Underground tunnel excavation and support method

Abstract

The application provides a kind of underground tunnel excavation and supporting method, it is related to tunnel construction technical field, this method obtains the geological characteristics in the preset range in front of face, determines supporting parameter based on geological characteristics, uses tunneling equipment to carry out segmented excavation along helical line path and installs articulated arch frame in excavated section at the same time, spoil is continuously transported out by centrifugal screw conveyor, supporting material is transported to face by parallel track reverse, the surrounding rock exposed surface of the excavated section installed with articulated arch frame is sprayed with low temperature resistant concrete, and the tunnel wall surface sprayed with low temperature resistant concrete is drilled and inserted with anchor rod to complete tunnel supporting. The synchronous advancement of tunnel excavation and supporting operation is realized, the exposure time of surrounding rock is reduced, not only low temperature resistant concrete is used but also electric heating nozzle is used to heat the concrete, which can guarantee the construction quality and improve the reliability of tunnel excavation and supporting in highland low temperature environment.

Description

Technical Field

[0001] This application relates to the field of tunnel construction technology, specifically to a method for underground tunnel excavation and support. Background Technology

[0002] With the continuous advancement of urbanization, the construction of underground transportation tunnels has gradually become one of the key measures to solve urban traffic congestion and improve traffic efficiency. Under complex geological conditions, especially in areas with large elevation differences and plateau regions, the excavation and support of underground transportation tunnels face many challenges, including the instability of geological conditions, difficulties in supporting the excavation face, and the extension of the construction period.

[0003] Traditional methods for excavating and supporting underground transportation tunnels typically rely on a single excavation and support process, often employing pre-defined, standardized support methods. However, in environments with significant elevation differences or high-altitude geological conditions, these methods are unable to effectively adapt to the pressure and stress variations brought about by complex geology, often requiring a long construction period and increasing project costs and risks.

[0004] For example, while mechanization and automation have improved construction efficiency in some aspects of tunnel excavation methods in high-altitude areas, problems such as lagging support technology and slow construction progress still exist when facing significant elevation differences and unique geological conditions in high-altitude regions. Traditional support methods, such as steel supports and shotcrete, can ensure the stability of the tunnel structure to a certain extent, but their effectiveness in dealing with changes in elevation and rock deformation is limited. Summary of the Invention

[0005] This application provides a method for underground tunnel excavation and support, which can improve the reliability of tunnel excavation and support in high-altitude and low-temperature environments.

[0006] This application provides a method for underground tunnel excavation and support, including: Obtain the geological features within a preset range in front of the tunnel face, including the surrounding rock structure, fault location, fracture zone thickness, aquifer distribution, and rockburst risk zone; Determine support parameters based on geological characteristics; The tunneling equipment is used to excavate in sections along a spiral path and an articulated arch frame is installed in the excavated section. The excavated soil is continuously transported out by a centrifugal spiral conveyor belt, and the support material is transported to the working face in the opposite direction by a parallel track. Low-temperature resistant concrete is sprayed onto the exposed rock surface of the excavated section with the hinged arch frame installed. The low-temperature resistant concrete is heated by an electric heating nozzle so that the outlet temperature is greater than or equal to the preset temperature, and the thickness of the sprayed layer is within the preset thickness range. After drilling holes in the tunnel wall coated with low-temperature resistant concrete, anchor bolts are inserted to complete the tunnel support.

[0007] Optionally, the low-temperature resistant concrete contains 8-12% silica, 2% calcium nitrite, and the remainder is C25 concrete.

[0008] Optionally, the tunneling equipment is used to excavate in segments along a spiral path, and an articulated arch frame is installed in the excavated section, including: The excavation advance is determined based on the surrounding rock structure; Excavation was carried out according to the excavation progress.

[0009] Optionally, support parameters are determined based on surrounding rock prediction data, including: If a rockburst risk zone is detected, the anchor density in the support parameters should be ≥1 bolt / square meter; If a fault fracture zone greater than or equal to 2 meters is identified, the grouting pressure in the support parameters should be set to 2.0-2.5 MPa.

