A method for constructing hard rock tunnels using water-jet drilling combined with hydraulic splitting

Abstract

This invention discloses a hard rock tunnel construction method combining water-jet drilling and hydraulic fracturing, comprising: S1. Construction preparation, including surveying and design, equipment preparation, and site layout; S2. Pre-fracturing drilling along the tunnel outline, using a water-jet drilling rig to drill pre-fracturing holes along the inner side of the excavation outline, with simultaneous sampling and analysis to verify rock mass parameters; S3. Hydraulic fracturing at the tunnel face, after safety preparation, starting the hydraulic fracturing equipment to directionally fracture the rock mass, followed by secondary crushing and muck removal; S4. Cleaning and circulation of the working face, repeating steps S2 to S3 after muck removal, forming a cyclical operation of "drilling-fracturing-muck removal" until tunnel breakthrough, with quality control implemented throughout. This invention successfully integrates the flexibility and economy of blasting methods with the safety and controllability of TBM methods through the organic combination of "mechanical drilling pre-fracturing" and "hydraulic static fracturing," effectively overcoming the disadvantages of the former (high risk and poor precision) and the latter (high cost and insufficient adaptability to hard rock).

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction technology, specifically relating to a tunnel construction method based on water-jet drilling and rock-breaking with rock splitters under hard rock geological conditions, which is suitable for the construction of hard rock tunnels with various cross-sectional shapes. Background Technology

[0002] Currently, based on the different geological conditions through which tunnels pass and the current development of tunnel construction technology, the main tunnel construction methods are as follows:

[0003] 1) Hard rock tunnels generally employ mining methods (drill and blast) and tunnel boring machine (TBM) methods. Mining methods are further divided into traditional mining methods and the New Austrian Tunneling Method (NATM). Traditional mining methods involve drilling and blasting excavation with steel and timber supports. TBM methods utilize cutting tools to mechanically break up rock to excavate tunnels, and then transport the broken rock fragments out of the machine. This combined excavation and muck removal operation allows for continuous tunneling.

[0004] 2) Shallow-buried and soft-soil tunnels generally employ open-cut, cut-and-cover, shallow-buried tunneling, and shield tunneling methods. The shield tunneling method uses a steel-framed movable protective device or support to construct tunnels through weak aquifers, particularly riverbeds, seabeds, and urban centers. Under its protection, the tunnel head can safely excavate the strata, with a single excavation equivalent to the width of one ring of prefabricated lining. The tail section can be fitted with prefabricated segments or blocks, quickly assembling them into the permanent tunnel lining. The gaps between the lining and the soil are then filled with cement grout to prevent further deformation of the surrounding strata and an increase in surrounding rock pressure. The open-cut method involves excavating the ground surface, cutting earth and rock from top to bottom to the design elevation, then constructing the tunnel from bottom to top from the foundation to complete the main tunnel structure, and finally backfilling the pit or restoring the ground surface.

[0005] 3) Underwater tunnels generally use the submerged method and the shield tunneling method.

[0006] Currently, in mountain tunnel construction, traditional mining methods mainly rely on explosive blasting. Due to the complex geology and environment inside the tunnel, blasting often carries high risks. Moreover, explosive blasting makes it difficult to control the excavation volume, leading to frequent over-excavation and under-excavation. In addition, blasting has a severe impact on the tunnel environment, seriously damaging the working environment of workers, making it difficult to achieve green construction, and posing challenges to the occupational health and safety of workers. As for tunnel boring machine (TBM) construction, its costs, including transportation, assembly, and dismantling, are high, resulting in high initial investment. It is not suitable for short tunnels, and it is difficult to change the excavation diameter and shape during construction. The cutterhead customization is limited by the tunnel cross-section. For hard rock with a strength exceeding 200 MPa, the cost of cutting tools increases dramatically, and the excavation speed and efficiency are also low. Summary of the Invention

[0007] This invention provides a hard rock tunnel construction method combining water-jet drilling and splitting to solve the technical problems existing in the prior art. This method can improve the efficiency and safety of hard rock tunnel construction, while also reducing construction costs.

