Method for correcting deformation of large-diameter shield tail under high water pressure environment of seabed

Abstract

The application discloses a large-diameter shield tail deformation correction method under a high water pressure environment of seabed, and aims to solve the problem of great adverse effect of large-diameter shield tail deformation on shield tunneling and construction safety under the high water pressure and complex external environment of seabed. The method comprises the steps of determining the shield tail deformation reason by hole exploration sampling, cleaning the outer wall of the shield tail by installing a water jet device and a flange pipe fitting, and correcting the deformation position by heating and cooperating with a jack, so that the correction problem of the large-diameter shield tail deformation under the high water pressure environment of seabed can be effectively solved. The correction process is safe and reliable, and the correction result has high accuracy. The method can be applied to shield tail deformation correction under different reasons, has wide application range, and has strong universality.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) construction technology, specifically to a method for correcting the deformation of the shield tail of a large-diameter TBM under high water pressure conditions on the seabed. Background Technology

[0002] With the continuous development of tunnel boring machine (TBM) technology, the development and application of underground space technologies have become increasingly mature, leading to the construction of a series of multifunctional highway, railway, river-crossing, and sea-crossing tunnels. Compared to small-diameter TBMs, ultra-large diameter TBMs face larger geological cross-sections with more complex strata. Furthermore, large-diameter slurry TBMs offer advantages over other types of TBMs in terms of adaptability to geological formations, control of surface settlement, and protection of surface structures. Therefore, the application of large-diameter slurry TBMs is gradually expanding, including in areas such as submarine tunneling.

[0003] During seabed tunneling, there is a risk of shield tail deformation due to geological changes or improper construction. Once shield tail deformation occurs, it can lead to insufficient gaps for segment installation, preventing segment installation, or even shield tail seal failure, posing a significant risk to the tunnel boring machine (TBM). Therefore, it is crucial to know how to correct and repair shield tail deformation that occurs under high water pressure and complex external environments on the seabed.

[0004] 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

[0005] The inventors discovered through research that as tunnel depth increases, tunnel boring machines (TBMs) face higher water pressure and grouting pressure. To ensure full grouting, TBMs incorporate one or more grout-stopping plates in their design. When the grouting pressure exceeds the surrounding soil pressure, the injected grout diffuses into the ground and may bypass the TBM's grout-stopping plates, reaching the area in front of them. Due to the obstruction of the grout-stopping plates, the injected grout remains in front of them and cannot be reduced during excavation. This results in the grout wrapping around the shield tail, with the wrapping diameter potentially larger than the excavation diameter. As the ground changes and the surrounding rock hardens, when the force exerted on the shield exceeds its compressive yield strength, the shield tail deforms. Furthermore, situations such as cutter drops or high-strength rock jamming can directly or indirectly create interfaces or points with diameters larger than the excavation diameter. If the compressive yield strength of the shield tail is less than the ground force, this can also cause shield tail deformation.

[0006] In view of at least one of the above technical problems, this disclosure provides a method for correcting the deformation of the shield tail of a large-diameter shield machine under high water pressure on the seabed, aiming to solve the problem that the deformation of the shield tail of a large-diameter shield machine under high water pressure on the seabed and complex external environment has a great adverse effect on the tunneling and construction safety of the shield machine.

[0007] According to one aspect of this disclosure, a method for correcting the deformation of the shield tail of a large-diameter tunnel boring machine under high water pressure conditions on the seabed is provided, comprising the following steps:

[0008] (1) Select the drilling points for the inner layer plate of the shield tail with the corresponding size and shape in the deformation area of ​​the shield tail.

[0009] (2) Using a drill bit with a diameter smaller than the designed borehole diameter, drill a pilot hole at the borehole location with a depth less than the thickness of the outer plate. Then, using a drill bit with a diameter matching the designed borehole diameter, drill an enlarged hole with a certain depth that is coaxial with the pilot hole and does not penetrate the outer plate. A threaded part is provided at the enlarged hole. Then, continue drilling at the enlarged hole until it penetrates the outer steel plate of the shield tail to form a borehole.

[0010] (3) After the drill is withdrawn, if pressurized material flows out of the probe hole, polyurethane is injected first for initial sealing, and then the corresponding bolts are screwed on at the threaded part for sealing, and grouting is performed around the shield body for reinforcement.

[0011] (4) After confirming that the strata outside the borehole are stable, use a twist drill or Luoyang shovel to drill and core at the borehole to determine the cause of shield tail deformation.

[0012] (5) Cut out the inner plate at the corresponding position in the deformation area, while retaining the shield ring ribs and longitudinal ribs, and fix the plate valve at the corresponding position in the outer plate area corresponding to the inner plate cutting area.

[0013] (6) If the shield tail deformation is caused by foreign objects outside the shield tail, cut off the outer layer plate of the shield tail within the range of the plate valve and remove the foreign objects accordingly, and skip the following steps (7) to (10).

[0014] (7) Select the drilling point for the cleaning hole in the outer layer plate of the shield tail corresponding to the plate valve, and install the flange pipe with the three-way valve corresponding to the pipe wall at the plate valve.

[0015] (8) Install and fix water jet equipment in the tail area, control the forward rotation of the water jet drill rod power head and the feed speed to drill at the cleaning hole drilling point, drill through the outer layer plate of the tail shield, and then retract the drill inside the flange pipe to the outside of the plate valve. Close the plate valve, and after depressurizing through the three-way valve at the flange pipe, completely retract the drill to the outside of the flange pipe.

