure of the propulsion cylinder, so that the shield machine resumes tunneling forward.

2. The method for escaping a slurry shield machine in a cement-based grouting body according to claim 1, characterized in that: The initial pressure value of the mud and water tank is increased to 1.2 times the pressure value of the ground water pressure on the excavation surface.

3. The method for escaping a slurry shield machine in a cement-based grouting body according to claim 2, characterized in that: The pressure value of the mud and water tank is increased again to 1.3 times the pressure value of the stratum water pressure on the excavation surface.

4. The method for escaping a slurry shield machine in a cement-based grouting body according to claim 1, characterized in that: The preset distance is 20 mm.

5. The method for escaping a slurry shield machine in a cement-based grouting body according to claim 1, characterized in that: Before initially increasing the pressure of the mud and water bin, the hinge sealing grease of the shield machine is additionally injected.

6. The method for escaping a slurry shield machine in a cement-based grouting body according to claim 1, characterized in that: A monitoring point is set at the shield tail of the shield machine to observe the displacement of the shield tail and the segments during the escape period.

7. The method for escaping a slurry shield machine in a cement-based grouting body according to claim 1, characterized in that: The steps of attempting to escape by rotating the cutter head of the shield machine at a low speed include: Starting the cutter disc at a low speed and rotating the cutter disc left and right once; Divide the thrust cylinder of the shield machine into four sections: upper, lower, left, and right; retract the thrust cylinders of the upper and lower sections and then rotate the cutterhead; After the propulsion oil cylinders of the left and right partitions are retracted, the cutter disc is rotated.

8. The method for escaping a slurry shield machine in a cement-based grouting body according to claim 1, characterized in that: The shield machine's propulsion cylinder produces eccentric force to try to escape the jam, including: Retract all the propulsion cylinders, and then extend the propulsion cylinders corresponding to each segment other than the capping block of the segment in a clockwise or counterclockwise direction to push the segment; The cutter head is rotated.

9. The method for escaping a slurry shield machine in a cement-based grouting body according to claim 8, characterized in that: The propulsion oil cylinder extends in a clockwise or counterclockwise direction through multiple rounds to push the pipe segment, and the propulsion oil pressure is increased step by step according to the rounds.

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