A combined construction method for TBMs traversing adverse geological formations

Abstract

This invention discloses a combined construction method for TBMs traversing adverse geological formations. Various combined technical measures are employed to identify and reinforce the adverse geological formations in front of the TBM cutterhead, enabling the TBM to safely and rapidly advance through these formations. These combined technical measures include long-distance advanced horizontal directional drilling, strong support, combined steel arch support, chemical grouting reinforcement, and advanced large-diameter pipe roof reinforcement at the top of the shield. For adverse geological formations prone to collapse, water inrush, and water surge, water is pre-emptively drained and the geological conditions are explored. Before the TBM reaches the adverse geological formations, advanced horizontal drilling is used to conduct exploratory boreholes. Based on the results of these exploratory boreholes, chemical grouting and advanced large-diameter pipe roof pre-reinforcement techniques are applied to reinforce the surrounding rock at the face in front of the cutterhead. During the tunneling process, strong support and combined steel arch support techniques are employed to ensure the TBM's safe and rapid passage through the adverse geological formations.

Description

Technical Field

[0001] This invention belongs to the field of TBM construction technology for long tunnels, specifically relating to a method for constructing TBMs through adverse geological formations. Background Technology

[0002] In open-face TBM construction tunnels, problems such as faults, sudden water inrushes, and large deformation of soft rock strata are frequently encountered. However, due to the structure and construction characteristics of TBMs, the difficulty of dealing with faults, sudden water inrushes, large deformation of soft rock strata, and unfavorable strata is much greater than that of drill-and-blast tunnel construction. This can not only cause delays in the construction period but may also damage the open-face TBM or even lead to the failure of TBM construction.

[0003] TBMs are hard rock tunneling machines, typically equipped with anchor drilling rigs, steel arch assemblers, and shotcrete systems for initial support. However, their shortcomings in supporting operations across fault lines, sudden water inrushes, soft rock with large deformations, and unfavorable strata remain significant. Support time is delayed, the process is too lengthy, safety near the shield is low, support operations are difficult, and jamming is highly likely. When TBMs are tunneling through fault lines, sudden water inrushes, soft rock with large deformations, and unfavorable strata, the immense resistance from rocks and water pressure cause a sharp increase in the TBM cutterhead torque, a rapid decrease in hydraulic cylinder thrust, and increased conveyor belt pressure. These phenomena can easily lead to a large amount of excavated material crushing the conveyor belt and forcing a shutdown. In severe cases, large-scale collapse of the shield top can damage the hydraulic equipment in the L1 zone, causing TBM jamming and sudden water inrush accidents.

[0004] In cases of collapse, a steel bar storage chamber is typically added at the tail of the shield. One end of the steel bar is installed in the storage chamber, and the other end is welded to a steel arch frame. As the TBM advances, the steel bar is released to intercept the rocks that collapse during the TBM's excavation. The steel bar can effectively intercept small collapses during TBM excavation. However, for medium to large collapses, the rigidity of the steel bar is insufficient to support the impact force of gravity on the steel bar under the weight of the collapsing rocks, causing it to deform and thus posing a risk of secondary collapse.

[0005] To address the issue of machine jamming, methods such as drilling and blasting a small pilot tunnel between the shield and the surrounding rock to enter the cutterhead and excavate further to free the machine, or loosening the TBM's supporting bridge and trolley to reduce the back tension of the TBM during tunneling and continuously increase the thrust of the main thrust cylinder to overcome the friction between the shield and the surrounding rock surface when the machine is jammed, are highly damaging to the machine itself and have a high probability of failure. The construction of the small pilot tunnel involves a large workload, a long construction period, and high safety risks.

[0006] In formations with sudden water inrush, the cutterhead is usually moved back, and a small pilot tunnel is manually constructed to enter between the cutterhead and the working face to implement curtain grouting for water stoppage. There is no protection around the annular surrounding rock excavation face, which poses high safety risks, involves complicated construction procedures, and is time-consuming.

[0007] Given the aforementioned background technology regarding TBM support for crossing faults, sudden water inrushes, large deformations in soft rock, and unfavorable strata, further exploration and research are needed to achieve the goal of safe and efficient TBM construction across unfavorable strata. Summary of the Invention

[0008] The purpose of this invention is to provide a combined construction method for TBMs traversing unfavorable strata, so as to solve the above-mentioned problems and achieve the goal of safe and efficient construction of TBMs traversing unfavorable strata.

[0009] This invention is achieved through the following technical solution:

[0010] A method for constructing a TBM through adverse geological formations includes:

[0011] Step 1: Under normal TBM tunneling operation without stopping, before the TBM cutterhead reaches the unfavorable strata, long-distance advanced horizontal directional drilling is used to drill advanced holes in the collapsed, water-inrushing, and mud-bursting sections of the unfavorable strata, so as to drain water and explore the geology.

[0012] The advanced horizontal directional drilling trajectory passes between the unfavorable strata end of the TBM tunnel and the TBM cutterhead, intersecting with the arch waist on one side of the TBM tunnel before continuing parallel to the longitudinal direction of the TBM tunnel. The height at which the advanced horizontal directional drilling trajectory intersects with the arch waist on one side of the TBM tunnel is 100cm above the invert block. The ultra-strong horizontal directional drilling proceeds parallel to the longitudinal direction of the TBM tunnel for at least 100m beyond the unfavorable strata end.

[0013] Advanced horizontal directional drilling serves both as an advanced water drainage system and an advanced geological exploration borehole. The hardness of the surrounding rock is determined by the drilling torque and drilling time during advanced horizontal directional drilling. Longer drilling times correspond to harder rock, and shorter times correspond to softer rock; time and hardness generally show a positive correlation. Given the relatively high overall torque, and excluding the influence of drill bit wear, based on past rock drilling experience, the rock is inferred to be hard. Downhole television is used to investigate the surrounding rock of unfavorable formations and its water content.

[0014] The following are common rock fissure conditions and their treatment measures:

[0015] If the surrounding rock has slightly developed fissures, is relatively broken, has a fragmented structure, contains a small amount of fissure water, and is located in a weakly water-rich area, and the top of the shield collapses slowly during the TBM tunneling process, forming a limited cavity, strong support should be adopted to pass through.

[0016] If the surrounding rock is fractured, broken, and has a fragmented structure, contains a small amount of fissure water, and is located in a weakly water-rich area, and the top of the shield collapses rapidly and a large number of blocks fall during the TBM tunneling process, forming a limited cavity, a combined steel arch support should be adopted to pass through.

[0017] If the fissures are slightly developed, relatively broken, fragmented, contain a large amount of fissure water, and are located in a medium-to-strong water-rich area, and the top of the shield collapses rapidly and a large number of blocks fall during the TBM tunneling process, forming a limited cavity with linear water flow, chemical grouting reinforcement + strong support measures should be adopted to pass through.

[0018] If the surrounding rock is fractured, broken, and has a fragmented structure with a large amount of fissure water, and is located in a medium-to-strong water-rich area, and the top of the shield collapses rapidly and a large number of blocks fall during the TBM tunneling process, forming a large cavity with infinite cavities and dripping water, and the surrounding rock converges locally, chemical grouting + combined steel arch support measures should be adopted to pass through.

[0019] If the surrounding rock is extremely fractured and broken, with a fragmented structure, containing a small amount of fissure water in some areas, and is located in a weakly water-rich area, and the top of the shield collapses slowly during the TBM tunneling process, forming a limited cavity with local linear water flow, and the surrounding rock convergence causes the machine to get stuck, chemical grouting reinforcement + strong support measures should be adopted to pass through.

