Self-adaptive regulation and control method for small-clear-distance large-longitudinal-slope shield construction in water-rich broken uneven stratum

Abstract

The invention belongs to the technical field of shield construction methods, and particularly relates to a water-rich broken uneven stratum small-clear-distance large-longitudinal-slope shield construction self-adaptive regulation and control method which comprises the steps that the working condition type of a small-clear-distance large-longitudinal slope is obtained; the type of the water-rich broken uneven stratum at the small-clear-distance and large-longitudinal-slope position is obtained; according to the working condition type, the stratum type and the working condition classification, selecting shield tunneling parameters; based on shield tunneling parameters, in the operation process, the stratum is reinforced, and meanwhile, segments are installed along the actual route of a shield tunneling machine; and according to the deviation data between the actual shield parameters in the shield construction operation and the previously selected shield parameters, the ground surface settlement change value and the segment slab staggering condition, the actual route and the shield parameters of the shield tunneling machine are adjusted. The invention provides a construction parameter regulation and control strategy and a flexible control method suitable for different stratums according to composition characteristics of soil layers. And according to the actual route deviation, the ground surface settlement change value and the duct piece slab staggering condition, the operation parameters are dynamically adjusted, and few people and unmanned operation are achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of shield tunneling methods, and particularly relates to an adaptive control method for shield tunneling in water-rich, fractured, and uneven strata with small clearance and large longitudinal slope. Background Technology

[0002] In modern tunnel and underground engineering construction, the shield tunneling method has become a widely used construction technology. Especially under complex geological conditions, the stability and construction efficiency of the shield machine directly affect the project progress and safety. In actual projects, traditional construction methods face many technical challenges when encountering extreme conditions such as small clearances, steep longitudinal slopes, and water-rich fractured strata.

[0003] Small clearances and steep gradients are common in urban underground pipeline construction and mountain tunnel construction. Small clearances severely limit the tunnel boring machine's (TBM) advance space, especially when close to adjacent tunnels or underground facilities. This can easily lead to collisions or displacement during advancement, affecting stability and safety. Steep gradients further increase the difficulty of the TBM's operation, particularly on steep slopes. Improper attitude control or insufficient thrust can cause instability or low operational efficiency during advancement.

[0004] The presence of water-rich, fractured strata presents another significant challenge. Under these geological conditions, groundwater permeability is high, water pressure is high, and the strata are severely fractured, resulting in a substantial decrease in their support capacity and stability. During tunnel boring machine (TBM) advancement, changes in water pressure, loosening of fractured rock layers, and water seepage can easily disturb the strata, potentially leading to localized collapses or rockfalls, thus affecting the tunnel's construction quality and safety.

[0005] Currently, several grouting, support, and protection technologies have been applied to address some of the problems associated with these complex construction conditions. However, these traditional technologies often suffer from drawbacks such as long construction cycles, uneven grouting effects, and uncontrollable ground deformation, making them ineffective in ensuring long-term safety, stability, and construction efficiency under complex geological conditions.

[0006] The existing earth pressure balance shield tunneling technology has the following main shortcomings:

[0007] (1) Most shield tunnel construction methods only address a single risk, and lack a systematic classification standard for working conditions under multiple risks such as large longitudinal slope, small clearance and water-rich fractured strata.

[0008] (2) Attitude control under small clearance and large longitudinal slope is difficult. Under the dual challenges of small clearance and large longitudinal slope, the attitude control of the tunnel boring machine becomes particularly complex. Existing attitude control technology is difficult to cope with thrust changes under large longitudinal slope conditions. Especially in the construction of large longitudinal slope, when the attitude deviation is large, traditional control methods are often difficult to correct in real time, which affects the stable advancement of the tunnel boring machine.

[0009] (3) In water-rich and fractured strata, the groundwater is highly mobile and the strata are fractured. During grouting, the grout is easily lost, resulting in insufficient grouting volume, which cannot effectively seal the seepage channels and the grouting effect is uneven. Existing grouting technology mainly relies on a single grouting material and lacks dynamic adaptation to different strata characteristics, resulting in unstable grouting effect and inability to guarantee the long-term stability of the strata.

[0010] (4) The ability to monitor ground settlement and segment floating in real time during construction is weak. The grouting parameters, such as grouting pressure, grout ratio and grouting volume, are not dynamically adjusted in conjunction with real-time monitoring data, such as buoyancy and grout fluidity.

[0011] Based on the aforementioned shortcomings of traditional technologies, we propose a shield tunneling method for water-rich, fractured, and uneven strata with small clearance and large longitudinal slope. Summary of the Invention

[0012] The purpose of this invention is to provide an adaptive control method for shield tunneling in water-rich, fractured, and uneven strata with small clearance and large longitudinal slope, in order to solve the above-mentioned problems.

[0013] To achieve the above objectives, the present invention provides the following solution:

[0014] An adaptive control method for shield tunneling in water-rich, fractured, and uneven strata with small clearances and large longitudinal slopes includes the following steps:

[0015] Obtain the working condition type with small clearance and large longitudinal slope;

[0016] Classification of working conditions based on small clearance and large longitudinal slope;

[0017] The working conditions include: conventional slope and conventional clearance, conventional slope and medium clearance, conventional slope and small clearance, medium slope and conventional clearance, medium slope and medium clearance, medium slope and small clearance, large longitudinal slope and conventional clearance, large longitudinal slope and medium clearance, and large longitudinal slope and small clearance.

[0018] To determine the water-rich, fractured, and heterogeneous strata at a small net distance and a large longitudinal slope;

[0019] Select the tunnel boring machine parameters based on the working condition type, geological type, and working condition classification.

[0020] Based on the shield tunneling parameters, during the operation, the strata are reinforced, and the tunnel segments are installed along the actual route of the shield machine.

[0021] Based on the deviation data between the actual shield parameters during shield tunneling operations and the previously selected shield parameters, the changes in ground settlement, and the misalignment of tunnel segments, the actual route of the shield machine and the aforementioned shield parameters are adjusted.

[0022] Optionally, the tunneling parameters include tunneling speed, cutterhead rotation speed, total thrust, and cutterhead torque.

[0023] Optionally, the step of obtaining the formation type includes:

[0024] The stratigraphic data includes information on the classification of surrounding rocks, structure, degree of joint development, and groundwater pressure within the section. The stratigraphic classification is performed based on the coefficient of heterogeneity.

[0025] Optionally, the formation type includes:

[0026] Weakly heterogeneous fractured strata, heterogeneous fractured strata, extremely heterogeneous fractured strata;

[0027] Select the synchronous grouting parameters according to the formation type.

[0028] Optionally, the grouting parameters include grouting volume, grouting pressure, and grout mix ratio.

[0029] Optionally, during the installation of tunnel segments, the elevation of the segments can be adjusted by grouting and by adjusting the actual route of the tunnel boring machine.

[0030] Optionally, after the tunnel segments detach from the shield tail of the tunnel boring machine by 2 to 3 rings, secondary grouting is performed in the assembly holes on both sides of the top of the tunnel segments.

[0031] Optionally, the steps for obtaining deviation data between the designed route and the actual route of the tunnel boring machine include:

[0032] Obtain the actual route of the tunnel boring machine (TBM) based on its attitude;

[0033] The deviation data is obtained by comparing the actual route of the tunnel boring machine with the designed route.

[0034] Optionally, the shield machine's attitude can be obtained through an automatic guidance system and manual measurement verification.

[0035] Optionally, a warning value and a warning level are set, and the deviation data is compared with the warning value to obtain the warning level.

[0036] Compared with the prior art, the present invention has the following advantages and technical effects:

[0037] (1) A multi-risk working condition system classification standard was established. Based on different combinations of small clearance, large longitudinal slope and water-rich fractured strata, a detailed construction parameter control system was formulated to ensure that the tunnel boring machine can operate stably under complex working conditions and avoid the problems caused by single risk treatment in traditional methods.

[0038] (2) Dynamically adjust the thrust distribution and attitude offset according to the actual construction environment to ensure that the tunnel boring machine maintains a stable advancing attitude in complex environments with large longitudinal slopes and small clearances, thereby improving the safety and efficiency of construction.

[0039] (3) By monitoring groundwater pressure and formation permeability in real time, the grouting pressure, grouting volume and grout ratio can be automatically adjusted according to the different characteristics of water-rich fractured and uneven formations, so as to ensure that the grout can penetrate deep into the fractured fissures and effectively block the seepage channels in a high water flow environment.

[0040] (4) By combining multiple sensor monitoring and real-time data feedback, dynamic control throughout the entire process was achieved by adjusting parameters such as grouting pressure, rate, grout ratio, thrust, and attitude, effectively avoiding ground disturbance, settlement, and uneven grouting problems. Through real-time monitoring and feedback adjustment of the tunnel boring machine and grouting system, the safety, accuracy, and efficiency of construction were improved. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a flowchart of the method of the present invention.

[0043] Figure 2 This is a detailed flowchart of the method of the present invention. Detailed Implementation

[0044] The technical solutions of 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.

