A tunnel construction method

Abstract

This invention relates to the field of tunnel engineering, specifically to a tunnel construction method, comprising the following steps: simultaneously excavating at both ends of the tunnel using both TBM (Tunnel Boring Machine) and drill-and-blast methods to form a TBM tunnel section and a drill-and-blast tunnel section; excavating the TBM tunnel section and the drill-and-blast tunnel section to both ends of the through tunnel section; firstly constructing a dismantling chamber using the drill-and-blast method, and then constructing a TBM through section to the dismantling chamber using the TBM method; dismantling the TBM tunneling machine in the dismantling chamber and transporting it out of the tunnel, thus completing the tunnel construction. This invention, through this simultaneous construction method at both ends, can effectively improve the overall excavation efficiency of extra-long tunnels, thereby significantly shortening the construction period of extra-long tunnels.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering, and in particular to a method for constructing a tunnel. Background Technology

[0002] The construction of extra-long tunnels (usually referring to tunnels with a length exceeding 10 kilometers) has always been an extremely challenging engineering task. Due to their large length span and complex and variable geological conditions, the selection of appropriate construction methods plays a crucial role in the smooth progress of the project, cost control, and quality assurance.

[0003] However, in the current actual construction of extra-long tunnels, the unidirectional penetration method is generally adopted. Although this traditional construction method has advantages such as relatively simple operation and convenient management, it also has obvious drawbacks, the most prominent of which is the excessively long construction period. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology in the construction of extra-long tunnels, which has a long construction period. To this end, a tunnel construction method is provided.

[0005] This invention provides a method for constructing a tunnel, comprising the following steps:

[0006] S1: TBM method and drill-and-blast method are used simultaneously at both ends of the tunnel to form TBM tunnel section and drill-and-blast tunnel section respectively;

[0007] S2: Excavate the TBM tunnel section and the drill-and-blast tunnel section to both ends of the through tunnel section. First, use the drill-and-blast method to construct the dismantling chamber, and then use the TBM method to construct the TBM through section to the dismantling chamber.

[0008] S3: The TBM tunneling machine is dismantled in the dismantling chamber and transported out of the tunnel to complete the tunnel construction.

[0009] TBM is an abbreviation for "Tunnel Boring Machine".

[0010] This invention provides a tunnel construction method that, compared to traditional unidirectional tunneling, simultaneously excavates at both ends of the tunnel using both TBM (Tunnel Boring Machine) and drill-and-blast methods. This allows for parallel operations, effectively improving construction efficiency and significantly shortening the construction cycle. Especially for extra-long tunnels, this method accelerates the overall progress and significantly reduces construction time. This invention uses the TBM method at only one end of the tunnel and the drill-and-blast method at the other, avoiding reliance on TBM equipment for the entire tunnel excavation. This effectively controls construction costs and prevents excessive costs due to excessive TBM usage. When excavating to both ends of the tunnel section, the drilling-and-blast method is used to construct the dismantling chamber, providing the necessary conditions for subsequent TBM construction of the TBM-connected section. If this method is not used, and instead drilling-and-blast is used directly to the TBM location, the strong vibrations and flying rocks generated during drilling and blasting could severely damage the TBM, affecting the smooth progress of subsequent construction. When the TBM tunneling machine advances into the dismantling chamber, the TBM tunneling machine can be dismantled quickly and conveniently in the dismantling chamber, ensuring the smoothness and efficiency of the construction process.

[0011] This invention proposes a tunnel construction method that involves simultaneous excavation at both ends of the tunnel. One end is excavated using the TBM method, while the other end is excavated using the drill-and-blast method. This simultaneous construction approach effectively improves the overall excavation efficiency of extra-long tunnels, thereby significantly shortening the construction period.

[0012] Preferably, in step S1, the construction of the TBM tunnel section includes the following steps:

[0013] S11: Excavate the tunnel starting section at the entrance of the TBM tunnel section, and the length of the tunnel starting section is consistent with the design length of the TBM tunneling machine;

[0014] S12: Construction of the TBM launching platform is carried out in front of the entrance of the TBM tunnel section;

[0015] S13: The TBM tunneling machine is assembled on the TBM launching platform. After assembly, the TBM tunneling machine is pushed into the tunnel launching section and the TBM tunneling machine is used to continue excavating the TBM tunnel section.