[0020] If the surrounding rock is extremely fractured and fragmented, with a small amount of fissure water in some areas, and is located in a weakly water-rich area, and the top of the shield collapses rapidly and a large number of blocks fall during the TBM tunneling process, forming an infinite cavity surrounding rock that causes the machine to converge, then advanced pipe roof pre-grouting reinforcement + combined steel arch frame should be adopted.

[0021] If the surrounding rock is extremely fractured and fragmented, containing a large amount of fissure water, and located in a highly water-rich area, and the top of the shield collapses slowly and a small number of blocks fall during the TBM tunneling process, forming a limited cavity, the surrounding rock convergence will cause the machine to get stuck.

[0022] Step 2: Before the TBM tunnels into the unfavorable strata, advance horizontal directional drilling is used to conduct advance exploratory boreholes. Based on the results of the exploratory boreholes, chemical grouting and advance large pipe roof technology measures are taken to pre-reinforce the surrounding rock at the face in front of the TBM cutterhead.

[0023] Before the TBM tunnels to unfavorable strata, any cutting tools on the cutterhead are removed, and the advanced drilling rig conducts advance exploratory drilling on the face in front of the cutterhead through the cutter compartment and cutter holes.

[0024] Core sampling is conducted during the advance exploratory borehole operation. The integrity of the core samples is used to assess the surrounding rock condition at the face in front of the cutterhead, providing a reference for pre-reinforcement and support measures. The N+1th advance exploratory borehole overlaps with the Nth advance exploratory borehole by at least 5m.

[0025] The steps for chemical grouting are as follows:

[0026] S1: Construction preparation. Construction preparation includes equipment and material preparation, as well as work environment preparation.

[0027] T1: Equipment and material preparation, including drilling equipment, chemical injection pumps, and chemical injection materials. The selection of chemical injection materials is based on the looseness of the reinforced strata, ambient temperature, and whether there is groundwater outflow, and the material additives are adjusted according to the temperature inside the tunnel.

[0028] T2: Preparation of the working environment, including cleaning the inside of the cutterhead and setting up a drilling platform at the tail of the shield. A temporary operating platform for the drilling rig is erected using the main beam of the main unit.

[0029] S2: Chemical grouting hole layout. The chemical grouting holes utilize the cutter holes on the TBM cutterhead and the pre-drilled holes on the shield.

[0030] S3: Drilling and Hole Cleaning. Drilling is performed using a guide rail drilling rig and a hand-operated pneumatic drill with the drill-and-blast method. Hole cleaning is performed using high-pressure air after drilling is completed.

[0031] S4: Install anchor bolts. Chemical grouting anchor bolts are fiberglass anchor bolts. One fiberglass anchor bolt is installed at each hole drilled. After installation, the gap between the anchor bolt's outer wall and the surrounding rock is sealed promptly.

[0032] S5: Connect the gasification tank pump and grouting pipeline for grouting. Specific steps are as follows:

[0033] T1: Select representative fiberglass anchors for a water pressure test to further check the reliability of the grouting pipeline and determine the hydrostatic pressure. Based on this, determine the initial and final grouting pressures according to the specifications. The initial grouting pressure is 1.2 to 1.5 times the hydrostatic pressure. The final pressure is 2 to 3 times the hydrostatic pressure.

[0034] Before formal grouting, a representative glass fiber anchor rod is selected for trial grouting. During the process, the grouting pressure, grout mix ratio and other related technical indicators are continuously optimized to achieve good grouting results.

[0035] T2: Full-section grouting, supplemented by segmented forward grouting.

[0036] Under normal circumstances, full-section grouting is used throughout the entire section.

[0037] If a mud layer or water inrush is encountered during drilling, drilling should be stopped immediately, and grouting should be carried out in a forward-moving manner until the designed grouting depth is reached.

[0038] The grouting sequence follows the principle of "from inside to outside, from low to high, from sidewalls to arch, and grouting at intervals within the same ring hole," with grouting done symmetrically on both sides.

[0039] For chemical grouting, the initial grouting speed is typically low to medium, around 10–120 L / min. Once the working face is confirmed to be operating normally and there is no backflow of grout, the grouting speed can be appropriately increased. When grouting pressure increases or backflow occurs, the grouting speed should be gradually reduced according to the construction situation.

[0040] S5: Standards for completion of grouting and single-hole grouting

[0041] The grouting standard is reached when grout overflows from the surface of the working face; a significant increase in grouting pressure indicates that the grouting conditions have been met.

[0042] The standard for completing single-hole grouting is to stop grouting when, under low-speed grouting conditions, the chemical grout seeps back from the cracks at the working face and around the grouting pipe, or when the grouting volume per meter of a single hole reaches 200 kg. At this point, the grouting of that grouting hole is complete.

[0043] The longitudinal length of the cyclic chemical grouting is N, the TBM excavation length after chemical grouting is Nn, and the reserved length n is not excavated as the TBM excavation cycle overlap for the next cycle.

[0044] The construction steps for advanced pipe roof are as follows:

[0045] S1: Expansion excavation of the pipe roof drilling rig work area.

[0046] The Nth pipe roof drilling rig working room is located at the tail end of the shield, and is an arc-shaped guide pit with an L×B×H (longitudinal×circular×depth) and an angle of α. It can be excavated using a hand-held pneumatic drill in conjunction with an anchor drilling rig.

[0047] The surrounding rock of the expanded excavation area is in good condition and can be excavated directly. After the excavation is completed, shotcrete and anchor mesh support will be used.

[0048] The surrounding rock at the excavation site is in poor condition, so it should be reinforced before excavation.

[0049] When the N+1th pipe roof drilling rig is excavating, the exposed pipe roof in the Nth pipe roof drilling rig is cut off and marked. When drilling the pipe roof, the hole position is adjusted appropriately according to the marking.

[0050] S2: Pipe roof drilling rig installation.

[0051] N curved beams are welded and fabricated on the main beam. The curved beams are fabricated using steel arch frames.

[0052] The drilling rig support plate is made of steel plate with a thickness of h. N holes with a diameter of B are drilled on the drilling rig support plate, and the pipe roof drilling rig is installed and fixed using high-strength U-bolts.

[0053] The pipe roof drilling rig is fixed to the arch frame assembly machine via N cantilever beams. The rotation of the arch frame assembly machine drives the rotation of the cantilever beams, which in turn drives the pipe roof drilling rig to rotate, completing the drilling operation within the α angle range of the excavation work area.

[0054] S3: Drilling and cleaning of pipe roofs.

[0055] Seamless steel pipes with a length of L and an inner diameter of D, and an outward inclination angle of β, are arranged in the working room of the pipe roof drilling rig at circumferential spacing B. The ends of the pipe roofs are processed into a cone shape, and overflow holes with a diameter of d are set around them. No overflow holes are set at the tail L′.

[0056] The borehole diameter is D′ > the inner diameter of the pipe roof, D.

[0057] The pipe roof drilling adopts the pipe-following drilling process. After drilling to the designed depth, high-pressure air is used to clean the hole and seal the gap between the outer wall of the pipe roof and the rock wall.

[0058] After the pipe roof is cleaned, a small-diameter steel cage is installed inside.

[0059] S3: Pipe roof grouting.

[0060] Pipe roof drilling and grouting are carried out using a perforated method.

[0061] Cement grout is used to fill waterless and dripping orifice sections, HC grout is used to fill linear flow orifice sections, and paste-like C-GT1 water-blocking grout is used to fill orifice sections with strong seepage and sudden water inrush.

[0062] Grouting construction follows the principle of "thin liquid first, thick liquid later; single liquid first, double liquid later".

[0063] The grouting construction of the pipe roof proceeds from both sides towards the arch. First, grout 2n holes, then 2n+1 holes. The grouting of the 2n+1 holes can be used to check the grouting status of the 2n holes. Alternatively, grout 2n+1 holes can be grouted first, then 2n holes. The grouting of the 2n holes can be used to check the grouting status of the 2n+1 holes.

