Reinforcing method for single-shield TBM in extremely broken and groundwater developed stratum

Abstract

The application belongs to the field of TBM grouting reinforcement, and discloses a reinforcement method for single-shield TBM in an extremely broken and groundwater-developed stratum, which comprises the following steps: step 1, multiple first freezing drill holes, second freezing drill holes and third freezing drill holes are opened; step 2, freezing is performed to form a frozen area; step 3, first grouting drill holes, second grouting drill holes and third grouting drill holes are opened, and grouting is performed to form a cutter head grouting stopping wall and a shield body grouting stopping wall; and step 4, a fourth grouting drill hole is opened, and grouting is performed on the fourth grouting drill hole to form a grouting reinforcement body; by constructing the cutter head grouting stopping wall and the shield body grouting stopping wall, the grout injected from the fourth grouting drill hole can be prevented from flowing back along the fissures of the broken stratum and wrapping the shield body of the single-shield TBM, the allowable grouting pressure of subsequent advanced grouting of the fourth grouting drill hole can be greatly improved, the grout diffusion range is controllable, the filling and consolidation are sufficient, and the grouting reinforcement effect of the deep broken stratum is ensured.

Description

Technical Field

[0001] This invention belongs to the field of TBM grouting reinforcement, and particularly relates to a reinforcement method for single-shield TBMs in extremely fractured and well-developed groundwater strata. Background Technology

[0002] Against the backdrop of my country's ongoing in-depth development of transportation infrastructure construction, tunnel engineering is increasingly facing the challenge of traversing complex geological zones such as fractured rock masses, water-rich sand layers, and karst development areas. Due to long-term geological tectonic movements, groundwater erosion, or differences in sedimentary environments, these strata naturally exhibit core problems such as poor integrity, loose structure, and insufficient stability. This not only poses extremely high safety risks to tunnel construction but also becomes a key bottleneck restricting project quality and progress.

[0003] Taking fractured rock mass as an example, the numerous joints and fissures developed inside it are mostly distributed in a network pattern. Some fissures are only a few millimeters to a few centimeters wide, and their extension direction is irregular and highly interconnected, which causes the rock mass to be cut into fragmented blocks, resulting in a significant reduction in its own bearing capacity and self-stabilizing ability.

[0004] Water-rich sand layers are characterized by loose, uncemented sand and abundant groundwater. The sand grains lack effective cohesion, making them prone to quicksand and piping under the action of groundwater infiltration. After tunnel excavation, the surrounding soil is extremely prone to instability and collapse.

[0005] Karst development areas are characterized by complex geological features such as caves, dissolution fissures, and underground rivers. Hollow areas lack rock mass support and have complex groundwater dynamics, which can easily lead to major engineering risks such as sudden water and mud outbursts and large deformation of surrounding rock.

[0006] Faced with the reinforcement needs of these complex geological formations, the limitations of traditional localized grouting technology are becoming increasingly apparent. Traditional localized grouting is mostly focused on point-to-point treatment of defects, that is, targeted grouting is carried out on obvious cracks, water inflow points, or local collapse risks discovered during excavation. Its grouting range is limited to a specific area and lacks systematic coverage of the entire stratum. In this mode, the grouting consolidation body is often distributed in an isolated manner, making it difficult to effectively connect with the surrounding rock and adjacent grout bodies. It is impossible to build a continuous and complete overall support system and cannot fundamentally improve the integrity and stability of complex strata.

[0007] When single-shield TBMs traverse the aforementioned geological formations, the risk of jamming is particularly prominent due to the poor self-stabilizing capacity of the surrounding rock and the disturbance caused by seepage from flowing water. Conventional pre-grouting is commonly used in engineering to improve the surrounding rock and control deformation, thereby enhancing the overall stability of the surrounding rock. However, the grout from conventional pre-grouting is highly susceptible to channeling along the annular gap between the shield and the surrounding rock, consolidating and hardening around the shield, further increasing the frictional resistance between the shield and the surrounding rock, exacerbating the propulsion load, and inducing continuous deviation of the shield's attitude. Simultaneously, the channeling grout easily intrudes into the gaps of the tail seal brush, causing the tail seal brush to harden and become stuck, directly leading to tail seal failure and creating a continuous channel for water inflow and grout leakage. Therefore, multiple risks such as jamming, loss of attitude control, lining damage, and tail leakage are coupled and superimposed, forming a chain of disasters that severely restrict the continuous and safe tunneling of the TBM. Summary of the Invention

[0008] The purpose of this invention is to provide a reinforcement method for single-shield TBMs in extremely fractured and water-rich strata, in order to solve the problems of chain disasters such as machine jamming, attitude loss, lining damage, and shield tail leakage that occur when single-shield TBMs are tunneling in extremely fractured and water-rich strata.