[0010] Optionally, after drilling holes in the tunnel wall coated with low-temperature resistant concrete, anchor bolts are inserted to complete the tunnel support, including: After the initial setting of the shotcrete, drill holes to install hollow grouting anchors; Anchoring agent is injected through the hollow pipe in the anchor bolt.

[0011] Optionally, an anchoring agent is injected through a hollow conduit in the anchor bolt, including: The temperature of the anchoring agent is maintained at 5°C to 8°C near the working face by water bath heating and circulating constant temperature.

[0012] Optionally, the method further includes, before using tunneling equipment to excavate in segments along a spiral path and before installing the articulated arch frame in the excavated section: Oxygenation equipment is installed near the working face to increase oxygen levels inside the tunnel.

[0013] Optionally, the method further includes: A distributed fiber optic strain system and a microseismic sensor array were installed in the excavated section with the articulated arch frame. Acquire surrounding rock deformation data and vibration monitoring data; When the surrounding rock deformation data and vibration monitoring data meet the preset rules, the support parameters are adjusted according to the preset rules.

[0014] Optionally, the preset rules include: When the deformation rate of the surrounding rock is greater than the preset rate or the micro-vibration energy is greater than or equal to the preset energy, the grouting pressure is increased to the first preset value, the anchor bolt spacing is reduced to the second preset value, and the anchor bolt spacing is reduced.

[0015] Optionally, the method further includes: After each section of tunnel is excavated and supported, a laser profiler is used to inspect the tunnel profile, and a bolt pull-out tester is used to detect the pull-out force of the bolt nodes.

[0016] As described above, the underground tunnel excavation and support method provided in this application has the following beneficial effects: This application discloses a method for underground tunnel excavation and support. The method involves acquiring geological features within a predetermined range ahead of the tunnel face, determining support parameters based on these features, using tunneling equipment to excavate in segments along a spiral path, and simultaneously installing articulated arch frames at the excavated sections. Excavated soil is continuously transported out via a centrifugal spiral conveyor belt, while support materials are transported in the opposite direction to the tunnel face via parallel tracks. Low-temperature resistant concrete is sprayed onto the exposed rock surface of the excavated section with the articulated arch frames. The low-temperature resistant concrete is heated using electric heating nozzles to ensure the outlet temperature is greater than or equal to a predetermined temperature, and the spray layer thickness falls within a predetermined range. After drilling holes in the tunnel wall with the sprayed low-temperature resistant concrete, anchor bolts are inserted to complete the tunnel support. This method achieves simultaneous tunnel excavation and support operations, reduces the exposure time of the surrounding rock, and ensures construction quality by using not only low-temperature resistant concrete but also electric heating nozzles to heat the concrete, thus improving the reliability of tunnel excavation and support in high-altitude, low-temperature environments.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings: Figure 1 This is a flowchart illustrating an exemplary embodiment of the method for excavation and support of an underground tunnel, as shown in this application. Figure 2 This is a flowchart illustrating an underground tunnel excavation and support method, which is another exemplary embodiment of this application. Detailed Implementation

[0019] The embodiments of this application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be understood that the preferred embodiments are only for illustrating this application and are not intended to limit the scope of protection of this application.

[0020] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0021] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present application. However, it will be apparent to those skilled in the art that embodiments of the present application may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present application.

[0022] Please see Figure 1 , Figure 1 This is a flowchart illustrating an exemplary embodiment of an underground tunnel excavation and support method according to this application. (Reference) Figure 1 It can be seen that the excavation and support methods for this underground tunnel may include: Step S110: Obtain the geological features within a preset range in front of the tunnel face.

[0023] The geological features include the surrounding rock structure, fault location, fracture zone thickness, aquifer distribution, and rockburst risk zone.

[0024] In one embodiment of this application, geological features within a predetermined range ahead of the tunnel face can be obtained. Geological exploration within this predetermined range ahead of the tunnel face can be performed using a TSP seismic wave detector or ground-penetrating radar.