[0016] (9) Replace the water jet drill bit with a high-pressure nozzle connected to the high-pressure pump, and after inserting the drill rod into the flange pipe, open the plate valve. After the high-pressure nozzle extends to the outer layer of the shield tail plate, start the high-pressure pump and adjust the high-pressure pump frequency and drill rod speed to stabilize the torque until the drill rod and high-pressure nozzle are advanced to the specified distance for flushing operation.

[0017] (10) After flushing, retract the drill to the outside of the plate valve inside the flange pipe, close the plate valve, and check the closed status of the plate valve through the three-way valve at the flange pipe. After the plate valve is completely closed, retract the drill to the outside of the flange pipe; remove and evacuate the water jet equipment.

[0018] (11) If there is no water seepage in the formation, cut off the plate valve and make a sealing block that matches the cleaning hole to seal the cleaning hole; otherwise, reinforce and seal the plate valve.

[0019] (12) Use a total station to measure the shield tail area, select multiple cross sections to set up monitoring points in a corresponding interval array, and calculate the shield tail deformation range and maximum deformation.

[0020] (13) Cut off the inner plate of the tail shield deformation area, retain the ring reinforcement and longitudinal reinforcement, and cut several V-shaped openings in an array at the corresponding positions of the ring reinforcement and longitudinal reinforcement;

[0021] (14) Install a fixed reaction tooling at the deformation area of ​​the shield tail, and set a jack between the reaction tooling and the deformation part, then heat the outer plate of the shield tail in a corresponding point and line shape, adjust the jacks, and check the roundness of the shield tail shell until it is corrected.

[0022] (15) Select a small plate with a size smaller than the corresponding inner plate size to seal the inner plate with a weld resistance weld, and weld a reinforcing bar between the small plate and the V-shaped opening of the ring and longitudinal bars to complete the shield tail correction.

[0023] In some embodiments of this disclosure, in step (1), the area to be cut off from the inner layer plate of the shield tail is matched with the size of the deformation zone and the size of the probe hole structure, and the drilling point of the probe hole is located outside the range of the interlayer stiffener of the double layer plate of the shield tail and at a position relative to the center of the deformation range.

[0024] In some embodiments of this disclosure, in step (2), the threaded portion includes a corresponding nut that is fixedly disposed coaxially at the enlarged hole or an internal thread of the enlarged hole that is tapped by a tapping tap.

[0025] In some embodiments of this disclosure, in step (2), after the hole is drilled, a pipe valve is set that is coaxial with the hole and fixed relative to the outer layer plate of the shield tail; the pipe valve includes a seamless steel pipe with one end fixed to the outer layer plate of the shield tail and the other end connected to a corresponding ball valve, and a three-way valve is connected at the corresponding position on the side wall of the seamless steel pipe.

[0026] In some embodiments of this disclosure, in step (3), grout is injected into the shield shell from top to bottom and left to right alternately through the radial grouting holes reserved in the shield shell of the tunnel boring machine. The grouting holes are connected in sequence to a one-way valve and a three-way valve that is connected to liquids A and B respectively. When grouting, liquid A is injected first for 1 minute and then liquid B is introduced. When grouting is finished, the pumping of liquid B is stopped first, and the pumping of liquid A is stopped 10 to 15 seconds later.

[0027] In some embodiments of this disclosure, in step (8), a drilling rig propulsion frame is set to fix the water jet drill rod perpendicular to the drilling point of the cleaning hole, and the drilling rig propulsion frame is fixedly connected to the shield tail by two side steel sections.

[0028] In some embodiments of this disclosure, in step (9), the angle between the axial direction of the high-pressure nozzle and the axial direction of the water jet drill rod is an acute angle such that the high-pressure nozzle sprays towards the shield, and the opening angle of the high-pressure nozzle is 105° to 120°.

[0029] In some embodiments of this disclosure, in step (10), after rinsing is completed, an industrial endoscope is inserted through the cleaning hole to observe the outer wall of the shield.

[0030] In some embodiments of this disclosure, in step (12), measuring points are set up every 100mm in the circumferential direction and the tunneling direction of the shield tail, and the points with a roundness deviation greater than 10mm are marked, and the areas with a roundness deviation greater than 10mm are marked by lines.

[0031] In some embodiments of this disclosure, in step (14), the jack layout path is matched with the heating path, and an oxygen-acetylene torch is used for heating, with a heating width of 50-100 mm and a heating temperature of 500-800 °C.

[0032] One or more technical solutions provided in the embodiments of this application have at least one of the following technical effects or advantages:

[0033] 1. This method, through steps including borehole sampling to determine the cause of shield tail deformation, installation of water jet equipment and flange fittings for cleaning the outer wall of the shield tail, and heating of the deformed area in conjunction with jacking for correction, can effectively solve the problem of correcting shield tail deformation of large-diameter shield machines under high water pressure conditions on the seabed. The correction process is safe and reliable, prevents surges and outbursts, and has high accuracy. It is applicable to shield tail deformation correction under different causes, has a wide range of applications, and strong versatility.

[0034] 2. The decision on whether grouting reinforcement is needed is based on the geological conditions reflected in the borehole after the test hole is completed. This can effectively avoid the problems of blind reinforcement, which is time-consuming, labor-intensive, and increases construction costs. In addition, the threaded part outside the test hole can promptly, effectively, and safely seal the test hole when water leakage occurs, ensuring the safety of the environment inside the shield.

[0035] 3. The combination of plate valves and flange pipes can effectively ensure safety during the drilling of cleaning holes, and can promptly seal the cleaning holes in the event of a sudden surge, thus ensuring construction safety.

[0036] 4. The opening direction and angle of the high-pressure nozzles can ensure efficient cleaning of the area near the shield, improving cleaning efficiency and effectiveness.

