Tunnel fine blasting excavation uses front mixed abrasive water jet drilling and cutting device and operation method

Abstract

The application belongs to the technical field of drilling and provides a front-mixing abrasive water jet drilling and cutting device for fine blasting excavation of a tunnel and an operation method. The device comprises a trolley, an abrasive water jet supply system and a cooperative control system. A plurality of supports are arranged on the trolley, a plurality of valve blocks are arranged on the supports, and a water jet drill bit is arranged on each valve block. The valve blocks are connected with the abrasive water jet supply system through pipelines. After the contour hole drilling operation is completed, the water jet drill bit is used to perform transverse cutting on the single side or both sides of the rock mass of the drilled hole according to the contour design requirements. The water jet drill bit comprises a plurality of groups, each group comprising a single nozzle or two nozzles arranged side by side. The single nozzle is used to simultaneously cut the upper and lower sides of the drilled hole, and the two nozzles are used to cut different sides of adjacent drilled holes. The cooperative control system is used to control the water jet drill bit, the abrasive water jet supply system and a rotating mechanism to control the drilling parameters and realize drilling and cutting. The application realizes efficient drilling and directional low-disturbance accurate blasting.

Description

Technical Field

[0001] This invention belongs to the field of drilling technology, specifically relating to a pre-mixed abrasive waterjet drilling and cutting device and its operation method for precision blasting excavation of tunnels. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Currently, blasting is the mainstream method for tunnel face excavation. While this method offers high construction efficiency and allows for rapid hard rock breaking and excavation, its inherent uncontrollable energy release of explosives makes it difficult to precisely control the blasting range. This easily leads to over-excavation or under-excavation around the tunnel face. Over-excavation wastes surrounding rock and increases the cost of support materials, while under-excavation requires secondary manual chiseling, wasting manpower and delaying the construction period. Both significantly increase the overall cost of tunnel construction. Furthermore, traditional blasting generates significant vibrations, causing severe damage to the surrounding rock and affecting the long-term stability of the tunnel.

[0004] To compensate for the lack of precision in traditional blasting methods, the industry often uses contour hole drilling to assist in precise blasting. However, existing drilling and cutting equipment generally suffers from insufficient angle adjustment flexibility and poor adaptability. In addition, contour hole drilling involves a large workload and complicated construction procedures, resulting in low overall drilling efficiency and difficulty in adapting to the complex construction conditions near the tunnel wall edge at the tunnel face. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a premixed abrasive waterjet drilling and cutting device and operating method for precision blasting excavation of tunnels. This invention utilizes premixed high-pressure abrasive jet to assist drilling, and premixed high-pressure abrasive waterjet to cut and guide blasting energy to isolate vibration, thereby achieving efficient drilling and directional, low-disturbance, and precise blasting.

[0006] According to some embodiments, the present invention adopts the following technical solution: A pre-mixed abrasive waterjet drilling and cutting device for precision blasting excavation of tunnels includes a trolley, an abrasive jet supply system, and a collaborative control system, wherein: The trolley is equipped with several supports, and several valve blocks are mounted on the supports. Each valve block is equipped with a jet drill bit, and a rotating mechanism is mounted on the valve block to adjust the setting angle of the jet drill bit. The valve block is connected to the abrasive jet supply system via pipelines; After the contour hole drilling is completed, a jet drill bit is used to cut the rock mass on one or both sides of the hole laterally according to the contour design requirements. The jet drill bit includes several groups, each group including a single nozzle or two nozzles arranged side by side. The single nozzle is used to cut the upper and lower sides of the drill hole simultaneously, and the two nozzles are used to cut different sides of adjacent drill holes. The collaborative control system is used to control the jet drill bit, the abrasive jet supply system, and the rotating mechanism to control the drilling parameters and achieve drilling and cutting.

[0007] As an alternative implementation, the jet drill bit includes a T-shaped nozzle with two cutting surfaces, a horizontal one and a vertical one, and the T-shaped nozzle is connected to a valve block via a high-pressure pipeline.

[0008] As an alternative implementation, the jet drill bit includes an L-shaped nozzle, which includes two horizontally spaced nozzles. Each nozzle is connected to a valve block in parallel via a high-pressure pipeline. The two nozzles have a spacing greater than a set value and are used to cut one side of two adjacent boreholes, respectively.