[0025] The tunnel face refers to the excavation face that is advancing during the excavation of a tunnel or underground project. In other words, the tunnel face can represent the front line of construction and the working face that is in direct contact with the rock and soil.

[0026] For example, the preset range can be 50-100 meters.

[0027] Step S120: Determine support parameters based on geological characteristics.

[0028] In one embodiment of this application, support parameters can be determined based on geological features.

[0029] For example, if a rockburst risk zone is detected, the anchor density in the support parameters should be ≥1 bolt / square meter; if a fault fracture zone greater than or equal to 2 meters is identified, the grouting pressure in the support parameters should be set to 2.0-2.5 MPa. This applies when the microseismic energy is greater than or equal to 5 × 10⁻⁶ m³ / m². 3 When J is reached, a rockburst risk zone can be identified. If the longitudinal extension width of the fault fracture zone in the tunnel excavation direction is greater than or equal to 2 meters, the grouting pressure in the support parameters can be set to 2.0-2.5 MPa.

[0030] It should be noted that the greater the thickness of the fracture zone, the worse the self-stabilizing ability of the surrounding rock. In this case, a higher grouting pressure is required to allow the grout to fully penetrate the surrounding rock and cement a larger area of ​​fractured rock mass.

[0031] In one embodiment of this application, before installing the articulated arch frame at the completed section after segmental excavation using tunneling equipment along a spiral path, the underground tunnel excavation and support method further includes: setting up an oxygenation device near the tunnel face to increase oxygen levels inside the tunnel. This oxygenation device can increase the oxygen content of the environment and maintain the stability of the underground tunnel excavation and support equipment. The oxygenation device can be an oxygen-enriched hydraulic system, ensuring that the power attenuation of the equipment does not exceed 10% at high altitudes and that continuous operation time exceeds 8 hours. Furthermore, the temperature control output can be adjusted in real time through an environmental monitoring module (e.g., a temperature and humidity sensor) to ensure a constant construction environment for the concrete and equipment.

[0032] In step S130, the tunneling equipment is used to excavate in sections along a spiral path, and articulated arch frames are installed at the completed sections. The excavated soil is continuously transported out by a centrifugal spiral conveyor belt, and the support materials are transported to the working face in the opposite direction by parallel tracks.

[0033] In one embodiment of this application, tunneling equipment can be used for segmented excavation along a spiral path. Excavated soil can be continuously transported downhill via a centrifugal screw conveyor belt, while support materials can be transported in the opposite direction to the tunnel face via parallel tracks. During segmented excavation, the excavation advance is 2.5-3.5 meters per cycle, meaning that the length advanced along the tunnel axis in a single tunnel construction cycle can be 2.5-3.5 meters. A single tunnel construction cycle can include drilling, blasting / mechanical excavation, muck removal, and support preparation.

[0034] It should be noted that the surrounding rock in high-altitude areas has poor stability. Limiting the single advance (≤3.5 meters) can reduce the exposed area of ​​the surrounding rock and lower the risk of collapse.

[0035] In one embodiment of this application, the method of using tunneling equipment to excavate in segments along a spiral path and installing articulated arches in the excavated sections includes: determining the excavation advance based on the surrounding rock structure; and excavating according to the excavation advance.

[0036] When the surrounding rock is classified as hard rock, the rock mass has high integrity and good self-stability. Excavation can be done mechanically (TBM or rock drilling rig), with a depth of 3.0 to 3.5 meters. When the surrounding rock is classified as soft rock, the rock mass is fractured and requires short depths and timely support. Excavation can be done by drill-and-blast, with a depth of 2.5 to 3.0 meters. The surrounding rock category can be determined based on the rock structure detected by a TSP seismic wave instrument or ground-penetrating radar. A rock mass integrity coefficient greater than or equal to 0.75 indicates hard rock, while a coefficient less than 0.75 indicates soft rock.

[0037] For example, the tunneling equipment can be high-altitude adapted equipment, such as an oxygen-enriched three-arm rock drilling rig or a small tunnel boring machine (TBM).