[0009] This invention employs the following technical solution: a method for reinforcing single-shield TBMs in extremely fractured and water-rich strata, comprising: Step 1: Open multiple first cryogenic boreholes horizontally in front of the working face through the cutter holes and scraper openings of the single-shield TBM cutterhead; open multiple second cryogenic boreholes inclined upwards towards the working face on the front shield of the single-shield TBM; open multiple third cryogenic boreholes vertically upwards on the tail shield of the single-shield TBM. Step 2: Liquid nitrogen is introduced into each of the first, second, and third freezing boreholes to freeze the water in the strata where the groundwater is relatively developed, forming a frozen area covering the cutterhead, front shield, middle shield, and tail shield of the single-shield TBM. Step 3: While continuously introducing liquid nitrogen into the first, second, and third freezing boreholes, respectively, grouting boreholes are drilled in the frozen areas where the first, second, and third freezing boreholes are located. A cutterhead grout stop wall is formed by grouting with fiberglass anchor bolts in the first grouting borehole, and a shield grout stop wall is formed by grouting with steel pipes in the second and third grouting boreholes. Step 4: Stop introducing liquid nitrogen into the first, second, and third freezing boreholes. Open the fourth grouting borehole on the middle shield of the single-shield TBM, tilting upwards towards the working face, and grout the fourth grouting borehole to form a grouting solidified body. The grouting solidified body is located on the front side of the cutterhead grout stop wall, diagonally above it. The frozen zone is used to prevent the grout injected from the first grouting borehole, the second grouting borehole, and the third grouting borehole from flowing back along the fractures of the broken strata and encasing the shield of the single-shield TBM. The cutterhead grout stop wall and the shield grout stop wall are used to prevent the grout injected from the fourth grouting borehole from flowing back along the fractures of the broken strata and wrapping around the shield of the single-shield TBM. Grouting is used to reinforce extremely fractured strata, thereby facilitating normal tunneling by a single-shield TBM.

[0010] The beneficial effects of this invention are: This invention utilizes the freezing method to construct frozen areas, relying on the frozen areas to achieve water blocking and isolation barriers, which can effectively seal the seepage channels in the strata and fundamentally avoid problems such as long-distance grout flow, shield body encapsulation, and grout intrusion into the shield tail sealing brush gap during conventional grouting construction. This invention, through the construction of a cutterhead grout stop wall and a shield grout stop wall, can prevent the grout injected from the fourth grouting borehole from flowing back along the fractures of the broken strata and enveloping the shield of the single-shield TBM. It can significantly increase the allowable grouting pressure for subsequent advanced grouting in the fourth grouting borehole, control the grout diffusion range, and ensure sufficient filling and consolidation, thus guaranteeing the grouting reinforcement effect of deep fractured strata. Attached Figure Description

[0011] Figure 1 This is a construction diagram of the present invention.

[0012] Among them: 1. Single-shield TBM; 2. Cutterhead; 3. Frozen zone; 4. Cutterhead grout stop wall; 5. Grouting reinforcement body; 6. First freezing borehole; 7. Second freezing borehole; 8. Third freezing borehole; 9. First grouting borehole; 10. Second grouting borehole; 11. Third grouting borehole; 12. Fourth grouting borehole. Detailed Implementation

[0013] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0014] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not 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 the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" means two or more. The term "orientation" in this invention refers to the orientation of the device or element according to the invention. Figure 1 Description of the state's progression.

[0015] This invention discloses a method for reinforcing single-shield TBMs in highly fractured and water-rich strata, such as... Figure 1 As shown, it includes 4 steps.