[0016] In this scheme, a tunnel launching section with a length consistent with the designed length of the TBM (Tunnel Boring Machine) is set up. Its core function is to provide the TBM with a stable and suitable initial working space. This design ensures that the TBM can start smoothly and operate stably during the subsequent excavation of the TBM tunnel section, avoiding problems such as equipment obstruction and reduced efficiency due to insufficient or unsuitable space, thus laying the foundation for efficient construction of the entire TBM tunnel section. The tunnel launching section can be constructed using the drill-and-blast method. A TBM launching platform is constructed in front of the tunnel entrance, providing a precise guiding and support platform for the TBM. After the TBM is assembled, the TBM launching platform ensures that the TBM smoothly enters the tunnel launching section according to the predetermined direction and angle, guaranteeing the safety and accuracy of tunnel construction and improving overall construction efficiency.

[0017] Preferably, in step S13, if the length of the TBM launching platform cannot meet the design length requirements of the TBM tunneling machine, the TBM tunneling machine is launched in sections and pushed into the tunnel launching section in stages.

[0018] In this scheme, by implementing the split launching of the TBM tunneling machine, the problem that the length of the TBM launching platform cannot meet the design length requirements of the TBM tunneling machine due to site limitations can be effectively solved, thereby ensuring that the TBM tunneling machine can smoothly enter the tunnel launching section.

[0019] Preferably, in step S3, the TBM tunneling machine includes a main unit, an equipment bridge, a rear support trolley, and supporting equipment on the rear support trolley. The disassembly of the TBM tunneling machine includes the following steps:

[0020] S31: Dismantle the main unit, which includes a shield, cutterhead, drive motor, main bearing, propulsion cylinder and segment installation machine;

[0021] S32: Remove the equipment bridge and the supporting equipment;

[0022] S33: Transport the main unit, the equipment bridge, and the supporting equipment out of the tunnel entrance of the drill-and-blast tunnel section, and drive the rear supporting trolley out of the tunnel entrance of the TBM tunnel section in reverse.

[0023] In this scheme, by carrying out the main unit, the equipment bridge, and the supporting equipment from the entrance of the drill-and-blast tunnel section, and by allowing the rear supporting trolley to reverse out from the entrance of the TBM tunnel section, the TBM tunneling machine can be quickly and efficiently removed from the tunnel, creating favorable conditions for subsequent tunnel construction, enabling subsequent construction to proceed as soon as possible, and effectively improving the overall construction efficiency.

[0024] Preferably, in step S2, constructing the TBM penetration section to the dismantling chamber using the TBM method includes the following steps:

[0025] S21: Geological drilling rigs are used to drill geological exploratory holes every 30m to explore the geological conditions of the TBM-connected section. The tunneling parameters are adjusted according to the explored geological conditions. The tunneling posture of the TBM is used to check whether there is an axial deviation in the TBM-connected section. The tunneling posture is corrected during the tunneling process according to the deviation, until the construction of the TBM-connected section is completed.

[0026] This scheme utilizes geological drilling rigs to construct exploratory boreholes, enabling advance understanding of the geological conditions of the TBM-connected section. This provides an accurate basis for adjusting tunneling parameters and avoids tunneling risks caused by unclear geology. Simultaneously, the scheme verifies whether there is any axial deviation in the TBM-connected section based on the tunneling posture of the TBM. If the deviation is found, the tunneling posture is corrected during the tunneling process, ensuring the accuracy of the TBM-connected section's tunneling and ultimately achieving the goal of successfully connecting the TBM-connected section to the dismantling chamber.

[0027] Preferably, during the construction of the TBM tunnel section, if the tunneling reaches altered rock or soft rock deformation sections, advanced geological drilling is used to detect the actual geological conditions ahead of the tunneling, and an advanced support scheme is determined based on the actual geological conditions. The purpose of this scheme is to ensure that the TBM can smoothly pass through the altered rock or soft rock deformation sections.

[0028] Preferably, during the construction of the TBM tunnel section, if the excavation reaches a high-stress rockburst tunnel section, a temporary protective net is installed near the cutterhead of the TBM, and pre-stress relief holes are constructed around the excavation face. The main purpose of this scheme is to ensure that the TBM can safely and smoothly pass through the high-stress rockburst tunnel section, minimizing the occurrence of personnel casualties. The temporary protective net serves to block flying debris during a rockburst, providing effective safety protection for construction personnel and equipment.