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Reference Figures 1 to 2 An adaptive control method for shield tunneling in water-rich, fractured, and uneven strata with small clearance and large longitudinal slope includes the following steps:

[0047] When a tunnel has both a large longitudinal slope and a small clearance (such as an urban underground utility tunnel crossing a complex terrain section), this patent adopts a "priority adaptation" strategy: it prioritizes meeting the parameter requirements of the large longitudinal slope (such as high thrust on the uphill section), and then adjusts the small clearance to balance the climbing requirements and the control of ground disturbance.

[0048] Specific control methods include:

[0049] Among them, the classification of working conditions with small clearance and large longitudinal slope is as follows:

[0050] Based on the slope (i) of the tunneling section, it can usually be divided into three levels:

[0051] Typical slope: i < 20‰, risk is controllable, and conventional measures can meet the requirements.

[0052] Medium longitudinal slope: 20‰≤i<30‰, the difficulty of shield attitude control increases, and the risk of segment floating is significant.

[0053] With a steep longitudinal slope (i≥30‰), the orientation of the tunnel segments is extremely difficult to control, making them prone to misalignment and damage, and posing a severe challenge to the drainage system.

[0054] Based on the ratio of the net distance (S) between two tunnels to the tunnel diameter (D), they can be divided into three levels:

[0055] Standard clearance: S / D≥2.0, with minimal mutual influence, standard control is sufficient.

[0056] Medium clearance: 1.5≤S / D<2.0. Construction of the subsequent line will significantly disturb the preceding line and requires active control.

[0057] Small clearance (S / D < 1.5) indicates a significant mutual influence and extremely high risk, requiring special comprehensive measures.

[0058] S3. Shield tunneling control measures under different risks

[0059] Taking the right line first and the left line later as an example, the shield tunneling parameters are adjusted for the uphill section.

[0060] 1. Standard slope and standard clearance: Slope < 20‰, clearance / diameter ≥ 2.0

[0061] Main risks: Poor formation stability, requiring control of tunneling speed and thrust to reduce disturbance to the formation.

[0062] Attitude pre-deflection: Before entering the small clearance section, the shield cut position is pre-deflected 3~5mm in the opposite direction of the longitudinal slope; the hydraulic cylinder stroke difference is ≤30mm.

[0063] The tunneling speed is controlled at 15-22 mm / min; the cutterhead rotation speed is 1.2-1.8 r / min; the total thrust is 8000-9000 KN; the cutterhead torque is 2000-3000 KN·m; and the cutterhead rotation speed is 1.0-1.6 r / min.

[0064] Monitoring: Automatic guidance and manual verification every 3-5 rings.

[0065] 2. Conventional slopes and moderate clearance: Slope < 20‰, 1.5 ≤ clearance / diameter < 2.0

[0066] Main risks: Disturbance to the leading line, resulting in poor formation stability.

[0067] Tunneling speed and thrust control measures: Top thrust approximately 2353kN, bottom thrust approximately 2470kN, left thrust (the side furthest from the lead line) approximately 3400kN, right thrust (adjacent side) approximately 2506kN, to reduce disturbance to the lead line. Tunneling speed slightly reduced to 12-18mm / min.

[0068] Cutter head parameter control: cutter head speed 1.0-1.6 r / min; cutter head torque 2000-3000 KN·m;

[0069] Tunnel Boring Machine (TBM) Attitude Control: The attitude should be pre-deflected by 3-6mm, prioritizing avoidance of the lead-in line direction; the hydraulic cylinder stroke difference should be ≤40-50mm to retain correction margin. When the TBM attitude deviates 5mm to one side of the lead-in line, the tunneling speed should be reduced to 10mm / min; when the deviation is ≥8mm, the machine should be stopped, and then the thrust on both sides should be balanced.

[0070] Monitoring: Manually check the displacement of the lead line and the interlayer stress every 3-5 rings; immediately reduce speed and add grout when the trigger threshold (lead line settlement 10mm) is reached.

[0071] 3. Standard slopes and small clearances: Slope < 20‰, clearance / diameter < 1.5

[0072] Main risks: The small clearance allows disturbances from the following line to be directly transmitted to the leading line, which can easily lead to segment misalignment and local voids, requiring control.

[0073] Tunneling speed and thrust control measures: top thrust approximately 1900.0 kN, bottom thrust approximately 2100.0 kN, left thrust (far side) approximately 3600 kN, right thrust (adjacent side) approximately 3000 kN;

[0074] Cutter head parameter control: cutter head torque is 2000-3000 KN·m; cutter head speed is 0.9-1.4 r / min;

[0075] Shield attitude control measures: pre-deflection of 5-10mm, hydraulic cylinder stroke difference ≤50mm, fine adjustment at any time; tunneling speed of 10-15mm / min, when the deviation is 3mm, it is reduced to about 10mm / min; when the deviation is ≥5mm, the machine must be stopped immediately and thrust balancing must be performed.

[0076] Ground reinforcement: Advanced deep-hole grouting or jet grouting piles are used in the interlayer of the double-line structure to improve the interlayer stiffness.

[0077] Monitoring: Review every 1-3 rings; use 3D laser scanning or radar point cloud to assess seams and voids.

[0078] 4. Medium slope and standard clearance: 20‰ ≤ slope < 30‰, clearance / diameter ≥ 2.0

[0079] Main risks: The tendency of the tunnel boring machine to "raise its head / bump its head" (attitude deviation) is increasing, and special attention needs to be paid to drainage and grout subsidence.

[0080] Tunneling speed and thrust control measures: The total thrust is controlled at about 11,500 kN, with the top thrust at about 2,300 kN, the bottom thrust at about 2,700 kN, the left thrust at about 3,100 kN, and the right thrust at about 2,600 kN. The thrust needs to be increased step by step on the uphill section and decreased step by step on the downhill section.

[0081] Cutter head parameter control measures: cutter head speed 0.8-1.5 r / min, avoid frequent speed changes; cutter head torque 2000-3000 KN·m;

[0082] Shield attitude control measures: pre-deflection increased to 8-12mm; bottom thrust 15-20% higher than top thrust. Hydraulic cylinder stroke difference can be increased to ≤50mm; articulated assistance can be used if necessary, with stroke difference fine-tuned by 10-15mm. Tunneling speed 10-18mm / min, maintained at 14-16mm / min; when deviation reaches 4mm, reduce to approximately 8mm / min; when deviation reaches 6mm, stop the machine and prioritize adjusting top and bottom thrust to restore the pitch angle.

[0083] Drainage: Set up temporary multi-stage pumping stations and strengthen drainage at the working face.

[0084] 5. Medium slope and medium net distance: 20‰≤i <30‰, 1.5≤S / D<2.0

[0085] Main risks: Difficulty in attitude control and significant propagation of backward disturbances to the leading line; increased risk of segment floating / misalignment.

[0086] Tunneling speed and thrust control measures: The total thrust is about 12,000 kN, with the top thrust being about 2,450 kN, the bottom thrust about 2,800 kN, the left (far side) about 3,100 kN, and the right (adjacent side) about 2,650 kN. The thrust needs to be gradually increased on the uphill section and gradually decreased on the downhill section to maintain the longitudinal slope attitude while minimizing disturbance to the lead line.

[0087] Cutter head parameter control measures: cutter head speed 0.9–1.4 r / min; cutter head torque 2000-2500 KN·m, reducing torque sudden changes;

[0088] Shield attitude control measures: pre-deflection of 10-12mm (adjusted according to slope, avoiding the lead-in line); hydraulic cylinder stroke difference ≤50mm and dynamically adjusted. Tunneling speed controlled at 13-15mm / min, speed reduced to about 10mm / min when deviation ≥3mm; machine stopped and thrust balancing performed when deviation ≥5mm.

[0089] Monitoring and emergency response: Check every 1-3 rings; if the settlement of the pilot line is ≥10mm or the attitude changes rapidly, immediately reduce the speed and add grout.

[0090] 6. Medium slope and small clearance: 20‰≤i <30‰, S / D<1.5

[0091] Main risks: The longitudinal slope causes a significant attitude deviation moment; the small clearance makes it difficult to attenuate disturbances, leading to local damage to the leading line and a high probability of misalignment.

[0092] Tunneling speed and thrust control measures: The total thrust is controlled at about 11,500 kN, with about 2,300 kN at the top, about 2,700 kN at the bottom, about 3,100 kN on the left (far side), and about 2,500 kN on the right (adjacent side). The thrust needs to be increased step by step on the uphill section and decreased step by step on the downhill section. The thrust on the far side needs to be further strengthened to ensure safe tunneling.

[0093] Cutter head parameter control measures: cutter head speed 0.8-1.2 r / min; cutter head torque 1800-2200 KN·m, reducing torque sudden changes;

[0094] Tunnel boring machine (TBM) attitude control measures: Pre-deflection of 12-15mm, activation of articulated hydraulic cylinders, with the cylinder stroke difference concentrated within the 10-15mm articulated movement range for rapid attitude correction. Tunneling speed maintained at 12-14mm / min; when deviation ≥3mm, it should be reduced to approximately 6mm / min; when deviation ≥5mm, the machine should be stopped immediately and thrust balancing performed.