[0038] In one embodiment of this application, a hinged arch frame can be installed in the excavated section. The hinged arch frame can be an adjustable hinged arch frame, comprising multiple hinged units; that is, the adjustable hinged arch frame can be composed of several independent segments connected by hinged nodes, each segment being 1.2-1.5 meters long. The hinged nodes allow adjacent segments to rotate relative to each other within a certain angle range to adapt to changes in tunnel curvature, and the segment length can be optimized according to the designed radius of curvature. Hydraulic push rods or electric auger cylinders can be installed between or within independent segments, which can push adjacent segments to change angles through telescopic movement.

[0039] It should be noted that the actual angle between adjacent independent segments can be measured in real time using an angle sensor, and the actual radius of curvature of the tunnel can be determined using a laser rangefinder and a gyroscope. The theoretical angle between adjacent independent segments can be determined based on the actual radius of curvature of the tunnel and the length of each independent segment. By comparing the actual angle with the theoretical angle, if the deviation between the actual angle and the theoretical angle is greater than 5%, the angle of the independent segment can be adjusted.

[0040] Step S140: Spray low-temperature resistant concrete onto the exposed rock surface of the excavated section with the hinged arch frame installed. The low-temperature resistant concrete is heated by an electric heating nozzle to make the outlet temperature greater than or equal to the preset temperature, and the thickness of the sprayed layer is within the preset thickness range.

[0041] In one embodiment of this application, low-temperature resistant concrete can be sprayed onto the exposed rock surface of the excavated section equipped with a hinged arch frame. The sprayed low-temperature resistant concrete can be heated using an electric heating nozzle to make the outlet temperature greater than or equal to a preset temperature, and the thickness of the sprayed layer can be within a preset thickness range.

[0042] For example, the preset temperature can be 10°C, and the preset thickness range can be 100-150 mm.

[0043] It should be noted that nano-silica and an accelerator can be added to C25 concrete in a certain proportion. The proportion of nano-silica can be 8-12%, and the proportion of calcium nitrite (i.e., the accelerator) can be 2%. Adding nano-silica can improve density and frost resistance, while adding an accelerator can accelerate the setting of concrete in low-temperature environments.

[0044] Maintaining the outlet temperature can prevent low temperatures from causing the concrete to lose fluidity or freeze and fail.

[0045] Step S150: After drilling holes in the tunnel wall coated with low-temperature resistant concrete, anchor bolts are inserted to complete the tunnel support.

[0046] In one embodiment of this application, anchor bolts can be inserted after drilling holes in the tunnel wall coated with low-temperature resistant concrete to complete tunnel support. The process of drilling holes in the tunnel wall coated with low-temperature resistant concrete and inserting anchor bolts to complete tunnel support may include: drilling holes and installing hollow grouting anchor bolts after the initial setting of the shotcrete; and injecting anchoring agent through the hollow pipes in the anchor bolts.

[0047] After the initial setting of the shotcrete, 25 mm hollow grouting anchors can be drilled and installed. A constant-temperature epoxy resin-based anchoring agent is injected through the hollow pipe of the anchor. Carbon fiber toughening agent can be added to the epoxy resin-based anchoring agent. The grouting pressure can be determined through step S120. The grouting process is carried out at a constant temperature, maintained between 5-8℃. The tail of the anchor is fastened to the arch frame node, and the end is embedded in the shotcrete layer. At high altitudes and low temperatures, epoxy resin easily solidifies. Maintaining a constant temperature ensures the grout density and maintains the fluidity of the epoxy resin. If the fault fracture zone is less than 2 meters, the grouting pressure can be 1.5-2.0 MPa.

[0048] In one possible implementation, the anchoring agent is injected through a hollow pipe in the anchor bolt, including maintaining the temperature of the anchoring agent at 5°C to 8°C near the working face by water bath heating and circulating constant temperature.

[0049] The sprayed layer quickly seals the surrounding rock, and the anchor bolts reinforce the deep rock mass; materials and temperature control ensure construction quality in a -25℃ environment; support parameters are adjusted in real time according to geological risks to ensure the reliability and safety of the plateau spiral tunnel support.

