Open type TBM tunnel fault fracture zone hole parallel advanced exploration integrated treatment method

Abstract

The present application relates to a kind of open TBM tunnel fault fracture zone hole parallel advance detection integrated treatment method, the method comprises the following steps: according to the position of geological survey report to determine the fault fracture zone in front of tunnel, calculate TBM face mileage;Tunnel two side walls are excavated ear hole in TBM equipment bridge area;Directional drilling rig is arranged in two side ear hole, uses arc drilling, reaches the fault fracture zone in front of tunnel face;Advance detection is carried out in the process of directional drilling;When judging that the collapse of TBM front fracture zone surrounding rock exists and causes TBM to be stuck risk, the arch surrounding rock of tunnel is consolidated grouting;When judging that there is sudden gushing risk, the curtain grouting is carried out to the surrounding rock of tunnel;Grouting effect is tested after grouting is completed.The present application integrates advance detection and pre-reinforcement management in the same construction process, constructs the continuous operation system of " sensing while drilling-intelligent identification-synchronous treatment", realizes the seamless connection of geological risk advance identification and engineering treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel engineering, and in particular relates to a method for parallel advanced exploration and treatment of a fault fracture zone in an open TBM tunnel. Background Art

[0002] Open-type TBMs (Open TBMs) are a key component of tunnel construction in major water network projects in my country. When traversing regional fault zones, TBM excavation faces numerous challenges. Severely fragmented and uneven rock formations can cause collapse above the shield and at the tunnel face, leading to TBM jams. Sudden, high-volume water and mud inrushes under high external water pressure often lead to equipment jams, system failures, or operational halts. These challenges not only increase construction complexity but also directly impact progress and costs.

[0003] Current technologies mostly rely on short-distance drilling and advance grouting from behind the shield to conduct local detection and pre-reinforcement after the TBM is shut down. However, the limitations of this method are obvious: (1) the detection distance is insufficient and the grouting reinforcement time is delayed; (2) the space for TBM equipment is small, and the number of holes drilled by the airborne advance drilling rig behind the shield is limited and the spacing is large, which makes it difficult to meet the disposal requirements of advance consolidation grouting. In addition, the drilling angle and depth are limited. If the expansion studio method is adopted, it will be difficult, time-consuming and inefficient; (3) there is a risk that the slurry will flow back to the contact surface between the cutter shield and the surrounding rock during advance grouting, which will increase the propulsion resistance of the TBM or even cause it to be completely stuck; (4) the advance grouting behind the shield and the TBM excavation require alternating shutdown operations. Frequent switching of processes leads to reduced efficiency, which restricts the continuous and efficient operation of the TBM.

[0004] Especially in areas with complex geological structures, traditional advance detection methods cannot effectively and timely reflect changes in fracture zones, making the resulting risks even more difficult to foresee and control. As tunnel construction technology advances into deeper and more complex geological conditions, ensuring construction safety while improving excavation efficiency has become a pressing challenge in all types of tunneling. Summary of the Invention

[0005] The present invention is proposed to solve the above-mentioned shortcomings, and its purpose is to provide an integrated method for parallel advanced exploration and treatment of the fault fracture zone in an open TBM tunnel. This method can not only effectively reduce the TBM downtime and improve the excavation efficiency, but also through accurate detection and timely reinforcement measures, minimize the impact of problems such as broken rock instability, machine jamming, sudden mud and water gushing on tunnel construction, thereby providing more reliable safety guarantees for tunnel projects.

[0006] In order to achieve the above purpose, the present invention adopts the following scheme:

[0007] A method for parallel advanced exploration and treatment of a fault fracture zone in an open TBM tunnel comprises the following steps:

[0008] S1: Determine the location of the fault fracture zone ahead of the tunnel based on the geological survey report. Calculate the TBM face mileage based on the daily TBM advance, the theoretical drilling rate of the drill, and the ear hole excavation period to ensure ear hole excavation and directional drilling exploration and treatment are completed before the TBM reaches the fault fracture zone.

[0009] S2: When the TBM face is at a predetermined distance from the fault fracture zone, ear holes are excavated on both sides of the tunnel wall in the TBM equipment bridge area. The ear holes are located close to the TBM face and have enough space for directional drilling to change direction.