[0008] The technical solution adopted by this invention to solve the technical problems existing in the prior art is: a hard rock tunnel construction method combining water-jet drilling and hydraulic splitting, comprising the following steps:

[0009] S1. Construction Preparation

[0010] (1) Exploration and scheme design: Based on the geological exploration results, complete the construction scheme design and determine the key parameters for water-jet drilling and hydraulic splitting construction;

[0011] (2) Equipment and material preparation: Prepare all construction equipment and consumables, including water-grinding drilling rig, hydraulic splitting system, down-the-hole drilling rig and rock sampler;

[0012] (3) Site layout: Plan the construction site and set up safety protection facilities and warning signs;

[0013] S2. Tunnel outline pre-splitting drilling construction

[0014] Pre-splitting holes are drilled along the inner side of the designed excavation outline at the tunnel face to create a regular free face for splitting the core rock mass. Specifically, this includes:

[0015] (1) Measurement and positioning: The location of the pre-splitting holes is measured at the working face, and the drilling direction is perpendicular to the working face or adjusted according to the joint orientation of the rock strata;

[0016] (2) Drilling operation: Drilling is carried out using a water-powered drilling machine according to the designed hole position, depth and angle;

[0017] (3) Rock sample analysis and parameter verification: Rock cores are collected synchronously during drilling to determine the physical and mechanical properties of the rock, which are used to verify or dynamically adjust subsequent splitting parameters;

[0018] S3. Hydraulic fracturing at the tunnel face

[0019] (1) Splitting preparation: Conduct a safety assessment and site clearing at the working face, and inspect and install the hydraulic splitting equipment;

[0020] (2) Implement splitting: Start the hydraulic splitting equipment and apply a controllable splitting force to the rock mass to be split, so that it splits in the predetermined direction;

[0021] (3) Crushing and slag removal: The large rock blocks generated by splitting are crushed a second time, and the slag is removed from the tunnel;

[0022] S4. Work surface cleaning and cyclical operation

[0023] (1) Slag removal and cleaning: Remove the crushed stone from the site and clean up the residue on the work surface to create conditions for the next cycle;

[0024] (2) Cyclic construction: Repeat steps S2 to S3 to form a continuous operation cycle of “contour pre-splitting drilling → hydraulic splitting → slag removal” until the tunnel is completed;

[0025] (3) Full-process quality control: In each construction cycle, the drilling accuracy, splitting effect, blasting block size and contour forming quality are monitored and inspected to ensure compliance with design and safety specifications.

[0026] Based on the above solution, the present invention has made the following improvements:

[0027] Step S3 is internal splitting, specifically including the following steps:

[0028] Construction of the main rock-breaking hole in the middle of the S3.1 tunnel face

[0029] (1) Measurement and positioning: In the central area of ​​the working face, accurately locate the position, inclination angle and depth of the main rock-breaking hole;

[0030] (2) Drilling and cleaning: Drilling is completed using a water-powered drilling machine according to the design parameters. Drilling parameters are adjusted in real time to adapt to changes in the rock strata. After drilling is completed, high-pressure air or water is used to thoroughly clean the hole.

[0031] S3.2 In-hole hydraulic fracturing operation

[0032] (1) Installation of splitting rods: Insert the hydraulic splitting rods into the cleaned borehole and reliably connect them to the hydraulic pump station; the diameter, number and spacing of the splitting rods need to be determined according to the rock strength, joint condition and hole depth.

[0033] (2) Implementing splitting: Start the hydraulic pump station, apply pressure in stages and slowly, and cause the rock to undergo tensile fracture along the line of least resistance through the radial expansion of the splitting rod;

[0034] (3) Secondary crushing and slag removal: The large rocks formed by splitting are subjected to secondary crushing using hydraulic breakers, and then the slag is removed from the tunnel using excavation and transportation equipment.

