Water-rich contact zone TBM tunneling small pilot hole cooperative drainage and slag removal construction method

Abstract

The application relates to the technical field of tunnel engineering construction, and discloses a water-rich contact zone TBM tunneling small pilot hole cooperative drainage and slag removal construction method, which comprises the following steps: after a machine is stuck, a small pilot hole is excavated, a flexible variable resistance drainage control component is installed, and an asymmetric fluid control environment is constructed; a trace preloading detection action is performed, and a machine sticking impedance index is calculated; when the index exceeds a threshold value, a transient pore water pressure excitation slag removal cycle is started, dynamic locking pressurization and asymmetric blasting drainage actions are alternately performed, accumulated slag is induced to be liquefied and directed to be discharged; after verification, a staged restart is performed in the order of reverse relaxation, hydraulic cleaning and load propulsion; and after the machine is unstuck, a pressure balance type plugging of the pilot hole is performed by using shield tail grease pressure feedback. The method solves the problems of rough pilot hole sealing difficulty and deep slag soil cleaning difficulty through a liquefied slag removal mechanism excited by physics, and realizes quantitative evaluation and safe unsticking of the machine sticking state.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering construction technology, specifically a method for coordinating drainage and slag removal during TBM excavation of a pilot tunnel in a water-rich contact zone. Background Technology

[0002] When tunnel boring machines (TBMs) traverse contact zones between soft and hard rock or water-rich fault fracture zones, they often experience jamming accidents due to increased frictional resistance around the shield caused by surrounding rock instability, high-pressure water inrush, and debris accumulation. The conventional solution for handling such jamming problems is to excavate a small pilot tunnel behind the TBM tail shield to approach the jammed area, and then carry out manual clearing or high-pressure water flushing.

[0003] However, in water-rich contact zone strata, the excavation of small pilot tunnels typically employs drill-and-blast methods, resulting in rough and uneven rock surfaces on the tunnel walls. These irregular boundary conditions limit the applicability of conventional rigid sealing devices, making it difficult to create an effective fluid-sealed environment at the tunnel entrance. Because a high-pressure sealed cavity cannot be constructed, the injected cleaning fluid easily leaks along the path of least resistance, failing to establish sufficient pore water pressure within the deep, compacted slag. Therefore, when facing already consolidated or highly compacted slag, simple hydraulic flushing usually only removes surface debris and cannot effectively release the lock-up around the shield, leading to low slag removal efficiency.

[0004] Furthermore, existing methods for extricating the machine from stuck conditions lack quantitative assessment of the degree of jamming. Construction workers often rely on experience to attempt extrication with high thrust or high torque, which, if the accumulated debris is not completely cleared or the lock is released, can easily lead to overload of the TBM main drive motor or damage to the cutterhead structure. Simultaneously, the backfilling and sealing of small pilot tunnels and cavities during the recovery tunneling phase after the TBM is extricated from its stuck state also poses risks. Conventional grouting processes lack coordinated control between grouting pressure and the shield tail seal's pressure-bearing capacity. If the grouting pressure is not properly controlled, the high-pressure grout can easily puncture the grease sealing system of the TBM shield tail, causing secondary disasters such as water and sand inrush, affecting the subsequent normal tunneling and tunnel construction safety. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for coordinating drainage and slag removal in a pilot tunnel during TBM excavation in a water-rich contact zone. This method solves the technical problems of shield jamming caused by high-pressure water inrush and slag accumulation when a full-face tunnel boring machine (TBM) crosses a geological contact zone, the low efficiency of conventional slag removal, and the risk of equipment damage from forced extrication.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for coordinated drainage and debris removal in a small pilot tunnel during TBM excavation in a water-rich contact zone includes: excavating small pilot tunnels on both sides behind the shield tail after the full-face tunnel boring machine (TBM) encounters jamming; installing flexible variable resistance flow control components at the tunnel openings; and simultaneously connecting equipment sensors to a data acquisition and closed-loop control network to construct an asymmetric fluid control environment. Based on this asymmetric fluid control environment, the equipment is controlled to perform a micro-preload detection action, and the jamming impedance index, which characterizes the severity of the current jamming, is calculated using real-time collected feedback data. When the jamming impedance index exceeds a set safety threshold... When the threshold is reached, the transient pore water pressure is activated to trigger the slag removal cycle. By alternately executing dynamic locking pressurization and asymmetric blasting discharge actions, the accumulated slag is liquefied and the elastic potential energy of the system is used to complete the directional spraying slag removal. The state after slag removal is measured and verified a second time. If the verification is successful, the staged restart is performed in the order of reverse relaxation, hydraulic cleaning and load propulsion. After the full-face tunnel boring machine is completely freed and drives away from the jammed area, the flexible variable resistance discharge control component is removed, and the pressure balance sealing of the small pilot tunnel and cavity is completed by using the real-time data feedback of the shield tail grease pressure sensor.

[0007] Preferably, in the step of constructing the asymmetric fluid control environment, a flexible variable resistance venting control component is configured. This component consists of a rigid support frame fixed at the guide tunnel opening, a flexible filling layer covering the outer periphery of the frame, and a quick-release control valve at the end of the venting pipe located at the center of the component. A radial preload is applied to the rigid support frame by a hydraulic pressure unit, causing the flexible filling layer to deform and conform to the inner wall of the guide tunnel, thereby constructing a high flow resistance boundary. The opening and closing state of the quick-release control valve controls the fluid flow. Simultaneously, the propulsion pressure sensor, drive torque sensor, and shield tail grease pressure sensor are connected to the data acquisition and closed-loop control network to form a closed-loop topology.

[0008] Preferably, in the step of calculating the jamming impedance index, the preset jamming impedance index calculation formula in the data acquisition and closed-loop control network is called, and the peak driving torque, static passive reaction force, and nominal shield diameter collected during the micro-preload detection action are used as input parameters for calculation. This calculation eliminates the influence of equipment size differences and water pressure on resistance assessment, and outputs a quantitative jamming degree index. A safe start-up threshold is set as the judgment criterion. When the index is higher than the threshold, it indicates that the slag has formed a force chain lock, and a slag removal cycle needs to be executed.

[0009] Preferably, the dynamic lock-up pressurization action in the transient pore water pressure-induced slag removal cycle is performed by controlling the propulsion cylinder assembly to perform micro-feed compression while the fast discharge control valve is closed. This step sets the propulsion speed parameter based on the minimum critical excitation rate formula, ensuring that the rate at which the slag volume is compressed is greater than the rate at which fluid leaks through the edge gaps of the flexible variable resistance flow control component. This establishes excess pore water pressure within the slag to counteract effective stress, causing the slag to enter a liquefied state.