[0037] 5. The V-shaped openings reserved at the circumferential and longitudinal ribs during shield shell correction facilitate shell restoration. By welding and fixing reinforcing ribs at these openings, reliable support can be provided for the sealed inner layer plate of the shield tail, ensuring the stability of the welded sealing of the inner layer plate.

[0038] 6. When sealing the inner layer plate of the cut area, small plates with relatively small dimensions are used for welding. This greatly facilitates the control of the curvature of the sealing plate, and the small plates can be arranged according to the position of the longitudinal and circumferential ribs, which helps to strengthen the structural strength. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the inner layer plate cutting area and the selection of probe hole locations in step 1 of an embodiment of this application.

[0040] Figure 2 This is a schematic diagram of the pilot hole drilling in one embodiment of this application.

[0041] Figure 3 This is a schematic diagram of the nut arrangement in one embodiment of this application.

[0042] Figure 4 This is a schematic diagram of the cross-sectional structure of the pipe valve in one embodiment of this application.

[0043] Figure 5 This is a schematic diagram of the inner layer plate removal area in step 5 of one embodiment of this application.

[0044] Figure 6 This is a schematic diagram of the plate valve and flange pipe installation structure in one embodiment of this application.

[0045] Figure 7 This is a schematic diagram of the V-shaped opening at the interlayer reinforcement in one embodiment of this application.

[0046] Figure 8 This is a diagram showing the usage state of the reaction tooling in one embodiment of this application.

[0047] In the above figures, 1 is the area where the inner plate is cut off in step 1, 2 is the drilling point of the exploratory hole, 3 is the outer plate of the shield tail, 4 is the pilot hole, 5 is the nut, 6 is the reaming hole, 7 is the seamless steel pipe, 8 is the ball valve, 9 is the three-way valve, 10 is the end cap, 11 is the area where the inner plate is cut off in step 5, 12 is the plate valve, 13 is the flange pipe, 14 is the Wie stiffening plate, 15 is the V-shaped opening, 16 is the reaction tooling, and 17 is the jack. Detailed Implementation

[0048] 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.

[0049] A railway project undertaken by China Railway Tunnel Group has a maximum burial depth of 115 meters and a designed maximum water pressure of 12 bar. As the burial depth increases, the tunnel boring machine (TBM) faces higher water pressure and grouting pressure. To ensure full grouting, several grout-stopping plates were added to the shield design. After the 597th ring of the TBM was excavated, an abnormally small gap was discovered at the shield tail during segment assembly, indicating bulging deformation at the shield tail. The deformation was located at approximately the 4 o'clock position, and measurements showed the shield tail steel plate bulging inwards, with a bulge area of ​​approximately 1.2 meters × 1.5 meters. This deformation at the shield tail resulted in insufficient clearance for segment installation, making segment installation impossible and posing a significant safety hazard due to the risk of shield tail seal failure.

[0050] Therefore, this example discloses a method for correcting the deformation of the shield tail of a large-diameter tunnel boring machine under high water pressure conditions on the seabed, which specifically includes the following steps:

[0051] (1) Select the drilling points of the inner layer plate of the shield tail with the corresponding size and shape in the deformation area of ​​the shield tail.

[0052] Since the tail of large-diameter slurry shield tunneling machines is generally made of double-layer composite steel plates, tail deformation is mainly caused by external forces from the strata on the outer plate. When the force exerted on the shield body by the strata exceeds the compressive yield strength of the shield body, deformation of the tail will occur. Additionally, deformation can also occur due to external conditions such as the tail being encased in mortar, cutter debris falling off, or high-strength rock becoming lodged, causing the diameter of the interface or point formed directly or indirectly on the tail to be larger than the excavation diameter. Therefore, when tail deformation occurs, it is necessary to first identify the cause of the deformation. Different solutions are needed for different situations, such as mortar encapsulation or foreign object blockage, to eliminate the cause of deformation and restore the shape and function of the tail.

[0053] Because the tunnel boring machine (TBM) is located in a high-pressure water zone on the seabed, it is necessary to open a probe hole in the shield shell at the tail of the shield to investigate the cause of the deformation. This allows for a safe investigation of the deformation and the selection of appropriate treatment measures. Considering that the tail of the shield in this case is a double-layered composite steel plate, part of the inner layer plate needs to be removed to expose the outer layer plate, facilitating the opening of the probe hole. To avoid the risk of a sudden surge of high-pressure water from the external environment after the probe hole is opened, a gate valve is welded and fixed at the probe hole. Therefore, when opening the inner plate of the TBM tail, it is necessary to consider both the size of the deformation area and the size of the opening, ensuring that the opening area of ​​the inner plate is within the deformation area and completely covers the probe hole opening. Furthermore, it is also necessary to consider the size of the gate valve to be fixed at the probe hole to prevent sudden surges, so that the gate valve can be installed through the opening area of ​​the inner plate to the outer plate. In this example, the shape and size of the inner plate cutting area are the minimum area required to meet the subsequent installation operations of gate valves, etc., so as to avoid the adverse effects on the shield tail structure caused by an excessively large inner plate cutting area.

[0054] Furthermore, because the double-layered slab contains a stiffening rib layer to strengthen the shield structure, in order to minimize the impact on the tunnel boring machine's structure, in this example, the borehole location is set outside the stiffening rib layer of the double-layered slab at the tail of the shield and at a position relatively central to the deformation range, in order to accurately investigate the cause of the tail deformation. See also Figure 1 After cutting away the corresponding area of ​​the inner plate using tools such as cutting guns and air gouging, the drilling points are selected at the tail of the shield and marked.

