A surrounding rock advance reinforcement method suitable for a VBE shaft tunneling machine

Abstract

This invention discloses a method for pre-reinforcement of surrounding rock suitable for VBE shaft boring machines. The method includes: setting up a reinforcement work chamber between the VBE shaft boring machine cutterhead and propulsion system; the reinforcement work chamber includes a rotating platform and a support mechanism mounted on the rotating platform; pre-detecting the geological information of the surrounding rock in front and on the sidewalls; when adverse geological conditions are detected in the surrounding rock in front, pausing the excavation and performing pre-reinforcement work; drilling and grouting the surrounding rock in front of the cutterhead; drilling and installing emergency anchor bolts in the shaft sidewalls in stages using the rotating platform; laying arch rib steel mesh on the emergency anchor bolts; and spraying concrete onto the section of surrounding rock with the mesh. This invention achieves simultaneous reinforcement of adverse surrounding rock in front during the excavation process, significantly improving the safety, efficiency, and continuity of shaft construction, and is particularly suitable for deep shaft engineering construction under complex geological conditions.

Description

Technical Field

[0001] This invention relates to the field of tunnel and underground engineering construction technology, specifically to a method for pre-reinforcement of surrounding rock suitable for VBE shaft boring machines. Background Technology

[0002] In deep shaft construction, adverse geological conditions such as faults, fractured zones, weak rock formations, or karst caves are frequently encountered. Traditional construction methods typically employ a sequence of excavation followed by support. The support platform of the tunneling machine is positioned above the machine and suspended via a hoisting system, leaving the cutterhead end without support. When the tunneling machine exposes unfavorable geological formations, it often needs to be stopped, requiring workers to enter the area in front of the excavation face to perform dangerous, rudimentary geological treatment and support work. This method is not only inefficient and time-consuming, but also poses extremely high safety risks to personnel working under unsupported exposed rock. Furthermore, traditional methods struggle to achieve immediate, proactive, and thorough reinforcement of the surrounding rock; incomplete rock treatment can easily lead to accidents involving the machine being buried due to rockfall.

[0003] VBE (Very High-Efficiency Beam) shaft boring machines (VBEs) are highly efficient mechanized shaft excavation equipment with significant advantages in continuous tunneling. However, the aforementioned traditional surrounding rock reinforcement methods are incompatible with them, becoming a technical bottleneck restricting their application in complex geological formations. Therefore, there is an urgent need for a construction method that can be highly integrated with VBEs and can simultaneously carry out tunneling and advanced reinforcement to ensure construction safety and improve project quality and efficiency. Summary of the Invention

[0004] To solve the above-mentioned technical problems, this invention provides a method for pre-reinforcement of surrounding rock suitable for VBE shaft boring machines.

[0005] A method for pre-reinforcement of surrounding rock suitable for VBE shaft boring machines, the specific steps of which are as follows: (1) A reinforced working chamber is set between the cutterhead and the propulsion system of the VBE shaft tunneling machine. The reinforced working chamber includes a rotating platform and a support mechanism set on the rotating platform. The rotating platform is coaxially set outside the main beam of the tunneling machine and rotates relative to the main beam. The support mechanism includes a down-the-hole drill, a slurry pumping device, a bolt drill and a spraying mechanical arm. (2) The VBE shaft tunneling machine should advance to the safe distance before reaching the estimated risk stratum, and conduct advance detection of the geological information of the surrounding rock in front of the tunneling working face and sidewalls. When adverse geological conditions are found in the surrounding rock in front, the tunneling should be suspended and the surrounding rock should be reinforced in advance. (3) Remove part of the roller cutter at the cutterhead of the VBE shaft tunneling machine to form a temporary working window. Use the window to carry out advanced drilling and grouting operations on the unexcavated surrounding rock in front of the cutterhead working face. After the grout has solidified to the preset strength, restore the roller cutter to its original position to close the window and complete the advanced pre-reinforcement. (4) Based on the single rotation angle of the rotating platform, the newly exposed surrounding rock section within the current cycle advance range is divided into multiple working sectors as the cutterhead advances; the rotating platform is controlled to rotate sequentially so that the support mechanism is aligned with each working sector; for the unfavorable surrounding rock in the current working sector, the anchor drilling machine is used to complete the emergency anchor drilling and installation. (5) After the full-section emergency anchor bolts are installed, the full-section arch rib steel mesh is installed and laid out on the rotating platform; (6) Control the rotation of the rotating platform to carry out shotcrete construction on the surrounding rock with arch rib steel mesh; complete all single-cycle emergency support operations and the tunneling machine continues to tunnel; (7) Repeat steps 2-6 above until all adverse geological surrounding rock reinforcement is completed.