[0029] Preferably, during the construction of the TBM tunnel section, if the tunneling reaches a section with high external water pressure and mudslide / water inrush, the water volume, water pressure, and water location ahead of the tunneling point are detected. Based on the detection results, drainage and pressure relief or pre-grouting to block the water is adopted. The purpose of this scheme is to ensure that the TBM can safely and smoothly pass through the section with high external water pressure and mudslide / water inrush.

[0030] Preferably, during the construction of the TBM tunnel section, if the tunneling reaches a section with toxic and harmful gases, a gas monitoring system is used to monitor and issue early warnings for the toxic and harmful gases in real time, and the return air velocity of the secondary ventilation system is increased to 1.1 to 1.3 times the original value. The purpose of this scheme is to ensure that the TBM can safely and smoothly pass through the section with toxic and harmful gases.

[0031] Preferably, during the construction of the TBM tunnel section, if the tunneling reaches ultra-hard rock and wear-resistant rock sections, the frequency of cutter inspection is increased. When the cutter wear exceeds the normal threshold, the cutter is replaced and the construction parameters are adjusted. The purpose of this scheme is to ensure that the TBM can smoothly and successfully pass through the ultra-hard rock and wear-resistant rock sections.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] This invention provides a tunnel construction method in which work is carried out simultaneously at both ends of the tunnel. One end is excavated using the TBM method, while the other end is excavated using the drill-and-blast method. This simultaneous construction method at both ends can effectively improve the overall excavation efficiency of extra-long tunnels, thereby significantly shortening the construction period of extra-long tunnels. Attached Figure Description

[0034] Figure 1 This is a flowchart of a tunnel construction method.

[0035] Figure 2 This is a schematic diagram of different tunnel sections in a tunnel construction method.

[0036] Marked in the image:

[0037] 1-TBM tunnel section,

[0038] 2-Through tunnel section,

[0039] 201 - Dismantling chamber, 202 - TBM breakthrough section

[0040] 3- Drill and blast tunnel section. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0042] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0043] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0044] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0045] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0046] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0047] Example 1

[0048] like Figure 1 and Figure 2 As shown, a tunnel construction method includes the following steps:

[0049] S1: TBM method and drill-and-blast method are used simultaneously at both ends of the tunnel to form TBM tunnel section 1 and drill-and-blast tunnel section 3.

[0050] S2: Excavate TBM tunnel section 1 and drill-and-blast tunnel section 3 to both ends of the through tunnel section 2. First, use the drill-and-blast method to construct the dismantling chamber 201, and then use the TBM method to construct the TBM through section 202 to the dismantling chamber 201.

[0051] S3: The TBM tunneling machine is dismantled in dismantling chamber 201 and transported out of the tunnel to complete the tunnel construction.

[0052] Specifically, the exact location of the dismantling chamber 201 can be predetermined or dynamically adjusted based on the actual construction progress of TBM tunnel section 1 and drill-and-blast tunnel section 3. For example, when the distance between TBM tunnel section 1 and drill-and-blast tunnel section 3 is approximately 400m-500m, the exact location of the dismantling chamber 201 can be determined based on the geological conditions of the rock strata in this section. Then, drill-and-blast tunnel section 3 continues excavation to the location of the dismantling chamber 201, and excavation work on the dismantling chamber 201 is carried out. The length of the dismantling chamber 201 can be 24m-30m, the height can be 10m-12m, and the width can be 9m-11m. The cross-sectional shape of the dismantling chamber 201 can be a city gate shape, with specific dimensions of 25m in length, 9m in width, and 10.6m in height.

[0053] Specifically, when the tunnel is an inclined tunnel, the TBM method is used at one end of the upward tunnel and the drill-and-blast method is used at one end of the downward tunnel. The upward tunnel refers to tunneling from a lower elevation to a higher elevation, and the downward tunnel refers to tunneling from a higher elevation to a lower elevation. Using the TBM method in the upward tunnel has significant drainage advantages. In areas with abundant groundwater, the upward tunnel can utilize gravity for natural drainage, reducing the complexity and cost of the drainage system and effectively preventing adverse effects on the TBM equipment caused by the inability to drain water in a timely manner.