[0055] (2) Use a drill bit with a diameter smaller than the designed borehole diameter to drill a pilot hole with a depth less than the thickness of the outer plate at the borehole drilling point. Then use a drill bit with a diameter matching the designed borehole diameter to drill an enlarged hole with a certain depth that is coaxial with the pilot hole and does not penetrate the outer plate. A threaded part is set at the enlarged hole. Then continue drilling at the enlarged hole until it penetrates the outer steel plate of the shield tail to form a borehole.

[0056] Because the inner and outer plates at the shield tail are curved, to ensure the accuracy of the borehole location and avoid misalignment due to the shield tail curvature, in this example, see... Figure 2 First, a magnetic drill is used to drill a pilot hole. The diameter of the drill bit used for the pilot hole is smaller than the designed borehole diameter to prevent deviation risk when using a large-diameter drill bit directly for borehole drilling. In this example, the designed borehole size is 20mm, and a 10mm diameter magnetic drill bit, smaller than the borehole diameter, is used for the pilot hole drilling. Furthermore, since the pilot hole is not the final hole and its function is to provide positioning for subsequent borehole drilling, the pilot hole depth is less than the outer plate thickness to avoid the risk of high-pressure water gushing out from outside the shield tail. In this example, the outer plate thickness is 40mm, and the pilot hole drilling depth is 10mm.

[0057] After the pilot hole is completed, a reaming hole coaxial with the pilot hole is drilled using a drill bit with the same design diameter as the exploratory hole. This further enlarges the pilot hole to match the diameter of the exploratory hole. In this example, a 20mm drill bit with the same diameter as the exploratory hole is used to drill a 30mm depth coaxially at the pilot hole location, avoiding drilling through the outer layer plate to prevent water inrush risk and ensure sealing of the reaming hole. In this example, to ensure timely, convenient, and reliable sealing of the exploratory hole should water inrush occur after drilling, a threaded section is provided at the reaming hole. This allows for timely and reliable sealing of the exploratory hole by screwing a bolt into the threaded section. Specifically, in this embodiment, see... Figure 3 An M27 nut, coaxial with the enlarged hole, is installed at the enlarged hole and welded to the outer layer plate, ensuring the weld between the nut and the outer layer plate is airtight. In some other embodiments, a tap is used to create internal threads in the enlarged hole to form a threaded portion.

[0058] To further ensure timely and reliable sealing in case of water inrush at the borehole, in this embodiment, a pipe valve coaxial with the borehole and welded to the outer layer of the shield tail is additionally installed. See also Figure 4 The valve comprises a seamless steel pipe 7, one end of which is fixed to the outer layer plate of the shield tail, and the other end is connected to a ball valve 8. A three-way valve 9 is installed at a corresponding position on the side wall of the seamless steel pipe 7. In this example, the seamless steel pipe 7 is coaxially arranged with the enlarged hole 6, and the seamless steel pipe 7 is welded to the outer layer plate to ensure the weld sealing between the two. In addition, to facilitate the connection between the seamless steel pipe 7 and the ball valve 8, an external thread is provided at one end of the seamless steel pipe 7, and the ball valve 8 is threadedly connected to the seamless steel pipe 7 through this external thread. The ball valve is a DN65 ball valve. In addition, the Φ15mm three-way valve welded to the side wall of the seamless steel pipe 7 can realize the pressure relief of high-pressure water in the valve and the flushing of mud and sand that have flowed into the valve. In some other embodiments, see Figure 4 An end cap 10 is provided on the top of the ball valve 8. The center of the end cap 10 is provided with a through hole coaxial with the expansion hole 6, and the diameter of the through hole is matched with the drill bit used for exploratory drilling, so that the drill bit can be inserted through the through hole for exploratory drilling. The end cap can prevent a large amount of water from flowing into the pipe valve end when water flows into the exploratory hole and the ball valve is not fully closed, thus playing a certain role in sealing.

[0059] (3) If pressurized material flows out of the borehole after the drill is withdrawn, first inject polyurethane for initial sealing, then tighten the corresponding bolts at the threaded part for sealing, and then grout around the shield body for reinforcement.

[0060] Because the tunnel boring machine (TBM) area is located in a high-pressure seabed environment, there is a risk of pressurized material gushing out during exploratory drilling and retraction. Although valves are installed at the exploratory boreholes to stop the gushing out in time, it is necessary to address the gushing out of pressurized material in order to determine the cause of the subsequent shield tail deformation. The pressurized material is generally groundwater, mud, or fractured geological materials such as silt and undisturbed soil. In this case, to ensure the sealing effect at the exploratory borehole, polyurethane was first injected for initial sealing. Then, matching M5-20mm*0.8 socket head cap bolts were screwed into the threaded portion of the exploratory borehole for final sealing. After sealing, the gushing out of the exploratory borehole was stopped. To resolve the gushing out of pressurized material, grouting reinforcement of the surrounding strata is required. In this case, because the excavation diameter of the tunnel boring machine (TBM) is slightly larger than the diameter of the shield body, gaps exist around the shield body. These gaps can easily allow pressurized materials to flow through them. In this example, grouting is injected into the outside of the shield body through 12 radial grouting holes pre-reserved in the shield shell via grouting pipelines, grouting pumps, and control systems. This fills the gap between the shield shell and the excavation outline, blocks the front-to-back communication of the external space of the shield body, and achieves the purpose of filling the gap between the shield body and the surrounding rock. This effectively fills and reinforces the soil outside the shield shell, and avoids adverse construction conditions caused by the backflow of mud from the mud-water chamber in front or a large groundwater flow.