[0006] A further technical solution is: the rotating platform includes a fixed layer, a rotating layer and a drive assembly. Both the fixed layer and the rotating layer are configured as hollow ring structures. The inner ring of the fixed layer is fixedly connected to the main beam of the tunneling machine. The rotating layer is supported on the fixed layer by a slewing support assembly, and the inner ring of the rotating layer is rotatably connected to the main beam of the tunneling machine by a connecting bearing. The drive assembly includes a motor, a first gear, and a second gear. The second gear is coaxially fixed at the bottom of the rotating layer, and the motor is fixed to the top surface of the fixed layer. The output shaft of the motor is fixedly connected to the first gear. The first gear is located radially outside the second gear and is rotatably connected to the bottom of the rotating layer. The first gear meshes with the second transmission gear so that the motor drives the second gear through the first gear, thereby causing the rotating layer to rotate around the main beam of the tunneling machine.

[0007] A further technical solution is: the slewing support assembly includes a support bearing and multiple support columns. The bottom of the inner ring of the support bearing is coaxially fixed to the top surface of the fixed layer, and the multiple support columns are evenly distributed on the top of the outer ring of the slewing bearing. The top of the support columns is fixedly connected to the bottom of the rotating layer.

[0008] A further technical solution is that the rotating platform rotates in steps according to the set single rotation angle, and the value range of the single rotation angle is 15° to 90°.

[0009] A further technical solution is that the single rotation angle mentioned in step 4 is dynamically adjusted according to the surrounding rock strength level detected in real time in step 2.

[0010] A further technical solution is to use at least one of the following methods for advanced geological exploration: ground-penetrating radar, borehole camera, or acoustic detection.

[0011] A further technical solution is as follows: Step 3, the advanced drilling and grouting operation, includes the following steps: The slurry is transported to the slurry pumping device of the rotating platform through the main unit's delivery pipeline; The grout pumping device uses a grouting pipeline to connect to the grouting nozzle, and inserts the grouting nozzle into the grouting hole; Turn on the grout pumping device to inject the grout under pressure, and monitor the grout pressure in the injection hole in real time; When the grout pressure inside the hole reaches the preset reinforcement final pressure value, stop pumping and seal the grouting hole. The grouting area is left to stand for at least 4 hours to allow the grout strength to meet the requirements for subsequent tunneling.

[0012] A further technical solution is: the reinforcing mesh is made of Φ22 threaded steel, the distribution bars are made of Φ10 round steel, and the mesh spacing is 150mm×150mm.

[0013] A further technical solution is: emergency anchor bolts are long bonded mortar anchor bolts, with a length of 2.5-4 meters and a spacing of 1.0 meter × 1.0 meter, arranged in a quincunx pattern.

[0014] The beneficial effects of this invention are: 1. Integration and high efficiency: By setting up a dedicated reinforcement work chamber between the VBE main machine's front-end cutterhead and the propulsion system, including a rotating platform and support mechanism, processes such as advance detection, drilling, grouting, anchor bolt installation, and steel mesh laying are integrated between the tunneling machine's cutterhead and support shoes, realizing integrated "tunneling-reinforcement" operations. This significantly reduces equipment transfer and process connection time, and improves construction efficiency.

[0015] 2. Comprehensive and Flexible Reinforcement: The rotating platform, combined with the sector-based construction technique, enables comprehensive and thorough pre-grouting and anchoring support for adverse geological formations within a 360° range in front of and around the shaft excavation face. The rotation angle of the rotating platform can be dynamically adjusted according to the surrounding rock conditions, achieving precise and customized reinforcement and effectively constraining surrounding rock deformation.