[0009] As an alternative implementation, the trolley includes several layers for housing the motor and power system, and a support rod is provided at the top of the trolley.

[0010] As an alternative implementation, a moving mechanism is also included, on which the abrasive jet supply system is mounted, so that the abrasive jet supply system moves with the drilling rig.

[0011] As an alternative implementation, the drilling parameters include drilling depth, retraction speed, jet pressure, abrasive concentration, and cutting angle. The collaborative control system is used to control the drilling parameters according to a preset contour surface cutting path.

[0012] An abrasive jet cutting system for tunnel excavation includes the aforementioned drilling and cutting device and a rock drill, wherein the rock drill is equipped with a water jet mechanism. Using a rock drill, peripheral holes are drilled along the designed positions on the outer contour of the tunnel face to complete the contour hole drilling operation; After the contour hole drilling is completed, the jet drill bit of the drilling and cutting device is used to cut the rock mass on one or both sides of the hole laterally according to the contour design requirements. Drilling and cutting operations are completed sequentially along the outer contour of the working face for each peripheral eye. The cutting gaps between adjacent drill holes are interconnected, eventually forming a complete closed contour gap.

[0013] As an alternative implementation, the end of the rock drill is detachably equipped with a direct-jet drill bit, which is provided with a plurality of water jet nozzles and is connected to the rotation center via a drill rod.

[0014] As a further defined embodiment, the direct injection drill bit adopts a straight jet structure with the jet direction forward, and is used for mechanized drilling operations of the face contour hole. The end of the direct injection drill bit is provided with a single nozzle or annular multi-nozzle structure. The direct injection drill bit and the drill rod adopt a quick-connect structure, and the internal flow channel of the direct injection drill bit is lined with a wear-resistant material.

[0015] The operation method based on the above system includes the following steps: Using a rock drill, peripheral holes are drilled along the designed location of the outer contour of the tunnel face. During the drilling stage, a direct-jet drill bit is used with the jet direction forward to complete the contour hole drilling operation. After the contour hole drilling is completed, the jet drill bit of the drilling and cutting device is used to cut the rock mass on one or both sides of the hole laterally according to the contour design requirements. Drilling and cutting operations are completed sequentially along the outer contour of the working face for each peripheral eye. The cutting gaps between adjacent drill holes are interconnected, eventually forming a complete closed contour gap. Directional blasting is carried out at a predetermined position on the tunnel face, using the closed contour crack as the blasting boundary.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention integrates water jet-assisted drilling function into the existing rock drill. It uses high-pressure water jet to assist mechanical rock drilling, realizing the mechanization upgrade of manual drilling, significantly reducing the labor intensity of manual drilling, improving drilling efficiency, and at the same time, the water jet plays a role in cooling the drill bit, removing slag, assisting in crushing, extending the life of the drill bit, improving drilling accuracy, and providing an accurate benchmark for subsequent cutting and blasting.

[0017] This invention provides two types of abrasive jet drill bit structures. The T-shaped nozzle enables a single cut to both the top and bottom sides of a drill hole, while the L-shaped nozzle enables simultaneous cutting of two drill holes. The cutting angle can be dynamically adjusted to meet the forming requirements of complex curved surface contours at the tunnel face. The drill bit and drill rod adopt a quick-connect structure, which supports drill bit replacement in a short time. This invention solves the technical problems of traditional unidirectional jets being unable to achieve lateral cutting and low equipment switching efficiency.

[0018] The trolley of this invention is equipped with a rotary joint to support the drilling rig to rotate at multiple angles. It is provided with several support layers to house the motor, power system and fixed actuators to ensure operational stability. In addition, a support rod is added to the top of the trolley to enhance overall rigidity, prevent shaking during operation and improve drilling and cutting accuracy.

[0019] This invention integrates the abrasive jet supply system onto an independent mobile mechanism, which can move with the drilling rig, facilitating on-site setup and relocation operations.