[0061] Specifically, during tail grouting, the grouting sequence proceeds sequentially from the top radial grouting hole downwards, alternating left and right. After a one-way check valve is installed at the grouting port, a high-pressure cleaner generates high-pressure water to flush out debris from the hole and clear the radial grouting holes of the shield body. Then, a tee and A and B liquid pipes are connected. Liquid A is mainly bentonite, and liquid B is water glass. Considering that the viscosity of the two mixtures cannot be transported by a grouting pump, liquid A is mixed in the mortar storage tank on the shield machine itself, and liquid B is pumped at the secondary grouting platform. Liquid A is pumped using a synchronous grouting pump, and liquid B is pumped using a secondary grouting pump. The two liquids enter the mixing pipeline 1.5m from the radial grouting hole, fuse together, and then enter the outside of the shield shell to fill and reinforce the soil outside the shield shell.

[0062] During grouting, first inject grout A for 1 minute to lubricate the pipe, then open the grout B valve to mix and inject. At the end of the hole, adjust the concentrations of A and B appropriately to accelerate the grout setting time and effectively fill the area near the hole, ensuring a sealing effect. After 10 minutes, remove the grouting head for recycling. At the end of grouting, considering the influence of water glass (liquid B) on the setting speed of the cement grout, stop the water glass pumping first to avoid A and B mixture remaining in the grouting pipe during sealing, causing blockage and abnormal pressure. Therefore, in this example, stop pumping liquid B first, and then stop pumping liquid A 10-15 seconds later.

[0063] (4) After confirming that the strata outside the borehole are stable, use a twist drill or Luoyang shovel to drill and core the borehole to determine the cause of the shield tail deformation.

[0064] After grouting reinforcement and stabilization of the strata outside the shield tail, core sampling is performed through boreholes to determine the cause of shield tail deformation. In this example, a Luoyang shovel is used for core sampling; in other embodiments, a twist drill is used. The core samples are used to determine whether the shield tail deformation is due to a falling tool, obstruction by high-strength rocks or other foreign objects, or due to geological factors.

[0065] (5) Cut out the inner plate at the corresponding position in the deformation area, while retaining the shield ring ribs and longitudinal ribs, and fix the plate valve at the corresponding position in the outer plate area corresponding to the inner plate cutting area.

[0066] Whether the shield tail deformation is caused by foreign object obstruction or geological structure, the outer plate needs to be treated. Furthermore, the cause of the external deformation must be eliminated through the outer plate. Therefore, the inner plate in the deformed area needs to be removed to facilitate subsequent processing and correction. To minimize the impact of correction on the shield structure, in this embodiment, when removing the inner plate, the circumferential and longitudinal ribs in the shield shell's double-layer plate interlayer are retained to avoid affecting the shield's structural strength and ensure the structural stability of the shield shell during the correction process. Additionally, see... Figure 5 When selecting the area to be cut from the inner plate, it should be located in the deformation zone and be the smallest area that matches the subsequent plate valves, cleaning holes or cleaning windows, so as to avoid large-scale cutting of the inner plate from having an adverse effect on the shield structure.

[0067] As subsequent operations will involve opening cleaning windows to remove obstructed foreign objects or opening cleaning holes to clean soil deformed by external geological factors, cleaning windows or holes will be installed to prevent water inrush from these areas. Therefore, plate valves are welded to the outer plate area corresponding to the inner plate removal zone. These valves can be used to promptly seal in case of sudden water inrush, ensuring the safety of the tunnel boring machine and construction. After the inner plate is partially removed, the plate valves are welded to the outer plate in this area, with full welding, and a pressure test is performed to ensure the sealing reliability of the valves and prevent water leakage.

[0068] (6) If the shield tail deformation is caused by foreign objects outside the shield tail, cut off the outer layer of the shield tail within the plate valve range and remove the foreign objects accordingly, skipping step (7) to step (10).

[0069] The cause of the shield tail deformation was found to be due to the presence of foreign objects such as detached cutters or high-strength rocks obstructing the shield tail. The foreign object was removed through the plate valve area. If a gushing occurred during the removal of the foreign object, the plate valve was closed in time. Then, polyurethane was injected around the opening and closing gate of the plate valve to compact it. The grouting reinforcement process in step (3) was repeated. After the strata outside the shield tail were completely stable, the plate valve was opened to remove the foreign object.

[0070] (7) Select the drilling point for the cleaning hole in the outer layer plate of the shield tail corresponding to the plate valve, and install the flange pipe with the corresponding three-way valve at the corresponding pipe wall at the plate valve.

[0071] In this embodiment, exploratory drilling revealed no hard objects or scrapers behind the shield tail shell. Furthermore, after sampling with a Luoyang shovel, the sample was found to be relatively dry with only minor water seepage. Therefore, water jet cleaning was employed to clean the shield shell and surrounding soil. Since water jet cleaning of the outside of the shield requires penetrating the outer layer of the shield tail plate, in this embodiment, the drilling point for the cleaning hole was selected at the location of the outer layer of the shield tail corresponding to the lower part of the plate valve. In this example, the drilling point for the cleaning hole was chosen at the location of the most severe shield tail protrusion to maximize the cleaning of the soil slurry around the shield tail. Additionally, in this embodiment, a flange pipe was installed perpendicular to the plate valve on the other side of the plate valve (see [reference]). Figure 6 The flange pipe 13 serves two purposes: firstly, it guides and limits the subsequent drilling and cleaning of the water jet drill rod; secondly, it facilitates the closure of the plate valve 12 after drill retraction in case of a sudden surge of pressurized material during drilling, acting as a temporary seal in conjunction with the drill rod. Furthermore, to prevent excessive pressure inside the flange pipe during drill retraction, a three-way valve is installed on the side wall of the flange pipe in this example to facilitate pressure relief during drill retraction.