[0016] 3. High Safety: This method reduces the risk of collapse and water inrush in the undisturbed surrounding rock in front of the cutterhead by drilling and grouting through temporary windows. For the exposed shaft wall surrounding rock behind the cutterhead, a rotating platform is used to implement step-by-step circumferential anchor-sprayed support construction to ensure the self-stability of the excavated shaft. It proactively reinforces dangerous strata before tunneling, preventing potential geological disasters such as collapses and water inrushes at their inception, greatly improving construction safety. Furthermore, all reinforcement work is completed within the protected internal space of the tunneling machine, ensuring the safety of the workers.

[0017] 4. Ensure the continuity of support: The arch rib steel mesh is laid before the support shoe travels to the section with poor geological conditions, ensuring that the support shoe can effectively support the shaft. Since the emergency support work was completed in the reinforcement work chamber in the early stage, it ensures that the shaft can be smoothly supported and excavated normally when passing through the section with poor geological conditions, avoiding the accident of the machine being buried due to the collapse of the surrounding rock of the poor geological conditions. Attached Figure Description

[0018] Figure 1 This is a flowchart of a pre-reinforcement method for surrounding rock suitable for VBE shaft boring machines.

[0019] Figure 2 This is a schematic diagram of advanced grouting reinforcement construction in the cutterhead area.

[0020] Figure 3 This is a schematic diagram of the rotating platform.

[0021] Figure 4 This is a schematic diagram of the arrangement at the bottom of the rotating layer.

[0022] In the picture: 1. Tunneling machine main beam, 2. Cutterhead, 3. Unexcavated surrounding rock, 4. Side wall surrounding rock, 5. Rotating platform, 6. Fixed layer, 7. Inner ring of fixed layer, 8. Support bearing, 9. Rotating layer, 10. Connecting bearing, 11. Support column, 12. Electric motor, 13. Electric motor output shaft, 14. First gear, 15. Second gear. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0024] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Example 1

[0026] This embodiment provides a method for pre-reinforcement of surrounding rock suitable for VBE shaft boring machines. The specific steps are as follows: (1) A reinforced working chamber is provided between the cutterhead 2 and the propulsion system of the VBE shaft tunneling machine. The reinforced working chamber includes a rotating platform 5 and a support mechanism set on the top surface of the rotating platform 5. The rotating platform 5 is coaxially set outside the main beam 1 of the tunneling machine and rotates relative to the main beam. The support mechanism includes a high-power down-the-hole drill, a slurry pumping device, a multi-functional anchor drill and a spraying mechanical arm.

[0027] The rotating platform 5 includes a fixed layer 6, a rotating layer 9, and a drive assembly. Both the fixed layer 6 and the rotating layer 9 are hollow annular structures. The inner ring 7 of the fixed layer is fixedly connected to the main beam 1 of the tunneling machine. The rotating layer 9 is supported on the fixed layer 6 by a slewing support assembly, and the inner ring of the rotating layer 9 is rotatably connected to the main beam 1 of the tunneling machine via a connecting bearing 10. The drive assembly includes a motor 12, a first gear 15, and a second gear 14. The second gear 14 is coaxially fixed to the bottom of the rotating layer 9, and the motor 12 is fixed to the top surface of the fixed layer 6. The output shaft 13 of the motor is fixedly connected to the first gear 15. The first gear 15 is located radially outside the second gear 14 and is rotatably connected to the bottom of the rotating layer 9. The first gear 15 meshes with the second gear 14 so that the motor 12 drives the second gear 14 through the first gear 15, thereby causing the rotating layer 9 to rotate around the main beam 1 of the tunneling machine.

[0028] The slewing support assembly includes a support bearing 8 and multiple support columns 11. The bottom of the inner ring of the support bearing 8 is coaxially fixed to the top surface of the fixing layer 6. The multiple support columns 11 are evenly distributed on the top of the outer ring of the support bearing 8, and the top of the support columns 11 is fixedly connected to the bottom of the rotating layer 9.