[0035] Step S3 is surface splitting, specifically including the following steps:

[0036] S3.1 Construction Preparation and Working Surface Treatment

[0037] (1) Site assessment and clearing: Assess the rock mass to be split, clear the working surface, and ensure that there are no personnel or equipment within the working radius;

[0038] (2) Equipment inspection: Inspect the hydraulic splitting rod, hydraulic pump station and pipelines to confirm that the equipment is in good condition and the operators are qualified after training;

[0039] (3) Surface treatment: Clean and level the rock surface at the designed splitting location, and chisel guide grooves if necessary to provide a stable base for installation;

[0040] S3.2 Surface hydraulic splitting construction

[0041] (1) Equipment installation: Align the jaws or anchoring device of the splitting bar clamp and securely install it on the pre-treated working surface;

[0042] (2) Connection and splitting: Reliably connect the hydraulic pipeline, start the pump station and pressurize in stages and slowly, and generate tensile stress through the expansion of the splitting rod to split the rock mass;

[0043] (3) Process monitoring: Monitor the pressure and cracking during the pressurization process, and make adjustments as necessary to ensure that the cracking proceeds in the predetermined direction;

[0044] (4) Secondary treatment and removal: The large rock mass generated by splitting is crushed and removed in a secondary manner. After completion, the system is depressurized, the equipment is disassembled and the site is cleaned up.

[0045] In steps S2 and S3.1, the water-powered drilling machine is mounted on a special trolley for drilling operations. The trolley includes:

[0046] The trolley frame is equipped with an operating platform;

[0047] The track system includes a vertical track fixed in front of the trolley frame, a transverse track slidably connected to the vertical track, and telescopic adjustable tracks located at both ends of the transverse track and slidable along it. Each track is equipped with a locking structure.

[0048] The positioning actuator includes a support arm mounted on a telescopic adjustment rail and a rotating shaft at its end, on which the water-grinding drill is mounted;

[0049] The drive and safety system includes the drive system that provides power to the various moving parts of the trolley, and the safety devices that include an emergency stop button and an overload protection device.

[0050] In steps S2 and S3.1, the water-powered drilling rig is installed as an attachment at the end of the working device of an excavator or similar tunnel construction machinery, and drilling is carried out by operating the boom system of the machinery.

[0051] The advantages and positive effects of this invention are:

[0052] Compared with the traditional drill-and-blast method, this invention:

[0053] 1. Intrinsically safe and environmentally friendly: The use of static hydraulic fracturing completely eliminates the high risks of blasting operations (such as misfires and shock waves), and also fundamentally eliminates the violent vibrations, noise and harmful gases generated by blasting, greatly improving the working environment inside the tunnel, protecting the occupational health of workers, and realizing green construction.

[0054] 2. Precise and controllable, with excellent quality: By pre-drilling holes along the design outline using a water-cooled drill, precise guidance is provided for splitting, enabling precise control of the excavation boundary and fracture direction. This effectively solves the common quality problems of over-excavation and under-excavation in blasting methods, resulting in good forming quality and contributing to the stability of the surrounding rock.

[0055] 3. Higher efficiency and lower cost: Eliminating the lengthy intervals required for complex approvals, warnings, evacuations, and hazard removal associated with blasting, it achieves a compact, streamlined operation of "drilling-splitting-slag removal," with continuous process connections and a significant increase in effective working time. Simultaneously, it avoids the additional costs of concrete backfilling and treatment due to over- or under-excavation, resulting in a more advantageous overall cost.

[0056] Compared with the tunnel boring machine (TBM) method, this invention:

[0057] 1. Highly economical and widely applicable: No need to invest in the exorbitant costs of purchasing, transporting, assembling, and maintaining TBMs. It is especially suitable for short and medium-sized tunnels, non-standard cross-section tunnels, and variable cross-section tunnels, significantly reducing investment threshold and construction costs.

[0058] 2. Overcoming the bottleneck of hard rock and achieving stable efficiency: When facing extremely hard rock with a strength exceeding 200 MPa, this method avoids the problems of drastically increased TBM cutter wear, sudden drop in tunneling efficiency, and frequent shutdowns for cutter replacement. This method employs a combination of drilling and static splitting, whose rock-breaking efficiency is less affected by rock strength, enabling it to maintain a continuous and stable tunneling speed in hard rock formations.

[0059] 3. Flexible and adaptable: Construction process parameters can be dynamically adjusted in real time according to changes in lithology, and are not limited by the size and form of fixed cutterhead. It can flexibly adapt to complex and varied geological conditions and different tunnel design sections, and its application flexibility is far higher than that of TBM.