[0072] (8) Install and fix the water jet equipment in the tail area, control the forward rotation of the water jet drill rod power head and the feed speed to drill at the cleaning hole drilling point, and drill through the outer layer plate of the tail shield. Then, retract the drill inside the flange pipe to the outside of the plate valve, close the plate valve, and release the pressure through the three-way valve at the flange pipe, and then completely retract the drill to the outside of the flange pipe.

[0073] After the cleaning hole locations were selected, the water jet equipment was brought in. In this example, the two high-pressure pumps, one hydraulic pump station, and one water tank of the water jet flushing equipment were transported to the bottom of trailer #1 near the shield tail area via a segment trolley. The drilling rig's propulsion frame was fixed to the side of the shield tail cleaning hole by welding steel sections on both sides. The water jet drill rod was adjusted to be perpendicular to the cleaning hole location to ensure that the water jet could uniformly clean the area around the deformation zone to the greatest extent possible after it extended, avoiding the inability to cover blocked areas due to the cleaning hole being skewed. Furthermore, after the water jet drill rod was relatively fixed and the drilling angle was adjusted, a DN50 interface was led out from the external circulation water pipeline to add water to the water tank for the two high-pressure pumps to operate in parallel. The suction ports of the two high-pressure pumps were inserted into the water tank through pipelines, and the outlets were connected to a high-pressure pipe to a tee in the shield tail area. The high-pressure pipe was then connected to the tail of the drilling rig via the tee. The pump station's oil pipe was connected to the drilling rig, and commissioning was completed. A 150mm² cable is drawn from the low-voltage switchgear of the tunnel boring machine and connected to the switchgear at the connecting bridge position to supply power to the water jet flushing equipment.

[0074] After adjusting the angle of the waterjet drill rod, open the clamp of the waterjet rotary rod, control the power head to rotate forward, and control the feed speed so that the drill rod and drill bit slowly drill at the selected cleaning hole drilling point. In this example, the outer plate thickness is 40mm, and drilling is stopped after the drill rod reaches a drilling depth of 45mm. At this time, the drill rod has penetrated the outer plate, and the drill bit is outside the shield tail. In order to prevent the problem of pressurized material surge due to the instability of the strata outside the shield tail, in this embodiment, the drill rod is first slowly withdrawn to outside the plate valve, while still inside the flange pipe, and then the plate valve is closed to seal the cleaning hole. At this time, in order to prevent excessive pressure in the flange pipe, the tee at the flange pipe wall is opened to perform pressure relief. After the pressure relief is completed, the drill rod is completely withdrawn to outside the flange pipe.

[0075] (9) Replace the water jet drill bit with a high-pressure nozzle connected to the high-pressure pump, and after inserting the drill rod into the flange pipe, open the plate valve. After the high-pressure nozzle extends to the outer layer of the shield tail plate, start the high-pressure pump and adjust the high-pressure pump frequency and drill rod speed to stabilize the torque until the drill rod and high-pressure nozzle are advanced to the specified distance for flushing operation.

[0076] After the cleaning hole is opened, water jet flushing is performed. First, the drill bit is replaced with a high-pressure nozzle. In this embodiment, to more effectively clean the shield, the angle between the axial direction of the high-pressure nozzle and the axial direction of the water jet drill rod is acute. This ensures that the spray direction of the high-pressure nozzle is towards the shield shell, achieving cleaning around the shield shell. Furthermore, the opening angle of the high-pressure nozzle is 105°–120°, thus ensuring the flushing efficiency and effectiveness of the water jet. After the drill rod is slowly inserted into the flange pipe, the plate valve is opened, and the drilling rod insertion depth is controlled to avoid interference between the high-pressure nozzle and the gate of the plate valve, preventing damage to the plate valve. After the high-pressure nozzle extends beyond the outer plate, the high-pressure pump is started, and the pump frequency is slowly adjusted to control the power head speed. Torque changes are observed. After flushing for a short time, the drill rod is pushed forward again, and the torque is observed to see if it increases immediately. This process is repeated until the drill rod and high-pressure nozzle have reached the designated distance.

[0077] (10) After flushing, retract the drill to the outside of the plate valve inside the flange pipe. After closing the plate valve, check the closed status of the plate valve through the three-way valve at the flange pipe. After the plate valve is completely closed, retract the drill to the outside of the flange pipe; remove and evacuate the water jet equipment.

[0078] After flushing, the power head is continuously rotated forward, and the lifting speed is controlled until the drill rod is retracted outside the plate valve but still inside the flange pipe. Then, the plate valve is closed. To confirm the closed state of the plate valve and prevent pressurized material from spraying out after retraction, the tee on the side wall of the flange pipe is opened before complete retraction to perform a pressure relief operation. The flow from the tee end is observed to confirm whether the plate valve is completely closed. If water continues to flow, the closing process is repeated: the plate valve is opened, the drill rod is inserted and retracted, and then closed again. Otherwise, the drill rod is completely pulled out. Furthermore, in this embodiment, a pressure gauge is connected to the tee on the flange pipe to detect the pressure and flow rate of the leaking material inside the flange pipe, ensuring that the pressure relief reaches a safe range. In this example, to ensure the flushing effect, after flushing, an industrial endoscope is inserted through the cleaning hole to observe the condition of the outer wall of the shield.