[0010] S3: Place directional drills in the two side holes, use arc drilling and gyroscope positioning to reach the fault fracture zone in front of the tunnel face;

[0011] S4: Conduct advance detection during directional drilling, analyze detection data, and comprehensively assess the geological risk of the fault fracture zone;

[0012] S5: When it is determined that there is a risk of collapse of the surrounding rock in the fracture zone ahead of the TBM, which may cause the TBM to jam, consolidation grouting is carried out on the surrounding rock of the tunnel arch. When it is determined that there is a risk of sudden surge, curtain grouting is carried out on the surrounding rock around the tunnel.

[0013] S6: After the grouting is completed, the grouting effect is tested. If it passes the test, the TBM continues to advance normally and pass through the fault fracture zone.

[0014] As a preferred embodiment, in step S1, the TBM face mileage satisfies the following relationship:

[0015] The duration for the directional drill to reach and pass through the fault fracture zone is:

[0016] ;

[0017] The total time required for directional drilling exploration and remediation is:

[0018] ;

[0019] The time required for the TBM to change direction through the required distance D2 of the directional drill is:

[0020] ;

[0021] According to T TBM Greater than T 探查-治理 The requirements, that is ;

[0022] The relationship between the mileage of the tunnel face and the starting mileage of the fault fracture zone:

[0023] ;

[0024] The TBM face mileage must meet the following requirements:

[0025] ;

[0026] Where, X1: the mileage of the tunnel face;

[0027] X2: starting mileage of the fault fracture zone;

[0028] D1: distance between the TBM equipment bridge area and the TBM tunnel face;

[0029] D2: distance required for the directional drill to change direction;

[0030] D3: width of fault fracture zone;

[0031] V1: TBM excavation speed;

[0032] V2: Theoretical drilling speed of directional drill in the formation;

[0033] T TBM : The time required for the TBM to advance from the current mileage to the fault fracture zone;

[0034] T 探查-治理 : The total construction period for completing ear hole construction, drilling and grouting treatment;

[0035] T1: ear piercing construction period;

[0036] T2: The time it takes for the drilling rig to reach the fault fracture zone;

[0037] T3: Fault zone grouting treatment period.

[0038] As a preferred embodiment, in step S3, directional drilling construction is completed within a range of 2 to 5 meters outside the tunnel excavation contour line.

[0039] As a preferred embodiment, in step S3, several exploration boreholes are constructed in the top arch using the ear holes on both sides, and the detection target area is located within a range of 2 to 5 meters outside the tunnel spandrel excavation contour line.

[0040] As a preferred embodiment, in step S4, before entering the fault zone, advanced detection is carried out by combining the drilling slag status, drilling rig parameters while drilling, and natural gamma detectors. After entering the fault, detection is carried out by combining core drilling, drilling rig parameters while drilling, and natural gamma detectors.

[0041] As a preferred embodiment, the drilling rig while drilling parameters include drilling rig torque, rotation speed, impact power and drilling stroke parameters.

[0042] As a preferred embodiment, in step S5, when it is determined that there is a risk of collapse of the surrounding rock in the broken zone ahead of the TBM causing the TBM to get stuck, consolidation grouting is performed on the surrounding rock of the tunnel arch by means of top arch exploration drilling.

[0043] As a preferred embodiment, in step S5, when it is determined that there is a risk of sudden surge, while grouting operations are being carried out in the exploration drilling holes of the top arch, directional drilling and high-pressure grouting operations are simultaneously carried out in several supplementary drilling holes of the invert arch to perform curtain grouting on the surrounding rock around the tunnel.

[0044] As a preferred embodiment, in step S5, the grouting method adopts segmented progressive grouting, using the reserved rock pillar at the TBM face away from the fault zone boundary as a grouting wall, and grouting is performed in the hole by lowering a flower pipe, and the grouting materials adopt modified single-liquid cement slurry and cement-water glass two-liquid slurry;

[0045] The grouting pressure is 1.5 to 2 times the measured external water pressure at the grouting section. The effective diffusion radius of the slurry is 8 to 10 m. The grouting diffusion circle forms an effective grouting reinforcement body within the diffusion radius with the center of the tunnel section as the center.

[0046] As a preferred embodiment, in step S6, after the grouting is completed, a water pressure test is carried out to test the grouting effect. If the water permeability of the grouting area after grouting is less than 5Lu, it is judged to be qualified.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] First, the present invention's integrated approach for parallel advanced exploration and treatment of fault fracture zones within open TBM tunnels maximizes directional drilling length reduction without impacting continuous TBM progress by selecting optimal timing for directional drilling ear holes. Furthermore, the innovative combination of directional drilling, gyroscope guidance, and natural gamma ray measurement provides more accurate geological information, thus better supporting open TBM construction.