[0064] S5: Backfilling of the excavated section and TBM tunneling.

[0065] After the pipe roof construction is completed, the support lining structure of the excavation work area will be constructed according to the designed cross-section, that is, from the outside to the inside radially: concrete backfilling → dense steel mesh → steel arch frame → shotcrete. The steel arch frames are connected by steel components with a circumferential spacing L, where L≤80cm.

[0066] Step 3: During the TBM tunneling process, strong support and combined steel arch support techniques are adopted to enable the TBM to safely and quickly pass through unfavorable strata.

[0067] The radial sequence of the reinforced support lining structure from the outside to the inside is as follows: lightweight material or concrete filling → densely arranged strip steel plates → steel arch frame → shotcrete. The construction steps for the reinforced support are as follows:

[0068] S1: The TBM stops tunneling, and the arch frame assembly machine assembles and positions the Nth ring of steel arch frame.

[0069] S2: Within the α-range at the top of the shield, the nth strip steel plate is welded to the top of the Nth ring steel arch. The other end of the nth strip steel plate is welded to the (N+1)th ring steel arch. The dimensions of the strip steel plate are L×B×h (length×width×thickness), with the length L laid along the tunnel excavation direction. The (n+1)th strip steel plate is placed circumferentially adjacent to the nth strip steel plate, and so on. The remaining strip steel plates are installed within the α-range at the top of the Nth ring steel arch. Several grouting holes are provided on the strip steel plates.

[0070] S3: The N+1 ring of steel arches is assembled inside the TBM shield using an arch frame assembly machine. The top 1 / 3 of the N+1 ring of steel arches is tightly attached to one end of the strip steel plate installed on the top of the Nth ring of steel arches. As the TBM advances forward, the N+1 ring of steel arches moves relatively backward and detaches from the inside of the shield. After one cycle of excavation, the arch frame assembly machine expands the Nth ring of steel arches to the designed inner arc surface and welds it firmly to several strip steel plates. The N+1 ring of steel arches is connected to the Nth ring of steel arches circumferentially using steel components.

[0071] S4: When the N+1 ring and the Nth ring steel arch frame reach the shotcrete zone, insert the grouting pipe steel pipe into the grouting hole, connect the grouting pipeline, and fill the cavity with concrete and lightweight materials in sequence. The shotcrete system sprays concrete to the design thickness.

[0072] The construction steps for combined steel arch support are as follows:

[0073] S1: The TBM stops tunneling. One top composite steel arch, two side composite steel arches, and one bottom composite steel arch of the Nth ring are transported to the arch assembly machine. The arch assembly machine is used to assemble them into a circle inside the shield and fix them in place. Grouting holes are reserved on the arc-shaped steel plate of the top composite steel arch.

[0074] S2: The TBM begins tunneling, and the Nth ring of combined steel arch frame, assembled into a circle by the arch frame assembly machine, slowly reveals the shield.

[0075] S3: After the TBM has completed one cycle of tunneling, it stops tunneling. Several steel pads are installed between the steel plate of the bottom composite steel arch frame and the rock wall. At least two anchor bolts are installed at the bottom stiffening ribs of the two side composite steel arch frames.

[0076] S4: Subsequently, assemble and install the N+1 ring combined steel arch frame closely adjacent to the Nth ring combined steel arch frame. The N+1 ring combined steel arch frame is connected to the Nth ring combined steel arch frame by means of pre-reserved pin holes.

[0077] S5: Activate the emergency spraying system, and spray concrete to the design thickness on the two side combined steel arch frames.

[0078] S6: TBM excavation, while simultaneously removing the detachable stiffening ribs of the bottom composite steel arch frame, installing the inverted arch block, and injecting fine stone concrete through the grouting hole of the inverted arch block.

[0079] S7: Insert the grouting hole through the pre-reserved hole in the arc-shaped steel plate on the top combined steel arch frame, insert the grouting pipe, fill the cavity with concrete and lightweight materials, and spray the designed thickness of the L2 zone sprayed concrete system.

[0080] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0081] 1. Before the TBM reaches unfavorable strata, long-distance advanced horizontal directional drilling technology is adopted. The drilling trajectory is first perpendicular to the TBM tunnel and then parallel to the TBM tunnel. This long-distance horizontal directional drilling has the function of advanced water drainage and advanced geological exploration. Finally, the geological conditions inside the hole are observed and analyzed by downhole television, which provides a basis for taking reasonable countermeasures in advance when the TBM passes through the fault fracture zone.

[0082] 2. For open-face TBMs without advanced geological prediction functions, high-power, high-torque advanced drilling rigs are used to conduct advanced drilling on the cutterhead face through the cutter compartment and cutter pre-reserved holes at the tail of the head frame or the lower part of the main beam. This further explores the surrounding rock geological conditions at the face in front of the cutterhead and guides the TBM to tunnel quickly and efficiently.

[0083] 3. For TBMs traversing unfavorable geological formations, the system anchor bolts in the initial support were eliminated, saving construction time, reducing further damage to the fractured surrounding rock, and accelerating construction progress. The surrounding rock was immediately covered with steel plates to intercept collapsing rocks and prevent secondary collapses.

[0084] 4. For situations where there is no reinforced concrete support structure or the reinforced concrete structure is not strong enough to withstand the impact of falling rocks in fault-collapsed strata, a combined support measure of chemical grouting and forced or combined steel arch frames is proposed. This method is safe and reliable to construct, with low safety risks, and reduces the damage to personnel and equipment caused by falling rocks during tunneling. It also avoids shutdowns caused by various factors such as excessive muck feed leading to belt conveyor failure, large loose material blocks causing excessive cutterhead torque, continuous muck feed with an infinite tendency to collapse the cavity, loss of control of the tunnel head, excessive workload for shield rear support and support shoe support, and shield jamming.

[0085] 5. The combined steel arch support measures consist of a powerful support structure composed of multiple adjacent circumferentially connected combined steel arch frames. It integrates the combined support functions of steel arch frames, steel mesh, and steel bar rows, and has the advantages of high strength, high rigidity, good longitudinal overall stability, and high load-bearing capacity. It can remain stable without deformation under the impact of large collapsed rock masses, forming an effective support system for the collapsed body, preventing the possibility of the collapsed body continuing to expand outward, and improving the safety and tunneling efficiency of the TBM in adverse geological sections.

[0086] 6. By employing strong support and combined steel arch frames, support can be provided during TBM tunneling, sealing off collapsed areas and effectively intercepting falling rocks. This reduces safety risks for construction workers and saves time spent repairing damaged equipment due to falling rocks. The combination of pre-reinforcement and enhanced support measures ensures the quality of initial support construction, improves TBM tunneling efficiency in adverse geological conditions, and saves tunneling time.

[0087] 7. By using chemical grouting and pre-reinforcement measures such as large pipe roof, the risk of TBM jamming during tunneling in soft rock with large deformation and collapsed strata is reduced. At the same time, the effective sealing of fissure water can achieve rapid improvement of the strata in a short period of time, avoiding the continuous collapse of the tunnel face and shield top caused by long-term shutdown. It has the characteristics of fast processing speed, achieves inherent safety in the TBM tunneling process, and saves all costs of jamming treatment.

[0088] 8. In the medium-water-rich strata, the cutterhead is used as a "protective plate". Chemical grouting is carried out on the working face through the cutter chamber and reserved cutter holes to form a water-stopping curtain, which further avoids the risk of sudden water inrush. There is no need to retreat the cutterhead. The construction personnel can enter the unprotected working face in front of the working face through a small pilot tunnel to carry out curtain grouting and water-stopping. The safety risk is low, the water-stopping quality is reliable, the construction organization is simple, and the time consumption is short.