[0020] This invention first completes jet cutting between the peripheral holes at the tunnel face to form a complete closed contour fracture, and then performs explosive blasting in the slotted holes and auxiliary holes. During blasting, the peripheral holes are not loaded with explosives or are loaded with very little explosives, and the fracture is guided only by the pre-formed fractures. The peripheral holes can be loaded with no explosives or with very little explosives, which greatly reduces the damage of blasting vibration to the surrounding rock, while saving explosive costs and achieving true smooth blasting.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0023] Figure 1 This is a schematic diagram of a trolley structure according to one embodiment; Figure 2 A schematic diagram of a T-shaped nozzle according to one embodiment; Figure 3 A schematic diagram of an L-shaped nozzle according to one embodiment; Figure 4 This is a structural diagram of a rock drill according to one embodiment; Figure 5 This is a schematic diagram of the internal structure of an L-shaped nozzle according to one embodiment; Figure 6 This is a schematic diagram of the internal structure of a T-shaped nozzle according to one embodiment.

[0024] The components include: 1. Nozzle, 2. High-pressure hard pipe, 3. Connector, 4. Valve block, 5. Cart, 6. Direct injection drill bit, and 7. Drill rod. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] Where there is no conflict, the embodiments and features described in this application may be combined with each other.

[0029] Example 1 A pre-mixed abrasive waterjet drilling and cutting device for precision blasting excavation of tunnels, such as Figure 1 As shown, it includes a trolley 5, an abrasive jet supply system, and a collaborative control system, wherein: The trolley 5 is equipped with several supports, and several valve blocks 4 are mounted on the supports. Each valve block 4 is equipped with a jet drill bit, and the valve block 4 is equipped with a rotating mechanism to adjust the setting angle of the jet drill bit. The valve block 4 is connected to the abrasive jet supply system via a pipeline; After the contour hole drilling is completed, a jet drill bit is used to cut the rock mass on one or both sides of the hole laterally according to the contour design requirements. The jet drill bit includes several groups, each group including a single nozzle 1 or two nozzles 1 arranged side by side. The single nozzle 1 is used to cut the upper and lower sides of the drill hole simultaneously, and the two nozzles 1 are used to cut different sides of adjacent drill holes. The collaborative control system is used to control the jet drill bit, the abrasive jet supply system, and the rotating mechanism to control the drilling parameters and achieve drilling and cutting.

[0030] In this embodiment, based on the different nozzle types and supply methods, there are two structural schemes: Option 1: T-shaped nozzle (single-pipe supply) The nozzle is T-shaped, cutting through the hole from top to bottom in a single cut. The actuator is a single pipe (with an internal high-pressure rigid pipe supplying power). The specific structure is as follows: Figure 2 As shown, nozzle 1 is connected to connector 3 via high-pressure rigid pipe 2, and then to valve block 4. Figure 6 As shown, the nozzle contains two vertically arranged pipes that form a connected T-shape, providing jets to the nozzles at both ends of the horizontally arranged pipes.

[0031] Option 2: L-shaped nozzle (dual-pipe supply) The overall shape of the implementing agency is C-shaped, such as Figure 3 As shown, it includes two L-shaped nozzles arranged side by side with a certain distance between them. Each L-shaped nozzle 1 is connected to a connector 3 via a high-pressure rigid pipe 2. The two connectors 3 are connected by a pipeline, and the pipeline is connected to a valve block 4. Figure 5 As shown, the nozzle contains two vertically arranged pipes that form a connected L-shape to provide a jet for the nozzle located at the end of the horizontally arranged pipe.

[0032] The L-shaped nozzle is used to cut two adjacent holes. Only one side of a hole can be cut. The other side is cut after moving the actuator.

[0033] Both designs enable rapid connection between the drill bit body and the drill rod, supporting quick switching between drilling and cutting operations. The internal flow channels of the drill bit are lined with a wear-resistant material to withstand long-term abrasive jet erosion.

[0034] like Figure 1 As shown, there can be multiple valve blocks 4, some of which are connected to T-shaped nozzles and some of which are connected to L-shaped nozzles.

[0035] In this embodiment, the trolley structure is equipped with multiple valve blocks 4, and the valve blocks 4 are equipped with a rotating mechanism to support multi-angle rotation, so as to meet the drilling and cutting requirements at different positions of the contour surface.

[0036] In this embodiment, the rotating mechanism consists of a rotatable bolt and nut. The bolt extends into the valve block 4, and a high-pressure rigid pipe 2 is installed through the valve block 4. By loosening the bolt, the high-pressure rigid pipe 2 is released, and the angle of the high-pressure rigid pipe 2 is rotated until a suitable angle is reached. Then, by tightening the bolt, the surface of the high-pressure rigid pipe 2 is pressed to fix the angle, thus achieving fine-tuning of the angle.