[0016] Step 1: Open multiple first freezing holes 6 horizontally in front of the face of the single-shield TBM1 cutterhead 2 through the cutter holes and scraper openings; open multiple second freezing holes 7 inclined upwards towards the face of the single-shield TBM1 front shield; open multiple third freezing holes 8 vertically upwards on the tail shield of the single-shield TBM1. Step 2: Liquid nitrogen is introduced into each of the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8 to freeze the water in the strata where the groundwater is relatively developed, forming a frozen area 3 covering the cutterhead, front shield, middle shield, and tail shield of the single-shield TBM1. Step 3: While continuously introducing liquid nitrogen into the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8, respectively, the first grouting borehole 9, the second grouting borehole 10, and the third grouting borehole 11 are opened in the frozen area 3 where the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8 are located; the first grouting borehole 9 is grouted with glass fiber anchor bolts to form a cutterhead grout stop wall 4, and the second grouting borehole 10 and the third grouting borehole 11 are grouted with steel pipes to form a shield grout stop wall; Step 4: Stop the flow of liquid nitrogen into the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8. Open the fourth grouting borehole 12 on the middle shield of the single shield TBM1, tilting upwards towards the working face, and grout the fourth grouting borehole 12 to form the grouting reinforcement body 5. The grouting reinforcement body 5 is located on the front side of the cutterhead grout stop wall 4, slightly above it. Among them, the frozen area 3 is used to prevent the grout injected from the first grouting borehole 9, the second grouting borehole 10, and the third grouting borehole 11 from flowing back along the fractures of the broken strata and wrapping the shield of the single-shield TBM1. Among them, the cutterhead grout stop wall 4 and the shield grout stop wall are used to prevent the grout injected from the fourth grouting borehole 12 from flowing back along the fractures of the broken strata and wrapping the shield of the single shield TBM1. Among them, the grouting and solidification unit 5 is used to reinforce the extremely broken strata, thereby facilitating the normal tunneling of the single-shield TBM1.

[0017] The depth of the fourth grouting borehole 12 is greater than the depths of the first grouting borehole 9, the second grouting borehole 10, and the third grouting borehole 11. The depths of the first grouting borehole 9, the second grouting borehole 10, and the third grouting borehole 11 are greater than the depths of the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8, respectively.

[0018] The inclination angles of the second freezing borehole 7 and the second grouting borehole 10 are both 10°-20°.

[0019] The inclination angle of the fourth grouting borehole 12 is 5°-15°.

[0020] Among them, the first freezing borehole 6 and the first grouting borehole 9 are arranged in an array along the cutterhead 2.

[0021] This invention first uses a freezing method to form a frozen area 3, which is used to reinforce the stratum and prevent grout from flowing back and enveloping the shield. Then, grouting is used to reinforce and form a cutterhead grout stop wall 4 and a shield grout stop wall, establishing a complete grout stop system to ensure the successful grouting of the subsequent fourth grouting borehole 12.

[0022] Example The construction area in this embodiment mainly traverses the western side of the mountains along the Jinsha River system, with ground elevations generally ranging from 3360m to 3507m and slope angles generally between 25° and 35°. The tunnel is located in the Lijiang platform margin fold belt (Ⅰ1) of the Yangtze quasi-platform, specifically the Heqing-Erhai platform fold bundle (Ⅰ1). 1 Within this area, the neotectonic movement belongs to the Heqing-Jianchuan differential depression zone, where fault tectonic activity is intense. The near-north-south trending Wandeng-Banqiao fault (F) is distributed within an 8km radius of the branch tunnel axis. Ⅱ-18 ), Huangfengchang-Qingshuijiang Fault (F Ⅱ-17 ), Xiamatang-Heinishao Fault (F Ⅱ-32（1） ), (F Ⅱ-32（2） ), (F Ⅱ-33 ), (F Ⅱ-34（1） The Machang Fault, trending nearly east-west (F Ⅱ-8 ), (F Ⅱ-35 ), Qingshiya fracture (F) Ⅱ-9（1） ), (FⅡ-9（2） ), (F Ⅱ-9（3） The Heqing-Eryuan Fault (F12) is an active Holocene fault. The main faults in the construction area are F101, F102, F103, and F104. Due to tectonic influence, the rock mass has well-developed fractures, mostly with gentle to moderate dip angles, followed by steep dip angles.