[0089] 9. Pre-reinforcement measures, such as chemical grouting and large pipe roof reinforcement at the top of the shield, rapidly improve the surrounding rock. The subsequent support adopts strong support and combined steel arch frame support to intercept the collapsed rocks. The targeted combination of pre-reinforcement and subsequent support technologies avoids the occurrence of sudden water inrush accidents. It also reduces the impact of TBM's normal tunneling caused by excessive muck feed crushing the conveyor belt, large loose material block size causing excessive cutterhead torque, continuous muck feed with an infinite tendency to collapse the cavity, uncontrolled machine head trend, large workload of shield rear support and support shoe support, and machine jamming. It has the characteristics of short construction period and low investment cost. Attached Figure Description

[0090] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation on the embodiments of the present invention.

[0091] Figure 1 Schematic diagram of an open-type TBM in an embodiment of the present invention;

[0092] Figure 2 Cross-sectional view of the open-type TBM combined steel arch frame lining in an embodiment of the present invention;

[0093] Figure 3 Side view of the open-type TBM combined steel arch lining in an embodiment of the present invention;

[0094] Figure 4 Schematic diagram of the combined steel arch frame in an embodiment of the present invention;

[0095] Figure 5 Cross-sectional view of an open-type TBM strong support structure in an embodiment of the present invention;

[0096] Figure 6 Side view of an open-type TBM strong support in an embodiment of the present invention;

[0097] Figure 7 Longitudinal section view of open-type TBM chemical grouting in an embodiment of the present invention;

[0098] Figure 8 Cross-sectional view of an open-type TBM chemical grouting system in an embodiment of the present invention;

[0099] Figure 9 Longitudinal section view of the open-type TBM advanced pipe shed construction in an embodiment of the present invention;

[0100] Figure 10 Cross-sectional view of the open-type TBM advanced pipe shed construction in an embodiment of the present invention;

[0101] Figure 11 This is a flowchart of the present invention.

[0102] In the diagram, 1-Cutoff head; 2-Shield; 3-Arch frame assembly machine; 4-Anchor drill; 5-Emergency shotcrete system; 6-Support shoe; 7-Service beam; 8-Invert arch block; 9-Shotcrete system; 10-Cavity rock wall; 11-Lightweight material; 12-Concrete; 13-Grouting hole; 14-Excavated rock wall; 15-Combined steel arch frame; 16-Steel pad block; 17-Anchor bolt; 18-Fine aggregate concrete; 19-Grouting hole; 20-Composite waterproof layer; 21-Geotextile; 22-Waterproof membrane; 23-Waterproof membrane; 24-Top composite steel arch Frame; 25-Side combined steel arch frame; 26-Bottom combined steel arch frame; 27-Steel plate; 28-Pin opening; 29-Pin; 30-Stiffening rib; 31-Removable stiffening rib; 32-Strip steel plate; 33-Structured steel arch frame; 34-Steel component; 35-Shotcrete; 36-Horizontal directional drill; 37-Main beam; 38-Shield reserved hole; 39-Tool hole; 40-Glass fiber anchor; 41-Pipe roof drilling rig work area; 42-Pipe roof drilling rig; 43-Support plate; 44-Arched beam; 45-Cantilever beam; 46-Seamless steel pipe. Detailed Implementation

[0103] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for illustrative purposes only and are not intended to limit the invention. It should be noted that this invention is already in the actual research and development stage.

[0104] according to Figure 1-11 As shown, a construction method for TBM traversing adverse geological formations includes:

[0105] Step 1: Under normal TBM tunneling operation without stopping, before the TBM cutterhead 1 tunnels to the unfavorable strata, long-distance advanced horizontal directional drilling 36 is used to drill advanced holes in the collapsed, water-inrushing, and mud-bursting sections of the unfavorable strata, so as to drain water and explore the geology.

[0106] The advanced horizontal directional drilling rig 36 traverses the area between the unfavorable geological end of the TBM tunnel and the TBM cutterhead 1, intersecting with the arch waist on one side of the TBM tunnel before continuing parallel to the longitudinal direction of the TBM tunnel. The intersection height between the advanced horizontal directional drilling rig 36 and the arch waist on one side of the TBM tunnel is 100cm above the invert block 8. The advanced horizontal directional drilling rig 36 continues parallel to the longitudinal direction of the TBM tunnel for at least 100m beyond the unfavorable geological end.

[0107] The advanced horizontal directional drilling rig 36 serves both as an advanced water drainage borehole and an advanced geological exploration borehole. The hardness of the surrounding rock is determined based on the drilling torque and drilling time during drilling. Longer drilling times correspond to harder rock, and shorter times correspond to softer rock; time and hardness generally show a positive correlation. Given the relatively high overall torque, and excluding the influence of drill bit wear, based on past rock drilling experience, the rock is inferred to be hard. Downhole television is used to investigate the surrounding rock of the unfavorable formation and its water content.

[0108] The following are common rock fissure conditions and their treatment measures:

[0109] If the surrounding rock has slightly developed fissures, is relatively broken, has a fragmented structure, contains a small amount of fissure water, and is located in a weakly water-rich area, and the top of the shield 2 collapses slowly during the TBM tunneling process, forming a limited cavity, strong support should be adopted to pass through.

[0110] If the surrounding rock is fractured, broken, and has a fragmented structure, contains a small amount of fissure water, and is located in a weakly water-rich area, and at the same time, the top of the shield 2 collapses rapidly and a large number of blocks fall during the TBM tunneling process, forming a limited cavity, then a combined steel arch frame 15 is adopted for support.

[0111] If the fissures are slightly developed, relatively broken, fragmented, contain a large amount of fissure water, and are located in a medium-to-strong water-rich area, and at the same time the top of the shield 2 collapses rapidly and a large number of blocks fall during the TBM tunneling process, forming a limited cavity with linear water flow, chemical grouting reinforcement + strong support measures should be adopted to pass through.

[0112] If the surrounding rock is fractured, broken, and has a fragmented structure with a large amount of fissure water, and is located in a medium-to-strong water-rich area, and at the same time the top of the shield 2 collapses rapidly and a large number of blocks fall during the TBM tunneling process, forming a large cavity with infinite cavities and rain-like dripping water, and the surrounding rock locally converges, chemical grouting + combined steel arch support measures should be adopted to pass through.

[0113] If the surrounding rock is extremely fractured and broken, with a fragmented structure, containing a small amount of fissure water in some areas, and is located in a weakly water-rich area, and the top of the shield 2 collapses slowly during the TBM tunneling process, forming a limited cavity with local linear water flow, and the surrounding rock convergence causes the machine to get stuck, chemical grouting reinforcement + strong support measures should be adopted to pass through.

[0114] If the surrounding rock is extremely fractured and fragmented, with a small amount of fissure water in some areas, and is located in a weakly water-rich area, and the top of the shield 2 collapses rapidly and a large number of blocks fall during the TBM tunneling process, forming an infinite cavity surrounding rock convergence jam, then advanced pipe roof pre-grouting reinforcement + combined steel arch frame should be adopted.

[0115] If the surrounding rock is extremely fractured and fragmented, containing a large amount of fissure water, and located in a highly water-rich area, and at the same time the top of the shield 2 collapses slowly and a small number of blocks fall during the TBM excavation process, forming a limited cavity, the surrounding rock convergence will cause the machine to get stuck.

[0116] Step 2: Before the TBM tunnels to the unfavorable strata, advance horizontal directional drilling 36 is used to conduct advance exploratory boreholes. Based on the results of the exploratory boreholes, chemical grouting and advance large pipe roof technology measures are adopted to pre-reinforce the surrounding rock at the face in front of the TBM cutterhead 1.

[0117] Before the TBM tunnels to the unfavorable strata, remove any cutting tools on the cutterhead 1. The advanced drilling rig then conducts advance exploratory drilling on the face in front of the cutterhead 1 through the cutter compartment and cutter hole 39.