[0050] It should be noted that the construction equipment in this application embodiment can adopt an electric drive or hydraulic system with high-altitude dynamic adaptability to reduce power attenuation.

[0051] Please see Figure 2This is another exemplary embodiment of the method for excavating and supporting underground tunnels, which may further include steps S210 to S230.

[0052] Step S210: Install a distributed fiber optic strain system and a microseismic sensor array in the excavated section where the articulated arch frame is installed.

[0053] Step S220: Obtain surrounding rock deformation data and vibration monitoring data.

[0054] Deformation data of surrounding rock can be obtained through a distributed fiber optic strain system, and vibration monitoring data can be obtained through a microseismic sensor array.

[0055] Step S230: When the surrounding rock deformation data and vibration monitoring data meet the preset rules, adjust the support parameters according to the preset rules.

[0056] The preset rules include: when the deformation rate of the surrounding rock is greater than the preset rate or the micro-vibration energy is greater than or equal to the preset energy, the grouting pressure is increased to the first preset value and the anchor spacing is reduced to the second preset value.

[0057] Hydrological sensors can also be installed in the excavated section with articulated arches to obtain the daily water inrush flow rate. The preset rules can include increasing the grouting pressure to a first preset value and reducing the anchor bolt spacing to a second preset value when the surrounding rock deformation rate is greater than a preset rate, the micro-vibration energy is greater than or equal to a preset energy, or the daily water inrush flow rate is greater than or equal to a preset flow rate.

[0058] For example, when the surrounding rock deformation rate is >2 mm / h or the microseismic energy is ≥1×10 4 When the daily water inrush flow rate is ≥50L / s, the grouting pressure can be increased to 2.5MPa, the anchor bolt spacing can be reduced to 0.7~0.8m, and a steel fiber spray layer can be added.

[0059] In one possible implementation, the underground tunnel excavation and support method may further include: after each section of tunnel excavation and support is completed, using a laser profiler to inspect the tunnel profile and using a bolt pull-out tester to detect the pull-out force of the bolt nodes. When using the laser profiler to inspect the tunnel profile, the allowable over-excavation / under-excavation error is ≤50mm; when using the bolt pull-out tester to detect ≥10% of the bolt nodes, the pull-out force is not less than the design value of 100kN; all monitoring data can be uploaded to a central database for comparison and correction with design parameters to optimize subsequent construction and support strategies, achieving intelligent feedback.

[0060] If the over- or under-excavation error is greater than 50mm, for under-excavation, use a hydraulic breaker or pneumatic drill to remove the rock mass exceeding the design outline until the error is less than or equal to 50mm. For over-excavation, spray concrete to fill the over-excavated area and restore the design cross-section. The central database can analyze the causes of over- or under-excavation, such as changes in geological hardness and equipment operation deviations, and adjust the parameters or steps in the underground tunnel excavation and support methods.

[0061] If the pull-out resistance of the anchor bolt joint is less than 100kN, a new anchor bolt can be added within 30cm of the failed anchor bolt. The length of the new anchor bolt can be increased by 0.5 meters, and the pull-out resistance should be retested. Epoxy resin grout can be injected into the original anchor bolt hole under high pressure at a pressure of 2.0~2.5MPa, and the grouting should be retested. During subsequent excavation and support operations, the grouting pressure and anchor bolt density can be increased.

[0062] It should be noted that this invention effectively overcomes the problems of low efficiency, poor adaptability, and lagging safety control in existing technologies by simultaneously excavating and supporting, dynamically adjusting the curvature of the arch frame, optimizing materials and equipment at high altitudes, and establishing a dynamic risk response mechanism. This significantly improves the reliability, continuity, and intelligence of spiral tunnel construction under complex geological conditions.

[0063] Embodiments of this application also provide an electronic device, including: one or more processors; and a storage device for storing one or more programs, which, when executed by one or more processors, cause the electronic device to implement the underground tunnel excavation and support methods provided in the above embodiments.