[0037] The trolley 5 is equipped with two layers of support. The first layer houses the motor and power system, while the second layer secures the actuators (drill rod, drill bit, angle fine-tuning mechanism, etc.) to ensure operational stability.

[0038] A support rod is added to the top of trolley 5 to enhance the overall rigidity of the trolley, prevent swaying or deviation during operation, and improve drilling and cutting accuracy.

[0039] like Figure 3 As shown, in this embodiment, the abrasive jet supply system includes a supply pipeline, an abrasive tank, a mixing chamber, and a control system. The abrasive tank adopts a pressure tank structure and achieves a stable supply of abrasive through compressed air. The abrasive supply amount is precisely controlled by a metering valve. The mixing chamber fully mixes the abrasive and high-pressure water before entering the drill bit to form a uniform abrasive water jet, ensuring cutting efficiency and stability. The control system is used to control the switching on and off of the abrasive jet supply system.

[0040] The abrasive tank is connected to each valve block 4 via a feed pipeline.

[0041] In this embodiment, the abrasive jet supply system also integrates an automatic sand-adding function, which adopts the following two methods: Gravity free fall type: The abrasive is naturally dropped from the storage tank to the supply pipeline by gravity. It has a simple structure, high reliability, and is suitable for high-flow continuous feeding scenarios.

[0042] Pneumatic feeding system: The abrasive is blown into the mixing chamber by compressed air. The feeding speed is controllable and flexible, and it is suitable for scenarios with high feeding accuracy requirements.

[0043] Both methods can be used individually or in combination according to construction needs, ensuring the stability, continuity and controllability of abrasive supply, reducing manual sand addition operations and lowering labor intensity.

[0044] In this embodiment, the high-pressure jet system (including high-pressure pump set, abrasive tank, control system, etc.) is integrated onto a separate flatbed truck. The flatbed truck can move with the drilling rig, facilitating on-site setup and relocation. The flatbed truck adopts a modular design, allowing for quick disassembly and assembly according to construction needs, thus improving system mobility.

[0045] The collaborative control system in this embodiment is integrated into the drilling rig control platform to coordinate parameters such as drilling depth, retraction speed, jet pressure, abrasive concentration, and cutting angle. Based on the preset contour surface cutting path, it supports one-click automatic operation, reduces human operation errors, and improves operation consistency.

[0046] The specific formula is as follows: ; Where h is the depth of the tunnel surrounding rock cut (mm / cm). P is the premixed high-pressure abrasive jet pressure (MPa). C represents the abrasive mass concentration (wt% or g / L); V is the nozzle retraction speed (mm / s or cm / min); K is the comprehensive working condition coefficient (related to the uniaxial compressive strength of the rock, nozzle diameter, target distance, and abrasive particle size, and is calibrated on site). a, b, and c are the nanoscale indices, determined through experimental fitting.

[0047] Example 2 An abrasive jet cutting system for tunnel excavation includes a drilling and cutting device and a rock drill as provided in Embodiment 1, wherein the rock drill is equipped with a water jet mechanism. Using a rock drill, peripheral holes are drilled along the designed positions on the outer contour of the tunnel face to complete the contour hole drilling operation; After the contour hole drilling is completed, the jet drill bit of the drilling and cutting device is used to cut the rock mass on one or both sides of the hole laterally according to the contour design requirements. Drilling and cutting operations are completed sequentially along the outer contour of the working face for each peripheral eye. The cutting gaps between adjacent drill holes are interconnected, eventually forming a complete closed contour gap.

[0048] In this embodiment, as Figure 4As shown, a water jet-assisted drilling function is integrated into a rock drill. High-pressure water jets assist mechanical rock drilling, significantly reducing the labor intensity of manual drilling and improving drilling efficiency. This mechanism enables coordinated operation of the rock drill and water jet. During drilling, the water jet cools the drill bit, removes slag, and assists in rock breaking, effectively extending drill bit life and increasing drilling speed.

[0049] The direct-jet drill bit 6 adopts a straight-jet structure with the jet direction forward, used for mechanized drilling of contour holes at the tunnel face. The drill bit end is equipped with a single nozzle or a ring-shaped multi-nozzle structure for efficient drilling. The drill bit body and drill rod 7 adopt a quick-connect structure, and the internal flow channels of the drill bit are lined with wear-resistant material to withstand long-term abrasive jet erosion.