[0023] The lithology along the tunnel route mainly consists of Permian Emeishan Formation (Pβ) basalt interbedded with tuff and other magmatic rocks, Upper Permian Heinishao Formation (P2h) gray sandstone, shale interbedded with limestone and coal seams, and Lower Triassic Qingtianbao Formation (T1q) bluish-gray and brownish-red mudstone, sandstone and silty mudstone. Quaternary overburden is less distributed, mainly in the channels of Xiaoqing River, Yinhe River and other water systems, as well as small gullies on both sides of the route and relatively flat low hills. The channels are mostly alluvial deposits (Qpal), and the slopes of the mountains are mostly colluvial deposits (Qedl). The thickness of the strongly weathered zone of basalt interbedded with tuff in the project area is generally 80-110m, the thickness of the weakly weathered zone is generally 140-240m, the thickness of the strongly weathered zone of sandstone and shale is generally 70-120m, and the thickness of the weakly weathered rock mass is generally 120-140m. There are intensified weathering phenomena along fault zones in the rock mass, and there are also pocket weathering phenomena in the basalt.

[0024] The tunnel project area has a low-latitude plateau monsoon climate, characterized by small seasonal temperature differences, distinct wet and dry seasons, significant vertical variations, and a pronounced three-dimensional climate. According to measured meteorological data from relevant meteorological stations along the route, the average annual precipitation ranges from 754 to 951 mm. Precipitation is unevenly distributed throughout the year and across regions, with small interannual variations. The flood season (May to October) accounts for approximately 85% of the annual precipitation. The average annual evaporation ranges from 2055 to 1166 mm (using a 20cm diameter evaporation pan), with uneven distribution throughout the year, mainly concentrated from February to August, accounting for about 70% of the annual total, with the most significant evaporation occurring from March to May. The average annual temperature is 12.0–13.5℃, with extreme maximum temperatures ranging from 32.0 to 33.4℃ and extreme minimum temperatures from -11.4 to -11.0℃; the average annual wind speed is 2.5–3.3 m / s.

[0025] The watershed where this section is located belongs to a low-latitude plateau monsoon climate zone. Heavy rainfall (daily rainfall greater than 50 mm) mainly occurs from May to October, concentrated in June to September, with very few years occurring in May or October. Floods are formed by heavy rainfall, and the timing and distribution of floods correspond to the rainfall patterns, mainly occurring from June to October. According to the flood series statistics measured at the Laiyuanqiao and Heqing hydrological stations near this section, the annual maximum flood peak flow occurs most frequently from July to September, accounting for approximately 85-90% of the annual floods, especially in August, with the highest probability of occurring in August, accounting for approximately 44-47%.

[0026] The flood events are characterized by rapid rises and falls, and short durations, with a single flood event lasting less than 24 hours, exhibiting the characteristics of mountain floods.

[0027] Therefore, the construction area is located in a highly fractured stratum with well-developed groundwater. As a result, the tunneling resistance of the single-shield TBM 1 increased dramatically, the thrust of the main hydraulic cylinder of the single-shield TBM 1 exceeded the limit, and it could not advance normally. The shield body of the single-shield TBM 1 deviated in attitude, failed to correct its vertical and horizontal deviations, misaligned and damaged segments, the shield tail brush was stuck by the solidified grout, the shield tail grease could not be injected, and grout and water continued to leak.

[0028] Therefore, the strata in this embodiment are determined to be extremely fractured and have relatively developed groundwater. The strata are then reinforced using the following method: Step 1: Open multiple first freezing holes 6 horizontally in front of the face of the single-shield TBM1 cutterhead 2 through the cutter holes and scraper openings; open multiple second freezing holes 7 inclined upwards towards the face of the single-shield TBM1 front shield; open multiple third freezing holes 8 vertically upwards on the tail shield of the single-shield TBM1.

[0029] The diameter of the first freezing borehole 6 and the third freezing borehole 8 is uniformly 32mm. There are 8 first freezing boreholes 6 and 10 third freezing boreholes 8. The depth of the first freezing borehole 6 and the third freezing borehole 8 is 2m. During the drilling process, the drilling rig is kept perpendicular to the shield and drills at a uniform speed to avoid borehole deviation and collapse. The drilling depth and borehole position deviation data are recorded in real time.