[0095] Reinforcement: If necessary, perform advanced deep-hole grouting and jet grouting to increase the stiffness of the interlayer and prevent water leakage.

[0096] Monitoring and contingency plans: Encryption is applied to every ring, and a level 3 early warning triggers an immediate halt to excavation and full-section reinforcement.

[0097] 7. Severe longitudinal slope and conventional clearance: 30‰≤i, S / D≥2.0

[0098] Main risks: High probability of loss of posture (head up or head down); uneven stress on tunnel segments and difficulty in drainage.

[0099] Tunneling speed and thrust control measures: The total thrust is about 12,500 kN, including about 2,600 kN at the top, about 3,000 kN at the bottom, about 3,200 kN on the left side and about 2,700 kN on the right side. The thrust needs to be increased step by step on the uphill section and decreased step by step on the downhill section.

[0100] Cutter head parameter control measures: cutter head speed 0.8-1.2 r / min; cutter head torque 1800-2200 KN·m, reducing torque sudden changes;

[0101] Tunnel boring machine (TBM) attitude control measures: Dynamic pre-deflection of 12-18mm, activation of articulation and differential thrust to generate a continuous upward torque; the hydraulic cylinder stroke difference and articulation action must be linked in real time. Tunneling speed is controlled at 15-18mm / min, reduced to about 8mm / min when the deviation is ≥3mm; the machine is stopped when the deviation is ≥5mm, and the pitch angle is adjusted with priority given to bottom / top thrust.

[0102] Drainage: Multi-stage drainage pumping stations and possible advance precipitation plans must be arranged.

[0103] 8. Severe longitudinal slope and moderate clearance: 30‰≤i, 1.5≤S / D<2.0

[0104] Main risks: The superposition of longitudinal slope attitude loss and subsequent disturbances significantly increases the risk of damage / seepage / misalignment of the leading line.

[0105] Tunneling speed and thrust control measures: Total thrust is about 11,800 kN, about 2,300 kN at the top, about 2,700 kN at the bottom, about 3,200 kN on the left side, and about 2,800 kN on the right side. The thrust needs to be increased step by step on the uphill section and decreased step by step on the downhill section.

[0106] Cutter head parameter control measures: cutter head speed 0.8-1.2 r / min to avoid sudden changes; cutter head torque 2000-2500 KN·m to reduce torque mutations.

[0107] Tunnel boring machine (TBM) attitude control measures: Pre-deflection of 15-18mm. Tunneling speed controlled at 14-17mm / min; reduced to approximately 10mm / min when deviation ≥3mm; shutdown and thrust balancing performed when deviation ≥5mm.

[0108] Reinforcement: Advanced deep-hole grouting and jet grouting are carried out to increase the stiffness of the interlayer and prevent water leakage.

[0109] Monitoring: Each ring is reviewed, and a Level 3 early warning is triggered to immediately stop excavation and implement full-section reinforcement.

[0110] 9. Severe longitudinal slope and small clearance: 30‰≤i, S / D<1.5

[0111] At this stage, gravity dominates the orientation, resulting in an extremely high risk of segment breakage and collapse of the narrow-clearance interlayer. Therefore, a "limiting parameters and multiple protection" strategy is required.

[0112] (1) Shield attitude control measures: dynamic adjustment of pre-deflection and articulated hydraulic cylinder assistance

[0113] Attitude pre-deflection: The pre-deflection amount is dynamically adjusted according to the real-time slope (30‰ slope pre-deflection 3~5mm, 35‰ slope pre-deflection 6~8mm). For small clearance sections, the "safe pre-deflection range" needs to be calculated in conjunction with the position of the leading line (e.g., when the left line moves first, the right line moves later with a rightward deflection amount ≤8mm) to avoid the attitude adjustment squeezing the leading line.

[0114] Thrust and articulation coordination: The bottom cylinder thrust is 25%~30% higher than the top cylinder thrust, and the articulation cylinder is activated at the same time (stroke difference controlled within 10~15mm) to assist in adjusting the angle of the tunnel boring machine body and reduce the tendency to "dive".

[0115] Tunneling parameter control: A low-thrust, low-torque operating mode is adopted to keep the tunnel boring machine (TBM) in a slow-speed tunneling state, thereby reducing the horizontal lateral thrust of the jacks on the tunnel segments and minimizing disturbance to the ground. The total thrust is controlled at approximately 11,500 kN, with approximately 2,400 kN at the top, 2,800 kN at the bottom, 3,000 kN on the left (far side), and 2,200 kN on the right (adjacent side). Thrust needs to be gradually increased on uphill sections and gradually decreased on downhill sections. The tunneling speed is reduced to 10-18 mm / min; the cutterhead rotation speed is 0.8 r / min-1.5 r / min; and the cutterhead torque is 1700-2500 kN·m, ensuring cutting efficiency while avoiding torque fluctuations.

[0116] Segment elevation adjustment: By coordinating grouting and attitude, if the segment rises more than 8mm, immediately reduce the top grouting volume (-15%) and increase the bottom thrust (5%); if it sinks more than 5mm, adjust in the opposite way, while avoiding excessive adjustment range that may cause misalignment of segments with small clearance.

[0117] (3) Special strata coordinated control measures: strata reinforcement as a backup and three-level early warning

[0118] For geological pretreatment: When the interlayer with small clearance is a soft upper layer and a hard lower layer, the upper sandy layer is reinforced with high-pressure jet grouting piles (pile diameter 600mm, spacing 400mm), and the lower hard rock is reinforced with deep-hole grouting (hole depth exceeding the tunnel diameter by 2 times) to form a "rigid isolation layer"; when it is a high water pressure stratum, an additional water-stop curtain (cement-water glass double liquid grout, diffusion radius ≥1.5m) is set between the two tunnels to prevent water inrush from causing the interlayer to become unstable.

[0119] Level III Early Warning and Emergency Response: Three levels of early warning are set: Yellow (deviation 8~12mm / settlement 10~15mm), Orange (deviation 12~15mm / settlement 15~20mm), and Red (deviation ≥15mm / settlement ≥20mm).

[0120] Yellow alert: Increase monitoring frequency and fine-tune grouting pressure (±0.02MPa);

[0121] Orange alert: Stop tunneling, start compensating grouting (inject dual-liquid grout into the pilot line side), and adjust thrust distribution (reduce thrust on the side closer to the pilot line by 10%).

[0122] Red Alert: Immediately stop the machine and perform full-section grouting reinforcement on the narrow gap interlayer. After the monitoring data recovers to a safe range (deviation ≤8mm / settlement ≤10mm), resume tunneling at a low speed of 8~15mm / min.

[0123] (4) Drainage guarantee: Multi-level drainage pumping stations (50m apart) are set up in the tunnel to prevent water accumulation on the longitudinal slope section from flooding the equipment or softening the interlayer strata with small clearance.

[0124] As an optional implementation method, the grouting parameters include grouting speed, grouting pressure, and grout mix ratio.

[0125] To ensure the safety of tunnel boring machine (TBM) excavation, synchronous grouting is required during the excavation process. This is to quickly fill the annular gap so that the tunnel segments can work together with the ground as soon as possible, preventing excessive ground deformation that could endanger the safety of the surrounding environment. At the same time, it serves as an external waterproofing and structural reinforcement layer for the tunnel segments, ensuring the effectiveness of the grouting.

[0126] Ordinary silicate 42.5 cement, fly ash, medium and fine sand, bentonite, and water-reducing agent were selected to prepare typical slow-setting single-liquid slurries with different components. Different slurry ratios were selected according to the classification of the strata in S1.

[0127] Obtain the stratigraphic type;

[0128] Stratigraphic types include: weakly heterogeneous fractured strata, heterogeneous fractured strata, and extremely heterogeneous fractured strata.

[0129] Select operating parameters based on the formation type;

[0130] Based on the operational parameters, at least two adjacent tunnels shall be operated, wherein the center-to-center distance between the adjacent tunnels shall be less than 1.5 times the tunnel diameter;

[0131] During the operation, the attitude of the tunnel boring machine is monitored in real time and the deviation data between the designed route and the actual route of the tunnel boring machine are obtained. When one of the adjacent tunnels is being operated, the other tunnel is stopped.

[0132] During the operation, the ground was reinforced, and tunnel segments were installed along the actual route of the tunnel boring machine.

[0133] Based on the deviation data, changes in surface settlement, and segment misalignment, the actual route and operating parameters of the tunnel boring machine are adjusted.

[0134] This invention classifies different sandy-soil composite strata types based on soil composition, combination, and clay content, and proposes construction parameter adjustment strategies and flexible control methods applicable to different strata. By dynamically adjusting operating parameters according to actual route deviations, surface settlement changes, and segment misalignment, it achieves reduced or no-manual operation, effectively improving construction efficiency. This invention also utilizes real-time optimization control based on multi-source monitoring data to efficiently control segment uplift and ground settlement under different geological conditions.