[0010] Preferably, the asymmetric explosive discharge action in the transient pore water pressure-induced slag removal cycle is triggered when the propulsion pressure reaches the critical liquefaction pressure and the driving torque shows a decreasing trend. By opening the quick discharge control valve and controlling the propulsion cylinder group to perform rapid unloading and rebound, the elastic strain energy accumulated in the shield structure and hydraulic system during the compression phase is used to generate a backward axial recovery displacement. Combined with the drag force generated by the fluid pressure gradient, the liquefied slag is discharged, thereby utilizing the system's elastic potential energy to complete directional jet slag removal.

[0011] Preferably, during the transient pore water pressure-induced slag removal cycle, a flow field directional guidance strategy based on eccentric unloading is activated. This strategy asymmetrically operates the partitioned cylinders of the propulsion cylinder group. While opening the small guide hole on one side for drainage, it maintains the pressure of the other partition and prioritizes and quickly unloads the pressure of the corresponding side partition. This creates a lateral pressure gradient within the slag that points towards the drainage port, guiding the migration of accumulated slag and assisting in the directional jet slag removal.

[0012] Preferably, the staged restart steps follow a specific sequence: In the reverse relaxation stage, the cutterhead drive system is controlled to perform a reverse action at low speed and low torque to eliminate residual contact stress; in the hydraulic cleaning stage, the cutterhead is kept rotating forward under no load and cleaning fluid is injected to lubricate and carry away the remaining slag until the slag content of the discharged fluid meets the preset requirements; in the load propulsion stage, a linear loading strategy is adopted to gradually restore thrust and speed until the equipment returns to the normal tunneling parameter range.

[0013] Preferably, in the pressure-balanced sealing step, backfilling and grouting are performed after the sealing wall is constructed at the pilot tunnel opening. During the grouting process, feedback values ​​from the shield tail grease pressure sensor are used, combined with a preset safe grouting pressure control formula, to calculate the real-time upper limit of the grouting backfilling pressure. The output pressure of the grouting pump is controlled via differential pressure linkage to ensure that the grouting pressure is below the breakdown threshold of the shield tail sealing system, thereby completing the pressure-balanced sealing.

[0014] Preferably, after resuming normal tunneling, the active defense interface is activated using a data acquisition and closed-loop control network. This interface collects thrust fluctuation amplitude, torque fluctuation amplitude, and pore water pressure monitoring values ​​in real time, and calculates the active defense trigger index using the active defense trigger index formula. When the index continuously exceeds the preset defense activation threshold, the propulsion cylinder group is forced into a micro-pulsation propulsion mode, which applies high-frequency, low-amplitude mechanical vibration to disrupt the bound water film and consolidation structure between the excavated soil particles.

[0015] This invention provides a method for coordinating drainage and debris removal during TBM tunneling in water-rich contact zones. It offers the following advantages: 1. This invention utilizes a flexible variable resistance discharge control component to construct a high flow resistance boundary within a rough small guide tunnel. Combined with transient pore water pressure to stimulate slag removal circulation, superpore water pressure is established inside the slag through micro-feed compression, causing the slag to transform from a solidified state to a fluid plastic state. Subsequently, the elastic potential energy accumulated in the system is released by asymmetric blasting discharge action to achieve directional jet slag discharge. This physically stimulated liquefaction slag discharge mechanism overcomes the shortcomings of traditional simple hydraulic flushing in effectively removing deep compacted slag and improves the slag removal efficiency under complex geological conditions in water-rich contact zones.

[0016] 2. This invention introduces the jamming impedance index as a quantitative evaluation indicator. By obtaining real-time feedback data through micro-preload detection actions, it achieves accurate judgment of the severity of jamming, avoiding the risk of equipment damage caused by blindly forcing the machine out of the jam. Combined with a graded restart strategy, it strictly follows the execution sequence of secondary verification, reverse relaxation, hydraulic cleaning and load propulsion to ensure that contact stress is gradually released during the extrication process, thus ensuring the safety of the cutterhead drive system and shield structure of the full-face tunnel boring machine.

[0017] 3. This invention employs pressure-balanced sealing technology to establish a linkage control mechanism between grouting pressure and shield tail grease pressure. This ensures that the pressure of backfilling grouting operations is always lower than the breakdown threshold of the sealing system, preventing high-pressure grout from damaging the shield tail sealing performance. In addition, by activating the active defense interface through data acquisition and closed-loop control network, the invention monitors the fluctuation of tunneling parameters in real time and automatically triggers the micro-pulsation propulsion mode, which disrupts the consolidation structure of the slag and reduces the risk of the machine jamming again after the equipment resumes normal tunneling. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the system control topology and hardware composition according to an embodiment of the present invention; Figure 2 This is a general construction process diagram of one embodiment of the present invention; Figure 3 This is a comparison chart of time-varying curves of parameters during the escape process according to an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] See attached document Figure 1This invention provides a method for coordinating drainage and slag removal during the excavation of a small pilot tunnel by a full-face tunnel boring machine in a water-rich contact zone. This method is based on the coordinated action of a constructed asymmetric discharge control system and the full-face tunnel boring machine.

[0021] like Figure 1 As shown, the system in this embodiment mainly consists of three parts: a full-face tunnel boring machine (TBM) main system, a small pilot tunnel fluid control module, and a data acquisition and closed-loop control network. The full-face TBM, as the main actuator, includes the shield body, propulsion cylinder assembly, cutterhead drive system, and shield tail, and communicates with external systems through an onboard control interface. To solve the jamming problem, the system logically constructs a left-side and a right-side small pilot tunnel as the carriers of physical muck removal channels.

[0022] Given the rough and uneven rock surfaces of the inner walls of the left and right pilot tunnels excavated using the drill-and-blast method, making direct closure with rigid gates impossible, this embodiment constructs a flexible variable-resistance drainage control component at the tunnel opening. The flexible variable-resistance drainage control component includes a rigid support frame, a flexible filling layer, and a hydraulic pressure unit. The rigid support frame, serving as the load-bearing structure, is fixed at the tunnel opening. The flexible filling layer, wrapped around the rigid support frame, is made of high-strength geotextile wrapped with sandbags or water-swellable rubber material, capable of deforming according to the shape of the rock surface. The hydraulic pressure unit, connected to the rigid support frame, applies radial preload to the periphery, forcing the flexible filling layer to tightly adhere to the rough inner wall of the pilot tunnel.

[0023] The flexible variable resistance venting control component does not pursue absolute airtightness. Instead, it constructs a high flow resistance boundary through physical compression, ensuring that the fluid leakage rate through the component's edge gaps is far lower than the rate at which the sludge volume is compressed during subsequent pressurization steps. A large-diameter vent pipe is pre-embedded in the central area of ​​the flexible variable resistance venting control component, and a quick-release control valve is installed at the end of the vent pipe. The quick-release control valve is a hydraulic ball valve or a slide gate valve, capable of responding to millisecond-level opening commands to instantly release the pressure within the sludge accumulation chamber.