[0060] In summary, this invention successfully integrates the flexibility and economy of blasting methods with the safety and controllability of TBM methods by organically combining "mechanical drilling pre-splitting" and "hydraulic static splitting." It effectively overcomes the shortcomings of the former (high risk and poor precision) and the latter (high cost and insufficient adaptability to hard rock), providing a novel hard rock tunnel construction solution that excels in efficiency, safety, cost, quality, and adaptability. It has significant engineering application value and promising prospects for promotion. Attached Figure Description

[0061] Figure 1This is a three-dimensional structural diagram of the drilling trolley used in this invention;

[0062] Figure 2 This is a three-dimensional structural diagram of the drilling rig used in this invention.

[0063] In the diagram: 1. Trolley frame; 2. Operating platform; 3. Track system; 31. Vertical track; 32. Horizontal track; 33. Telescopic adjustment track; 4. Drive system; 5. Safety device; 6. Water-powered drilling rig. Detailed Implementation

[0064] To further understand the invention's content, features, and effects, the following embodiments are provided, and detailed descriptions are given below in conjunction with the accompanying drawings:

[0065] Please see Figure 1 and Figure 2 A method for constructing hard rock tunnels using a combination of water-jet drilling and hydraulic fracturing, comprising the following steps:

[0066] S1. Construction Preparation

[0067] (1) Exploration and scheme design: Based on the geological exploration results, complete the construction scheme design and determine the key parameters for water-jet drilling and hydraulic splitting construction;

[0068] (2) Equipment and material preparation: Prepare all construction equipment and consumables, including water-grinding drilling rig, hydraulic splitting system, down-the-hole drilling rig and rock sampler;

[0069] (3) Site layout: Plan the construction site and set up safety protection facilities and warning signs;

[0070] S2. Tunnel outline pre-splitting drilling construction

[0071] Please see Figure 1 Pre-splitting holes are drilled along the inner side of the designed excavation outline at the tunnel face to create a regular free face for splitting the core rock mass. Specifically, this includes:

[0072] (1) Measurement and positioning: The location of the pre-splitting holes is measured at the working face, and the drilling direction is perpendicular to the working face or adjusted according to the joint orientation of the rock strata;

[0073] (2) Drilling operation: Drilling is carried out using a water-powered drilling machine according to the designed hole position, depth and angle;

[0074] (3) Rock sample analysis and parameter verification: Rock cores are collected synchronously during drilling to determine the physical and mechanical properties of the rock, which are used to verify or dynamically adjust subsequent splitting parameters;

[0075] S3. Hydraulic fracturing at the tunnel face

[0076] (1) Splitting preparation: Conduct a safety assessment and site clearing at the working face, and inspect and install the hydraulic splitting equipment;

[0077] (2) Implement splitting: Start the hydraulic splitting equipment and apply a controllable splitting force to the rock mass to be split, so that it splits in the predetermined direction;

[0078] (3) Crushing and slag removal: The large rock blocks generated by splitting are crushed a second time, and the slag is removed from the tunnel;

[0079] S4. Work surface cleaning and cyclical operation

[0080] (1) Slag removal and cleaning: Remove the crushed stone from the site and clean up the residue on the work surface to create conditions for the next cycle;

[0081] (2) Cyclic construction: Repeat steps S2 to S3 to form a continuous operation cycle of “contour pre-splitting drilling → hydraulic splitting → slag removal” until the tunnel is completed;

[0082] (3) Full-process quality control: In each construction cycle, the drilling accuracy, splitting effect, blasting block size and contour forming quality are monitored and inspected to ensure compliance with design and safety specifications.

[0083] The specific implementation method of the hydraulic fracturing construction at the tunnel face described in step S3 of this invention can be comprehensively judged and selected based on the on-site rock mass conditions, construction stage, and specific fracturing target, including the following two parallel technical solutions:

[0084] Option A: In-hole splitting

[0085] This approach is preferred when dealing with hard rock masses that are well-integrated and require large-scale fracturing. It includes the following steps:

[0086] Specifically, the following steps are included:

[0087] Construction of the main rock-breaking hole in the middle of the S3.1 tunnel face

[0088] (1) Measurement and positioning: In the central area of ​​the working face, accurately locate the position, inclination angle and depth of the main rock-breaking hole;

[0089] (2) Drilling and cleaning: Drilling is completed using a water-powered drilling machine according to the design parameters. Drilling parameters are adjusted in real time to adapt to changes in the rock strata. After drilling is completed, high-pressure air or water is used to thoroughly clean the hole.