[0054] In an optional implementation, step S1, the construction of TBM tunnel segment 1 may include the following steps:

[0055] S11: Excavate the tunnel starting section at the entrance of TBM tunnel section 1, the length of which is consistent with the design length of the TBM tunneling machine;

[0056] S12: Construction of the TBM launching platform is carried out in front of the entrance of TBM tunnel section 1;

[0057] S13: The TBM tunneling machine is assembled on the TBM launching platform. After assembly, the TBM tunneling machine is pushed into the tunnel launching section and the TBM tunneling machine is used to continue excavating the TBM tunnel section 1.

[0058] Specifically, the construction of the tunnel's starting section also includes face sealing and cross-section inspection.

[0059] After the tunnel's starting section is completed to the location where the TBM will be used for excavation, if the surrounding rock at the tunnel face is stable and there is no significant water seepage, the end should be sealed. Otherwise, excavation should continue until a stable position is reached. Sealing should be avoided at locations with seepage to minimize the need for drainage pipes at the tunnel face and to prevent secondary treatment of the tunnel face. Before sealing, two layers of sealed geogrid can be used for reinforcement support. The tunnel face should be sealed with C20 plain concrete with a thickness of not less than 150mm.

[0060] After the excavation of the tunnel's starting section is completed, the bottom invert of the starting section is first cleaned. Following this, the cross-section of the completed tunnel is checked. Using the centerline position as the control benchmark for clearance width measurement, measurements are appropriately intensified in areas exceeding the limits to accurately determine the mileage of these areas. Based on the cross-section measurement results, locally exceeding-limit areas are removed.

[0061] After the cross-section treatment is completed, the guide platform is constructed in the tunnel's starting section. The guide platform can be a C30W6F100 reinforced concrete structure, and rails can be pre-embedded on it. The rails can be 43kg / m steel rails. The guide platform can be 0.526 meters high, 4.191 meters wide, with a central arc radius of 2.43 meters and a length of 2.54 meters, and a corresponding included angle of 60°.

[0062] The guide platform can use steel bars of two specifications: φ12mm and φ14mm. The rails are welded to the already constructed steel reinforcement cage. The guide platform is constructed in 10-meter sections, using a reverse construction method, that is, from the inside to the outside in the tunnel's starting section. To facilitate concrete pouring, a concrete pump truck is used on-site for pumping, with each section using 10m³-12m³ of concrete.

[0063] Specifically, the construction of the starting site is also included before the TBM tunneling machine enters the site. The starting site includes a gantry crane, a TBM starting platform and a reaction platform. The TBM starting platform includes a TBM guide platform and a TBM starting trough. The starting track is arranged on the TBM guide platform.

[0064] Before the TBM tunneling machine enters the site, a TBM launching trench and a TBM guide platform are constructed 15m away from the tunnel entrance. The reinforcement arrangement and concrete strength requirements of the TBM launching trench are the same as those of the guide platform, so as to meet the assembly conditions of the TBM tunneling machine.

[0065] In an optional implementation, in step S13, if the length of the TBM launching platform cannot meet the design length requirements of the TBM tunneling machine, the TBM tunneling machine can be launched in sections and pushed into the tunnel launching section in an empty manner.

[0066] Specifically, the following specific scheme can be used for the separate launching method of TBM tunneling machine.

[0067] In this scheme, the total design length of the TBM tunneling machine, the rear-mounted trolley, and the inclined rail is 328m, and the usable land length of the TBM launching platform is 138m. The configuration and length of each trolley of the TBM tunneling machine are shown in Table 1.

[0068] Table 1: Statistical Table of Equipment Configuration and Layout Length of Each TBM Tunneling Machine Unit

[0069]

[0070] Taking into account the equipment configuration of each TBM tunneling machine, the minimum configuration of horizontal transportation equipment, and the maximum distance that the TBM tunneling machine can be arranged according to the design of the TBM launching platform, and considering minimizing the investment in the TBM's separate ventilation, water, and electricity systems, in order to reduce construction risks and technical difficulties.

[0071] According to Table 1, to ensure the TBM's stepping, segment assembly, and gravel backfilling functions, it is essential to guarantee that the TBM's transformer is energized, the air compressor system and pump station system are operating normally, and the water supply system can provide cooling water to the air compressor system and hydraulic system. Based on this, the TBM disassembly steps are determined as follows:

[0072] (1) The TBM tunneling machine is disconnected from trolley #13 and trolley #14, that is, it is disconnected at the design length of 166.5m of the trolley. At the same time, trolleys #29 and #30 and the inclined rail need to be connected to trolley #13. Then the length of the TBM tunneling machine after being split is 166.5m + 34.5m = 201m. The first segment is shown in Table 2.