[0029] In the reinforcement work chamber, the down-the-hole drill, anchor drill, slurry pumping device, and spraying mechanical arm are fixed to the rotating layer 9 and symmetrically distributed to ensure the stability of the cutterhead 2 during tunneling and the overall stability of the platform. The cable, laid via the main beam 1 of the tunneling machine, reaches the reinforcement work chamber and is then transferred to a power distribution cabinet fixed to the main beam. The power supply lines for the working equipment within the reinforcement work chamber are independent and can be connected to the aforementioned distribution cabinet. The length of the power supply line should be greater than three times the circumference of the rotating platform to prevent workers from forgetting to disconnect the cable during rotation. After one rotation, workers should unplug the power supply to the working equipment, adjust the cable position to prevent tangling, and reconnect the distribution cabinet before the next start of the advanced reinforcement operation.

[0030] The grout pumping device uses a mixing tank equipped with a pneumatic grouting pump to store and periodically mix the grouting slurry.

[0031] A vertical ladder is constructed between the rotating platform 5 and the main working platform of the shaft boring machine. Access points are provided on the rotating and fixed layers of the rotating platform, and a detachable ladder is installed between the access points of the rotating platform and the cutterhead 2 area to facilitate personnel access. Material transport within the reinforcement work chamber is achieved through multiple paths: anchor bolts, reinforcing bars, and other components are hoisted via a winch on the material platform of the shaft boring machine; grouting materials such as cement and admixtures are transported to the grout pumping device through a closed pipeline installed within the shaft boring machine. Preferably, a protective fence is installed on the outside of the rotating layer 9 to ensure construction safety.

[0032] (2) When the VBE shaft tunneling machine tunnels to 2-5 meters before the estimated risk stratum, it will conduct advance detection of the geological information of the surrounding rock in front and on the side. When it is found that there are adverse geological conditions in the surrounding rock in front, the tunneling operation will be suspended and the surrounding rock will be reinforced in advance.

[0033] During advanced geological exploration, a ground-penetrating radar system integrated on the rotating platform 5 scans the surrounding rock within a 15-20 meter range ahead of and along the sides of the tunnel face to detect any adverse geological conditions. Simultaneously, a small number of pilot boreholes are drilled using a down-the-hole drill rig, and combined with borehole cameras, the presence of fault zones, water-bearing cavities, or extremely soft rock ahead is determined. Advanced exploration can also incorporate acoustic detection technology.

[0034] (3) The shaft boring machine completely stops its tunneling operation. Construction personnel enter the cutterhead 2 area and, according to the design location, remove a total of 4-6 cutters from various locations on the cutterhead 2 to form multiple temporary working windows. The working windows should be evenly distributed in the cutterhead 2 area to ensure uniform grouting effect. Using the windows, advance drilling and grouting operations are carried out on the unexcavated surrounding rock 3 in front of the cutterhead working face. After the grout has solidified to the preset strength, the cutters are restored to their original positions to close the windows, completing the advance pre-reinforcement.

[0035] During drilling operations, construction workers use handheld drilling rigs to drill grouting holes of a certain depth and angle into the surrounding rock. During grouting, a grout pump is connected to a grouting nozzle via a grouting pipeline, and the nozzle is inserted into the grouting hole. Prepared cement-based grout is hydraulically injected into the hole. The water-cement ratio of the cement-based grout is 0.8:1. The grout pressure inside the grouting hole is monitored in real time, maintaining the grouting pressure between 1.0 and 2.0 MPa. When the grout pressure inside the hole reaches the preset final pressure value and remains there for 5 minutes, grouting is stopped and the grouting hole is sealed. The grouted holes are then left to stand for 4 hours to allow the grout strength to meet the requirements for subsequent tunneling.

[0036] (4) Based on the single rotation angle of the rotating platform 5, the newly exposed fractured sidewall rock section within the current cycle advance range is divided into multiple working sectors as the cutterhead advances.

[0037] The rotating platform 5 is rotated sequentially to align the support mechanism with each working sector. For the unfavorable surrounding rock in the current working sector, an anchor drilling rig is used to drill and install emergency anchor bolts. Construction personnel use the anchor drilling rig on the rotating platform to drill emergency anchor bolt holes in the exposed sidewall surrounding rock 4 within each working sector, complete grouting using grouting pipelines, and then install the emergency anchor bolts. The emergency anchor bolt grouting procedure in step 4 is basically the same as the grouting procedure in step 3, but the grout pressure can be appropriately reduced according to the actual working conditions. Once the grout fills the borehole, full-length bonded mortar anchor bolts are immediately installed. The anchor bolts are 2.5-4 meters long, spaced 1.0 meter × 1.0 meter apart, arranged in a staggered pattern. The rotating platform 5 rotates step by step according to the set single rotation angle until the 360° full-section emergency anchor bolt installation is completed.