[0090] S3.2 In-hole hydraulic fracturing operation

[0091] (1) Installation of splitting rods: Insert the hydraulic splitting rods into the cleaned borehole and reliably connect them to the hydraulic pump station; the diameter, number and spacing of the splitting rods need to be determined according to the rock strength, joint condition and hole depth.

[0092] (2) Implementing splitting: Start the hydraulic pump station, apply pressure in stages and slowly, and cause the rock to undergo tensile fracture along the line of least resistance through the radial expansion of the splitting rod;

[0093] (3) Secondary crushing and slag removal: The large rocks formed by splitting are subjected to secondary crushing using hydraulic breakers, and then the slag is removed from the tunnel using excavation and transportation equipment.

[0094] Option B: Surface splitting

[0095] This approach is preferred when modifying existing free-faced rock masses, contour surfaces, or breaking up locally protruding rock blocks. It includes the following steps:

[0096] S3.1 Construction Preparation and Working Surface Treatment

[0097] (1) Site assessment and clearing: Assess the rock mass to be split, clear the working surface, and ensure that there are no personnel or equipment within the working radius;

[0098] (2) Equipment inspection: Inspect the hydraulic splitting rod, hydraulic pump station and pipelines to confirm that the equipment is in good condition and the operators are qualified after training;

[0099] (3) Surface treatment: Clean and level the rock surface at the designed splitting location, and chisel guide grooves if necessary to provide a stable base for installation;

[0100] S3.2 Surface hydraulic splitting construction

[0101] (1) Equipment installation: Align the jaws or anchoring device of the splitting bar clamp and securely install it on the pre-treated working surface;

[0102] (2) Connection and splitting: Reliably connect the hydraulic pipeline, start the pump station and pressurize in stages and slowly, and generate tensile stress through the expansion of the splitting rod to split the rock mass;

[0103] (3) Process monitoring: Monitor the pressure and cracking during the pressurization process, and make adjustments as necessary to ensure that the cracking proceeds in the predetermined direction;

[0104] (4) Secondary treatment and removal: The large rock mass generated by splitting is crushed and removed in a secondary manner. After completion, the system is depressurized, the equipment is disassembled and the site is cleaned up.

[0105] The selection criteria include, but are not limited to: the integrity, strength, joint development, volume and location of the rock mass to be fractured, and construction efficiency and safety requirements. The two schemes can be applied independently or used in combination within the same working face depending on the rock mass conditions of different areas.

[0106] In the above-mentioned step S2, tunnel outline pre-splitting drilling, and / or step S3.1, main rock-breaking hole construction, a water-cooled drilling rig is required for drilling operations at the tunnel face. To achieve flexible adjustment and precise positioning of the drilling location, the water-cooled drilling rig can be installed in the following two ways:

[0107] Method 1: Mounted on a dedicated drilling trolley

[0108] This method is achieved by building a dedicated drilling rig. This rig provides a stable working platform for the core equipment and, through its multi-directional adjustable track system, drives the water-jet drilling rig to move in three-dimensional space, thereby accurately locating any designed hole position around the tunnel cross-section.

[0109] Please see Figures 1-2 The trolley includes:

[0110] A trolley frame 1, on which an operating platform 2 is mounted;

[0111] The track system 3 includes a vertical track 31 fixed in front of the trolley frame, a transverse track 32 slidably connected to the vertical track 31, and telescopic adjustable tracks 33 located at both ends of the transverse track and slidable along it. Each track is provided with a locking structure.

[0112] The positioning actuator includes a support arm mounted on the telescopic adjustment rail 33 and a rotating shaft at its end, on which the water mill drill 6 is mounted.

[0113] The drive and safety system includes a drive system 4 that provides power to the various moving parts of the trolley, and a safety device 5 that includes an emergency stop button and an overload protection device.