[0073] Table 2: Configuration of the First Section of TBM Tunneling Machine Cart Equipment

[0074]

[0075] (2) At this time, the horizontal transport train can only be placed on the 34.5m section from the No. 29 trolley to the ramp for transporting segments, gravel and public supply materials. The train cannot go down to the ground track.

[0076] (3) Considering that when the TBM main shield body with a length of 12.5m enters the starting section of the tunnel, it is not necessary to assemble the full ring of segments and fill the gravel. Only the bottom segment needs to be placed for stepping. Then, after the TBM main shield body enters the starting section of the tunnel, the train can run to the ground track to hoist and transport segments, gravel and public supply materials.

[0077] (4) In order to ensure the blasting of gravel, the air compressor and air tank on trolleys 14 and 15 must be put into use. Therefore, trolleys 13 and 14 need to be equipped with air and water pipes and extension lines and extension pipes of the main cable and control cable of the air compressor.

[0078] (5) Remove the high-voltage cable branch box from the 24# trolley and reinstall it on the 13# trolley near the high-voltage switchgear. Connect the external 20kV high-voltage cable directly to the high-voltage cable branch box. The 20kV high-voltage cable moves forward as the TBM steps (it is dragged manually during the stepping).

[0079] (6) At the same time, a 160m long track is laid parallel to the left side of the TBM main unit to the 13# trolley for placing the 14#-24# trolleys (the length of this section of trolley is 94m) to ensure that this section of trolley can move with the TBM when it is stepping, under the application of external force, so as to save materials such as air, water and cables for the split stepping.

[0080] Table 3: Configuration of the Second Section of the TBM Tunneling Machine Cart Equipment

[0081]

[0082] (7) After the TBM has advanced 66m (160m-94=66m), the extension pipeline between 13# and 14# is removed. The 14#-21# trolleys are then reconnected and installed according to the overall layout design requirements of the TBM. Then, the 21# and 22# trolleys are disconnected and the extension pipeline is added. At this point, only the water hose reel and the AUX auxiliary cabinet's piping and cables need to be provided. Following step (6), the 22#-24# trolleys move under external force as the TBM advances until all remaining trolleys can be installed according to the overall TBM layout design. The second section is shown in Table 3.

[0083] (8) After the TBM has advanced 200m of the tunnel's starting section, there is still a 128m section of the trolley outside the tunnel that has not yet entered the tunnel (328m-200m=128m). At this point, it is not yet feasible to install a continuous belt conveyor. It is necessary to excavate another 50m using the conventional horizontal transport method for muck removal before the continuous belt conveyor can be installed. Therefore, at this time, it is necessary to connect and adjust the rear-mounted belt (belt #2) and improve the muck outlet to ensure that the conventional horizontal transport hopper can receive the material.

[0084] In an optional implementation, in step S3, the TBM tunneling machine includes a main unit, an equipment bridge, a rear support trolley, and supporting equipment on the rear support trolley. The disassembly of the TBM tunneling machine may include the following steps:

[0085] S31: Dismantle the main unit, which includes a shield, cutterhead, drive motor, main bearing, propulsion cylinder and segment installation machine;

[0086] S32: Remove the equipment bridge and the supporting equipment;

[0087] S33: Transport the main unit, the equipment bridge, and the supporting equipment out of the tunnel entrance of the drill-blast tunnel section 3, and drive the rear supporting trolley out of the tunnel entrance of the TBM tunnel section 1 in reverse.

[0088] In an optional implementation, step S2, constructing the TBM penetration section 202 to the dismantling chamber 201 using the TBM method, may include the following steps:

[0089] S21: Geological drilling rigs are used to drill geological boreholes every 30m to investigate the geological conditions of the TBM-connected section 202. The tunneling parameters are adjusted according to the investigated geological conditions. The tunneling posture of the TBM is used to check whether there is an axial deviation in the TBM-connected section 202. The tunneling posture is corrected during the tunneling process according to the deviation, until the construction of the TBM-connected section 202 is completed.

[0090] Specifically, the need for advanced support measures can be determined based on the geological conditions of the TBM-connected section 202. The tunneling parameters for TBM-connected section 202 can be controlled by reducing the thrust pressure and cutterhead rotation speed to control the cutterhead penetration, ensuring uniform tunneling and preventing the surrounding rock of TBM-connected section 202 from collapsing due to sudden increases or decreases in TBM thrust. The length of TBM-connected section 202 can be 150m-200m, and it is located between TBM tunnel section 1 and dismantling chamber 201.