[0030] Twelve second freezing boreholes (7) were drilled, using a zoned, sequential, and intermittent drilling method to avoid excessive disturbance to the surrounding rock caused by concentrated drilling. The second freezing borehole (7) had a depth of 2.5m, and the drilling trajectory was strictly controlled to ensure straight boreholes and regular bottoms.

[0031] After the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8 are completed, the freezing pipes should be installed in a timely manner.

[0032] Step 2: Liquid nitrogen is introduced into each of the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8 to freeze the water in the strata where the groundwater is relatively developed, forming a frozen area 3 covering the cutterhead, front shield, middle shield, and tail shield of the single-shield TBM1.

[0033] Ensure the sealing of the openings of the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8. Connect the freezing unit to carry out continuous low-temperature freezing operations, monitor the freezing temperature, the cooling rate of the surrounding rock, and the consolidation state of the surrounding soil throughout the process, and ensure that the surrounding rock within a 2m depth of the top of the shield is completely frozen, forming a uniform and completely sealed frozen area 3, effectively blocking groundwater seepage and preventing grout leakage or runoff problems in subsequent grouting operations.

[0034] Step 3: While continuously introducing liquid nitrogen into the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8, the first grouting borehole 9, the second grouting borehole 10, and the third grouting borehole 11 are respectively opened in the frozen area 3 where the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8 are located; the first grouting borehole 9 is grouted with glass fiber anchor rods to form a cutterhead grout stop wall 4, and the second grouting borehole 10 and the third grouting borehole 11 are grouted with steel pipes to form a shield grout stop wall.

[0035] The depths of the first grouting borehole 9 and the third grouting borehole 11 are both 4m, the depth of the second grouting borehole 10 is 5m, and the diameters of the first grouting borehole 9, the second grouting borehole 10, and the third grouting borehole 11 are all 32mm. The number of the first grouting borehole 9, the second grouting borehole 10, and the third grouting borehole 11 are 8, 12, and 10, respectively.

[0036] Specifically, a YT-28 handheld pneumatic drill with an A32mm drill bit was used for drilling operations to precisely control the drilling position and diameter accuracy. After the first grouting hole 9 was completed, a 4m long glass fiber anchor rod with a specification of Ф32×1.5mm was installed. After the second grouting hole 10 and the third grouting hole 11 were completed, steel pipes were used for grouting, and cement-water glass double liquid grout was injected simultaneously. The maximum grouting pressure of the double liquid grout was strictly controlled at 3.0MPa during construction.

[0037] During grouting, the grouting pressure and volume are monitored in real time, and the grout return and seepage in the surrounding rock are observed to ensure that the grout fully fills the fissures in the surrounding rock around the shield. After the grout solidifies, it forms a dense, high-strength cutterhead grout stop wall 4 and a shield grout stop wall, effectively preventing grout backflow and leakage and reinforcing the loose surrounding rock around the shield. After grouting a single hole is completed, the hole is sealed in time and left to cure until the grout has initially solidified.

[0038] In step 3, the use of fiberglass anchor bolts for grouting the first grouting borehole 9 is to avoid affecting the cutterhead of the single-shield TBM 1 during tunneling. Because fiberglass anchor bolts have low shear strength, the cutterhead of the single-shield TBM 1 can be directly cut, and no separate treatment is required after grouting. Using steel perforated pipes for grouting the second grouting borehole 10 and the third grouting borehole 11 can reduce costs, as these boreholes do not affect the cutterhead of the single-shield TBM 1 during tunneling.

[0039] Step 4: Stop the flow of liquid nitrogen into the first freezing borehole 6, the second freezing borehole 7, and the third freezing borehole 8. Open the fourth grouting borehole 12 on the middle shield of the single shield TBM1, tilting upwards towards the working face, and grout the fourth grouting borehole 12 to form the grouting solid body 5. The grouting solid body 5 is located on the front side of the cutterhead grout stop wall 4, slightly above it.