[0049] Secondly, this invention integrates advanced detection and pre-reinforcement management into the same construction process, building a continuous operation system of "drilling perception-intelligent identification-synchronous treatment", achieving a seamless connection between advanced identification of geological risks and engineering treatment. Compared with traditional processes, its core advantage is that it significantly improves the continuity of TBM construction, completing targeted reinforcement before the risk area is fully exposed at the face, effectively avoiding shutdowns, jams and flooding caused by geological mutations; at the same time, relying on information sharing in the exploration-treatment process, it eliminates redundant construction links, greatly shortens the process cycle, and ensures construction progress while reducing grouting material consumption.

[0050] Third, the present invention fundamentally changes the passive emergency operation mode in the treatment of TBM crossing fault fracture zones. By constructing an active defense system, it systematically reduces the risks of surrounding rock instability, TBM jamming, and mud and water inrush, providing reliable guarantee for efficient TBM excavation in complex formations.

[0051] Fourthly, the present invention first controls the timeliness of fault treatment construction by comprehensively considering the TBM excavation progress, drilling speed, and the required treatment period. It then reversely calculates the time window for completing lateral ear hole excavation and directional drilling in advance, and derives a formula for the minimum reserved advance distance of the TBM face. This ensures that when the TBM approaches the fault zone, it reserves sufficient distance to complete the advance reinforcement treatment without excessive downtime, thereby achieving simultaneous optimization of excavation and treatment. Traditional methods often lack this quantitative algorithm and often rely on experience to determine the downtime distance, which may result in excessive waiting or insufficient risks. This method achieves the coordinated development of fault pre-reinforcement and continuous TBM excavation, making advance treatment more timely and controllable, and improving construction organization efficiency and safety margin.

[0052] Fifth, this invention represents a groundbreaking innovation in its integrated exploration and remediation layout. "Ear holes" are excavated on either side of the TBM bridge area to serve as advance construction platforms. A directional drill is deployed to drill along an arc-shaped trajectory, using gyroscopes for precise guidance. The borehole bypasses the TBM's front face and reaches the target area in the fault fracture zone ahead. This is the first time that multi-dimensional spatial utilization has been achieved within a tunnel: the lateral ear holes expand the construction working surface, and the arc-shaped directional drilling overcomes the limitation of conventional TBM faces, which are limited to linear exploration drilling. More importantly, this arrangement enables advance exploration and reinforcement operations to be carried out in parallel, partially freeing the confined space in front of the TBM, thus achieving spatial staggered and coordinated operation of the TBM mainframe. For example, by completing exploration drilling and pre-reinforcement grouting within the ear holes, exploration and pre-treatment tasks, which traditionally require TBM downtime, can be moved forward and completed in parallel. Compared to existing technologies that rely primarily on built-in exploration holes within the TBM or short-distance pipe-roof construction, this multi-dimensional integrated layout significantly improves the coverage and efficiency of advance fault remediation, representing a pioneering approach to simultaneous advance exploration and remediation within a tunnel.

[0053] Sixthly, in the aspect of geological risk detection and decision-making, the method constructs an innovative application of a fusion multi-source sensing system. Multi-parameter information is collected synchronously during drilling, including rock debris morphology, drilling construction parameters (such as drilling pressure, torque, footage speed, etc.), and borehole natural gamma anomalies, etc. These data from different sensing channels are integrated and analyzed to form a comprehensive evaluation of fault zone geological risk. Through multi-source data fusion, adverse geological features in the front fault fracture zone, such as lithology mutation, water-rich anomaly or loose zone thickness, can be identified earlier and more accurately. The decision logic established accordingly can automatically identify the potential risk type: if there is a risk of jamming, it is a warning of unstable surrounding rock, and if there is a risk of sudden gushing, it is a warning of high water pressure fracture zone. Traditional TBM advanced prediction methods mainly use single sensing technology (such as seismic wave method or resistivity method independently applied), which is difficult to make timely comprehensive judgments. The present application organically integrates engineering, geological and geophysical information, embodies the innovation of multi-sensor information fusion in advanced prediction, improves the reliability of risk identification and the intelligent level of decision-making, and provides a scientific basis for timely selection of reinforcement measures on site.