[0135] As an optional implementation, the step of obtaining the formation type includes:

[0136] Acquire stratigraphic data, which includes information on the classification, structure, and degree of joint development of the surrounding rocks within the section, as well as groundwater pressure data.

[0137] Stratigraphic classification based on stratigraphic data;

[0138] Weakly heterogeneous fractured strata, heterogeneous fractured strata, and extremely heterogeneous fractured strata.

[0139] Geological exploration:

[0140] By investigating and mapping the topography and landforms, geomorphic units are divided and their genetic types are determined. The lithology, structure, texture, and occurrence of strata are investigated, as well as the structural characteristics and weathering degree of rock masses, to understand the hardness of the rocks and the integrity of the rock masses. The age of fill deposition, the thickness of pit and pond silt layers, and the distribution and engineering geological characteristics of special soils such as soft soil, saline soil, expansive soil, weathered rock, and residual soil are investigated.

[0141] During drilling, use ordinary composite drill bits or diamond drill bits, with reverse circulation drilling using casing or mud wall support. Continuous core sampling is required throughout the hole. In cohesive soils and rock formations, the depth per pass should be controlled within 1.0-1.5m. In silt and saturated sand, the depth per pass should not exceed 1.0m; in fractured rock and weak interlayers, the depth per pass should be 0.5m-0.8m. For fractured rock masses, use 75mm diamond drill bits and double-layer core tubing or wireline core drilling. Core recovery rate: silt and cohesive soil ≥90%, sandy soil ≥70%, gravel ≥50%. The recovery rate for strongly weathered rock formations should not be less than 70%, and for moderately to slightly weathered rock formations, not less than 75%. If the core recovery rate is lower than the above standards, additional wave velocity testing or other geophysical methods should be performed.

[0142] During sampling, core samples are taken from technical boreholes according to different lithological layers and different weathering layers. Drilling is required using diamond drill bits with a diameter ≥89mm. Samples are taken from different lithologies and different degrees of weathering within the same geological unit, with no fewer than 6 samples (sets) for each major lithology. Hydrological boreholes are laid out in the main aquifer areas to conduct pumping tests, and the permeability coefficient and inflow of the Quaternary aquifers are determined layer by layer. This provides hydrogeological parameters for tunnel excavation, dewatering, and support, and estimates the tunnel water inflow.

[0143] During in-situ testing, the SD-IV type acoustic wave detector was used for single-hole testing to measure the longitudinal and transverse wave velocities of rock and soil. This was done to evaluate the soil type and site category, and to provide a basis for delineating the weathering zone of the rock mass and evaluating its quality. The test intervals for the longitudinal and transverse wave velocities of the rock and soil were 0.5m and 1.0m, respectively.

[0144] Based on six factors obtained from geological surveys—intact rock strength, core quality indicators, structural plane spacing, structural plane condition, groundwater conditions, and structural plane occurrence—the RMR system is used to classify fractured soil strata into the following types:

[0145] Weakly heterogeneous fractured formation: RMR>60;

[0146] Heterogeneous fractured formation: 40≤RMR≤60;

[0147] Extremely heterogeneous and fractured formations: RMR≤40;

[0148] Construction sequence and parameter coordinated control

[0149] Optimization of tunneling sequence: "skip-tunnel" tunneling is adopted. The tunnel is first excavated to 50-100m before the tunnel construction is started. This avoids the two tunnel boring machines operating at the same time in the small clearance section and reduces the superposition of vibrations.

[0150] 1) Weakly heterogeneous and fractured strata:

[0151] The formation has strong stability, increasing the tunneling speed by 15%; the cutterhead rotation speed is increased by 10%; and the thrust is evenly distributed, eliminating the need to apply additional thrust to any one side.

[0152] 2) Heterogeneous and fractured strata:

[0153] The formation is relatively unstable, so the tunneling speed is reduced by 10%-15%; the cutterhead speed is reduced by 5%-10% to reduce the contact speed between the cutter and the formation, thereby reducing wear and cutting of the formation; a higher thrust is applied to the side away from the weakly fractured zone to ensure that the thrust can be evenly distributed around the fractured zone.

[0154] 3) Extremely heterogeneous and fractured strata:

[0155] Due to the poor stability of the strata, the tunneling speed is reduced by 20%-25% to avoid excessively rapid advancement that could cause severe disturbance to the strata; the cutterhead speed is reduced by 15%-20%, and segmented tunneling is adopted. During each segment of tunneling, the cutters are replaced according to the actual wear condition to avoid excessive wear affecting the efficiency of subsequent tunneling. The cutter replacement cycle is adjusted to avoid using a single cutter for too long. Regularly replacing the cutters prevents the efficiency of the cutters from decreasing due to excessive wear; a higher thrust is applied to the side away from the weakly fractured zone to ensure that the thrust around the fractured zone is evenly distributed.

[0156] The slurry mix ratio is selected as follows:

[0157] 1) Weakly heterogeneous and fractured strata:

[0158] Water-cement ratio (water / cement and fly ash) 0.90~1.50, mortar-cement ratio (cement and fly ash / sand aggregate) 0.40~0.93, water-swelling ratio (bentonite / water) 0.20~0.30, fly ash / water ratio 3.25~4.68, water-reducing agent dosage 0.2%~1.5%, cellulose dosage 0.4%~1.5%;

[0159] 2) Heterogeneous and fractured strata:

[0160] Water-cement ratio (water / cement and fly ash) 0.80~1.20, mortar-cement ratio (cement and fly ash / sand aggregate) 0.40~0.78, water-swelling ratio (bentonite / water) 0.15~0.30, fly ash / water ratio 3.50~4.58, water-reducing agent dosage 0.3%~2%, cellulose dosage 0.5%~2.5%;

[0161] 3) Extremely heterogeneous fractured rock:

[0162] Water-cement ratio (water / cement and fly ash) 0.60~1.10, mortar-cement ratio (cement and fly ash / sand aggregate) 0.40~0.88, water-swelling ratio (bentonite / water) 0.10~0.40, fly ash / water ratio 2.50~5.88, water-reducing agent dosage 0.3%~2%, cellulose dosage 0.5%~2.5%;

[0163] Different grouting strategies are selected based on the classification of the strata.

[0164] The grouting strategy selection is as follows:

[0165] 1) Weakly heterogeneous and fractured strata:

[0166] The grouting pressure is controlled at 0.2-0.3 MPa; the grouting volume per ring is 8.9-10.1 m³.

[0167] 2) Heterogeneous and fractured strata:

[0168] The grouting pressure is controlled at 0.25-0.35 MPa, allowing for rapid entry into the fracture zone under higher pressure; the grouting volume per ring is 9.5-11.0 m³, ensuring that the grout can fill a larger area of ​​fractures.

[0169] 3) Extremely heterogeneous and fractured strata:

[0170] To address the challenges of highly heterogeneous and fractured strata with significant permeability differences, strong fracture connectivity, and the tendency for grout to preferentially diffuse along high-permeability channels, a method was first employed: advanced detection and construction monitoring were used to identify high-permeability fractures and water-rich channels. A two-component grout was then used for targeted sealing to rapidly reduce local permeability and cut off short-circuit seepage. The grouting pressure was controlled at 0.3-0.4 MPa to ensure efficient penetration of the grout into deep fractured zones and rapid sealing. The grouting volume per ring was 10.0-12.0 m³; this increased volume helped ensure the grout covered a larger area and filled large-area fractures. Advanced geological forecasting and pore water pressure monitoring were used to identify major water flow channels, and pre-treatment for drainage and pressure reduction in high-permeability areas was carried out before grouting.

[0171] As an alternative implementation method, the elevation of the tunnel segments is adjusted during the installation process by grouting and adjusting the actual route of the tunnel boring machine.

[0172] During the construction of tunnel segments, deviations in the route may cause an elevation difference between two adjacent tunnel segments.

[0173] For example, when segment floating occurs, during the synchronous grouting stage, the grouting speed and volume in the grouting pipeline can be adjusted to adopt a "more at the top, less at the bottom" strategy. This means increasing the grouting volume in the top area of ​​the segment and decreasing the grouting volume in the bottom area, thereby balancing the buoyancy and limiting the floating trend. The grouting volume and grouting pressure need to be adjusted according to the density and permeability of the formation to ensure that the grout can fully fill the gap between the formation and the segment.

[0174] The key to controlling the floating of tunnel segments lies in ensuring that the upper part of the segments is fully filled with grout to suppress their vertical displacement.

[0175] As an alternative implementation method, after the tunnel segments detach from the shield tail of the tunnel boring machine 2 to 3 rings, secondary grouting is performed in the assembly holes on both sides of the top of the tunnel segments.

[0176] Secondary grouting is carried out 2-3 rings after the tunnel segments separate from the shield tail.

[0177] During secondary grouting, high-pressure grouting is first applied to the upper half of the segment at a pressure of 300–400 kPa. After the grout has solidified and stabilized, the lower half is then grouted at a lower pressure. By controlling the grout distribution pressure and filling sequence in stages, the overall floating amount of the segment is further reduced, achieving millimeter-level precision control.