[0038] The range of a single rotation angle is 15° to 90°, and the initial value is recommended to be set to 60°.

[0039] The single rotation angle is dynamically adjusted based on the real-time detected rock strength level in step 2. If the detected rock strength is low during the current tunneling process, the single rotation angle is reduced accordingly, increasing the number of working sectors within a single cycle to achieve denser reinforcement; conversely, the single rotation angle is increased accordingly, reducing the number of working sectors within a single cycle. Specifically, when the detected rock strength level is V, the single rotation angle ranges from greater than 15° to less than or equal to 30°; when the rock strength level is IV, the range is greater than 30° to less than or equal to 45°; and when the rock strength level is III, the range is greater than 45° to less than or equal to 90°.

[0040] (5) After the full-section emergency anchor bolts are installed, the full-section arch rib steel mesh is installed and laid out on the rotating platform; The pre-fabricated steel arch ribs, manufactured on the wellhead platform, are transported to the rotating platform and securely fixed to the emergency anchor bolts to form a steel mesh. The main reinforcement bars of the steel mesh are made of Φ22 threaded steel, and the distribution bars are made of Φ10 round steel, with a mesh spacing of 150mm×150mm.

[0041] (6) Control the rotation of the rotating platform to carry out shotcrete construction on the surrounding rock with arch rib steel mesh; complete all single-cycle emergency support operations and the tunneling machine continues to tunnel; The main pipeline of the tunneling machine delivers shotcrete to the shotcrete robotic arm on the rotating platform for shotcrete application. This completely encapsulates the steel mesh of the arch ribs, forming a higher-strength composite support structure. By adjusting the rotation speed of the rotating platform, the thickness of each shotcrete layer is controlled, achieving 360° shotcrete support for the well wall.

[0042] (7) Repeat steps 2-6 above until all adverse geological surrounding rock reinforcement is completed. Example 2

[0043] The method steps in this embodiment are basically the same as those in Embodiment 1, except that: When advanced geological information detection is performed in step 2 and the feedback indicates that the strength of the surrounding rock ahead is extremely low, the single rotation angle parameter in step 4 is adjusted. In step 4, the single rotation angle of the rotating platform 5 is adjusted to 30°, and the entire shaft cross-section is divided into 12 sectors for step-by-step reinforcement. When drilling the surrounding rock 4 of the shaft sidewall in each sector, the spacing of the anchor bolt holes is increased to 0.6 meters × 0.6 meters, and the spacing of the grouting holes is also reduced accordingly.

[0044] This "small angle, high density" reinforcement method can form a denser and stronger reinforcement ring under extremely unfavorable geological conditions, effectively constraining the deformation of the surrounding rock, and can achieve reinforcement of weak and broken surrounding rock with extremely low strength and poor integrity.

[0045] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for advance reinforcement of surrounding rock suitable for a VBE shaft heading machine, characterized in that, The specific steps are as follows: (1) A reinforced working chamber is set between the cutterhead and the propulsion system of the VBE shaft tunneling machine. The reinforced working chamber includes a rotating platform and a support mechanism set on the rotating platform. The rotating platform is coaxially set outside the main beam of the tunneling machine and rotates relative to the main beam. The support mechanism includes a down-the-hole drill, a slurry pumping device, a bolt drill and a spraying mechanical arm. (2) The VBE shaft tunneling machine should advance to the safe distance before reaching the estimated risk stratum, and conduct advance detection of the geological information of the surrounding rock in front of the tunneling working face and sidewalls. When adverse geological conditions are found in the surrounding rock in front, the tunneling should be suspended and the surrounding rock should be reinforced in advance. (3) Remove part of the roller cutter at the cutterhead of the VBE shaft tunneling machine to form a temporary working window. Use the window to carry out advanced drilling and grouting operations on the unexcavated surrounding rock in front of the cutterhead working face. After the grout has solidified to the preset strength, restore the roller cutter to its original position to close the window and complete the advanced pre-reinforcement. (4) Based on the single rotation angle of the rotating platform, the newly exposed surrounding rock section within the current cycle advance range is divided into multiple working sectors as the cutterhead advances; the rotating platform is controlled to rotate sequentially so that the support mechanism is aligned with each working sector; for the unfavorable surrounding rock in the current working sector, the anchor drilling machine is used to complete the emergency anchor drilling and installation. (5) After the full-section emergency anchor bolts are installed, the full-section arch rib steel mesh is installed and laid out on the rotating platform; (6) Control the rotation of the rotating platform to carry out shotcrete construction on the surrounding rock with arch rib steel mesh; complete all single-cycle emergency support operations and the tunneling machine continues to tunnel; (7) Repeat steps 2-6 above until all adverse geological surrounding rock reinforcement is completed.