[0054] Seventhly, in the aspect of advanced reinforcement technology, the present application innovatively designs the grouting method, grout material and diffusion control according to the TBM construction characteristics to improve the adaptability to TBM tunneling. Firstly, a segmented advancing grouting process is adopted: the advanced long borehole is divided into several segments, and grouting is carried out step by step, and a high-pressure grout retaining wall (such as a mid-way blocking section) is set to control the flow of grout to non-target areas, ensuring the formation of a continuous and dense reinforcement curtain in the fault fracture zone; secondly, the advantages of fast hardening and high permeability are complementary by using a combination of grout materials; thirdly, the grouting pressure is strictly controlled within 1.5-2 times the external water pressure: this pressure control criterion ensures that the grout has enough power to penetrate the rock mass cracks against the groundwater pressure, and avoids excessive pressure that may cause further damage to the surrounding rock or excessive loss of grout. The above innovations enable the permeability of the reinforced surrounding rock to be reduced to <5 Lu through water pressure testing, forming a nearly impermeable reinforced zone. For TBM, this means that the surrounding rock has been significantly reinforced and the groundwater has been effectively blocked when passing through the fault zone, greatly reducing the risk of TBM jamming due to sudden water gushing and collapse of loose bodies. Compared with the combination of chemical grout reinforcement and pipe roof advanced support commonly used in the past for open TBM passing through faults, the high-pressure multi-segment full-face curtain grouting of the present application has obvious advantages in reinforcement effect and adaptability to TBM continuous tunneling.

[0055] In summary, the innovation of the present invention lies in the organic integration of detection and treatment into an integrated process, and the simultaneous completion before the TBM excavation process, which minimizes the time that the TBM is stagnant due to detection and reinforcement. Through the innovative ear hole + directional drilling layout, the expansion of the coverage of advance reinforcement from "line" to "surface" is achieved; through multi-source information fusion judgment, a leap from experience-based decision-making to data-driven intelligent decision-making is achieved; through the grouting process optimized for TBM, the pre-reinforcement effect is improved from "general reliability" to "efficient adaptation". These breakthroughs effectively make up for the shortcomings of existing TBM fault crossing technologies at home and abroad. In the context of complex fault zones that have long plagued TBM construction, this parallel advance exploration and treatment integrated disposal method provides a new solution, coupling detection and prediction, advance reinforcement and mechanical excavation depth, significantly improving the safety and construction efficiency of TBM tunnels crossing fault fracture zones, and has significant technical innovation advantages and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of the layout of the ear holes and directional drilling on both sides of the TBM tunnel;

[0057] Figure 2 Schematic diagram of cross-section for ear piercing and drilling arrangement;

[0058] Figure 3 This is a schematic diagram of the top arch grouting section layout and grouting intersection;

[0059] Figure 4 It is the schematic diagram of the layout of the circumferential grouting section and the grouting intersection;

[0060] Figure 5 Schematic diagram of the process of a parallel advanced exploration and treatment method for a fault fracture zone in an open TBM tunnel according to an embodiment of the present invention;

[0061] In the figure, 1-ear hole construction area, 2-directional drilling axis, 3-fault fracture zone, 4-crawler directional drilling rig, 5-equipment bridge area, 6-tunnel, 7-ear hole, 8-tunnel excavation section, 9-borehole diameter, 10-slurry diffusion diameter, D1-distance between the TBM equipment bridge area and the TBM face, D2-distance required for the directional drill to change direction, D3-fault fracture zone width, Z1-first exploration borehole, Z2-second exploration borehole, Z3-first supplementary borehole, Z4-second supplementary borehole. DETAILED DESCRIPTION

[0062] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0063] It should be understood that the drawings are for illustrative purposes only and are not to be construed as limiting this patent. To better illustrate the embodiments, some components in the drawings may be omitted, enlarged, or reduced in size, and do not represent actual product dimensions. Those skilled in the art will understand that some well-known structures and their descriptions may be omitted from the drawings. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting this patent.