[0118] Core sampling is conducted during the advance exploratory borehole operation. The integrity of the core samples is used to determine the surrounding rock condition at the face in front of cutterhead 1, providing a reference for pre-reinforcement and support measures. The N+1th advance exploratory borehole overlaps with the Nth advance exploratory borehole by at least 5m.

[0119] The steps for chemical grouting are as follows:

[0120] S1: Construction preparation. Construction preparation includes equipment and material preparation, as well as work environment preparation.

[0121] T1: Equipment and material preparation, including drilling equipment, chemical injection pumps, and chemical injection materials. The selection of chemical injection materials is based on the looseness of the reinforced strata, ambient temperature, and whether there is groundwater outflow, and the material additives are adjusted according to the temperature inside the tunnel.

[0122] T2: Preparation of the working environment, including cleaning the inside of the cutterhead 1 and setting up a drilling platform at the tail of the shield 2. A temporary operating platform for the drilling rig is set up using the main beam 37 of the main unit.

[0123] S2: Arrangement of chemical grouting holes. The chemical grouting holes utilize the cutter hole 39 on the TBM cutterhead 1 and the reserved hole on the shield 2 as chemical grouting holes.

[0124] S3: Drilling and Hole Cleaning. Drilling is performed using a guide rail drilling rig and a hand-operated pneumatic drill with the drill-and-blast method. Hole cleaning is performed using high-pressure air after drilling is completed.

[0125] S4: Install anchor bolts. The chemical grouting anchor bolts are fiberglass anchor bolts 40. One fiberglass anchor bolt 40 is installed at each hole drilled. After installation, the gap between the outer wall of the anchor bolt and the surrounding rock is sealed promptly.

[0126] S5: Connect the gasification tank pump and grouting pipeline for grouting. Specific steps are as follows:

[0127] T1: A representative glass fiber anchor rod (40mm) was selected for a water pressure test to further check the reliability of the grouting pipeline and determine the hydrostatic pressure. Based on this, the initial and final grouting pressures were determined according to the specifications. The initial grouting pressure was 1.2 to 1.5 times the hydrostatic pressure. The final pressure was 2 to 3 times the hydrostatic pressure.

[0128] Before formal grouting, a representative glass fiber anchor rod 40 was selected for trial grouting. During the process, the grouting pressure and grout mix ratio were continuously optimized to achieve good grouting results.

[0129] T2: Full-section grouting, supplemented by segmented forward grouting.

[0130] Under normal circumstances, full-section grouting is used throughout the entire section.

[0131] If a mud layer or water inrush is encountered during drilling, drilling should be stopped immediately, and grouting should be carried out in a forward-moving manner until the designed grouting depth is reached.

[0132] The grouting sequence follows the principle of "from inside to outside, from low to high, from sidewalls to arch, and grouting at intervals within the same ring hole," with grouting done symmetrically on both sides.

[0133] For chemical grouting, the initial grouting speed is typically low to medium, around 10–120 L / min. Once the working face is confirmed to be operating normally and there is no backflow of grout, the grouting speed can be appropriately increased. When grouting pressure increases or backflow occurs, the grouting speed should be gradually reduced according to the construction situation.

[0134] S5: Standards for completion of grouting and single-hole grouting

[0135] The grouting standard is reached when grout overflows from the surface of the working face; a significant increase in grouting pressure indicates that the grouting conditions have been met.

[0136] The standard for completing single-hole grouting is to stop grouting when, under low-speed grouting conditions, the chemical grout seeps back from the cracks at the working face and around the grouting pipe, or when the grouting volume per meter of a single hole reaches 200 kg. At this point, the grouting of that grouting hole is complete.

[0137] The longitudinal length of the cyclic chemical grouting is N, the TBM excavation length after chemical grouting is Nn, and the reserved length n is not excavated as the TBM excavation cycle overlap for the next cycle.

[0138] The construction steps for advanced pipe roof are as follows:

[0139] S1: Pipe roof drilling rig work area 41 widening excavation.

[0140] The Nth pipe roof drilling rig working room 41 is located at the tail end of the shield 2. It is an arc-shaped guide pit with an L×B×H (longitudinal×circular×depth) and an angle of α. It can be excavated by a hand-held pneumatic drill in conjunction with the anchor drilling rig 4.

[0141] The surrounding rock of the expanded excavation area is in good condition and can be excavated directly. After the excavation is completed, shotcrete and anchor mesh support will be used.

[0142] The surrounding rock at the excavation site is in poor condition, so it should be reinforced before excavation.

[0143] When the N+1th pipe roof drilling rig working room 41 is expanded, the exposed pipe roof of the Nth pipe roof drilling rig working room 41 is cut off and marked. When drilling the pipe roof, the hole position is adjusted appropriately according to the marking.

[0144] S2: Pipe roof drilling rig 42 installation.

[0145] N curved beams 44 are welded and fabricated on the main beam 37. The curved beams 44 are fabricated using steel arch frames 33.

[0146] The drilling rig support plate 43 is made of steel plate 27 with a thickness of h. N holes with a diameter of B are drilled on the drilling rig support plate 43, and the pipe roof drilling rig 42 is installed and fixed using high-strength U-bolts.

[0147] The pipe roof drilling rig 42 is fixed to the arch frame assembly machine 3 through N cantilever beams 45. The rotation of the arch frame assembly machine 3 drives the cantilever beams 45 to rotate, and the cantilever beams 45 drive the pipe roof drilling rig 42 to rotate, thus completing the drilling operation within the α angle range of the excavation work chamber.

[0148] S3: Drilling and cleaning of pipe roofs.

[0149] Seamless steel pipes 46 with a length of L and an inner diameter of D, and an outward inclination angle of β, are arranged in the working room 41 of the pipe roof drilling rig at circumferential spacing B. The ends of the pipe roof are processed into a cone shape, and overflow holes with a diameter of d are set around the perimeter. No overflow holes are set at the tail L′.

[0150] The borehole diameter is D′ > the inner diameter of the pipe roof, D.

[0151] The pipe roof drilling adopts the pipe-following drilling process. After drilling to the designed depth, high-pressure air is used to clean the hole and seal the gap between the outer wall of the pipe roof and the rock wall.

[0152] After the pipe roof is cleaned, a small-diameter steel cage is installed inside.

[0153] S3: Pipe roof grouting.

[0154] Pipe roof drilling and grouting are carried out using a perforated method.

[0155] Cement grout is used to fill waterless and dripping orifice sections, HC grout is used to fill linear flow orifice sections, and paste-like C-GT1 water-blocking grout is used to fill orifice sections with strong seepage and sudden water inrush.

[0156] Grouting construction follows the principle of "thin liquid first, thick liquid later; single liquid first, double liquid later".

[0157] The grouting construction of the pipe roof proceeds from both sides towards the arch. First, grout 2n holes, then 2n+1 holes. The grouting of the 2n+1 holes can be used to check the grouting status of the 2n holes. Alternatively, grout 2n+1 holes can be grouted first, then 2n holes. The grouting of the 2n holes can be used to check the grouting status of the 2n+1 holes.

[0158] S5: Backfilling of the excavated section and TBM tunneling.

[0159] After the pipe roof construction is completed, the support lining structure of the excavation work area is constructed according to the designed cross-section, that is, from the outside to the inside radially as follows: concrete backfill 12 → dense steel mesh → steel arch frame 33 → shotcrete 35. The steel arch frames 33 are connected by steel components 34 with a circumferential spacing L, where L≤80cm.

[0160] Step 3: During the TBM tunneling process, strong support and combined steel arch frame 15 support techniques were adopted to enable the TBM to safely and quickly pass through unfavorable strata.