[0178] During the secondary grouting, a two-component grout is used, which is prepared by selecting cement-based single grout and water glass. The water-cement ratio is 0.8 to 1.6, the expansion-water ratio is 0 to 0.3, and the cement-water glass volume ratio is 1:1 to 5:1.

[0179] As an optional implementation method, the steps for obtaining deviation data between the designed route and the actual route of the tunnel boring machine include:

[0180] Obtain the actual route of the tunnel boring machine (TBM) based on its attitude;

[0181] The deviation data is obtained by comparing the actual route of the tunnel boring machine with the designed route.

[0182] Adjustment and control of the attitude of the tunnel boring machine in small radius curves: If the tunnel segments float significantly during tunnel construction, the tunnel boring machine's attitude can be adjusted to a lower position. The downward sinking of the attitude can be used to offset the vertical upward displacement of the tunnel segments, thereby effectively controlling the deviation between the actual axis of the formed tunnel and the design axis, ensuring that it meets the allowable range of the specifications (usually ≤30mm).

[0183] This method actively reduces the vertical inclination angle of the tunnel boring machine's trajectory, balancing the upward tendency of the tunnel segments caused by unconsolidated grouting or ground buoyancy, ultimately achieving precise control of the tunnel axis.

[0184] In short, the attitude control of a tunnel boring machine (TBM) involves adjusting the pressure difference between several groups of propulsion cylinders and combining this with the adjustment of the winch cylinders to make the TBM move towards the axis of rotation.

[0185] With the tunnel axis as the target, the deviation is controlled within the design range based on the axis deviation and deviation trend displayed by the automatic measurement system. At the same time, the shield attitude is adjusted during the tunneling process to ensure that the segments are not damaged and the misalignment is small.

[0186] The specific measures for adjusting and controlling the attitude of the tunnel boring machine on small-radius curves include the following steps:

[0187] 1) Using the tail position of the shield as the control point, adjust the attitude of the shield head in advance. For example, when the segments float up by 100mm, adjust the vertical attitude down by 50mm to ensure that the attitude is within the allowable deviation range.

[0188] 2) The tunneling adjustment amount is generally controlled within 5mm / m. In special cases, it is adjusted in advance according to the turning radius of the line, such as shifting to the right in advance before turning right.

[0189] 3) The trend adjustment should match the segment wedge amount to avoid excessive trend leading to hasty correction. The difference in cylinder working stroke is usually no more than 50mm, and in special cases no more than 60mm, and no more than the segment wedge amount to prevent jamming.

[0190] 4) For active articulation, if the position of the cut ring and the middle shield is good, the position of the articulation is also ideal; if the deviation is large, the trapezoidal advancement method is used for adjustment.

[0191] 5) The tunneling speed is closely related to the direction adjustment. A slower speed is conducive to the direction adjustment. When the direction adjustment is difficult, the speed should be slowed down. Observe the attitude change every 300-500mm of cylinder stroke. If the stroke difference increases but the direction does not change or moves in the opposite direction, the machine should be stopped immediately for feedback.

[0192] Specifically, in the case of adjusting and controlling the attitude of the tunnel boring machine (TBM) on a small-radius curve segment, the attitude of the TBM can be obtained in the following ways:

[0193] For the adjustment and control of the tunnel boring machine's attitude on small-radius curved sections, in specific situations, when the shield is advancing along a circular curve, the advance of the left and right hydraulic cylinders needs to be calculated in advance. This can be done through calculation or measurement using AutoCAD drawing. During advancement, the cutter control center should be offset towards the center of the curve. The offset amount depends on the curve radius; the smaller the radius, the larger the offset. Under normal construction conditions, the error should be controlled within ±10mm, with a maximum of ±20mm. The working thrust of the left and right hydraulic cylinders must maintain a difference, and fine-tuned according to the force on the cutterhead to ensure that the stroke difference is consistent with the advance amount, with a maximum error not exceeding 10mm. The tunnel segments should be selected, assembled, and processed according to the designed segment arrangement diagram for the curved section.

[0194] In adjusting and controlling the attitude of the tunnel boring machine (TBM) on small-radius curves, particularly during vertical curve TBM excavation, the shield slope must be closely monitored and precisely adjusted to ensure it is basically consistent with the longitudinal slope of the design axis, with an error not exceeding 2%. During straight-line advancement, the cut-off position should be close to the axis, with the error typically controlled within ±10mm and a maximum error of ±20mm. Based on the actual slope, adjust the hydraulic pressure of the upper and lower propulsion cylinders to maintain slope stability, and fine-tune the cylinder stroke according to the force on the cutterhead, ensuring consistent stroke between the upper and lower cylinders, with a stroke difference not exceeding 50mm. Simultaneously, closely monitor the positions of the winch and tail of the shield, controlling deviations within ±20mm. If the deviation exceeds this range, timely correction is necessary, but the cut-off position adjustment must be cautious, maintaining it within ±20mm. Furthermore, the winch cylinder stroke should be maintained between 30-80mm, with the stroke difference between the upper and lower winch cylinders not exceeding 10mm. If the deviation is too large, immediate correction is required to prevent loss of shield attitude control and localized damage.

[0195] As an alternative implementation method, the shield machine attitude is obtained through an automatic guidance system and manual measurement verification.

[0196] The automatic guidance system is equipped with guidance, automatic positioning, tunneling program software, and displays, enabling it to dynamically display the deviation and trend of the tunnel boring machine's current position from the tunnel's design axis in the main control room around the clock. Adhering to the principle of "frequent corrections and minor adjustments," it controls the attitude and alignment of the tunnel boring machine. The shield attitude axis control value is ±5mm, ensuring that fine-tuning of the shield attitude is completed immediately while normal tunneling is underway.

[0197] As an optional implementation method, a warning value and a warning level are set, and the deviation data is compared with the warning value to obtain the warning level.

[0198] Establish a detection-response-decision system.

[0199] The detection-response-decision system includes a detection system, a response system, and a decision-making system. The detection system includes a level, a laser rangefinder, and a total station. The response system includes a total station monitoring system, a ground-penetrating radar, a three-dimensional laser scanning system, and an on-site drilling device. The decision-making system is an interactive application that can comprehensively consider the classification of the high-water-pressure composite sandy soil strata in S1, tunneling parameters, and grouting effects to adjust grouting parameters and tunneling parameters in real time, and control and adjust the shield tunneling posture.

[0200] The testing items of the testing system include:

[0201] The level and laser rangefinder were used to measure the settlement of the tunnel segment structure and the convergence of the tunnel segment clearance, with a detection accuracy of ±1mm.

[0202] The level instrument is used to measure building settlement and ground surface settlement, with a detection accuracy of ±1mm.

[0203] The settlement of the arch of the connecting passage and the convergence of the clearance of the connecting passage were measured using a level, total station and laser rangefinder, with a detection accuracy of ±1mm.

[0204] The system can use 3D laser scanning technology to obtain the geometric parameters of the tunnel inner wall. Through the decision system, it can perform joint detection on the projection image constructed by the 3D point cloud and accurately assess the floating and misalignment of the concrete segments. After grouting is completed, the SIR-4000 ground penetrating radar equipment is used to scan at a constant speed of 3 kilometers per hour. It adopts a continuous data acquisition mode and sets up six detection paths along the top, double arch shoulders, side walls and bottom areas of the tunnel. It analyzes the distribution of voids behind the lining structure through electromagnetic wave reflection spectrum and performs grouting quality assessment and shield parameter correction based on real-time imaging results.

[0205] Determine monitoring and control values ​​and early warning values, strengthen monitoring and measurement of surrounding risk sources, control the deformation of risk sources within the allowable range, classify early warning levels into three levels: yellow, orange, and red, and respond to early warnings.

[0206] The warning levels include:

[0207] 1) Yellow Alert: When the measured cumulative value reaches 70% but less than 85% of the cumulative control value; or when the daily rate of change reaches 70% but less than 85% of the rate of change control value. Send an alert bulletin, encrypt monitoring, and assist in analyzing the cause.

[0208] 2) Orange Alert: When the measured cumulative value reaches 85% of the cumulative control value but not 100%; or when the daily rate of change reaches 85% of the rate of change control value but not 100%. An early warning bulletin will be sent, monitoring will be intensified, a consultation mechanism will be initiated, and measures such as adjusting the construction schedule, optimizing support parameters, and improving process methods will be taken.

[0209] 3) Red Alert: When the measured cumulative value reaches the cumulative control value; or when the daily rate of change reaches the rate of change control value; or when the daily rate of change shows a sharp increase. Send an early warning bulletin, intensify monitoring, activate the consultation mechanism and emergency plan, and immediately take necessary measures such as reinforcement or suspension of construction.

[0210] The control standards for monitoring and early warning values ​​are as follows: the settlement control value for the tunnel segment structure and pipeline is set at 20mm; the tunnel segment clearance convergence is 10mm; the ground surface settlement control value is 30m; the settlement control value for the arch of the connecting passage is 20mm; the clearance convergence control value for the connecting passage is 10mm; and the horizontal and vertical displacement control values ​​for the retaining wall (slope) are 30mm.