[0091] In an optional implementation, during the construction of TBM tunnel section 1, if the tunnel reaches altered rock or soft rock deformation section, advanced geological drilling can be used to detect the actual geological conditions ahead of the tunnel, and an advanced support scheme can be determined based on the actual geological conditions.

[0092] Specifically, the countermeasures for construction of the altered rock and soft rock deformation tunnel sections include:

[0093] Strengthen advanced geological prediction and forecasting: Use methods such as seismic wave method, transient electromagnetic method, induced polarization method, ground-penetrating radar method or advanced geological drilling to accurately predict the actual geological conditions ahead and provide basic data so as to formulate construction plans and contingency plans to deal with possible large deformations before excavation.

[0094] Advanced support: When constructing in areas prone to large deformation, strengthen advanced support measures. Use a TBM-equipped drilling rig to reinforce the surrounding rock by using advanced large pipe roof, advanced small guide pipe, and fiberglass anchor grouting support through cutterhead holes or pre-reserved holes in the shield. If loose or broken surrounding rock is encountered, double-liquid grouting can be used to quickly consolidate the broken sections of surrounding rock.

[0095] Allow for deformation: Based on monitoring and measurement data and the deformation of the formed segments, use TBM over-excavation tools in a timely manner to expand the tunnel, ensure the tunnel clearance size, and avoid encroachment on the tunnel cross-section after large deformation.

[0096] Segment structure reinforcement: In soft rock sections with large deformation, based on the deformation monitoring data of the formed segments, measures such as increasing segment thickness, reinforcement ratio, and concrete strength are taken in a timely manner when necessary to effectively control the development of deformation.

[0097] Secondary grouting reinforcement: If segment deformation still exists after the pre-grouting is performed, secondary grouting reinforcement can be carried out through the grouting holes reserved in the segments.

[0098] Strengthen equipment maintenance for rapid progress. Special attention must be paid to equipment maintenance in altered rock and soft rock deformation tunnel sections to ensure that the TBM equipment is in good working order. During construction, rapid organization is crucial to reduce abnormal downtime caused by equipment failure and human factors.

[0099] In an optional implementation, during the construction of TBM tunnel section 1, if the tunneling reaches a high-stress rockburst tunnel section, a temporary protective net can be set up near the cutterhead of the TBM tunneling machine, and pre-stress relief holes can be made around the excavation face.

[0100] Specifically, the countermeasures for construction of the high-stress rockburst tunnel section include:

[0101] Temporary protective netting is set up to prevent sudden rockbursts from injuring people and damaging machinery. Nylon netting and wire mesh are mainly used to shield exposed rock formations. Protective netting is suspended near the cutterhead on the main conveyor to prevent rockbursts from entering the work area. The observation holes of the telescopic shield are closed and secured with pins to prevent rockbursts from entering the work area. Critical equipment such as the main drive motor is wrapped with woven bags or sponges to prevent damage from flying rocks.

[0102] Waiting for shelter: When a rockburst is particularly violent, in order to prevent accidents caused by flying rocks, construction workers can choose a safe area to take shelter for a period of time until the surrounding rock calms down.

[0103] Remove dangerous rocks: Remove loose rocks generated by rockbursts. These loose rocks are of the fractured and loose rockburst type and do not pose a significant hazard from ejection. They need to be removed promptly. During the removal process, it is necessary to strengthen inspection and handling of dangerous rocks, and carefully observe the dynamics of the surrounding rock. If tearing sounds are detected, personnel and equipment should be evacuated immediately.

[0104] Spraying water jets: Spraying and high-pressure water flushing onto the working face or other exposed rock surfaces can appropriately alter the physical properties of the rock, reduce its brittleness, and decrease the likelihood of flying rocks.

[0105] Personnel protection: When working in rockburst sections, workers must wear appropriate personal protective equipment, including safety helmets, work clothes, and safety shoes, to ensure their safety during construction.

[0106] Advanced stress release: If required for construction, advanced stress release holes can be made around the excavation face according to the actual situation to form a fracture zone within a certain range, reduce the stress of the surrounding rock within the tunnel body, and release energy.