2. The method according to claim 1, characterized in that, The rotating platform includes a fixed layer, a rotating layer, and a drive assembly. Both the fixed layer and the rotating layer are hollow ring structures. The inner ring of the fixed layer is fixedly connected to the main beam of the tunneling machine. The rotating layer is supported on the fixed layer by a slewing support assembly, and the inner ring of the rotating layer is rotatably connected to the main beam of the tunneling machine by a connecting bearing. The drive assembly includes a motor, a first gear, and a second gear. The second gear is coaxially fixed at the bottom of the rotating layer, and the motor is fixed to the top surface of the fixed layer. The output shaft of the motor is fixedly connected to the first gear. The first gear is located radially outside the second gear and is rotatably connected to the bottom of the rotating layer. The first gear meshes with the second transmission gear so that the motor drives the second gear through the first gear, thereby causing the rotating layer to rotate around the main beam of the tunneling machine.

3. The method according to claim 2, characterized in that, The slewing support assembly includes a support bearing and multiple support columns. The bottom of the inner ring of the support bearing is coaxially fixed to the top surface of the fixed layer, and the multiple support columns are evenly distributed on the top of the outer ring of the slewing bearing. The top of the support columns is fixedly connected to the bottom of the rotating layer.

4. The method for advance reinforcement of surrounding rock for a VBE shaft heading machine according to claim 1, characterized in that, The rotating platform rotates in steps according to the set single rotation angle, which ranges from 15° to 90°.

5. The method for advance reinforcement of surrounding rock for a VBE shaft heading machine according to claim 4, characterized in that, The single rotation angle mentioned in step 4 is dynamically adjusted according to the surrounding rock strength level detected in real time in step 2.

6. The method for pre-reinforcement of surrounding rock suitable for VBE shaft boring machines according to claim 1, characterized in that, Advanced geological exploration employs at least one of the following methods: ground-penetrating radar, borehole photography, or acoustic detection.

7. The method for pre-reinforcement of surrounding rock suitable for VBE shaft boring machines according to claim 1, characterized in that, Step 3, the advanced drilling and grouting operation, includes the following steps: The slurry is transported to the slurry pumping device of the rotating platform through the main unit's delivery pipeline; The grout pumping device uses a grouting pipeline to connect to the grouting nozzle, and inserts the grouting nozzle into the grouting hole; Turn on the grout pumping device to inject the grout under pressure, and monitor the grout pressure in the injection hole in real time; When the grout pressure inside the hole reaches the preset reinforcement final pressure value, stop pumping and seal the grouting hole. The grouting area is left to stand for at least 4 hours to allow the grout strength to meet the requirements for subsequent tunneling.

8. The method for pre-reinforcement of surrounding rock suitable for VBE shaft boring machines according to claim 1, characterized in that, The reinforcing mesh is made of Φ22 threaded steel, the distribution bars are made of Φ10 round steel, and the mesh spacing is 150mm×150mm.

9. A method for pre-reinforcement of surrounding rock suitable for VBE shaft boring machines according to claim 1, characterized in that, Emergency anchor bolts are long bonded mortar anchor bolts, with a length of 2.5-4 meters and a spacing of 1.0 meter × 1.0 meter, arranged in a quincunx pattern.

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