[0211] The following is one application example based on the above method:

[0212] The section between Haiyun'an Station and Hudao Station on Qingdao Metro Line 5 runs along the old city of Qingdao. It is a single-bore, single-track, double-track tunnel. Starting from Haiyun'an Station, the tunnel runs under Hangzhou Road, then northwest, passing under Hangzhou Garden and Ruijin Jiayuan residential areas before entering Ruichang Road to Hudao Station. The section is constructed using the earth pressure shield tunneling method. The horizontal alignment of the section includes a 400m radius curve. The longitudinal profile of the section is a unidirectional slope, with a downhill gradient of 29.8‰ from Hudao Station to Haiyun'an Station. The vertical curve radius is 3000m.

[0213] Based on the above working conditions, and according to a dynamic construction method for an earth pressure balance tunnel boring machine in composite sandy soil strata, the following operational steps are formulated:

[0214] Classification of different composite stratigraphic types:

[0215] Classification of different composite stratigraphic types:

[0216] Based on heterogeneity and compositional characteristics, water-rich heterogeneous strata are classified as follows:

[0217] Weakly heterogeneous fractured formation: RMR>60;

[0218] Heterogeneous fractured formation: 40≤RMR≤60;

[0219] Extremely heterogeneous and fractured formations: RMR≤40;

[0220] When a tunnel has both a large longitudinal slope and a small clearance (such as an urban underground utility tunnel crossing a complex terrain section), this patent adopts a "priority adaptation" strategy: it prioritizes meeting the parameter requirements of the large longitudinal slope (such as high thrust on the uphill section), and then adjusts the small clearance to balance the climbing requirements and the control of ground disturbance.

[0221] Specific control methods include:

[0222] Among them, the classification of working conditions with small clearance and large longitudinal slope is as follows:

[0223] Based on the slope (i) of the tunneling section, it can usually be divided into three levels:

[0224] Typical slope: i < 20‰, risk is controllable, and conventional measures can meet the requirements.

[0225] Medium longitudinal slope: 20‰≤i<30‰, the difficulty of shield attitude control increases, and the risk of segment floating is significant.

[0226] With a steep longitudinal slope (i≥30‰), the orientation of the tunnel segments is extremely difficult to control, making them prone to misalignment and damage, and posing a severe challenge to the drainage system.

[0227] Based on the ratio of the net distance (S) between two tunnels to the tunnel diameter (D), they can be divided into three levels:

[0228] Standard clearance: S / D≥2.0, with minimal mutual influence, standard control is sufficient.

[0229] Medium clearance: 1.5≤S / D<2.0. Construction of the subsequent line will significantly disturb the preceding line and requires active control.

[0230] Small clearance (S / D < 1.5) indicates a significant mutual influence and extremely high risk, requiring special comprehensive measures.

[0231] S3. Shield tunneling control measures under different risks

[0232] Taking the right line first and the left line later as an example, the shield tunneling parameters are adjusted for the uphill section.

[0233] 1. Standard slope and standard clearance: Slope < 20‰, clearance / diameter ≥ 2.0

[0234] Main risks: Poor formation stability, requiring control of tunneling speed and thrust to reduce disturbance to the formation.

[0235] Attitude pre-deflection: Before entering the small clearance section, the shield cut position is pre-deflected 3~5mm in the opposite direction of the longitudinal slope; the hydraulic cylinder stroke difference is ≤30mm.

[0236] The tunneling speed is controlled at 15-22 mm / min; the cutterhead rotation speed is 1.2-1.8 r / min; the total thrust is 8000-9000 KN; the cutterhead torque is 2000-3000 KN·m; and the cutterhead rotation speed is 1.0-1.6 r / min.

[0237] Monitoring: Automatic guidance and manual verification every 3-5 rings.

[0238] 2. Conventional slopes and moderate clearance: Slope < 20‰, 1.5 ≤ clearance / diameter < 2.0

[0239] Main risks: Disturbance to the leading line, resulting in poor formation stability.

[0240] Tunneling speed and thrust control measures: Top thrust approximately 2353kN, bottom thrust approximately 2470kN, left thrust (the side furthest from the lead line) approximately 3400kN, right thrust (adjacent side) approximately 2506kN, to reduce disturbance to the lead line. Tunneling speed slightly reduced to 12-18mm / min.

[0241] Cutter head parameter control: cutter head speed 1.0-1.6 r / min; cutter head torque 2000-3000 KN·m;

[0242] Tunnel Boring Machine (TBM) Attitude Control: The attitude should be pre-deflected by 3-6mm, prioritizing avoidance of the lead-in line direction; the hydraulic cylinder stroke difference should be ≤40-50mm to retain correction margin. When the TBM attitude deviates 5mm to one side of the lead-in line, the tunneling speed should be reduced to 10mm / min; when the deviation is ≥8mm, the machine should be stopped, and then the thrust on both sides should be balanced.

[0243] Monitoring: Manually check the displacement of the lead line and the interlayer stress every 3-5 rings; immediately reduce speed and add grout when the trigger threshold (lead line settlement 10mm) is reached.

[0244] 3. Standard slopes and small clearances: Slope < 20‰, clearance / diameter < 1.5

[0245] Main risks: The small clearance allows disturbances from the following line to be directly transmitted to the leading line, which can easily lead to segment misalignment and local voids, requiring control.

[0246] Tunneling speed and thrust control measures: top thrust approximately 1900.0 kN, bottom thrust approximately 2100.0 kN, left thrust (far side) approximately 3600 kN, right thrust (adjacent side) approximately 3000 kN;

[0247] Cutter head parameter control: cutter head torque is 2000-3000 KN·m; cutter head speed is 0.9-1.4 r / min;

[0248] Shield attitude control measures: pre-deflection of 5-10mm, hydraulic cylinder stroke difference ≤50mm, fine adjustment at any time; tunneling speed of 10-15mm / min, when the deviation is 3mm, it is reduced to about 10mm / min; when the deviation is ≥5mm, the machine must be stopped immediately and thrust balancing must be performed.

[0249] Ground reinforcement: Advanced deep-hole grouting or jet grouting piles are used in the interlayer of the double-line structure to improve the interlayer stiffness.

[0250] Monitoring: Review every 1-3 rings; use 3D laser scanning or radar point cloud to assess seams and voids.

[0251] 4. Medium slope and standard clearance: 20‰ ≤ slope < 30‰, clearance / diameter ≥ 2.0

[0252] Main risks: The tendency of the tunnel boring machine to "raise its head / bump its head" (attitude deviation) is increasing, and special attention needs to be paid to drainage and grout subsidence.

[0253] Tunneling speed and thrust control measures: The total thrust is controlled at about 11,500 kN, with the top thrust at about 2,300 kN, the bottom thrust at about 2,700 kN, the left thrust at about 3,100 kN, and the right thrust at about 2,600 kN. The thrust needs to be increased step by step on the uphill section and decreased step by step on the downhill section.

[0254] Cutter head parameter control measures: cutter head speed 0.8-1.5 r / min, avoid frequent speed changes; cutter head torque 2000-3000 KN·m;

[0255] Shield attitude control measures: pre-deflection increased to 8-12mm; bottom thrust 15-20% higher than top thrust. Hydraulic cylinder stroke difference can be increased to ≤50mm; articulated assistance can be used if necessary, with stroke difference fine-tuned by 10-15mm. Tunneling speed 10-18mm / min, maintained at 14-16mm / min; when deviation reaches 4mm, reduce to approximately 8mm / min; when deviation reaches 6mm, stop the machine and prioritize adjusting top and bottom thrust to restore the pitch angle.

[0256] Drainage: Set up temporary multi-stage pumping stations and strengthen drainage at the working face.

[0257] 5. Medium slope and medium net distance: 20‰≤i <30‰, 1.5≤S / D<2.0

[0258] Main risks: Difficulty in attitude control and significant propagation of backward disturbances to the leading line; increased risk of segment floating / misalignment.

[0259] Tunneling speed and thrust control measures: The total thrust is about 12,000 kN, with the top thrust being about 2,450 kN, the bottom thrust about 2,800 kN, the left (far side) about 3,100 kN, and the right (adjacent side) about 2,650 kN. The thrust needs to be gradually increased on the uphill section and gradually decreased on the downhill section to maintain the longitudinal slope attitude while minimizing disturbance to the lead line.

[0260] Cutter head parameter control measures: cutter head speed 0.9–1.4 r / min; cutter head torque 2000-2500 KN·m, reducing torque sudden changes;

[0261] Shield attitude control measures: pre-deflection of 10-12mm (adjusted according to slope, avoiding the lead-in line); hydraulic cylinder stroke difference ≤50mm and dynamically adjusted. Tunneling speed controlled at 13-15mm / min, speed reduced to about 10mm / min when deviation ≥3mm; machine stopped and thrust balancing performed when deviation ≥5mm.