[0107] Optimize construction organization to quickly traverse high-stress rockburst areas.

[0108] In an optional implementation, during the construction of TBM tunnel section 1, if the tunnel reaches a section with high external water pressure and mudslide, the water volume, water pressure and water location ahead of the tunnel can be detected, and drainage and pressure relief or pre-grouting can be used to plug the water according to the detection results.

[0109] Specifically, the countermeasures for construction during the high external water pressure mudslide and water inrush tunnel section include:

[0110] Strengthen water exploration: Adopt comprehensive geological forecasting methods that combine long-distance and short-distance forecasting, geophysical exploration and drilling, and macroscopic and microscopic methods to accurately determine the possible water volume, water pressure and location in front of the work face, so as to take targeted measures based on the forecast results.

[0111] Drainage and pressure relief: In areas with large water volume and pressure, advance geological drilling can be carried out in advance to discharge some water, reduce water pressure, avoid water inrush, and ensure construction safety.

[0112] Pre-grouting for water plugging: For water-rich fault fracture zones and water-rich sandstone tunnel sections, pre-grouting pipe roof, small pipe, glass fiber anchor bolt grouting and radial grouting on the back of the pipe segments can be used to reduce water inrush and prevent mud and water inrush.

[0113] Sufficient pumping and drainage equipment should be prepared: Sufficient pumping and drainage equipment should be provided at the construction site, and a dual-circuit power supply should be used. High-powered pumps should be used to drain the gushing water out of the well. The pumping and drainage equipment should have sufficient capacity to ensure that water can be pumped out promptly after a surge, preventing well flooding accidents.

[0114] Optimize tunnel drainage conditions: If the tunnel TBM is excavating uphill, it is more conducive to tunnel drainage. However, during the excavation and muck removal process, there may be muck falling from the conveyor belt, which may cause muck accumulation at the bottom of the tunnel. Before installing the locomotive rail panel, the muck should be thoroughly cleaned to provide favorable construction conditions for downhill drainage for TBM excavation.

[0115] Emergency Response Plan: During tunnel construction, a targeted emergency response plan for mudslides and water inrushes should be developed, and emergency escape routes should be set up as required, with appropriate emergency rescue materials and equipment provided. Emergency escape routes should be clearly marked. Regular emergency drills should be conducted to ensure rapid evacuation to a safe area in the event of unforeseen circumstances, avoiding casualties.

[0116] In an optional implementation, during the construction of TBM tunnel section 1, if the tunnel reaches a section with toxic and harmful gases, a gas monitoring system can be used to monitor and warn of toxic and harmful gases in real time, and the return air velocity of the secondary ventilation system can be increased to 1.1 to 1.3 times the original value, specifically 1.1, 1.2, or 1.3 times.

[0117] Specifically, the countermeasures for the construction of tunnel sections containing toxic and harmful gases include:

[0118] Equipped with multiple gas monitoring systems such as O2 / CO / CO2 / CH4 / SO2 / H2S / NH3 / NO2, it can perform real-time gas detection in the main unit area, slag discharge area, main control room, and flammable and explosive equipment areas.

[0119] Raise the detection and alarm standards for toxic and harmful gases such as CO, monitor and issue early warnings in real time, automatically shut down the machine when the standard is exceeded, strengthen ventilation, reduce the concentration of harmful gases, and carry out spraying or grouting for sealing when necessary.

[0120] Enhance the capacity of the secondary ventilation system and increase the return air velocity, for example, from 0.5 m / s to 0.6 m / s.

[0121] Oxygen supply devices are installed in the main control room, rest room, and rear waiting area.

[0122] In an optional implementation, during the construction of TBM tunnel section 1, if the tunneling reaches the ultra-hard rock and wear-resistant rock sections, the frequency of tool inspection can be increased. When the tool wear exceeds the normal threshold, the tool is replaced and the construction parameters are adjusted.

[0123] Specifically, the countermeasures for construction in the aforementioned ultra-hard rock and abrasion-resistant rock sections include:

[0124] We conducted a survey of domestic and international cutting tool suppliers and selected those with independent R&D capabilities, who can carry out specialized design and modification for ultrahard rock and wear-resistant rock formations.

[0125] Adjusting tool parameters involves primarily increasing the tool's hardness in ultrahard rock and its toughness in wear-resistant rock, thus adapting tools with different physical properties to different formations.