[0024] like Figure 1 As shown in the control topology, the construction method of this invention relies on real-time monitoring of a data acquisition and closed-loop control network. The data acquisition and closed-loop control network, as the core control node, is connected to data sensing nodes such as the propulsion pressure sensor, drive torque sensor, and shield tail grease pressure sensor via signal lines. The propulsion pressure sensor is logically connected to the hydraulic circuit of the propulsion cylinder assembly and is used to collect thrust and passive reaction force data of the propulsion system. The drive torque sensor is installed at the motor output end of the cutterhead drive system and is used to monitor the rotational resistance of the cutterhead. The shield tail grease pressure sensor is arranged in the sealing chamber of the shield tail and is used to monitor the pressure status of the sealing system.

[0025] See attached document Figure 1 and attached Figure 2 This invention provides a method for co-drainage and slag removal construction of a small pilot tunnel during TBM excavation in a water-rich contact zone, comprising the following steps: S1, after the full-face tunnel boring machine encounters water-rich contact belt jamming machine, excavates the left small pilot tunnel and the right small pilot tunnel on both sides behind the shield tail respectively, and installs a flexible variable resistance discharge control component including rigid support frame, flexible filling layer and fast discharge control valve at the pilot tunnel opening, and connects data acquisition and closed-loop control network at the same time, thereby constructing an asymmetric fluid control environment for subsequent fluid control. S2, based on the constructed asymmetric fluid control environment, keeps the fast discharge control valve in the open discharge state, controls the full-face tunnel boring machine to perform micro preload detection action, and uses the real-time collected propulsion pressure and drive torque feedback data of the data acquisition and closed-loop control network to calculate and output the jamming impedance index that characterizes the current jamming severity. S3 compares the calculated card impedance index with the preset safety threshold. If it exceeds the threshold, the transient pore water pressure excitation slag removal cycle is started. By alternately executing dynamic lock-up pressurization and asymmetric blasting discharge actions, the slag liquefaction is artificially induced and the elastic potential energy of the system is used to achieve directional jet slag discharge until a relaxed slag state that meets the restart conditions is obtained. S4. The state of the relaxed slag after treatment is subjected to secondary impedance measurement and verification. If the verification is successful, the full-face tunnel boring machine is restarted in stages according to the sequence of reverse relaxation, hydraulic cleaning and load propulsion. The machine is considered to be in a completely freed state after the equipment is confirmed to have restored normal tunneling capacity. S5, after the full-face tunnel boring machine is completely freed and has left the jammed area, removes the flexible variable resistance drainage control component, and uses the real-time data feedback from the shield tail grease pressure sensor to control the grouting backfill pressure, completing the pressure balance sealing of the small pilot tunnel and cavity.

[0026] The following section will elaborate on the key control logic, physical excitation mechanism, and parameter calculation model in the above construction process, taking into account the specific technical details of each step.

[0027] See attached document Figure 1 To address the jamming problem of full-face tunnel boring machines (TBMs) in water-rich contact zones caused by sudden water inrush and debris accumulation, this embodiment utilizes... Figure 1 The data acquisition and closed-loop control network shown integrates distributed physical execution units into a unified asymmetric fluid control environment. This process specifically includes the following sub-steps: S101, constructing a physical pressure relief channel and protection system. After confirming that the full-face tunnel boring machine has encountered a jam, using the shield tail as the reference plane, small pilot tunnels are opened on the left and right sides respectively at a distance of 2m from the shield tail (corresponding to chainage PK139+928.6). The small pilot tunnels are designed to be 1.8m high, 1m wide, and approximately 8m long, with the working chamber being 1.8m high, 1m wide, and 1.5m deep. The construction adopts the drill-and-blast method for full-face excavation. To prevent the blasting from penetrating the side shield cylinders, a straight seven-hole excavation method is used, with three blasts, each using no more than 4kg of explosives and advancing no more than 1m.

[0028] Meanwhile, a protective platform was erected in front of the small tunnel workshop. The protective platform was constructed using I-beams, with 125 H-beams for the columns and beams, and No. 10 channel steel for the connectors. No. 10 channel steel purlins (spaced 0.5m apart) were installed at the top, bottom, and front of the workshop, and a 10mm thick steel plate was laid on top to create a stable physical environment to protect the TBM equipment and construction platform.

[0029] S102, Install the control components and construct a high flow resistance boundary. Based on the aforementioned protective platform and small guide tunnel structure, install the discharge control components. Considering the temporary support provided by 18-beam welded portal frames (1m spacing) inside the guide tunnel, and the rough inner rock surface, construct a variable resistance boundary at the guide tunnel opening based on steel plate sealing and concrete backfilling. Reserve a large-diameter discharge pipe and a fast-discharge control valve for subsequent control of slag release. The flexible variable resistance drainage control component specifically includes: a rigid support frame, serving as the main load-bearing structure, fixed to the surrounding rock at the tunnel entrance by anchor bolts to withstand the axial thrust generated when pressure builds up within the slag accumulation cavity; a flexible filling layer, covering the outer periphery of the rigid support frame, made of a high-strength geotextile-wrapped dense sandbag assembly or water-swellable rubber strip, capable of plastic deformation according to the rock surface shape; and a hydraulic pressure unit, located between the rigid support frame and the flexible filling layer, configured with multiple radially distributed hydraulic jacks to apply continuous radial clamping force to the periphery, forcing the flexible filling layer into the gaps in the rough inner wall of the tunnel. After the component installation is completed and the quick-drainage control valve is closed, a penetrating borehole is drilled through the pre-reserved channel of the drainage pipe to break through the pre-reserved water-sealing rock column, thus officially connecting the tunnel to the core area of ​​slag accumulation.

[0030] Through the above coordination, the flexible variable drag flow control component constructs a high flow resistance boundary at the guide hole opening. The physical characteristics of this boundary are: although it does not pursue absolute airtightness, it greatly increases the frictional and local resistance of fluid flow through physical compression. This limits the fluid leakage through the edge gaps of the component to an extremely low level when the fast discharge control valve is closed, thereby ensuring that the volume compression rate caused by the subsequent TBM propulsion is significantly greater than this leakage rate, satisfying the kinetic conditions for establishing superpore water pressure.

[0031] A large-diameter drain pipe is pre-embedded in the central area of ​​the rigid support frame, and a quick-release control valve is installed at the end of the large-diameter drain pipe. The quick-release control valve is a hydraulically driven straight-through ball valve or slide valve, equipped with an accumulator to support millisecond-level instantaneous opening, used to control the establishment and instantaneous release of the pressure difference between the inside and outside of the slag accumulation chamber.

[0032] S103 connects the data acquisition and closed-loop control network. The control system of the full-face tunnel boring machine and the newly added monitoring nodes are integrated into the data acquisition and closed-loop control network to form a closed-loop topology. Specifically, this includes: connecting a propulsion pressure sensor to the hydraulic main circuit of the propulsion cylinder group to collect real-time data on the total thrust and static passive reaction force of the propulsion system; connecting a drive torque sensor to the output of the variable frequency motor of the cutterhead drive system to monitor the resistance torque during shield and cutterhead rotation; and connecting a tail grease pressure sensor to the grease injection port at the rear end of the tail grease distribution valve to monitor the real-time pressure status of the sealing system. The real-time aggregation of the above sensor data signifies the completion of the asymmetric fluid control environment construction, providing the system with the hardware foundation for subsequent jamming impedance determination and pulse cleaning cycles.