[0262] Monitoring and emergency response: Check every 1-3 rings; if the settlement of the pilot line is ≥10mm or the attitude changes rapidly, immediately reduce the speed and add grout.

[0263] 6. Medium slope and small clearance: 20‰≤i <30‰, S / D<1.5

[0264] Main risks: The longitudinal slope causes a significant attitude deviation moment; the small clearance makes it difficult to attenuate disturbances, leading to local damage to the leading line and a high probability of misalignment.

[0265] Tunneling speed and thrust control measures: The total thrust is controlled at about 11,500 kN, with about 2,300 kN at the top, about 2,700 kN at the bottom, about 3,100 kN on the left (far side), and about 2,500 kN on the right (adjacent side). The thrust needs to be increased step by step on the uphill section and decreased step by step on the downhill section. The thrust on the far side needs to be further strengthened to ensure safe tunneling.

[0266] Cutter head parameter control measures: cutter head speed 0.8-1.2 r / min; cutter head torque 1800-2200 KN·m, reducing torque sudden changes;

[0267] Tunnel boring machine (TBM) attitude control measures: Pre-deflection of 12-15mm, activation of articulated hydraulic cylinders, with the cylinder stroke difference concentrated within the 10-15mm articulated movement range for rapid attitude correction. Tunneling speed maintained at 12-14mm / min; when deviation ≥3mm, it should be reduced to approximately 6mm / min; when deviation ≥5mm, the machine should be stopped immediately and thrust balancing performed.

[0268] Reinforcement: If necessary, perform advanced deep-hole grouting and jet grouting to increase the stiffness of the interlayer and prevent water leakage.

[0269] Monitoring and contingency plans: Encryption is applied to every ring, and a level 3 early warning triggers an immediate halt to excavation and full-section reinforcement.

[0270] 7. Severe longitudinal slope and conventional clearance: 30‰≤i, S / D≥2.0

[0271] Main risks: High probability of loss of posture (head up or head down); uneven stress on tunnel segments and difficulty in drainage.

[0272] Tunneling speed and thrust control measures: The total thrust is about 12,500 kN, including about 2,600 kN at the top, about 3,000 kN at the bottom, about 3,200 kN on the left side and about 2,700 kN on the right side. The thrust needs to be increased step by step on the uphill section and decreased step by step on the downhill section.

[0273] Cutter head parameter control measures: cutter head speed 0.8-1.2 r / min; cutter head torque 1800-2200 KN·m, reducing torque sudden changes;

[0274] Tunnel boring machine (TBM) attitude control measures: Dynamic pre-deflection of 12-18mm, activation of articulation and differential thrust to generate a continuous upward torque; the hydraulic cylinder stroke difference and articulation action must be linked in real time. Tunneling speed is controlled at 15-18mm / min, reduced to about 8mm / min when the deviation is ≥3mm; the machine is stopped when the deviation is ≥5mm, and the pitch angle is adjusted with priority given to bottom / top thrust.

[0275] Drainage: Multi-stage drainage pumping stations and possible advance precipitation plans must be arranged.

[0276] 8. Severe longitudinal slope and moderate clearance: 30‰≤i, 1.5≤S / D<2.0

[0277] Main risks: The superposition of longitudinal slope attitude loss and subsequent disturbances significantly increases the risk of damage / seepage / misalignment of the leading line.

[0278] Tunneling speed and thrust control measures: Total thrust is about 11,800 kN, about 2,300 kN at the top, about 2,700 kN at the bottom, about 3,200 kN on the left side, and about 2,800 kN on the right side. The thrust needs to be increased step by step on the uphill section and decreased step by step on the downhill section.

[0279] Cutter head parameter control measures: cutter head speed 0.8-1.2 r / min to avoid sudden changes; cutter head torque 2000-2500 KN·m to reduce torque mutations.

[0280] Tunnel boring machine (TBM) attitude control measures: Pre-deflection of 15-18mm. Tunneling speed controlled at 14-17mm / min; reduced to approximately 10mm / min when deviation ≥3mm; shutdown and thrust balancing performed when deviation ≥5mm.

[0281] Reinforcement: Advanced deep-hole grouting and jet grouting are carried out to increase the stiffness of the interlayer and prevent water leakage.

[0282] Monitoring: Each ring is reviewed, and a Level 3 early warning is triggered to immediately stop excavation and implement full-section reinforcement.

[0283] 9. Severe longitudinal slope and small clearance: 30‰≤i, S / D<1.5

[0284] At this stage, gravity dominates the orientation, resulting in an extremely high risk of segment breakage and collapse of the narrow-clearance interlayer. Therefore, a "limiting parameters and multiple protection" strategy is required.

[0285] (1) Shield attitude control measures: dynamic adjustment of pre-deflection and articulated hydraulic cylinder assistance

[0286] Attitude pre-deflection: The pre-deflection amount is dynamically adjusted according to the real-time slope (30‰ slope pre-deflection 3~5mm, 35‰ slope pre-deflection 6~8mm). For small clearance sections, the "safe pre-deflection range" needs to be calculated in conjunction with the position of the leading line (e.g., when the left line moves first, the right line moves later with a rightward deflection amount ≤8mm) to avoid the attitude adjustment squeezing the leading line.

[0287] Thrust and articulation coordination: The bottom cylinder thrust is 25%~30% higher than the top cylinder thrust, and the articulation cylinder is activated at the same time (stroke difference controlled within 10~15mm) to assist in adjusting the angle of the tunnel boring machine body and reduce the tendency to "dive".

[0288] Tunneling parameter control: A low-thrust, low-torque operating mode is adopted to keep the tunnel boring machine (TBM) in a slow-speed tunneling state, thereby reducing the horizontal lateral thrust of the jacks on the tunnel segments and minimizing disturbance to the ground. The total thrust is controlled at approximately 11,500 kN, with approximately 2,400 kN at the top, 2,800 kN at the bottom, 3,000 kN on the left (far side), and 2,200 kN on the right (adjacent side). Thrust needs to be gradually increased on uphill sections and gradually decreased on downhill sections. The tunneling speed is reduced to 10-18 mm / min; the cutterhead rotation speed is 0.8 r / min-1.5 r / min; and the cutterhead torque is 1700-2500 kN·m, ensuring cutting efficiency while avoiding torque fluctuations.

[0289] Segment elevation adjustment: By coordinating grouting and attitude, if the segment rises more than 8mm, immediately reduce the top grouting volume (-15%) and increase the bottom thrust (5%); if it sinks more than 5mm, adjust in the opposite way, while avoiding excessive adjustment range that may cause misalignment of segments with small clearance.

[0290] (3) Special strata coordinated control measures: strata reinforcement as a backup and three-level early warning

[0291] For geological pretreatment: When the interlayer with small clearance is a soft upper layer and a hard lower layer, the upper sandy layer is reinforced with high-pressure jet grouting piles (pile diameter 600mm, spacing 400mm), and the lower hard rock is reinforced with deep-hole grouting (hole depth exceeding the tunnel diameter by 2 times) to form a "rigid isolation layer"; when it is a high water pressure stratum, an additional water-stop curtain (cement-water glass double liquid grout, diffusion radius ≥1.5m) is set between the two tunnels to prevent water inrush from causing the interlayer to become unstable.

[0292] Level III Early Warning and Emergency Response: Three levels of early warning are set: Yellow (deviation 8~12mm / settlement 10~15mm), Orange (deviation 12~15mm / settlement 15~20mm), and Red (deviation ≥15mm / settlement ≥20mm).

[0293] Yellow alert: Increase monitoring frequency and fine-tune grouting pressure (±0.02MPa);

[0294] Orange alert: Stop tunneling, start compensating grouting (inject dual-liquid grout into the pilot line side), and adjust thrust distribution (reduce thrust on the side closer to the pilot line by 10%).

[0295] Red Alert: Immediately stop the machine and perform full-section grouting reinforcement on the narrow gap interlayer. After the monitoring data recovers to a safe range (deviation ≤8mm / settlement ≤10mm), resume tunneling at a low speed of 8~15mm / min.

[0296] (4) Drainage guarantee: Multi-level drainage pumping stations (50m apart) are set up in the tunnel to prevent water accumulation on the longitudinal slope section from flooding the equipment or softening the interlayer strata with small clearance.