[0064] The present invention provides a method for parallel advanced exploration and treatment of a fault fracture zone in an open TBM tunnel, comprising:

[0065] S1: Determine the location of the fault fracture zone ahead of the tunnel based on the geological survey report. Calculate the TBM face mileage based on the daily TBM advance, the theoretical drilling speed of the drill, and the ear hole excavation period to ensure that ear hole excavation and directional drilling exploration and treatment are completed before the TBM reaches the fault fracture zone. The fundamental requirement for determining the TBM face mileage is to complete the directional drilling exploration and treatment in the tunnel before the TBM reaches the fault fracture zone, without affecting the normal TBM excavation in the fault fracture zone. That is, the ear hole excavation period, the drilling period to reach the fracture zone, and the period required for grouting in the fracture zone must be less than the period required for the TBM to advance through D2. The formula is as follows:

[0066] The duration for the directional drill to reach and pass through the fault fracture zone is:

[0067] ;

[0068] The total time required for directional drilling exploration and remediation is:

[0069] ;

[0070] The time required for the TBM to change direction through the required distance D2 of the directional drill is:

[0071] ;

[0072] According to T TBM Greater than T 探查-治理 The requirements, that is ;

[0073] The relationship between the mileage of the tunnel face and the starting mileage of the fault fracture zone:

[0074] ;

[0075] The TBM face mileage must meet the following requirements:

[0076] ;

[0077] Where, X1: the mileage of the tunnel face;

[0078] X2: starting mileage of the fault fracture zone;

[0079] D1: distance between the TBM equipment bridge area and the TBM tunnel face;

[0080] D2: distance required for the directional drill to change direction;

[0081] D3: width of fault fracture zone;

[0082] V1: TBM excavation speed;

[0083] V2: Theoretical drilling speed of directional drill in the formation;

[0084] T TBM : The time required for the TBM to advance from the current mileage to the fault fracture zone;

[0085] T 探查-治理 : The total construction period for completing ear hole construction, drilling and grouting treatment;

[0086] T1: ear piercing construction period;

[0087] T2: The time it takes for the drilling rig to reach the fault fracture zone;

[0088] T3: Fault zone grouting treatment period.

[0089] S2: When the TBM face is within a predetermined distance from the fault fracture zone, ear holes are excavated in the tunnel sidewalls in the TBM equipment bridge area. The ear holes are located close to the TBM face and allow for directional drilling changes. The TBM equipment bridge area has sufficient space for ear hole excavation and is close to the face to minimize ineffective drilling length. The target area for advance detection is the fault fracture zone ahead of the face. The rock from the TBM shield tail to the ear hole has been excavated and exposed, representing the ineffective drilling length. Once the ear hole excavation is complete in the TBM equipment bridge area, drilling can officially begin.

[0090] S3: Directional drilling rigs are deployed in two side holes, using an arc-shaped drilling pattern and gyroscope positioning to reach the fault fracture zone ahead of the tunnel face. Based on the results of previous geological exploration and the spatial location of the side holes, a curved drilling trajectory is designed to ensure that the drill hole accurately covers the fault fracture zone ahead of the tunnel axis. To enhance grouting effectiveness, side holes are opened on both sides of the tunnel. This dual-sided side hole design allows for simultaneous advance exploration and grouting treatment operations from both sides, extending the advance exploration coverage to a larger area on both sides of the tunnel and enhancing the efficiency and effectiveness of advance grouting treatment. This avoids the limited exploration range and inadequate localized grouting consolidation caused by directional drilling from only one side. During the drilling phase, a high-precision gyroscope guidance system is used to correct the drilling direction in real time based on the previously designed arc, ensuring that the directional drilling trajectory remains within 2-5 meters of the tunnel excavation outline. For the exploration part of the integrated exploration and treatment, an exploration drilling hole is carried out using the ear holes on both sides, and the detection target area is located 2 to 5 meters outside the tunnel spandrel excavation contour line.

[0091] S4: Conduct advance surveys during directional drilling, analyze survey data, and comprehensively assess the geological risks of the fault fracture zone. Before entering the fault zone, advance surveys are conducted using a combination of drill cuttings status, drill rig while-drilling parameters, and natural gamma ray detection. After entering the fault zone, surveys are conducted using a combination of core sampling, drill rig while-drilling parameters, and natural gamma ray detection. During drilling, core or cutting samples are collected to intuitively determine the lithology and degree of fracture, identify the specific boundaries of the fault fracture zone, and provide a basis for grouting treatment. The drill rig while-drilling parameter analysis and acquisition system collects parameters such as drill torque, speed, impact power, and drilling stroke, and uses regression models to invert the physical and mechanical properties of the rock mass (uniaxial compressive strength and degree of fracture). Directional natural gamma ray testing technology is employed, utilizing two azimuthal natural gamma ray sensors positioned 180° apart. The data processing unit converts these azimuthal gamma ray counts in cps (centimeter per second) into azimuthal gamma ray counts, enabling direct determination of stratum information within the borehole and lithology classification. The above technologies can be used to analyze the integrity of the rock mass, the degree of fracture development and the water content in front of the TBM in real time.