[0033] See attached document Figure 2 After constructing the asymmetric fluid control environment described above, this embodiment proceeds to the dynamic measurement and quantitative evaluation stage of the jamming impedance benchmark. The core of this stage lies in accurately quantifying the degree of mechanical locking of the shield body by the accumulated debris using physical detection methods, specifically including the following sub-steps: S201, perform micro-preloading detection. Utilizing the established asymmetric fluid control environment, firstly, keep the fast-discharge control valves at the left and right small pilot tunnels fully open. The physical principle of this operation is to release the free water pressure inside the slag deposits using open boundaries, thereby eliminating the contribution of pore water pressure to the total resistance in subsequent measurements and achieving isolated observation of purely mechanical friction resistance. Subsequently, the full-face tunnel boring machine is controlled to perform micro-preloading detection through data acquisition and a closed-loop control network. The specific logic is as follows: control the cutterhead drive system to output a gradually increasing test torque until it reaches 10% to 15% of the equipment's rated torque. During this process, the feedback from the drive torque sensor is closely monitored to ensure that the shield and cutterhead do not undergo substantial rotation (angular displacement Δθ≈0), only keeping the mechanical transmission chain under tension.

[0034] S202, Construct a jamming impedance index calculation model and output the results. While the full-face tunnel boring machine maintains the aforementioned tension state, the data acquisition and closed-loop control network synchronously collects pressure data from the propulsion pressure sensor and torque data from the drive torque sensor. The system processes the above data using the jamming impedance index calculation formula, calculates and outputs the jamming impedance index, which characterizes the current severity of the jamming. The jamming impedance index calculation formula is: ; in, The impedance index of the shield is a dimensionless physical quantity, and its physical meaning is equivalent to the equivalent static friction coefficient of the slag contact interface. Peak drive torque refers to the maximum output torque value (unit: kN) monitored by the drive torque sensor during the micro-preload detection action. ; This represents the static passive reaction force, which is the force applied when the peak driving torque is applied while the propulsion cylinder assembly maintains a constant cylinder extension length (speed is 0). Under these conditions, the axial resultant force (unit: kN) of the shield body constrained by the surrounding rock and slag accumulation, measured by the propulsion pressure sensor. ; This indicates the nominal diameter of the shield body, i.e., the design outer diameter of the full-face tunnel boring machine (unit: m). ; This represents a normalized torque reference, used to eliminate the influence of equipment size variations on impedance evaluation. It has cross-model compatibility.

[0035] S203, Perform a slag removal cycle start-up threshold determination. The calculated jamming resistance index is compared with the system's preset safe start-up threshold. The safe start-up threshold is typically set between 0.6 and 0.8, corresponding to the critical static friction coefficient of saturated sandy mudstone slag. The determination logic is as follows: If the impedance index of the slag is greater than or equal to the safe start threshold, it indicates that a stable force chain structure has formed between the slag particles. Simply increasing the driving force can easily lead to motor overload or structural yielding. Therefore, it is determined that the transient pore water pressure-induced slag removal cycle must be started (i.e., step S3). ; If the impedance index of the slag block is less than the safe start threshold, it indicates that the slag structure is relatively loose and the system is ready to start directly. In this case, the slag cleaning step is skipped and the subsequent staged restart process is directly entered.

[0036] When the jamming resistance index measured in step S2 exceeds the set threshold, it indicates that the slag has formed a high-stress consolidation. In this embodiment, the transient pore water pressure-induced slag removal cycle is initiated. This process utilizes the hydraulic power and structural elasticity of the full-face tunnel boring machine to alternately create "ultra-high pressure liquefaction" and "transient unloading" environments in an asymmetric fluid control environment. Specifically, it includes the following execution steps: S301 executes dynamic interlocking and slag liquefaction initiation control. First, the fast-discharge control valve in the flexible variable resistance discharge control component is closed via data acquisition and closed-loop control network, cutting off the discharge channels of the left and right small guide tunnels. Then, the propulsion cylinder group is controlled to perform micro-feed compression. The physical principle of this action is based on the effective stress principle in soil mechanics. This embodiment addresses the white marble slag and the milky white, fine-slag-containing sudden inrush water (peak flow reached 1500 m³ / h). 2 The characteristics of / h) cause a rapid increase in pore water pressure inside the slag by quickly compressing its volume. When the pore water pressure approaches the total overburden pressure, the effective stress acting between the slag particles approaches zero, leading to a loss of shear strength and thus artificially inducing the slag to enter a liquefied suspension state. To ensure that superpore water pressure is successfully established before fluid leaks through the gaps in the flexible variable resistance flow control component, the propulsion speed of the propulsion cylinder assembly must be greater than the critical value. In this embodiment, the minimum critical excitation speed formula is used to calculate and set the speed parameters of the micro-feed compression action. The minimum critical excitation speed formula is: ; In the formula, This represents the minimum critical excitation velocity, which is the minimum axial extension velocity that the propulsion cylinder assembly must reach when performing the compression action (unit: m / s). ; The boundary leakage flux is the volumetric flow rate of fluid seeping out through the edge gaps of the flexible variable resistance flow control component under the target pressure (unit: m). 3 / s This value is obtained by inverting the pressure decay curve during the low-pressure test in the previous S2 step; The coefficient of mass slag and soil mixture represents the volumetric compressibility of the mixture of slag and water under pressure (unit: Pa). -1 ， The values ​​were determined based on on-site soil and waste sampling tests. This represents the equivalent volume of the slag accumulation cavity, i.e., the total volume of the annular space in front of the cutterhead and around the shield filled with silted slag (unit: m). 3 ; The target pressurization rate is set as the total overburden pressure and the preset liquefaction initiation time (typically 5 to 10 seconds). The ratio (unit: Pa / s) ; The effective propulsion cross-sectional area refers to the total effective working area of ​​the pistons in the propulsion cylinder assembly (unit: m²). 2 S302 executes asymmetric explosive venting and release of system elastic potential energy. During the continuous micro-feed compression action, the data acquisition and closed-loop control network monitors the system status in real time. When the value fed back by the propulsion pressure sensor reaches the preset critical liquefaction pressure, and the resistance torque displayed by the drive torque sensor shows a significant decrease (indicating that the slag has entered a liquefied suspension state), the slag discharge procedure is immediately triggered.