[0297] To ensure the safety of tunnel boring machine (TBM) excavation, synchronous grouting is required during the excavation process to quickly fill the annular gaps and allow the tunnel segments to interact with the strata as early as possible. This prevents excessive ground deformation from endangering the surrounding environment. Simultaneously, it serves as an external waterproofing and structural reinforcement layer for the tunnel segments. Ordinary silicate 42.5 cement, fly ash, medium and fine sand, bentonite, and a water-reducing agent are selected to prepare typical retarded single-liquid grouts with different components. Different grout ratios are chosen according to the strata classification in S1. Its characteristics are:

[0298] The slurry mix ratio is selected as follows:

[0299] 1) Weakly heterogeneous and fractured strata:

[0300] Water-cement ratio (water / cement and fly ash) 0.90~1.50, mortar-cement ratio (cement and fly ash / sand aggregate) 0.40~0.93, water-swelling ratio (bentonite / water) 0.20~0.30, fly ash / water ratio 3.25~4.68, water-reducing agent dosage 0.2%~1.5%, cellulose dosage 0.4%~1.5%;

[0301] 2) Heterogeneous and fractured strata:

[0302] Water-cement ratio (water / cement and fly ash) 0.80~1.20, mortar-cement ratio (cement and fly ash / sand aggregate) 0.40~0.78, water-swelling ratio (bentonite / water) 0.15~0.30, fly ash / water ratio 3.50~4.58, water-reducing agent dosage 0.3%~2%, cellulose dosage 0.5%~2.5%;

[0303] 3) Extremely heterogeneous and fractured strata:

[0304] Water-cement ratio (water / cement and fly ash) 0.60~1.10, mortar-cement ratio (cement and fly ash / sand aggregate) 0.40~0.88, water-swelling ratio (bentonite / water) 0.10~0.40, fly ash / water ratio 2.50~5.88, water-reducing agent dosage 0.3%~2%, cellulose dosage 0.5%~2.5%;

[0305] Different grouting strategies are selected based on the classification of the strata.

[0306] The grouting strategy selection is as follows:

[0307] 1) Weakly heterogeneous and fractured strata:

[0308] The grouting pressure is controlled at 0.2-0.3 MPa; the grouting volume per ring is 8.9-10.1 m³.

[0309] 2) Heterogeneous and fractured strata:

[0310] The grouting pressure is controlled at 0.25-0.35 MPa, allowing for rapid entry into the fracture zone under higher pressure; the grouting volume per ring is 9.5-11.0 m³, ensuring that the grout can fill a larger area of ​​fractures.

[0311] 3) Extremely heterogeneous and fractured strata:

[0312] The grouting pressure is controlled at 0.3-0.4 MPa to ensure that the grout can efficiently penetrate into the deep fractured zone and quickly seal it. The grouting volume per ring is 10.0-12.0 m³, and the increased grouting volume helps to ensure that the grout can cover more areas and fill large-area fissures. By using advanced geological prediction and pore water pressure monitoring, the main water flow channels are identified, and high-permeability areas are pre-drained and depressurized before grouting.

[0313] As an alternative implementation method, the elevation of the tunnel segments is adjusted during the installation process by grouting and adjusting the actual route of the tunnel boring machine.

[0314] The core of controlling segment uplift lies in ensuring sufficient grout filling in the upper part of the segment to suppress its vertical displacement. During the synchronous grouting stage, the grouting speed and volume of the grouting pipeline can be adjusted, adopting a "more at the top, less at the bottom" strategy. This means increasing the grouting volume in the top area of ​​the segment and reducing the grouting volume in the bottom area, thereby balancing buoyancy and limiting the upward trend. During the shield tunneling process, the synchronous grouting volume is controlled at 8.9–10.1 m³ / ring. After the segment separates from the shield tail 2–3 rings, secondary grouting begins at the assembly holes on both sides of the top of the tunnel segment. During secondary grouting, high-pressure grouting is prioritized for the upper half of the segment at a pressure of 300–400 kPa. After the grout has solidified and stabilized, lower pressure is used to supplement the grouting in the lower half. By controlling the grout distribution pressure and filling sequence in stages, the overall uplift of the segment is further reduced, achieving millimeter-level precision control.

[0315] Adjustment and control of tunnel boring machine (TBM) attitude on small-radius curves: During TBM construction, if the segment floats significantly, the TBM's attitude can be adjusted to a lower position. This downward adjustment counteracts the vertical upward displacement of the segments, effectively controlling the deviation between the actual tunnel axis and the design axis, ensuring it meets the allowable range (usually ≤30mm). This method actively reduces the vertical inclination angle of the TBM's trajectory, balancing the upward tendency of the segments caused by unconsolidated grouting or ground buoyancy, ultimately achieving precise control of the tunnel axis. In short, TBM attitude control involves adjusting the pressure difference between several groups of propulsion cylinders, combined with adjustments to the hinge cylinders, to make the TBM tend towards the axis. Using the tunnel axis as the target, the deviation is controlled within the design range based on the axis deviation and trend displayed by the automatic measurement system. Simultaneously, TBM attitude adjustments are made during excavation to ensure no segment damage and minimal misalignment.

[0316] A detection-response-decision system is established, comprising a detection system, a response system, and a decision-making system. The detection system includes a level, a laser rangefinder, and a total station. The response system includes a total station monitoring system, ground-penetrating radar, a 3D laser scanning system, and an on-site drilling device. The decision-making system is an interactive application that integrates data from the detection and feedback systems into a storage medium. It comprehensively considers the classification of high-water-pressure composite sandy soil strata, tunneling parameters, and grouting effects to adjust grouting and tunneling parameters in real time, thereby controlling and adjusting the shield tunneling posture.

[0317] Determine monitoring and control values ​​and early warning values, strengthen monitoring and measurement of surrounding risk sources, control the deformation of risk sources within the allowable range, classify early warning levels into three levels: yellow, orange, and red, and respond to the early warnings. Determine construction control measures and adjust grouting parameters and shield tunneling parameters according to different early warning levels.

[0318] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0319] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An adaptive control method for shield tunneling construction in water-rich, fractured, and uneven strata with small net distances and large longitudinal slopes, characterized in that: Includes the following steps: Obtain the working condition type with small clearance and large longitudinal slope; Classification of working conditions based on small clearance and large longitudinal slope; The working conditions include: conventional slope and conventional clearance, conventional slope and medium clearance, conventional slope and small clearance, medium slope and conventional clearance, medium slope and medium clearance, medium slope and small clearance, large longitudinal slope and conventional clearance, large longitudinal slope and medium clearance, and large longitudinal slope and small clearance. To determine the water-rich, fractured, and heterogeneous strata at a small net distance and a large longitudinal slope; Select the tunnel boring machine parameters based on the working condition type, geological type, and working condition classification. Based on the shield tunneling parameters, during the operation, the strata are reinforced, and the tunnel segments are installed along the actual route of the shield machine. Based on the deviation data between the actual shield parameters during shield tunneling operations and the previously selected shield parameters, the changes in ground settlement, and the misalignment of tunnel segments, the actual route of the shield machine and the aforementioned shield parameters are adjusted.

2. The adaptive control method for shield tunneling construction in water-rich, fractured, and uneven strata with small net distance and large longitudinal slope as described in claim 1, characterized in that: The tunnel boring machine (TBM) parameters include tunneling speed, cutterhead rotation speed, total thrust, and cutterhead torque.

3. The adaptive control method for shield tunneling construction in water-rich, fractured, and uneven strata with small net distances and large longitudinal slopes according to claim 1, characterized in that, The steps for obtaining the formation type include: The stratigraphic data includes information on the classification of surrounding rocks, structure, degree of joint development, and groundwater pressure within the section. The stratigraphic classification is performed based on the coefficient of heterogeneity.

4. The adaptive control method for shield tunneling construction in water-rich, fractured, and uneven strata with small net distance and large longitudinal slope as described in claim 3, is characterized in that... The stratigraphic types include: Weakly heterogeneous fractured strata, heterogeneous fractured strata, extremely heterogeneous fractured strata; Select the synchronous grouting parameters according to the geological type and adjust the corresponding tunneling parameters.

5. The adaptive control method for shield tunneling construction in water-rich, fractured, and uneven strata with small net distance and large longitudinal slope as described in claim 4, characterized in that: The grouting parameters include grouting volume, grouting pressure, and grout mix ratio.

6. The adaptive control method for shield tunneling construction in water-rich, fractured, and uneven strata with small net distance and large longitudinal slope as described in claim 1, characterized in that: During the installation of tunnel segments, the elevation of the segments is adjusted by grouting and by adjusting the actual route of the tunnel boring machine.

7. The adaptive control method for shield tunneling construction in water-rich, fractured, and uneven strata with small net distance and large longitudinal slope as described in claim 6, characterized in that: After the tunnel segments detach from the shield tail of the tunnel boring machine by 2 to 3 rings, secondary grouting is carried out in the assembly holes on both sides of the top of the tunnel segments.

8. The adaptive control method for shield tunneling construction in water-rich, fractured, and uneven strata with small net distance and large longitudinal slope as described in claim 1, is characterized in that... The steps for obtaining deviation data between the designed route and the actual route of the tunnel boring machine include: Obtain the actual route of the tunnel boring machine (TBM) based on its attitude; The deviation data is obtained by comparing the actual route of the tunnel boring machine with the designed route.

9. The adaptive control method for shield tunneling construction in water-rich, fractured, uneven strata with small net distance and large longitudinal slope as described in claim 8, characterized in that: The shield machine's attitude is obtained through an automatic guidance system and manual measurement and verification.

10. The adaptive control method for shield tunneling construction in water-rich, fractured, and uneven strata with small net distance and large longitudinal slope as described in claim 1, characterized in that: Set a warning value and a warning level, compare the deviation data with the warning value, and obtain the warning level.

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