[0092] During this process, various exploration technologies can be flexibly incorporated according to the needs of different projects to ensure that the detection objectives under different geological conditions are met. For example, in situations where hydrological conditions are complex or aquifers are strong in fault fracture zones, acoustic imaging, electromagnetic wave detection, or underground radar can be combined to further enhance the detection capabilities of factors such as stratum fissures, aquifers, and sudden water inrush. For projects requiring deep and detailed fracture zone detection, microseismic monitoring and in-hole imaging can be used to obtain real-time dynamic changes in the rock mass and accurate three-dimensional stratigraphic distribution, further optimizing the delineation of fault fracture zone boundaries.

[0093] This flexible combination of exploration solutions can not only effectively improve the accuracy of exploration, but also provide more appropriate technical means to meet the requirements of different projects and different geological environments, ensuring a more accurate fault fracture zone detection solution in complex geological environments.

[0094] For the treatment part of the exploration-treatment system, priority is given to the implementation of two exploration boreholes (exploration boreholes and grouting holes) in the top arch. After the exploration boreholes reach the fault fracture zone, the drilling and coring operation is started. The geological conditions of the fracture zone are comprehensively analyzed and judged by combining the drilling rig's drilling parameters and natural gamma detection technology.

[0095] S5: When it is judged that the surrounding rock of the broken zone ahead of the TBM is at risk of collapse, resulting in the TBM getting stuck, consolidation grouting is carried out on the surrounding rock of the tunnel arch; when it is judged that there is a risk of sudden surge, curtain grouting is carried out on the surrounding rock around the tunnel; if the surrounding rock of the fault is extremely broken and poorly cemented, and the water output of the borehole is relatively small, it is judged that the surrounding rock of the broken zone ahead of the TBM is at risk of collapse, resulting in the TBM getting stuck, and there is no risk of sudden surge, two exploration boreholes in the top arch are used for pretreatment of the surrounding rock consolidation grouting of the tunnel arch; if the return water volume in the exploration borehole increases suddenly, the flow rate and water pressure are monitored in real time through the orifice. If the water output shows no decreasing trend and the gushing water is pressurized, it is judged that there is a large risk of sudden surge, and while grouting operations are being carried out in the two exploration boreholes in the top arch, directional drilling and high-pressure grouting work are carried out simultaneously in two supplementary boreholes in the invert arch, forming a continuous closed grouting curtain around the tunnel.

[0096] In this scheme, the reserved rock pillar at the distance from the TBM face to the fault zone boundary is used as a grouting wall. The grouting method adopts segmented forward grouting, and the hole grouting is carried out by lowering the flower pipe. The grouting materials used are modified single-liquid cement slurry and cement-water glass two-liquid slurry. The grouting pressure is determined according to the external water head (grouting pressure = 1.5-2 times the measured external water pressure at the location of the grouting section). Based on the effective grouting diffusion radius of 8-10m, the grouting diffusion circle forms an effective grouting reinforcement body with a certain radius range centered on the center of the tunnel section, thereby achieving a one-time grouting reinforcement treatment of the top arch or circumference of the tunnel section in the fault fracture zone in front.

[0097] S6: After the grouting is completed, a water pressure test is carried out to test the grouting effect. If it passes the test (the permeability of the grouting area after grouting is <5Lu), the TBM continues to advance normally and pass through the fault fracture zone.

[0098] Example:

[0099] The method for parallel advanced exploration and treatment of a fault fracture zone in an open TBM tunnel of the present invention comprises the following steps:

[0100] S1: An open-type TBM was used for the tunnel, with an excavation diameter of 10.0 m. The TBM bridge was 35 m from the cutterhead. Based on the location of the fault fracture zone identified in the preliminary geological survey report, the TBM's daily advances, the theoretical drilling rate, and the ear hole excavation schedule, the appropriate TBM face distance for ear hole construction was calculated.

[0101] S2: When the TBM face is at a predetermined distance from the fault fracture zone 3, ear holes 7 are excavated on both sides of the side walls of the tunnel 6 in the TBM equipment bridge area. The ear hole construction area 1 is arranged in the equipment bridge area 5. An ear hole with a depth of 4m, a length of 10m, and a height of 3m is excavated on both sides of the tunnel.