[0064] Another aspect of this application provides a computer-readable storage medium storing a computer program thereon, which, when executed by a computer's processor, causes the computer to perform the underground tunnel excavation and support methods provided in the various embodiments described above. This computer-readable storage medium may be included in the electronic devices described in the above embodiments, or it may exist independently and not assembled into the electronic device.

[0065] Another aspect of this application provides a computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the underground tunnel excavation and support methods provided in the various embodiments described above.

[0066] In the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "comprising" and "including" as used throughout the specification and claims are open-ended terms and should therefore be interpreted as "comprising but not limited to".

[0067] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A method for excavation and support of underground tunnels, characterized in that, include: Obtain the geological features within a preset range in front of the tunnel face, including the surrounding rock structure, fault location, fracture zone thickness, aquifer distribution, and rockburst risk zone; Determine support parameters based on geological characteristics; The tunneling equipment is used to excavate in sections along a spiral path, and articulated arch frames are installed at the completed sections. The excavated soil is continuously transported out by a centrifugal spiral conveyor belt, and the support materials are transported to the working face in the opposite direction by parallel tracks. Low-temperature resistant concrete is sprayed onto the exposed rock surface of the excavated section with the hinged arch frame installed. The low-temperature resistant concrete is heated by an electric heating nozzle so that the outlet temperature is greater than or equal to the preset temperature, and the thickness of the sprayed layer is within the preset thickness range. After drilling holes in the tunnel wall coated with low-temperature resistant concrete, anchor bolts are inserted to complete the tunnel support. The low-temperature resistant concrete contains 8-12% silica, 2% calcium nitrite, and the remainder is C25 concrete.

2. The method for excavation and support of underground tunnels according to claim 1, characterized in that, The tunneling equipment is used to excavate in sections along a spiral path, and articulated arch frames are installed in the completed sections, including: The excavation advance is determined based on the surrounding rock structure; Excavation was carried out according to the excavation progress.

3. The method for excavation and support of underground tunnels according to claim 1, characterized in that, Support parameters are determined based on surrounding rock prediction data, including: If a rockburst risk zone is detected, the anchor density in the support parameters should be ≥1 bolt / square meter; If a fault fracture zone greater than or equal to 2 meters is identified, the grouting pressure in the support parameters should be set to 2.0-2.5 MPa.

4. The method for excavation and support of underground tunnels according to claim 1, characterized in that, After drilling holes in the tunnel wall coated with low-temperature resistant concrete, anchor bolts are inserted to complete the tunnel support, including: After the initial setting of the shotcrete, drill holes to install hollow grouting anchors; Anchoring agent is injected through the hollow pipe in the anchor bolt.

5. The method for excavation and support of underground tunnels according to claim 4, characterized in that, Anchoring agent is injected through the hollow tube in the anchor bolt, including: The temperature of the anchoring agent is maintained at 5°C to 8°C near the working face by water bath heating and circulating constant temperature.

6. The method for excavation and support of underground tunnels according to claim 1, characterized in that, The method further includes, before using tunneling equipment to excavate in segments along a spiral path and before installing the articulated arch frame in the excavated section: Oxygenation equipment is installed near the working face to increase oxygen levels inside the tunnel.

7. The method for excavation and support of underground tunnels according to claim 1, characterized in that, The method further includes: A distributed fiber optic strain system and a microseismic sensor array were installed in the excavated section with the articulated arch frame. Acquire surrounding rock deformation data and vibration monitoring data; When the surrounding rock deformation data and vibration monitoring data meet the preset rules, the support parameters are adjusted according to the preset rules.

8. The method for excavation and support of underground tunnels according to claim 7, characterized in that, The preset rules include: When the deformation rate of the surrounding rock is greater than the preset rate or the micro-vibration energy is greater than or equal to the preset energy, the grouting pressure is increased to the first preset value, the anchor bolt spacing is reduced to the second preset value, and the anchor bolt spacing is reduced.

9. The method for excavation and support of underground tunnels according to claim 1, characterized in that, The method further includes: After each section of tunnel is excavated and supported, a laser profiler is used to inspect the tunnel profile, and a bolt pull-out tester is used to detect the pull-out force of the bolt nodes.

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