[0161] The radial sequence of the reinforced support lining structure from the outside to the inside is as follows: lightweight material 11 or concrete 12 filling → closely arranged strip steel plates 32 → steel arch frame 33 → shotcrete 35. The construction steps for the reinforced support are as follows:

[0162] S1: TBM stops tunneling, and arch frame assembly machine 3 assembles and positions the Nth ring steel arch frame 33.

[0163] S2: Within the top α range of the Nth ring steel arch 33 of the shield 2, the nth strip steel plate 32 is welded to the top, and the other end of the nth strip steel plate 32 is welded to the N+1th ring steel arch 33. The dimensions of the strip steel plate 32 are L×B×h, length×width×thickness, with the length L direction laid along the tunnel excavation direction. The n+1th strip steel plate 32 is set circumferentially adjacent to the nth strip steel plate 32, and so on. Within the top α angle range of the Nth ring steel arch 33, the remaining strip steel plates 32 are installed. Several grouting holes 13 are provided on the strip steel plates 32.

[0164] S3: The N+1 ring steel arch frame 33 is assembled inside the TBM shield using an arch frame assembly machine 3. The top 1 / 3 of the N+1 ring steel arch frame 33 is tightly attached to one end of the strip steel plate 32 installed on the top of the Nth ring steel arch frame 33. As the TBM advances forward, the N+1 ring steel arch frame 33 moves relatively backward and detaches from the inside of the shield. After one cycle of excavation, the arch frame assembly machine 3 expands the Nth ring steel arch frame 33 to the designed inner arc surface and welds it firmly to several strip steel plates 32. The N+1 ring steel arch frame 33 is connected to the Nth ring steel arch frame 33 circumferentially using steel components 34.

[0165] S4: When the N+1 ring and the Nth ring steel arch frame 33 reach the shotcrete zone, insert the grouting pipe steel pipe into the grouting hole 13, connect the grouting pipeline, and fill the cavity with concrete 12 and lightweight material 11 in sequence. The shotcrete system 9 sprays concrete 35 to the design thickness.

[0166] The construction steps for the combined steel arch frame 15 support are as follows:

[0167] S1: The TBM stops tunneling. One top composite steel arch 24, two side composite steel arches 25, and one bottom composite steel arch 26 of the Nth ring composite steel arch frame 15 are transported to the arch frame assembly machine 3. The arch frame assembly machine 3 assembles them into a circle inside the shield 2 and fixes them in place. Grouting holes 13 are pre-drilled on the arc-shaped steel plate 27 of the top composite steel arch frame 24.

[0168] S2: The TBM begins tunneling, and the Nth ring of combined steel arch frame 15, which is assembled into a circle by the arch frame assembly machine 3, slowly reveals the shield 2.

[0169] S3: After the TBM has completed one cycle of tunneling, it stops tunneling. Several steel pads 16 are installed between the bottom combined steel arch frame 26, steel plate 27 and the rock wall. At least two locking anchor rods 17 are installed at the bottom stiffening rib 30 of the two side combined steel arch frames 25.

[0170] S4: Subsequently, assemble and install the N+1 ring combined steel arch frame 15 close to the Nth ring combined steel arch frame 15. The N+1 ring combined steel arch frame 15 and the Nth ring combined steel arch frame 15 are connected by pins 29 through the reserved pin holes 28.

[0171] S5: Activate the emergency spraying system 5, 2 side combined steel arch frames 25 sprayed concrete 35 to the design thickness.

[0172] S6: TBM excavation, while simultaneously removing the detachable stiffening ribs 31 of the bottom combined steel arch frame 26, installing the inverted arch block 8, and injecting fine stone concrete 18 through the grouting hole 13 of the inverted arch block 8.

[0173] S7: Insert the grouting hole 13 through the reserved hole of the arc-shaped steel plate 27 on the top combined steel arch frame 24, insert the grouting pipe, fill the cavity with concrete 12 and lightweight material 11, and spray concrete 35 at the designed thickness of the L2 zone spraying system 9. Example

[0174] like Figures 1-10As shown, in combination with a 22.13km long tunnel in Xinjiang, located in a high-altitude and cold region, the tunnel adopts a "3 tunnels + 4 shafts" design scheme. The central pilot tunnel is excavated using the open-face TBM method, with a designed excavation diameter of 8430mm and a total machine length of 285m. The open-face TBM excavated 10.801km, successively crossing moderately weathered granite porphyry, marble interbedded with sandy slate, and granite, and crossing 4 fault zones. Among them, the F7 fault zone is the key and difficult point in the TBM excavation process, and it is also the "bottleneck" project of this TBM construction.

[0175] The F7 fault, 125m long, is influenced by the Central Tianshan Fold Belt and presents construction risks such as collapse, water inrush, and large deformation of soft rock. Before the TBM traversed the F7 fault, the project first adopted long-distance horizontal directional drilling technology, drilling a length of 1718m to cross the F7 fault. Water inrush during tunnel construction was predicted by observing water inrush in the horizontal directional drilling exploration holes. Intermittent core sampling and in-hole television testing techniques were used to analyze the lithological distribution and joint and fracture development of the surrounding rock. Based on the water content of the F7 fault and the fracture condition of the surrounding rock, short-distance geological exploration holes were then conducted using the Hamai drilling rig to further verify the water content and geological conditions of the surrounding rock ahead of the tunnel face. Targeted treatment measures were implemented, including a combination of steel arch frames, strong support, chemical grouting at the tunnel face, and pre-grouting reinforcement with advanced pipe roofs. The TBM successfully traversed the F7 fault in 43 days, 144 days ahead of schedule. The specific methods of crossing are shown in Table 1.

[0176] Table 1. Overview of TBM construction methods through fault fracture zones

[0177]

[0178] In the TBM crossing of the F7 fault, a combined construction method for TBM crossing adverse strata as described in this invention was used. The TBM includes a cutterhead 1, a shield 2, an arch frame assembly machine 3, an anchor drilling rig 4, an emergency shotcrete system 5, a support shoe 6, a service beam 7, an inverted arch block 8, a shotcrete system 9, a cavity rock wall 10, lightweight materials 11, concrete 12, grouting holes 13, an excavated rock wall 14, a combined steel arch frame 15, steel pads 16, anchor bolts 17, fine aggregate concrete 18, grouting holes 13, a composite waterproof layer 20, and geotextile 2. 1. Waterproof membrane 22. Waterproof membrane 22. Top composite steel arch frame 24. Side composite steel arch frame 25. Bottom composite steel arch frame 26. Steel plate 27. Pin hole 28. Pin 29. Stiffening rib 30. Detachable stiffening rib 31. Strip steel plate 32. Steel arch frame 33. Steel component 34. Shotcrete 35. Horizontal directional drilling 36. Main beam 37. Shield reserved hole 38. Tool hole 39. Fiberglass anchor 40. Pipe roof drilling rig work area 41. Pipe roof drilling rig 42. Support plate 43. Curved beam 44. Cantilever beam 45. Seamless steel pipe 46.

[0179] By employing advanced geological forecasting methods combining long-distance horizontal directional drilling and advanced exploration boreholes at the tunnel face of the Hamai drilling rig, water was drained and the geological conditions of the surrounding rock ahead of the tunnel face were determined. Chemical grouting at the tunnel face and pre-reinforcement measures such as the large pipe roof at the top of shield 2 were adopted. A strong support and combined steel arch frame 15 support scheme were implemented. During the TBM tunneling support process, a combination of pre-reinforcement and support measures were adopted, and the F7 fault zone was successfully crossed.