[0114] The support arm and rotating shaft are the core mechanical structures on the trolley used for precise and flexible adjustment of the water-grinding drill's spatial position. Their function can be understood as follows:

[0115] Support arm: This is essentially a telescopic and swinging mechanical arm. Its main function is to adjust the drill's position over a wide range—front-to-back, left-to-right, and up-down—to move it to the rough area where drilling is needed.

[0116] Rotary axis: Usually mounted at the end of the support arm, it is equivalent to the joint of a mechanical wrist. Its main function is to make fine adjustments to the angle and direction, ensuring that the drill rod can be precisely aligned with the hole position according to the design requirements in terms of angle and azimuth.

[0117] In short, their collaborative workflow is as follows:

[0118] Coarse adjustment of the support arm: Move the heavy drill rig from its parking position to the approximate drilling area.

[0119] Fine-tuning of the rotating shaft: Based on the positioning of the support arm, finely adjust the pitch and yaw angles of the drill rod to make it perfectly aligned with the hole position and design angle for measurement and layout.

[0120] This design avoids the difficulties of manually moving heavy drilling rigs and enables mechanized and precise control of drilling position and angle, which is a key equipment function to ensure drilling accuracy.

[0121] This structure enables water-cooled drilling rigs to be precisely positioned and stably drilled along the tunnel contour and face in three-dimensional space.

[0122] Use of the trolley:

[0123] Cart positioning and leveling: Move the car to the predetermined working area on the working face and stabilize and level it using its outrigger system.

[0124] Positioning and Drilling: The operating trolley's track system precisely moves the water-powered drill rig mounted at its end to the target hole location. After locking the position, the water-powered drill rig is started to begin drilling.

[0125] Displacement and Cycling: After a single hole is drilled, the lock is released, and the water-powered drill is quickly moved to the next hole position via the track system. The above process is repeated until all holes within the outline or cross-section are completed.

[0126] Method 2: Mounted on general construction machinery

[0127] This method uses a water-jet drilling rig as a hydraulic attachment, installed at the end of the boom of an excavator or similar multi-functional construction machinery. By controlling the boom, stick, and bucket cylinders of the construction machinery itself, the water-jet drilling rig can achieve flexible positioning and drilling operations over a wide range at the working face, making it suitable for working conditions with variable operating spaces or requiring rapid relocation.

[0128] Although preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other modifications under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these modifications are within the scope of protection of the present invention.

Claims

1. A method for constructing hard rock tunnels using a combination of water-jet drilling and hydraulic fracturing, characterized in that, The following steps are used: S1. Construction Preparation (1) Exploration and scheme design: Based on the geological exploration results, complete the construction scheme design and determine the key parameters for water-jet drilling and hydraulic splitting construction; (2) Equipment and material preparation: Prepare all construction equipment and consumables, including water-grinding drilling rig, hydraulic splitting system, down-the-hole drilling rig and rock sampler; (3) Site layout: Plan the construction site and set up safety protection facilities and warning signs; S2. Tunnel outline pre-splitting drilling construction Pre-splitting holes are drilled along the inner side of the designed excavation outline at the tunnel face to create a regular free face for splitting the core rock mass. Specifically, this includes: (1) Measurement and positioning: The location of the pre-splitting holes is measured at the working face, and the drilling direction is perpendicular to the working face or adjusted according to the joint orientation of the rock strata; (2) Drilling operation: Drilling is carried out using a water-powered drilling machine according to the designed hole position, depth and angle; (3) Rock sample analysis and parameter verification: Rock cores are collected synchronously during drilling to determine the physical and mechanical properties of the rock, which are used to verify or dynamically adjust subsequent splitting parameters; S3. Hydraulic fracturing at the tunnel face (1) Splitting preparation: Conduct a safety assessment and site clearing at the working face, and inspect and install the hydraulic splitting equipment; (2) Implement splitting: Start the hydraulic splitting equipment and apply a controllable splitting force to the rock mass to be split, so that it splits in the predetermined direction; (3) Crushing and slag removal: The large rock blocks generated by splitting are crushed a second time, and the slag is removed from the tunnel; S4. Work surface cleaning and cyclical operation (1) Slag removal and cleaning: Remove the crushed stone from the site and clean up the residue on the work surface to create conditions for the next cycle; (2) Cyclic construction: Repeat steps S2 to S3 to form a continuous operation cycle of "contour pre-splitting drilling → hydraulic splitting → slag removal" until the tunnel is completed; (3) Full-process quality control: In each construction cycle, the drilling accuracy, splitting effect, blasting block size and contour forming quality are monitored and inspected to ensure compliance with design and safety specifications.