[0040] The fourth grouting borehole, numbered 12, consists of eight holes, each 18 meters deep. During the drilling and grouting process, acrylate grout was injected to ensure the loose rock mass was cemented. After drilling, the grouting machine was used for segmented retraction, retracting the drill bit 2 meters at a time, injecting a two-component grout to ensure a grouting pressure of no less than 5 MPa. During grouting, a phosphoric acid-water glass two-component grout was used around the drill rod for protection, isolation, and grout blocking to maintain the grouting pressure at the bottom of the hole.

[0041] After the above grouting reinforcement treatment and the completion of all grouting procedures, and after the geological conditions meet the requirements for tunneling, the single-shield TBM1 restarted tunneling construction, and the construction efficiency was restored to 9-10 meters / 1-2 days, that is, it takes about 1 to 2 days to complete 9-10 meters of tunneling.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for reinforcing a single-shield TBM in highly fractured and water-rich strata, characterized in that, include: Step 1: Open multiple first freezing holes (6) horizontally in front of the face of the tunnel through the cutter hole and scraper opening of the cutter head (2) of the single shield TBM (1); open multiple second freezing holes (7) inclined upward in front of the face of the tunnel on the front shield of the single shield TBM (1); open multiple third freezing holes (8) vertically upward on the tail shield of the single shield TBM (1). Step 2: Liquid nitrogen is introduced into each of the first freezing borehole (6), the second freezing borehole (7), and the third freezing borehole (8) to freeze the water in the strata where the groundwater is relatively developed, forming a frozen area (3) covering the cutterhead, front shield, middle shield, and tail shield of the single-shield TBM (1). Step 3: While continuously introducing liquid nitrogen into the first freezing borehole (6), the second freezing borehole (7), and the third freezing borehole (8), open the first grouting borehole (9), the second grouting borehole (10), and the third grouting borehole (11) in the frozen area (3) where the first freezing borehole (6), the second freezing borehole (7), and the third freezing borehole (8) are located, respectively; use glass fiber anchor rods to grout the first grouting borehole (9) to form a cutterhead grout stop wall (4), and use steel pipes to grout the second grouting borehole (10) and the third grouting borehole (11) to form a shield grout stop wall; Step 4: Stop introducing liquid nitrogen into the first cryogenic borehole (6), the second cryogenic borehole (7), and the third cryogenic borehole (8). Open a fourth grouting borehole (12) on the middle shield of the single-shield TBM (1) tilting upward toward the working face, and grout the fourth grouting borehole (12) to form a grouting solid (5). The grouting solid (5) is located on the front side of the cutterhead grout stop wall (4) at an angle above it. The frozen area (3) is used to prevent the grout injected from the first grouting borehole (9), the second grouting borehole (10), and the third grouting borehole (11) from flowing back along the fractures of the broken strata and encasing the shield of the single-shield TBM (1). The cutterhead grout stop wall (4) and the shield grout stop wall are used to prevent the grout injected from the fourth grouting borehole (12) from flowing back along the fractures of the broken strata and wrapping the shield of the single-shield TBM (1). The grouting reinforcement (5) is used to reinforce the extremely broken strata, thereby facilitating the normal tunneling of the single-shield TBM (1); The grouting pressure of the fourth grouting borehole (12) is not less than 5 MPa.

2. The method for reinforcing a single-shield TBM in highly fractured and water-rich strata according to claim 1, characterized in that, The depth of the fourth grouting borehole (12) is greater than the depth of the first grouting borehole (9), the second grouting borehole (10), and the third grouting borehole (11). The depths of the first grouting borehole (9), the second grouting borehole (10), and the third grouting borehole (11) are greater than the depths of the first freezing borehole (6), the second freezing borehole (7), and the third freezing borehole (8), respectively.

3. The reinforcement method for a single-shield TBM in highly fractured and water-rich strata according to claim 1, characterized in that, The inclination angles of the second freezing borehole (7) and the second grouting borehole (10) are both 10°-20°.

4. The method for reinforcing a single-shield TBM in highly fractured and water-rich strata according to claim 1, characterized in that, The inclination angle of the fourth grouting borehole (12) is 5°-15°.

5. The method for reinforcing a single-shield TBM in highly fractured and water-rich strata according to claim 1, characterized in that, The first cryogenic borehole (6) and the first grouting borehole (9) are arranged in an array along the cutterhead (2).

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