[0180] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for constructing a TBM through adverse geological formations, characterized in that, Includes the following steps: Step 1: Under the condition of TBM normal tunneling without stopping, before the TBM cutterhead (1) tunnels to the unfavorable strata, long-distance advanced horizontal directional drilling (36) is used to carry out advanced drilling in the collapse, water inrush and mud inrush sections of the unfavorable strata, so as to drain water and explore the geology; Step 2: Before the TBM tunnels to the unfavorable strata, advanced horizontal directional drilling (36) is used to conduct advanced exploration. Based on the results of the exploration, chemical grouting and advanced large pipe roof technology measures are taken to pre-reinforce the surrounding rock at the face in front of the TBM cutterhead (1) and the top of the shield (2). Before the TBM tunnels to the unfavorable strata, remove any cutting tools on the cutterhead (1). The advanced drilling rig conducts advanced exploration holes on the face in front of the cutterhead (1) through the cutter compartment and the cutter hole (39). Core sampling is carried out during the advance exploration process. The condition of the surrounding rock at the face in front of the cutterhead (1) is judged based on the integrity of the core sample, so as to provide a reference for pre-reinforcement and support measures. The N+1th advance exploration section overlaps with the Nth advance exploration section by at least 5m. Step 3: During the TBM tunneling process, strong support and combined steel arch frame (15) support are adopted to enable the TBM to pass through the poor strata safely and quickly. If the surrounding rock is slightly developed, relatively broken, fragmented structure, contains a small amount of fissure water, and is in a weak water-rich area, and the top of the shield (2) collapses slowly during the TBM tunneling process, forming a limited cavity, strong support is adopted to pass through; the lining structure of the strong support is arranged radially from the outside to the inside as follows: lightweight material (11) or concrete (12) filling → strip steel plate (32) densely arranged → steel arch frame (33) → shotcrete (35); The following are common rock fissures and their treatment measures: If the surrounding rock is fractured, broken, and has a fragmented structure, contains a small amount of fissure water, is located in a weakly water-rich area, and the top of the shield (2) collapses rapidly and a large number of blocks fall during the TBM tunneling process, forming a limited cavity, a combined steel arch frame (15) is adopted for support. If the fissures are slightly developed, relatively broken, fragmented structure, containing a large amount of fissure water, and located in a medium-strong water-rich area, and at the same time, the top of the shield (2) collapses quickly and there are a large number of falling blocks during the TBM tunneling process, forming a limited cavity with linear water flow, chemical grouting reinforcement + strong support measures are adopted to pass through. If the surrounding rock is fractured, broken, and has a fragmented structure, contains a large amount of fissure water, and is located in a medium-strong water-rich area, and at the same time, the top of the shield (2) collapses quickly and there are a large number of falling blocks during the TBM tunneling process, forming a large cavity with infinite cavities and rain-like dripping water, the surrounding rock locally converges, and chemical grouting + combined steel arch support measures are adopted to pass through. If the surrounding rock is extremely well-developed and extremely broken, with a fragmented structure, containing a small amount of fissure water in some areas, and is located in a weakly water-rich area, and the top of the shield (2) collapses slowly during the TBM excavation process, forming a limited cavity, with local linear water flow, and the surrounding rock convergence causes the machine to get stuck, chemical grouting reinforcement + strong support measures are adopted to pass through. If the surrounding rock is extremely well-developed and extremely broken, with a fragmented structure, containing a small amount of fissure water in some areas, and is located in a weakly water-rich area, and at the same time, the top of the shield (2) collapses rapidly and a large number of blocks fall during the TBM excavation process, forming an infinite cavity surrounding rock convergence jam, adopting advanced pipe roof pre-grouting reinforcement + combined steel arch frame. If the surrounding rock is extremely well-developed and extremely broken, with embedded fragmented structures, containing a large amount of fissure water, and located in a highly water-rich area, and at the same time, the top of the shield (2) collapses slowly and a small number of blocks fall during the TBM tunneling process, forming a limited cavity, the surrounding rock converges and jams the machine, chemical grouting reinforcement + advanced pipe roof pre-grouting reinforcement is adopted.

2. The method for TBM crossing adverse geological formations according to claim 1, characterized in that, Step one specifically includes: The advanced horizontal directional drilling (36) trajectory passes between the end of the TBM tunnel in the unfavorable strata and the TBM cutterhead (1), and intersects with the arch waist on one side of the TBM tunnel before drilling parallel to the longitudinal direction of the TBM tunnel. The height at which the advanced horizontal directional drilling (36) trajectory intersects with the arch waist on one side of the TBM tunnel is at least 100cm above the inverted arch block (8). The advanced horizontal directional drilling (36) is parallel to the longitudinal direction of the TBM tunnel and drills at least 100m beyond the end of the unfavorable strata. The advanced horizontal directional drilling (36) has the functions of advanced water drainage and advanced geological exploration. The hardness of the surrounding rock is judged by the drilling torque and drilling time during the drilling of the advanced horizontal directional drilling (36). The longer the time, the greater the rock hardness, and the shorter the time, the less rock hardness. The time and hardness are generally positively correlated. The overall torque is relatively large. After eliminating the influence of drill bit wear, based on the previous rock drilling experience, it is inferred that the rock is a hard rock. The unfavorable surrounding rock and water content are determined by the use of downhole television.

3. The method for TBM crossing adverse geological formations according to claim 1, characterized in that, The steps for chemical grouting are as follows: S1: Construction preparation, which includes equipment and material preparation and work environment preparation. T1: Equipment and material preparation work, including drilling equipment, chemical irrigation pump, chemical irrigation material, and chemical irrigation tank material selection based on the looseness of the reinforced stratum, ambient temperature, and whether there is groundwater outflow, and adjustment of material additives according to the temperature inside the tunnel. T2: Preparation of the working environment, including cleaning inside the cutterhead (1) and setting up a drilling work platform at the tail of the shield (2), and setting up a temporary drilling platform using the main beam (37) of the main machine; S2: Chemical grouting hole arrangement, the chemical grouting holes utilize the tool hole (39) on the TBM cutter head (1) and the reserved hole on the shield (2) as chemical grouting holes; S3: Drilling and hole cleaning. Drilling is carried out using a guide rail drilling machine and a hand-operated pneumatic drill using the drill-explosion method. Hole cleaning is performed after drilling is completed using high-pressure air. S4: Install anchor bolts. The chemical grouting anchor bolts are glass fiber anchor bolts (40). Install one glass fiber anchor bolt (40) at each hole. After the glass fiber anchor bolt (40) is installed, seal the gap between the outer wall of the anchor bolt and the surrounding rock in time. S5: Connect the gasification tank pump and grouting pipeline for grouting. The specific steps are as follows: T1: Select a representative glass fiber anchor rod (40) for a water pressure test to further check the reliability of the grouting pipeline and determine the hydrostatic pressure. Then, determine the initial pressure and termination pressure of grouting according to the specifications. The initial pressure of grouting is 1.2 to 1.5 times the hydrostatic pressure, and the final pressure is 2 to 3 times the hydrostatic pressure. Before formal grouting, a representative glass fiber anchor rod (40) was selected for trial grouting. During the process, the grouting pressure and grout mix ratio were continuously optimized to achieve a good grouting effect. T2: Full-section grouting, supplemented by segmented forward grouting; Under normal circumstances, full-section grouting is used throughout the entire section. If a mud layer or water inrush is encountered during drilling, drilling should be stopped immediately, and grouting should be carried out in a forward-moving manner until the designed grouting depth is reached. The grouting sequence follows the principle of "from inside to outside, from low to high, first the side walls then the arch, and grouting at intervals within the same ring hole" and is symmetrically grouted from left to right. For grouting speed, chemical grout should generally be started at a low to medium speed, with a grouting speed of about 10 to 120 L / min. When it is confirmed that the working face is working normally and there is no backflow of grout, the grouting speed can be appropriately increased. When the grouting pressure increases or there is backflow of grout, the grouting speed should be gradually reduced according to the construction situation. S5: Standards for completion of grouting and single-hole grouting The grouting standard is reached when grout overflows from the surface of the working face; a significant increase in grouting pressure indicates that the grouting conditions have been met. The standard for completing single-hole grouting is to stop grouting when the chemical grout seeps back from the cracks on the working face and around the grouting pipe under low-speed grouting conditions, or when the grouting volume per meter of a single hole reaches 200 kg, and the grouting of that grouting hole is completed. The longitudinal length of the cyclic chemical grouting is N, the TBM excavation length after chemical grouting is Nn, and the reserved length n is not excavated as the TBM excavation cycle overlap for the next cycle.