[0079] (11) If there is no water seepage in the formation, cut off the plate valve and make a sealing block that matches the cleaning hole to seal the cleaning hole; otherwise, reinforce and seal the plate valve.

[0080] If water seepage is present in the formation, the valve plate will be reinforced and welded again, and polyurethane will be injected to seal the valve plate, leaving it in the interlayer inside the shield shell.

[0081] (12) Use a total station to measure the shield tail area, select multiple cross sections to set up monitoring points in a corresponding interval array, and calculate the shield tail deformation range and maximum deformation.

[0082] To determine the deformation area and amount of deformation at the shield tail, a total station is used to measure the roundness of the shield tail area. Specifically, in this embodiment, a measuring point is set up every 100mm in the circumferential direction and the tunneling direction of the shield tail, and the points with a roundness deviation greater than 10mm are marked. The areas with a roundness deviation greater than 10mm are marked with lines according to the marks.

[0083] (13) Cut off the inner plate of the tail shield deformation area, retain the ring reinforcement and longitudinal reinforcement, and cut several V-shaped openings in an array at the corresponding positions of the ring reinforcement and longitudinal reinforcement.

[0084] Following the marked lines, the inner layer plate in the deformed area of ​​the shield tail was removed. To minimize damage to the shield structure, in this example, the circumferential and longitudinal ribs of the shield shell were preserved during the removal of the inner layer plate, and the cut was made straight. For the inner layer plate above the grease pipe, carbon arc gouging assisted by a straight mill was used to remove it to ensure construction safety. Furthermore, for ease of subsequent restoration of the inner layer plate, see [link to relevant documentation]. Figure 7 V-shaped openings 15 are cut at the circumferential and longitudinal reinforcements of the stiffening plate 14 to facilitate the subsequent welding and fixing of the reinforcing circumferential reinforcements at the openings, providing support points for the inner plate and improving the recovery effect of the inner plate.

[0085] (14) Set up a fixed reaction tool at the deformation area of ​​the shield tail, and after setting up a jack between the reaction tool and the deformation part, heat the outer plate of the shield tail in a corresponding point and line shape, adjust the jack, and check the roundness of the shield tail shell until it is corrected.

[0086] After the inner layer corresponding to the deformed area is cut off, the outer layer can be straightened. However, when using external force for straightening, corresponding support points are required. Therefore, in this embodiment, [the following is a partial sentence fragment:] ... Figure 8 A reaction fixture 16 is welded to the inner layer plate. This reaction fixture is located above the area where the inner layer plate was cut and is made of 200mm steel. Jacks 17 are placed between the reaction fixture 16 and the outer layer plate in the deformed area for jacking and correction. Specifically, in this embodiment, two rows of jacks are set below the reaction fixture, with three jacks per row, for a total of six 50t mechanical jacks, to correct the deformed parts. In addition, in areas where the contact area between the jacks and the outer layer plate is small, steel pads are placed between the jacks and the outer layer plate to avoid local deformation of the shell. Before the jacks apply force, an oxygen-acetylene torch is used to heat the outer shell in a point-to-line pattern. The heating path is determined according to the deformation trend and matches the layout path of the jacks. The heating width is 50-100mm, and the heating temperature is 500-800℃. During heating, the jacks are adjusted in a timely manner to keep them under stress. The roundness of the shell in the deformed area is checked multiple times during the correction process until the correction is qualified. If deformation of the reaction tooling or the inner shell at the location of the reaction tooling is found, stop the calibration. Repeat this step, gradually adjusting each deformed part until it meets the requirements.

[0087] (15) Select a small plate with a size smaller than the corresponding inner plate size to seal the inner plate with a weld resistance weld, and weld a reinforcing bar between the small plate and the V-shaped opening of the ring and longitudinal bars to complete the shield tail correction.

[0088] Considering the inner layer plate is curved, to facilitate control of its curvature during restoration of the cut area, in this embodiment, small plates with a thickness of 40mm are selected for welding to seal the cut area. Furthermore, the positions and arrangements of the small plates can be adjusted according to the longitudinal and transverse ribs, which helps to strengthen the structural strength. The welding between the small plates uses a single-sided V-shaped full penetration groove. After welding, ultrasonic and magnetic particle testing are performed to ensure the reliability of the welding. In this example, to ensure the structural strength of the inner layer plate, reinforcing ribs perpendicular to the repaired small plate are welded between the repaired area and the V-shaped openings of the circumferential and longitudinal ribs to provide good support and improve the strength of the repaired inner layer plate.

[0089] 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.