[0102] S3: Two ZDY-6000 crawler directional drills 4 for coal mines are selected and arranged at the ear holes 7 on both sides. Drilling is carried out according to the designed directional drill drilling axis 2. After the directional drilling holes are turned, they are arranged within a radius of 7.5m from the center of the tunnel section.

[0103] S4: Before entering the fault zone, advance exploration is conducted using methods including drilling debris status, drill-while-drilling parameters, and natural gamma ray detection. After entering the fault, exploration is conducted using core sampling, drill-while-drilling parameters, and natural gamma ray detection. Priority is given to drilling two exploration holes (both exploration holes and grouting holes) in the top arch. After the exploration holes (first exploration hole Z1 and second exploration hole Z2) reach the fault fracture zone, coring operations are initiated. The geological conditions of the fracture zone are comprehensively assessed using drill-while-drilling parameters and natural gamma ray detection.

[0104] S5: If the fault surrounding rock is extremely broken and poorly cemented, and the borehole water output is relatively small, it is judged that there is a risk of collapse of the surrounding rock in the broken zone, which may cause the TBM to jam. If there is no risk of sudden surge, two exploration boreholes (first exploration borehole Z1 and second exploration borehole Z2) of the top arch are used to carry out consolidation grouting pretreatment of the surrounding rock of the tunnel arch. The arrangement of the top arch grouting section and the arrangement relationship of the tunnel excavation section 8, the borehole circle diameter 9 and the slurry diffusion circle diameter of the grouting intersection are as follows: Figure 3 shown.

[0105] If the amount of water returning from the exploration borehole increases suddenly, the flow rate and water pressure will be monitored in real time through the orifice. If the water output shows no decreasing trend and the gushing water is pressurized, and it is judged that there is a large risk of sudden inrush, grouting operations will be carried out in the two exploration boreholes of the top arch (the first exploration borehole Z1 and the second exploration borehole Z2), while directional drilling and high-pressure grouting work will be carried out in two supplementary boreholes (the first supplementary borehole Z3 and the second supplementary borehole Z4) of the invert arch at the same time, forming a continuous closed grouting curtain around the tunnel.

[0106] The reserved rock pillar at the distance from the fault zone boundary to the TBM face is used as a grouting wall. The grouting method adopts segmented forward grouting. Grouting is carried out in the hole by lowering the flower pipe. The grouting materials are modified single-liquid cement slurry and cement-water glass two-liquid slurry. The grouting pressure is determined according to the external water head (grouting pressure = 1.5~2 times the measured external water pressure at the location of the grouting section). The effective grouting radius is 8.0m. The grouting diffusion circle forms an effective grouting reinforcement body with a certain radius range and the center of the tunnel section as the center, thereby achieving a one-time grouting reinforcement treatment of the top arch or the periphery of the fault fracture zone in front. The arrangement of the periphery grouting section and the arrangement relationship of the tunnel excavation section 8, the borehole circle diameter 9 and the grouting diffusion circle diameter are shown as follows. Figure 4 shown.

[0107] S6: After the grouting treatment is completed, a water pressure test is carried out to verify the grouting effect. After meeting the standard (the permeability of the grouting area after grouting is <5Lu), the TBM can proceed normally through the fault fracture zone.

[0108] The above embodiments are merely illustrative of the technical solutions of the present invention. The present invention is not limited to the contents described in the above embodiments, but is subject to the scope defined by the claims. Any modifications, supplements, or equivalent substitutions made by those skilled in the art based on these embodiments are within the scope of protection claimed in the claims of the present invention.