[0126] Strengthen the inspection and replacement system for cutting tools, and increase the frequency of tool inspections in ultra-hard rock and wear-resistant rock formations. If tool wear exceeds the normal threshold or abnormal wear is found, replace the tool and adjust the construction parameters in a timely manner.

[0127] Strengthen the management of construction parameters and adopt different construction parameters for different geological conditions of different rock types.

[0128] A tool repair workshop was set up on-site to promptly repair tools and ensure a continuous supply of tools.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements 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 of tunnel construction, characterised in that, Includes the following steps: S1: TBM method and drill-and-blast method are used to excavate at both ends of the tunnel simultaneously to form TBM tunnel section (1) and drill-and-blast tunnel section (3). S2: Excavate the TBM tunnel section (1) and the drill-and-blast tunnel section (3) to both ends of the through tunnel section (2), first use the drill-and-blast method to construct the dismantling chamber (201), and then use the TBM method to construct the TBM through section (202) to the dismantling chamber (201). S3: The TBM tunneling machine is dismantled in the dismantling chamber (201) and transported out of the tunnel to complete the tunnel construction; In step S1, the construction of the TBM tunnel section (1) includes the following steps: S11: Excavate the tunnel starting section at the entrance of the TBM tunnel section (1), and the length of the tunnel starting section is consistent with the design length of the TBM tunneling machine; S12: Construction of the TBM launching platform is carried out in front of the entrance of the TBM tunnel section (1); S13: The TBM tunneling machine is assembled on the TBM launching platform. After assembly, the TBM tunneling machine is pushed into the tunnel launching section and the TBM tunneling machine is used to continue excavating the TBM tunnel section (1). In step S13, if the length of the TBM launching platform cannot meet the design length requirements of the TBM tunneling machine, the TBM tunneling machine will be launched in sections and pushed into the tunnel launching section in an empty manner. In step S3, the TBM tunneling machine includes a main unit, an equipment bridge, a rear auxiliary trolley, and auxiliary equipment on the rear auxiliary trolley. The disassembly of the TBM tunneling machine includes the following steps: S31: Dismantle the main unit, which includes a shield, cutterhead, drive motor, main bearing, propulsion cylinder and segment installation machine; S32: Remove the equipment bridge and the supporting equipment; S33: Transport the main unit, the equipment bridge and the supporting equipment out of the opening of the drill-blast tunnel section (3), and drive the rear supporting trolley out of the opening of the TBM tunnel section (1) in reverse. In step S2, constructing the TBM through section (202) to the dismantling chamber (201) using the TBM method includes the following steps: S21: Geological drilling rigs are used to drill geological boreholes every 30m to investigate the geological conditions of the TBM-connected section (202), and the tunneling parameters are adjusted according to the investigated geological conditions; the tunneling posture of the TBM tunneling machine is used to check whether there is an axial deviation in the TBM-connected section (202), and the tunneling posture is corrected during the tunneling process according to the deviation, until the construction of the TBM-connected section (202) is completed; During the construction of the TBM tunnel section (1), if the tunneling reaches the high ground stress rockburst tunnel section, a temporary protective net is set up near the cutterhead of the TBM tunneling machine, and pre-stress relief holes are made around the excavation face. During the construction of the TBM tunnel section (1), if the tunnel reaches the section with high external water pressure and mud and water inrush, the water volume, water pressure and water position in front of the tunnel are detected, and drainage pressure relief or pre-grouting is adopted according to the detection situation to block water.

2. A method of tunnel construction according to claim 1, wherein, During the construction of the TBM tunnel section (1), if the tunnel reaches the altered rock or soft rock deformation section, advanced geological drilling is used to detect the actual geological conditions ahead of the tunnel, and an advanced support scheme is determined based on the actual geological conditions.

3. The tunnel construction method according to claim 1, characterized in that, During the construction of the TBM tunnel section (1), if the tunnel reaches a section with toxic and harmful gases, a gas monitoring system is used to monitor and warn of the toxic and harmful gases in real time, and the return air velocity of the secondary ventilation system is increased to 1.1 to 1.3 times the original value.

4. The tunnel construction method according to claim 1, characterized in that, During the construction of the TBM tunnel section (1), if the tunnel reaches the section of ultra-hard rock and wear-resistant rock, the frequency of tool inspection is increased. When the wear of the tool exceeds the normal threshold, the tool is replaced and the construction parameters are adjusted.

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