[0090] Obviously, those skilled in the art can make various modifications and variations to this application without departing from its inventive spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for correcting the deformation of the shield tail of a large-diameter tunnel boring machine under high water pressure conditions on the seabed, characterized in that, Includes the following steps: (1) Select the drilling points for the inner layer plate of the shield tail with the corresponding size and shape in the deformation area of ​​the shield tail. (2) Using a drill bit with a diameter smaller than the designed borehole diameter, drill a pilot hole at the borehole location with a depth less than the thickness of the outer plate. Then, using a drill bit with a diameter matching the designed borehole diameter, drill an enlarged hole with a certain depth that is coaxial with the pilot hole and does not penetrate the outer plate. A threaded part is provided at the enlarged hole. Then, continue drilling at the enlarged hole until it penetrates the outer steel plate of the shield tail to form a borehole. (3) After the drill is withdrawn, if pressurized material flows out of the probe hole, polyurethane is injected first for initial sealing, and then the corresponding bolts are screwed on at the threaded part for sealing, and grouting is performed around the shield body for reinforcement. (4) After confirming that the strata outside the borehole are stable, use a twist drill or Luoyang shovel to drill and core at the borehole to determine the cause of shield tail deformation. (5) Cut out the inner plate at the corresponding position in the deformation area, while retaining the shield ring ribs and longitudinal ribs, and fix the plate valve at the corresponding position in the outer plate area corresponding to the inner plate cutting area. (6) If the shield tail deformation is caused by foreign objects outside the shield tail, cut off the outer layer plate of the shield tail within the range of the plate valve and remove the foreign objects accordingly, and skip the following steps (7) to (10). (7) Select the drilling point for the cleaning hole in the outer layer plate of the shield tail corresponding to the plate valve, and install the flange pipe with the three-way valve corresponding to the pipe wall at the plate valve. (8) Install and fix water jet equipment in the tail area, control the forward rotation of the water jet drill rod power head and the feed speed to drill at the cleaning hole drilling point, drill through the outer layer plate of the tail shield, and then retract the drill inside the flange pipe to the outside of the plate valve. Close the plate valve, and after depressurizing through the three-way valve at the flange pipe, completely retract the drill to the outside of the flange pipe. (9) Replace the water jet drill bit with a high-pressure nozzle connected to the high-pressure pump, and after inserting the drill rod into the flange pipe, open the plate valve. After the high-pressure nozzle extends to the outer layer of the shield tail plate, start the high-pressure pump and adjust the high-pressure pump frequency and drill rod speed to stabilize the torque until the drill rod and high-pressure nozzle are advanced to the specified distance for flushing operation. (10) After flushing, retract the drill to the outside of the plate valve inside the flange pipe, close the plate valve, and check the closed status of the plate valve through the three-way valve at the flange pipe. After the plate valve is completely closed, retract the drill to the outside of the flange pipe; remove and evacuate the water jet equipment. (11) If there is no water seepage in the formation, cut off the plate valve and make a sealing block that matches the cleaning hole to seal the cleaning hole; otherwise, reinforce and seal the plate valve. (12) Use a total station to measure the shield tail area, select multiple cross sections to set up monitoring points in a corresponding interval array, and calculate the shield tail deformation range and maximum deformation. (13) Cut off the inner plate of the tail shield deformation area, retain the ring reinforcement and longitudinal reinforcement, and cut several V-shaped openings in an array at the corresponding positions of the ring reinforcement and longitudinal reinforcement; (14) Install a fixed reaction tooling at the deformation area of ​​the shield tail, and set a jack between the reaction tooling and the deformation part, then heat the outer plate of the shield tail in a corresponding point and line shape, adjust the jacks, and check the roundness of the shield tail shell until it is corrected. (15) Select a small plate with a size smaller than the corresponding inner plate size to seal the inner plate with a weld resistance weld, and weld a reinforcing bar between the small plate and the V-shaped opening of the ring and longitudinal bars to complete the shield tail correction.

2. The shield tail deformation correction method according to claim 1, characterized in that, In step (1), the area to be cut off from the inner plate of the shield tail is matched with the size of the deformation zone and the size of the probe hole structure, and the drilling point of the probe hole is located outside the range of the interlayer stiffener of the double plate of the shield tail and at the relative center of the deformation range.

3. The shield tail deformation correction method according to claim 1, characterized in that, In step (2), the threaded portion includes a corresponding nut that is fixedly mounted on the same axis at the enlarged hole or an internal thread of the enlarged hole that is tapped by a tapping tap.

4. The shield tail deformation correction method according to claim 1, characterized in that, In step (2), after the hole is drilled, a pipe valve is set that is coaxial with the hole and fixed relative to the outer layer plate of the shield tail. The pipe valve includes a seamless steel pipe with one end fixed to the outer layer plate of the shield tail and the other end connected to a corresponding ball valve. A three-way valve is connected to the corresponding position on the side wall of the seamless steel pipe.

5. The shield tail deformation correction method according to claim 1, characterized in that, In step (3), grout is injected into the shield shell from top to bottom and left to right in sequence through the radial grouting holes reserved in the shield shell of the tunnel boring machine. The grouting holes are connected in sequence to one-way valves and three-way valves that are respectively connected to liquids A and B. When grouting, liquid A is injected first for 1 minute and then liquid B is introduced. When grouting is finished, the pumping of liquid B is stopped first, and the pumping of liquid A is stopped 10 to 15 seconds later.

6. The shield tail deformation correction method according to claim 1, characterized in that, In step (8), the drilling rig propulsion frame is set to fix the water jet drill rod perpendicular to the drilling point of the cleaning hole, and the drilling rig propulsion frame is fixedly connected to the shield tail by the side steel sections.

7. The shield tail deformation correction method according to claim 1, characterized in that, In step (9), the angle between the axial direction of the high-pressure nozzle and the axial direction of the water jet drill rod is an acute angle such that the high-pressure nozzle sprays towards the shield, and the opening angle of the high-pressure nozzle is 105° to 120°.

8. The shield tail deformation correction method according to claim 1, characterized in that, In step (10), after rinsing is completed, an industrial endoscope is inserted through the cleaning hole to observe the outer wall of the shield.

9. The shield tail deformation correction method according to claim 1, characterized in that, In step (12), measuring points are set up every 100mm in the circumferential direction and the tunneling direction of the shield tail, and the points with a roundness deviation greater than 10mm are marked. The area with a roundness deviation greater than 10mm is marked by drawing lines according to the markings.

10. The shield tail deformation correction method according to claim 1, characterized in that, In step (14), the jack layout path is matched with the heating path, and an oxygen-acetylene torch is used for heating, with a heating width of 50-100mm and a heating temperature of 500-800℃.

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