[0037] The system sends an opening command to the quick-discharge control valve, simultaneously connecting the left and right small guide tunnels to the atmosphere and establishing a pressure gradient between the slag accumulation chamber and the external space. Simultaneously, the propulsion cylinder assembly is controlled to perform a rapid unloading and rebound action. This action utilizes the elastic strain energy accumulated in the shield and propulsion cylinder hydraulic columns under the high pressure of step S301. At the instant the active thrust is released, the full-face tunnel boring machine generates a backward axial elastic recovery displacement, which, combined with the fluid drag force generated by the valve opening, ejects the liquefied and suspended slag at high speed into the small guide tunnels.

[0038] S303, execute flow field directional guidance based on eccentric unloading. During the cyclic execution of the above steps, if the data acquisition and closed-loop control network detects uneven distribution of accumulated debris through earth pressure sensors installed at different locations on the shield, the flow field directional guidance strategy is activated.

[0039] The control system operates the propulsion cylinder group's partitioned cylinders asymmetrically. For example, when slag buildup is detected on the right side, while opening the quick-release control valve of the right-side small guide tunnel to release the slag, the pressure on the left partition of the propulsion cylinder group is maintained, prioritizing the rapid unloading of pressure from the right partition. This asymmetrical force system operation forces a slight deflection in the shield's attitude, creating a lateral pressure gradient within the slag and pointing towards the discharge port, guiding the slag trapped in the dead zone towards the unobstructed guide tunnel opening.

[0040] After completing the aforementioned transient pore water pressure-induced slag removal cycle, in order to ensure the safe resumption of tunneling by the full-face tunnel boring machine, this embodiment employs a strategy that includes secondary impedance measurement and verification, and a three-stage step-by-step startup. This process specifically includes the following sub-steps: S401, Perform secondary impedance measurement and verification. After completing one or more slag removal cycles, the control system pauses operation to allow the pressure in the slag accumulation cavity to return to the natural hydrostatic pressure level. Subsequently, the detection logic in step S2 is invoked again to control the full-face tunnel boring machine to perform a micro-preload detection action.

[0041] The data acquisition and closed-loop control network reacquires real-time data from the propulsion pressure sensor and drive torque sensor, and recalculates the current jammer impedance index (denoted as S2) using the jammer impedance index calculation formula. .

[0042] At this point, the system performs the following closed-loop decision: like The safety start threshold indicates that although the sludge has been removed, the mechanical locking effect of the sludge has not been released. The system determines that the current state does not meet the restart conditions and automatically jumps back to step S3 to continue the next round of transient pore water pressure-induced sludge removal cycle. like The safe start threshold indicates that the slag structure is loose and the full-face tunnel boring machine has reached a relaxed slag state. The system determines that the risk of machine jamming has been eliminated, terminates the slag removal cycle, and enters the subsequent graded restart process.

[0043] S402, execute Level 1 restart: reverse relaxation. After confirming that the full-face tunnel boring machine is in a relaxed slag accumulation state, in order to further destroy the local dead zone slag accumulation arch effect remaining at the bottom of the shield and the edge of the cutterhead, control the cutterhead drive system to execute a reverse relaxation action.

[0044] The physical principle behind this action is that accumulated rock particles often form a directional, tightly packed structure (texture) during long-term unidirectional rotary tunneling. Reverse rotation can effectively shear these existing force chains. Specifically, the cutterhead drive system is controlled to rotate in the reverse direction at a low speed (0.1-0.3 rpm). During this stage, the system sets a reverse output limit, restricting the torque to 40% to 50% of the equipment's rated torque to prevent overload of the main bearing due to localized hard rock jamming. This process lasts 2 to 5 minutes, during which the propulsion cylinder assembly remains in a zero-thrust floating state, relying solely on the cutterhead rotation to eliminate residual contact stress.

[0045] S403, perform a second-level restart: hydraulic cleaning. After completing the reverse relaxation, keep the cutterhead drive system in an unloaded low-speed forward rotation state (speed increased to 0.5-1.0 rpm), and at the same time open the water / grouting pipelines of the cutterhead panel and the shield body to inject cleaning fluid (such as water or low-viscosity lubricating mud) into the front of the cutterhead and around the shield.

[0046] At this point, the quick-discharge control valve in the flexible variable resistance discharge control assembly remains fully open. The injected cleaning fluid forms a lubricating film around the shield and carries the suspended slag agitated by the cutterhead. Driven by the fluid pressure gradient, it is continuously discharged through the left and right small guide tunnels. This step utilizes the lubrication and carrying capacity of the fluid to further reduce the friction coefficient between the shield and the surrounding rock until a significant decrease in the slag content of the discharged fluid is observed.

[0047] S404, execute level three restart: load propulsion. After confirming that the muck discharge channel is unobstructed and the cutterhead rotation resistance is stable, control the full-face tunnel boring machine to enter the load propulsion stage.

[0048] The control system employs a linear loading strategy to resume tunneling, meaning the thrust of the propulsion cylinder assembly is slowly increased at a rate of 5% to 10% per minute of rated thrust, while simultaneously raising the speed and torque limits of the cutterhead drive system. During the first 100 to 200 millimeters of propulsion, the system operates in a "trial tunneling" mode, with data acquisition and a closed-loop control network continuously monitoring the changing trend of the jamming impedance index. If all parameters smoothly transition to the normal tunneling parameter range, the full-face tunnel boring machine is deemed to have reached a fully unblocked state.

[0049] Once the full-face tunnel boring machine determines that it is completely free from its pre-set obstacles and has advanced more than a preset safe distance (usually 1 to 1.5 times the shield length), in order to repair the cavities caused by the opening of the left and right pilot tunnels and the slag removal operations, and to prevent secondary surges of groundwater along the pilot tunnel channels, this embodiment enters the pressure balance sealing stage, which specifically includes the following steps: S501 employs multi-layered cavity support and composite material backfilling. After the full-face tunnel boring machine 100 departs from the core area of ​​the machine, the disturbed cavities formed around the pilot tunnel and shield are treated using a strategy of "strong support + zoned and qualitative backfilling": Backfilling of the small guide tunnel: Steel plates were welded between the two arch frames as templates, and Φ22 steel bars were used as transverse ribs for longitudinal connection on the outside (spaced 10cm). C30 concrete was pumped to backfill and seal the entire cross section.

[0050] Construction of the cavity strong support system: After the TBM tail emerges, a support system consisting of "large arch frame with close spacing + I-beam transverse bracing + longitudinal reinforcement + steel plate enclosure" is immediately constructed. Specifically, HW175×175 steel arch frames are used, with a longitudinal spacing of 45cm, connected by No. 14 I-beams, and lined with 1.5mm steel plates and steel reinforcement bars spaced 10cm apart. During the erection of the frame, HW175 steel (1 set of 2 pieces) is used as temporary supports to transfer the load on the upper and lower parts of the main beam.

[0051] Zoned and tertiary backfilling: The area below the arch waist is reinforced by grouting with a two-component grout (water-cement ratio 1:1) made of ordinary Portland cement P.O42.5 and water glass through a 42 steel pipe to rebuild the strength of the surrounding rock foundation.