Claims

1. A method for parallel advanced exploration and treatment of fault fracture zones in an open TBM tunnel, characterized by: The steps include: S1: Determine the location of the fault fracture zone ahead of the tunnel based on the geological survey report. Calculate the TBM face mileage based on the daily TBM advance, the theoretical drilling rate of the drill, and the ear hole excavation period to ensure ear hole excavation and directional drilling exploration and treatment are completed before the TBM reaches the fault fracture zone. S2: When the TBM face is at a predetermined distance from the fault fracture zone, ear holes are excavated on both sides of the tunnel wall in the TBM equipment bridge area. The ear holes are located close to the TBM face and have enough space for directional drilling to change direction. S3: Place directional drills in the two side holes, use arc drilling and gyroscope positioning to reach the fault fracture zone in front of the tunnel face; S4: Conduct advance detection during directional drilling, analyze detection data, and comprehensively assess the geological risk of the fault fracture zone; S5: When it is determined that there is a risk of collapse of the surrounding rock in the fracture zone ahead of the TBM, which may cause the TBM to jam, consolidation grouting is carried out on the surrounding rock of the tunnel arch. When it is determined that there is a risk of sudden surge, curtain grouting is carried out on the surrounding rock around the tunnel. S6: After the grouting is completed, the grouting effect is tested. If it passes the test, the TBM can continue to advance normally and pass through the fault fracture zone; Wherein, in step S1, the TBM face mileage satisfies the following relationship: The duration for the directional drill to reach and pass through the fault fracture zone is: ； The total time required for directional drilling exploration and remediation is: ； The time required for the TBM to change direction through the required distance D2 of the directional drill is: ； According to T TBM Greater than T 探查-治理 The requirements, that is ; The relationship between the mileage of the tunnel face and the starting mileage of the fault fracture zone: ； The TBM face mileage must meet the following requirements: ； Where, X1: the mileage of the tunnel face; X2: starting mileage of the fault fracture zone; D1: distance between the TBM equipment bridge area and the TBM tunnel face; D2: distance required for the directional drill to change direction; D3: width of fault fracture zone; V1: TBM excavation speed; V2: Theoretical drilling speed of directional drill in the formation; T TBM : The time required for the TBM to advance from the current mileage to the fault fracture zone; T 探查-治理 : The total construction period for completing ear hole construction, drilling and grouting treatment; T1: ear piercing construction period; T2: The time it takes for the drilling rig to reach the fault fracture zone; T3: Fault zone grouting treatment period.

2. The method for parallel advanced exploration and treatment of fault fracture zones in open TBM tunnels according to claim 1 is characterized by: In step S3, directional drilling construction is completed within a range of 2 to 5 meters outside the tunnel excavation contour line.

3. The method for parallel advanced exploration and treatment of fault fracture zones in an open TBM tunnel according to claim 1 or 2, characterized in that: In step S3, a plurality of exploration boreholes are constructed in the top arch by using the ear holes on both sides, and the detection target area is located within a range of 2 to 5 meters outside the tunnel spandrel excavation contour line.

4. The method for parallel advanced exploration and treatment of fault fracture zones in an open TBM tunnel according to claim 3 is characterized by: In step S4, before entering the fault zone, advance detection is carried out by combining the drilling slag status, drilling rig parameters while drilling, and natural gamma detectors. After entering the fault, detection is carried out by combining core drilling, drilling rig parameters while drilling, and natural gamma detectors.

5. The method for parallel advanced exploration and treatment of fault fracture zones in an open TBM tunnel according to claim 4 is characterized in that: The drilling rig parameters include drilling rig torque, rotation speed, impact power and drilling stroke parameters.

6. The method for parallel advanced exploration and treatment of fault fracture zones in an open TBM tunnel according to claim 5 is characterized by: In step S5, when it is determined that there is a risk of collapse of the surrounding rock in the broken zone ahead of the TBM causing the TBM to get stuck, consolidation grouting is performed on the surrounding rock of the tunnel arch by drilling exploration holes in the top arch.

7. The method for parallel advanced exploration and treatment of fault fracture zones in an open TBM tunnel according to claim 6 is characterized in that: In step S5, when it is determined that there is a risk of sudden surge, while grouting is being carried out in the exploration borehole of the top arch, directional drilling and high-pressure grouting of several supplementary boreholes are simultaneously carried out in the invert arch to perform curtain grouting on the surrounding rock around the tunnel.

8. The method for parallel advanced exploration and treatment of fault fracture zones in an open TBM tunnel according to claim 7 is characterized in that: In step S5, the grouting method adopts segmented progressive grouting, using the reserved rock pillar at the TBM face away from the fault zone boundary as a grouting wall, and grouting is carried out in the hole by lowering a flower pipe. The grouting materials adopt modified single-liquid cement slurry and cement-water glass two-liquid slurry; The grouting pressure is 1.5 to 2 times the measured external water pressure at the grouting section. The effective diffusion radius of the slurry is 8 to 10 m. The grouting diffusion circle forms an effective grouting reinforcement body within the diffusion radius with the center of the tunnel section as the center.

9. The method for parallel advanced exploration and treatment of fault fracture zones in an open TBM tunnel according to claim 1 or 2, characterized in that: In step S6, after the grouting is completed, a water pressure test is carried out to test the grouting effect. If the water permeability of the grouting area after grouting is less than 5Lu, it is judged to be qualified.

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