2. The hard rock tunnel construction method combining water-jet drilling and hydraulic splitting according to claim 1, characterized in that, Step S3 is internal splitting, specifically including the following steps: Construction of the main rock-breaking hole in the middle of the S3.1 tunnel face (1) Measurement and positioning: In the central area of ​​the working face, accurately locate the position, inclination angle and depth of the main rock-breaking hole; (2) Drilling and cleaning: Drilling is completed using a water-powered drilling machine according to the design parameters. Drilling parameters are adjusted in real time to adapt to changes in the rock strata. After drilling is completed, high-pressure air or water is used to thoroughly clean the hole. S3.2 In-hole hydraulic fracturing operation (1) Installation of splitting rods: Insert the hydraulic splitting rods into the cleaned borehole and reliably connect them to the hydraulic pump station; the diameter, number and spacing of the splitting rods need to be determined according to the rock strength, joint condition and hole depth. (2) Implementing splitting: Start the hydraulic pump station, apply pressure in stages and slowly, and cause the rock to undergo tensile fracture along the line of least resistance through the radial expansion of the splitting rod; (3) Secondary crushing and slag removal: The large rocks formed by splitting are subjected to secondary crushing using hydraulic breakers, and then the slag is removed from the tunnel using excavation and transportation equipment.

3. The hard rock tunnel construction method combining water-jet drilling and hydraulic splitting according to claim 1, characterized in that, Step S3 is surface splitting, specifically including the following steps: S3.1 Construction Preparation and Working Surface Treatment (1) Site assessment and clearing: Assess the rock mass to be split, clear the working surface, and ensure that there are no personnel or equipment within the working radius; (2) Equipment inspection: Inspect the hydraulic splitting rod, hydraulic pump station and pipelines to confirm that the equipment is in good condition and the operators are qualified after training; (3) Surface treatment: Clean and level the rock surface at the designed splitting location, and chisel guide grooves if necessary to provide a stable base for installation; S3.2 Surface hydraulic splitting construction (1) Equipment installation: Align the jaws or anchoring device of the splitting bar clamp and securely install it on the pre-treated working surface; (2) Connection and splitting: Reliably connect the hydraulic pipeline, start the pump station and pressurize in stages and slowly, and generate tensile stress through the expansion of the splitting rod to split the rock mass; (3) Process monitoring: Monitor the pressure and cracking during the pressurization process, and make adjustments as necessary to ensure that the cracking proceeds in the predetermined direction; (4) Secondary treatment and removal: The large rock mass generated by splitting is crushed and removed in a secondary manner. After completion, the system is depressurized, the equipment is disassembled and the site is cleaned up.

4. The hard rock tunnel construction method combining water-jet drilling and hydraulic fracturing according to claims 1 and 2, characterized in that, In steps S2 and S3.1, the water-powered drilling machine is mounted on a special trolley for drilling operations. The trolley includes: The trolley frame is equipped with an operating platform; The track system includes a vertical track fixed in front of the trolley frame, a transverse track slidably connected to the vertical track, and telescopic adjustable tracks located at both ends of the transverse track and slidable along it. Each track is equipped with a locking structure. The positioning actuator includes a support arm mounted on a telescopic adjustment rail and a rotating shaft at its end, on which the water-grinding drill is mounted; The drive and safety system includes the drive system that provides power to the various moving parts of the trolley, and the safety devices that include an emergency stop button and an overload protection device.

5. The hard rock tunnel construction method combining water-jet drilling and hydraulic fracturing according to claims 1 and 2, characterized in that, In steps S2 and S3.1, the water-powered drilling rig is installed as an attachment at the end of the working device of an excavator or similar tunnel construction machinery, and drilling is carried out by operating the boom system of the machinery.

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