[0052] Arch crown area: Concrete pumping pipes are embedded, and C30 concrete is used for backfilling in layers by pumping. The thickness of the backfill layer is not less than 3.5m to form a rigid load-bearing arch.

[0053] Remaining micro-cavities and dead corners: After the concrete has fully set, the remaining dead corners are filled with chemical grouting material. The chemical grouting material is divided into AB components. Component A is a basic isocyanate, and component B is a combination of polyether polyols. The pure grout ratio is 1:1. A tracer is added to the AB components to monitor the grout diffusion trajectory in real time, and its high permeability and rapid reaction characteristics are used to form a flexible buffer sealing layer.

[0054] S502 implements differential pressure linkage control based on the safety of the shield tail seal. During the aforementioned grouting operation, the grouting area is close to the shield tail of the full-face tunnel boring machine, and the strata have interconnected fissures after disturbance. The physical risk is that if the external fluid pressure exceeds the support pressure of the sealing grease inside the shield tail, the grease film between the sealing brushes will rupture, leading to high-pressure grout penetrating the sealing system and entering the tunnel.

[0055] Therefore, this embodiment does not employ constant pressure grouting, but instead relies on data acquisition and a closed-loop control network to implement differential pressure linkage control. The system reads the pressure data fed back by the shield tail grease pressure sensor in real time and uses it as a safety benchmark to dynamically adjust the output pressure of the grouting pump. This embodiment uses a safe grouting pressure control formula to calculate the real-time upper limit of the grouting backfill pressure. The safe grouting pressure control formula is: ; In the formula: This indicates the upper limit of grouting backfill pressure, i.e., the maximum fluid pressure allowed to be applied in the backfill grouting pipeline (unit: bar). When the measured grouting pressure reaches this value, the data acquisition and closed-loop control network automatically triggers the grouting pump to depressurize or stop. This represents the minimum grease pressure at the shield tail, specifically the minimum grease pressure value (unit: bar) collected by the shield tail grease pressure sensor in each sealing chamber of the shield tail at the current moment. This value characterizes the current sealing system's ultimate ability to resist external fluid intrusion; This indicates the sealing safety margin, which is a preset buffer pressure value (unit: bar) to cope with grouting pulsation pressure and sensor measurement errors. Its value is set to 10% to 15%.

[0056] This control logic ensures that the pressure in the grouting area is always lower than the shield tail's penetration threshold, thus achieving pressure-balanced sealing of small guide tunnels and cavities while guaranteeing equipment safety.

[0057] After the full-face tunnel boring machine (TBM) 100 successfully escaped its stuck state and resumed normal tunneling, this embodiment activated an active defense interface based on "geophysical exploration + drilling + chemical irrigation" to address the potential risks of white marble alteration and water inrush in the densely jointed zone from PK139+913 to PK139+270. This mode integrates real-time tunneling parameters with advanced geological prediction data to proactively prevent the risk of the machine getting stuck. The process specifically includes the following steps: A combined geophysical exploration and drilling defense system is configured. A geological risk response module is integrated into the data acquisition and closed-loop control network 400. At the hardware level, HSP acoustic reflection method and CFC complex frequency conductivity method detection equipment are configured for long-distance prediction, and a Hamai YXZ-70A drilling rig is pre-installed in the TBM main beam for short-distance verification. When a risk is determined, the system will no longer blindly advance, but will switch to "advanced reinforcement mode" to pre-treat the surrounding rock using chemical grouting materials. The chemical grouting material is an AB two-component material (component A is basic isocyanate, component B is a combination of polyether polyols, volume ratio 1:1), which utilizes its high permeability and water-swelling properties (expansion ratio 10-15 times) to form a water-proof curtain in front of the shield.

[0058] The system executes risk triggering logic based on multi-parameter fusion. During tunneling, to quantify the deterioration of the surrounding rock condition and accurately determine the timing for initiating advanced drilling, the data acquisition and closed-loop control network 400 simultaneously acquires data from the propulsion pressure sensor 401, drive torque sensor 402, and pore water pressure gauge on the shield surface. Combined with wave velocity anomalies from advanced geophysical exploration, the system performs real-time calculations using an active defense triggering index formula. The active defense triggering index formula is as follows: ; In the formula: This represents the proactive defense trigger index, used to quantify the urgency of initiating advanced drilling and grouting. , These represent the real-time fluctuation amplitudes of thrust and torque, respectively, reflecting the load instability caused by the fracturing of the surrounding rock; This represents the real-time pore water pressure monitoring value; This represents the lateral earth pressure in the formation theory; , , As a weighting coefficient, in the densely jointed marble zone of this embodiment, it is set to... To increase the water pressure weight.

[0059] When the calculation results If the defense activation threshold (set to 0.65 in this embodiment) is exceeded for 10 seconds, the system determines that there is a risk of high-pressure fracture water or weak interlayers in the surrounding rock ahead, and immediately triggers the following graded defense actions: Stop the machine for exploration: Control the TBM to stop tunneling and use the Hamai YXZ-70A drilling rig to conduct advance drilling through the pre-reserved holes on the cutterhead to explore the geological conditions within a range of 20m-30m ahead; Chemical irrigation reinforcement: If a large inflow of water (>10) occurs in the borehole If the borehole collapses, the drill pipe is used as a grouting channel, and a high-pressure grouting pump is used to inject a mixture of isocyanate and polyether polyol (AB material). The grouting pressure is controlled at 1.5-2.0 times the hydrostatic pressure until a reinforced zone with a certain strength is formed, at which point tunneling can be resumed. Parameter reduction: In the early stage of resuming tunneling, the advance speed is forcibly limited to no more than 10 mm / min to prevent disturbance from inducing water inrush again.

[0060] Specific application examples: Project Background: The diameter of the TBM tunneling machine in this tunnel section The section, spanning meters, traverses strata consisting of white marble and marbled limestone, situated within a densely jointed zone and a water-rich fractured zone. At kilometer marker PK139+923.6, a sudden water inrush occurred (peak flow rate reaching...). hydrostatic pressure is approximately This caused a large amount of milky white rock debris to accumulate and compact, resulting in a sharp increase in the cutterhead torque to the point of tripping, and the equipment was stuck.

[0061] Implementation steps: S1: Constructing an asymmetric fluid control environment: 2.0 meters behind the TBM tail, small pilot tunnels are excavated along the left and right side walls using the drill-and-blast method, extending 4.5 meters until connecting to the core area of ​​accumulated debris. To ensure construction safety, a protective platform consisting of 125H-shaped steel columns and No. 10 channel steel is erected in front of the pilot tunnel working chamber. A flexible variable drag flow control component is installed at the pilot tunnel entrance, using a welded steel plate portal frame combined with a C30 concrete sealing wall as rigid support, with water-swellable sealing strips at the edges to ensure the component adheres tightly to the rough rock wall. A data acquisition network is connected to receive signals for propulsion pressure, drive torque, and tail grease pressure.