4. The method for combined construction of TBM crossing adverse strata according to claim 1, characterized in that, The construction steps for advanced pipe roof are as follows: S1: Pipe roof drilling rig work area (41) widening excavation; The Nth pipe roof drilling rig workroom (41) is located at the tail end of the shield (2), and is an arc-shaped guide pit with L×B×H, longitudinal×ring×depth, and an angle of α. It can be excavated by using a hand-held wind drill in conjunction with an anchor drilling rig (4). The surrounding rock of the expanded excavation area is in good condition and can be excavated directly. After the excavation is completed, shotcrete and anchor mesh support will be used. The surrounding rock at the excavation site is in poor condition; it should be reinforced before excavation. When the N+1th pipe roof drilling rig workroom (41) is expanded, the exposed pipe roof of the Nth pipe roof drilling rig workroom (41) is cut off and marked. When the pipe roof drilling is carried out, the hole position is adjusted appropriately according to the marking. S2: Installation of pipe roof drilling rig (42); N curved beams (44) are welded and fabricated on the main beam (37). The curved beams (44) are fabricated using steel arch frames (33). The drilling rig support plate (43) is made of steel plate (27) with a thickness of h. N holes with a diameter of B are opened on the drilling rig support plate (43), and the pipe roof drilling rig (42) is installed and fixed using high-strength U-bolts. The pipe roof drilling rig (42) is fixed to the arch frame assembly machine (3) through N cantilever beams (45). The cantilever beams (45) are rotated by the rotation of the arch frame assembly machine (3), and the cantilever beams (45) are rotated by the rotation of the cantilever beams (45), thus completing the drilling operation within the α angle range of the excavation work room. S3: Pipe roof drilling and hole cleaning; Seamless steel pipes (46) with a length of L and an inner diameter of D, and an outward inclination angle of β, are arranged in the working room (41) of the pipe roof drilling rig according to the circumferential spacing B. The ends of the pipe roof are processed into a cone shape, and overflow holes with a diameter of d are set around the perimeter. No overflow holes are set at the tail L′. The borehole diameter D′ is greater than the inner diameter of the pipe roof D; The pipe roof drilling adopts the pipe-following drilling process. After drilling to the designed depth, high-pressure air is used to clean the hole and seal the gap between the outer wall of the pipe roof and the rock wall. After the pipe roof is cleaned, a small-diameter steel cage is installed inside. S4: Pipe roof grouting; Pipe roof drilling and grouting are carried out using a perforated method. Cement grout is used to fill the sections with no water and dripping water at the orifice; HC grout is used to fill the sections with linear flow at the orifice; and paste-like C-GT1 water-blocking grout is used to fill the sections with strong seepage and sudden water inrush at the orifice. Grouting construction follows the principle of "thin before thick, single liquid before double liquid"; The grouting construction of the pipe roof proceeds from both sides towards the arch. First, grout 2n holes, then 2n+1 holes. The grouting of the 2n+1 holes can be used to check the grouting status of the 2n holes. Alternatively, grout 2n+1 holes can be grouted first, then 2n holes. The grouting of the 2n holes can be used to check the grouting status of the 2n+1 holes. S5: Backfilling of the widened section and TBM tunneling After the pipe roof construction is completed, the excavation work area is constructed according to the design section support lining structure, that is, from the outside to the inside radial direction: concrete (12) backfilling → dense steel mesh → steel arch frame (33) → shotcrete (35). The steel arch frames (33) are connected by steel components (34) with a circumferential spacing L, where L≤80cm.

5. The method for combined construction of TBM crossing adverse strata according to claim 1, characterized in that, The construction steps for the reinforced support are as follows: S1: TBM stops tunneling, arch frame assembly machine (3) assembles and positions the Nth ring steel arch frame (33). S2: The top of the Nth ring steel arch (33) within the top α range of the shield (2) is welded with the nth strip steel plate (32). The other end of the nth strip steel plate (32) is welded to the N+1th ring steel arch (33). The dimensions of the strip steel plate (32) are L×B×h, length×width×thickness. The length L direction is laid along the tunnel excavation direction. The n+1th strip steel plate (32) is set circumferentially adjacent to the nth strip steel plate (32). The remaining strip steel plates (32) are installed within the top α angle range of the Nth ring steel arch (33). Several grouting holes (13) are provided on the strip steel plate (32). S3: The N+1 ring steel arch frame (33) is assembled on the inner side of the TBM shield using the arch frame assembly machine (3). The top 1 / 3 of the N+1 ring steel arch frame (33) is close to one end of the strip steel plate (32) installed on the top of the N ring steel arch frame (33). While the TBM is tunneling forward, the N+1 ring steel arch frame (33) moves backward and is removed from the inner side of the shield. After tunneling one cycle, the arch frame assembly machine (3) rounds the N ring steel arch frame (33) to the designed inner arc surface and welds it firmly with several strip steel plates (32). The N+1 ring steel arch frame (33) and the N ring steel arch frame (33) are connected in the circumferential direction by steel components (34). S4: When the N+1 ring and the Nth ring steel arch frame (33) reach the sprayed concrete zone, insert the grouting pipe steel pipe into the grouting hole (13), connect the grouting pipeline, and fill the cavity with concrete (12) and lightweight material (11) in sequence. The sprayed concrete system (9) sprays concrete (35) to the design thickness.

6. The method for TBM crossing adverse geological formations according to claim 1, characterized in that, The construction steps for the combined steel arch frame (15) support are as follows: S1: TBM stops tunneling. One top composite steel arch (24), two side composite steel arches (25), and one bottom composite steel arch (26) of the Nth ring composite steel arch (15) are transported to the arch frame assembly machine (3). The arch frame assembly machine (3) assembles them into a circle inside the shield (2) and fixes them. Grouting holes (13) are reserved on the arc-shaped steel plate (27) of the top composite steel arch (24). S2: TBM begins tunneling, arch frame assembly machine (3) supports the Nth ring combined steel arch frame (15) assembled into a circle, and slowly exposes the shield (2). S3: After the TBM has been excavated to one cycle, it stops excavating. Several steel pads (16) are installed between the bottom combined steel arch frame (26) steel plate (27) and the rock wall. At least two locking anchors (17) are installed at the bottom stiffening rib (30) of the two side combined steel arch frames (25). S4: Then, the N+1 ring combined steel arch frame (15) is assembled and installed close to the Nth ring combined steel arch frame (15). The N+1 ring combined steel arch frame (15) and the Nth ring combined steel arch frame (15) are connected by pins (29) through the reserved pin holes (28). S5: Activate the emergency spraying system (5), and spray concrete (35) to the design thickness on the two side combined steel arch frames (25); S6: TBM excavation, while removing the detachable stiffening ribs (31) of the bottom composite steel arch frame (26), installing the inverted arch block (8), and injecting fine stone concrete (18) through the grouting hole (13) of the inverted arch block (8). S7: Insert the grouting hole (13) through the reserved hole of the arc steel plate (27) on the top combined steel arch frame (24), insert the grouting pipe, fill the cavity with concrete (12) and lightweight material (11), and spray concrete (35) of the L2 zone spraying system (9) with the designed thickness.

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