[0062] S2: The TBM initiates a micro-preload by opening the quick-release control valve after the impedance reference measurement. Data acquisition results: Peak drive torque. Static passive reaction force of propulsion system Substitute into the formula to calculate the card impedance index. : ; The set safe startup threshold is 0.65. Judgment result: If the slag is determined to be in a high-stress locked state, simply increasing the torque will risk damaging the equipment, and the slag removal cycle must be started.

[0063] S3: Execute transient pore water pressure-activated sludge removal cycle Close the quick-release control valve and calculate the minimum critical excitation rate. Parameter settings: Boundary leakage flux (Measured) Compression coefficient of slag and soil mixture Equivalent volume of sludge cavity Target boost rate Pa / s; Effectively advances cross-sectional area .

[0064] Calculation process: ; The system controls the propulsion cylinder to perform micro-feed compression at a speed of 0.25 m / s. When the propulsion pressure monitoring value reaches 1.2 MPa, the quick discharge control valve is opened instantaneously and the cylinder is controlled to retract, using the pressure difference and elastic rebound to spray the liquefied slag into the small guide tunnel. This process is repeated 5 times.

[0065] S4: Secondary impedance measurement and graded restart: Perform micro-preloading again and measure... kN·m, passive reaction force kN. Calculate the new exponent: ; S5: Pressure Balanced Sealing Result: 0.358 < 0.65, the restart condition is met.

[0066] Perform the following steps in sequence: 1. Reverse the cutter head at 0.2 rpm for 3 minutes; 2. Inject clean water and lubricant to clean for 5 minutes; 3. Resume load and advance.

[0067] After the TBM leaves the machine area by 5 meters, keep the flexible variable resistance drainage control component in the installed closed state and connect the grouting pipeline to the large-diameter drainage pipe. Minimum pressure of the shield tail grease. bar, setting a safety margin bar. Calculate the upper limit of grouting backfill pressure: bar (0.4 MPa); Using a grouting pump, AB chemical grouting material (component A is basic isocyanate, component B is a combination of polyether polyols) is injected into the tiny gaps in the guide tunnel and cavity, while C30 concrete is pumped in to backfill larger disturbed spaces. The real-time grouting pressure is controlled between 0.35 MPa and 0.38 MPa (meeting the requirement of being below the upper limit of 0.4 MPa and above the hydrostatic pressure of 0.25 MPa). After the material has reacted, solidified, and reached its water-stopping strength, the external components are removed, completing the sealing process.

[0068] Subsequent defense mechanisms: During subsequent tunneling, the system calculates the active defense trigger index. When thrust fluctuation amplitude is detected Increased and real-time pore water pressure monitoring values Abnormally high, leading to When the value exceeds 0.65, a micro-pulse propulsion with a frequency of 1.0Hz is automatically triggered to prevent the device from freezing again.

[0069] Experimental verification and effect comparison: To verify the effectiveness of this invention, a 1:10 scale physical simulation test bench for TBM tunneling was constructed. The test bench simulated the TBM jamming condition caused by water-rich sandstone and mudstone interbedded layers, comparing the "conventional high-torque escape method" (control group) with the "small pilot tunnel coordinated drainage and slag removal method of this invention" (experimental group).

[0070] Experimental conditions: Surrounding rock environment: a mixture of saturated clay and gravel with a compaction degree of 95%.

[0071] Initial surrounding rock pressure: 0.5 MPa.

[0072] Criteria for determining machine jamming: The starting torque of the cutter head exceeds 120% of the rated value.

[0073] Conclusion Analysis: See attached document Figure 3 Based on the data from the aforementioned embodiments and the curve characteristics in the attached figures, the following conclusions can be drawn: The impedance relief effect of the card machine is obvious: from Figure 3 (a) It can be seen that in the initial stage of jamming (50 to 150 seconds), the driving resistance torque of both methods reached a peak of 8000 kN·m. When using the conventional high-torque escape method (dashed line), although the equipment continuously outputs high torque to attempt forced rotation, the resistance torque consistently remained at a high oscillation level above 8000 kN·m, indicating that the physical blockage of the slag was not broken. In contrast, the method of this invention (solid line) showed a clear stepwise decreasing trend in resistance torque during the period from 150 to 450 seconds through three cycles of "blocking pressurization and explosive venting." After each cycle, the resistance torque decreased by approximately 2000 kN·m, finally stabilizing at a normal tunneling level of 2000 kN·m around 450 seconds. This indicates that through asymmetric fluid control, the force chain structure of the slag was successfully disrupted, reducing the jamming resistance index below the safe start-up threshold.

[0074] The pore water pressure activation mechanism is effective: Figure 3 (b) The physical mechanism of the resistance reduction was revealed. In conventional methods, the pore water pressure within the slag accumulation cavity is maintained at around 500 kPa for a long period (dashed line). This constant high pressure intensifies the compaction effect of the slag. However, the method of this invention (solid line) artificially creates significant pressure pulsations during the slag cleaning cycle (150 to 450 seconds). In each cycle, the pore water pressure is first surged to around 900 kPa (liquefaction activation), then drops sharply to 200 kPa due to the instantaneous opening of the valve (transient unloading). This drastic pressure gradient change (pressure difference of up to 700 kPa) generates strong seepage forces within the slag accumulation, causing slag particles to be expelled from the cavity under the combined effects of liquefaction and high-speed flow, thus achieving physical slag cleaning.

[0075] Security and timeliness verification: comprehensive (a) (b) As shown in the two figures, the method of this invention completed the entire process from complete jamming to normal operation within approximately 600 seconds (10 minutes), and no torque overload peak occurred throughout the process. Compared with conventional methods, this solution utilizes fluid energy instead of mechanical energy for slag removal, avoiding the risk of overheating due to prolonged stalling of the cutterhead motor. Furthermore, the pressure balance control in step S5 prevents shield tail seal rupture accidents caused by rapid pressure relief, demonstrating the high efficiency and safety of this construction method under complex conditions in water-rich contact zones.

Claims

1. A method for coordinating drainage and debris removal during TBM tunneling in water-rich contact zones, characterized in that... Includes the following steps: After the full-face tunnel boring machine encounters a jam, small guide tunnels are excavated on both sides behind the shield tail and flexible variable resistance flow control components are installed. Data acquisition and closed-loop control networks are connected to construct an asymmetric fluid control environment. Based on the aforementioned asymmetric fluid control environment, the full-face tunnel boring machine is controlled to perform a micro-preload detection action. The peak driving torque during this micro-preload detection action is synchronously acquired using the data acquisition and closed-loop control network. The static passive reaction force is also measured while the propulsion cylinder assembly maintains a constant cylinder extension length under the condition that the peak driving torque is applied. Based on the nominal diameter of the shield body, the jamming resistance index, characterizing the severity of the current jamming, is calculated using the following formula: ； In the formula, This indicates the impedance index of the card reader; This represents the peak driving torque measured during the micro-preload detection action; This represents the axial resultant force on the shield body caused by the constraint of the surrounding rock and slag, measured by the propulsion cylinder assembly under the condition that the cylinder extension length remains unchanged when the peak driving torque is applied; This indicates the nominal diameter of the shield body of a full-face tunnel boring machine; When the impedance index of the card exceeds the safe start threshold, the transient pore water pressure is activated to stimulate the slag removal cycle. By alternately executing dynamic lock-up pressurization and asymmetric explosive discharge actions, the slag liquefaction is artificially induced and the system's elastic potential energy is used to complete the directional jet slag discharge. The state after slag discharge is subjected to secondary impedance measurement and verification. If the verification is successful, the staged restart is carried out in the order of reverse relaxation, hydraulic cleaning and load propulsion. After the full-face tunnel boring machine is completely freed and drives away from the jammed area, the flexible variable resistance drainage control component is removed, and the pressure balance of the small pilot tunnel and cavity is completed by using the real-time data feedback from the shield tail grease pressure sensor.

2. The method for co-construction of drainage and slag removal in TBM tunneling with small pilot tunnel in water-rich contact zone according to claim 1, characterized in that, The steps for constructing the asymmetric fluid control environment include: After the full-face tunnel boring machine encountered a jam, small pilot tunnels were excavated on both sides behind the shield tail and flexible variable resistance flow control components were installed at the entrance of the pilot tunnels. Based on the flexible variable resistance flow control component, a radial preload is applied to the rigid support frame inside the component using a hydraulic pressure unit, which forces the flexible filling layer covering the outer periphery of the frame to tightly adhere to the inner wall of the guide hole, thereby constructing a high flow resistance boundary. In conjunction with the high flow resistance boundary, a fast-discharge control valve located at the center of the flexible variable resistance discharge control component is used to control the flow on and off, thereby creating an asymmetric fluid control environment.

3. The method for co-construction of drainage and slag removal in TBM tunneling with small pilot tunnel in water-rich contact zone according to claim 1, characterized in that, The safe start threshold is set to 0.6 to 0.

8.

4. The method for co-construction of drainage and slag removal in TBM tunneling with small pilot tunnel in water-rich contact zone according to claim 1, characterized in that, In the step of initiating transient pore water pressure-induced sludge removal circulation, the dynamic locking pressurization action includes: When the impedance index of the card machine exceeds the safe start threshold, the quick discharge control valve is closed and the propulsion cylinder group is controlled to perform micro-feed compression action; Based on the micro-feed compression action, the speed parameter is set using the minimum critical excitation speed formula to ensure that the rate at which the slag volume is compressed is greater than the rate at which the fluid leaks through the edge gaps of the flexible variable resistance flow control component, thereby completing the dynamic lock-in pressurization.

5. The method for co-construction of drainage and slag removal in TBM tunneling with small pilot tunnel in water-rich contact zone according to claim 1, characterized in that, In the step of initiating transient pore water pressure-induced slag removal circulation, the asymmetric explosive discharge action includes: After alternately executing the dynamic lock-up boosting action, monitor the changes in propulsion pressure and drive torque. When the liquefaction critical condition is met, open the quick discharge control valve and control the propulsion cylinder group to perform a rapid unloading and rebound action. The rapid unloading and rebound action releases the elastic strain energy of the shield and hydraulic system, thereby generating a backward axial recovery displacement, which, in conjunction with the fluid drag force, discharges the liquefied slag. By discharging the liquefied slag, directional jet slag discharge is achieved using the system's elastic potential energy.

6. The method for co-drainage and slag removal construction of TBM tunneling in water-rich contact zone according to claim 5, characterized in that, The step of using the system's elastic potential energy to complete directional spray slag removal includes: While performing the rapid unloading and rebound action, a flow field orientation guidance strategy based on eccentric unloading is activated; Based on the flow field orientation guidance strategy based on eccentric unloading, the partitioned cylinders of the propulsion cylinder group are operated asymmetrically. While opening the small guide hole on one side for drainage, the pressure of the other partition is maintained and the pressure of the corresponding side partition is preferentially and quickly unloaded, thereby constructing a lateral pressure gradient. The lateral pressure gradient is used to guide the internal flow field of the slag towards the discharge port, thus assisting in the directional spraying and slag discharge.

7. The method for co-construction of drainage and slag removal in TBM tunneling with small pilot tunnel in water-rich contact zone according to claim 1, characterized in that, The steps for performing a graded restart include: After the slag discharge status is verified, the cutter head drive system is controlled to perform a reverse relaxation action at low speed and low torque. After completing the reverse relaxation action to eliminate residual contact stress, keep the cutter head rotating forward under no load and inject cleaning fluid for hydraulic cleaning; After the hydraulic cleaning process continues until the slag content of the discharged fluid decreases, a linear loading strategy is employed to restore thrust and rotational speed for load propulsion.

8. The method for co-construction of drainage and slag removal in TBM tunneling with small pilot tunnel in water-rich contact zone according to claim 1, characterized in that, The pressure-balanced sealing steps for the small guide hole and cavity include: After the full-face tunnel boring machine is completely freed and driven away from the jammed area, the flexible variable resistance flow control component is removed and a sealing wall is built at the pilot tunnel entrance before backfilling and grouting are carried out. At the same time, the data of the shield tail grease pressure sensor is read. The data from the shield tail grease pressure sensor is used as feedback values ​​and substituted into the safe grouting pressure control formula. Based on the aforementioned safe grouting pressure control formula, the real-time upper limit of grouting backfill pressure is calculated, and differential pressure linkage control is applied to the output pressure of the grouting pump to achieve pressure-balanced sealing.

9. The method for co-construction of drainage and slag removal in TBM tunneling with small pilot tunnel in water-rich contact zone according to claim 1, characterized in that, Following the pressure-balanced sealing, the process also includes activating the active defense interface after resuming normal tunneling. The data acquisition and closed-loop control network is used to collect thrust fluctuation amplitude, torque fluctuation amplitude and pore water pressure monitoring values ​​in real time, and substitute them into the active defense trigger index formula; The active defense trigger index is calculated using the aforementioned active defense trigger index formula; When the active defense trigger index is detected to continuously exceed the defense activation threshold, the hydraulic cylinder group is forced to enter the micro-pulsation propulsion mode.

10. The method for co-construction of drainage and slag removal in TBM tunneling with small pilot tunnel in water-rich contact zone according to claim 1, characterized in that, The steps for connecting the data acquisition and closed-loop control network include: The propulsion pressure sensor is connected to the hydraulic circuit of the propulsion cylinder group, and the drive torque sensor is connected to the output end of the cutterhead drive system motor to obtain tunneling parameter data. A grease pressure sensor is placed inside the tail shield sealing chamber to obtain sealing pressure data. The tunneling parameter data and the sealing pressure data are connected to the data acquisition and closed-loop control network to form a closed-loop topology.

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