[0050] The angle fine-tuning mechanism is located between the drilling rig's rotation center and the drill rod 7. It adopts a worm gear or hydraulic drive structure and can achieve precise fine-tuning of the drilling angle of the drill bit during the retraction process.

[0051] The angle fine-tuning mechanism integrates an angle sensor and a closed-loop control system. Operators can preset the drilling angle through the control platform, and the system automatically adjusts and locks the angle. The mechanism has a self-locking function to ensure that the angle remains stable during drilling and to prevent angle deviation due to vibration or recoil.

[0052] Example 3 Based on Embodiment 1 and Embodiment 2, a drilling and cutting integrated operation method is provided, which adopts a continuous operation mode of "drilling first and then cutting, one machine for two purposes". The specific steps are as follows: Step 1: Water jet-assisted drilling with rock drill A rock drill with integrated water jet assistance was used to drill peripheral holes along the designed locations on the outer contour of the tunnel face. Water jet-assisted drilling reduces manual labor intensity, improves drilling efficiency, and precisely controls the drilling depth, angle, and spacing according to design requirements.

[0053] Based on the design parameters of the tunnel face's outer contour, the rock drill is operated to mechanically drill holes along the designed positions of the peripheral holes. Using a direct-jet drill bit, the jet direction is forward to complete the contour hole drilling operation. The drilling depth, angle, and spacing are all precisely controlled according to design requirements, providing an accurate benchmark for subsequent cutting.

[0054] Step 2: Quick Drill Bit Switching After all contour hole drilling is completed, jet drill bits are installed on the trolley, and either a T-shaped nozzle (single-pipe supply) or an L-shaped nozzle (dual-pipe supply) solution is selected according to construction requirements.

[0055] Step 3: Retract the jet drill bit for transverse cutting. Insert the T-shaped or L-shaped jet drill bit into the drilled hole, start the rotating mechanism, and adjust the cutting angle according to the contour design requirements. Start the jet pump set and abrasive supply system to output abrasive water jets. During the drilling rig's retraction process, the jets on both sides of the drill bit perform transverse cutting of the rock mass on both sides of the borehole.

[0056] The cutting methods are the same for both schemes: T-shaped nozzle: Cuts both the top and bottom sides of a drill hole in one go.

[0057] L-shaped nozzle: A single drill hole can only cut one side adjacent to it. The actuator needs to be moved to the adjacent drill hole to cut the other side. Eventually, the cutting cracks of the two drill holes are connected to each other.

[0058] Step 4: Crack Closure and Contour Shaping Drilling and cutting operations were carried out sequentially along the outer contour of the tunnel face, with the cutting fractures between adjacent drill holes interconnecting to ultimately form a complete closed contour fracture. This fracture effectively isolated the core blasting zone of the tunnel face from the surrounding rock, providing a precise energy release boundary for subsequent blasting.

[0059] Step 5: Coordinated blasting operation Using closed contour fissures as the blasting boundary, explosives are placed at predetermined positions on the tunnel face. Peripheral holes may be unloaded or lightly loaded, relying on pre-fabricated fissures for guided fracturing. During blasting, the fissures guide the explosive energy to be released directionally along the designed contour surface, effectively suppressing the disorderly diffusion of energy into the surrounding rock, achieving a low-vibration, high-precision smooth blasting effect, and fundamentally solving the problems of over-excavation / under-excavation and excessive vibration during blasting.

[0060] Example 4 This method for precise shaping and excavation of the tunnel face outline is specifically designed for scenarios involving precise shaping and excavation of the tunnel face outline (with assisted blasting). The specific operational steps are as follows: Drill bit adaptation: Replace the original drill bit with a T-shaped jet drill bit. The double-sided jet structure of this drill bit can realize the jet beam to spray and cut on both sides, which matches the construction requirements of transverse cutting of the outer contour of the tunnel face.

[0061] Outline hole drilling: Based on the design parameters of the outer contour of the tunnel face, the drilling rig is controlled to mechanically drill outline holes on the edge of the face. No manual intervention is required throughout the process, reducing labor costs. Moreover, the drilling accuracy can match the outline design requirements, laying the foundation for subsequent prefabricated crack cutting.

[0062] Hole retraction and cutting: After the drilling operation is completed, the drilling machine is operated to perform hole retraction. During the hole retraction process, the cutting angle of the T-shaped jet drill bit is finely adjusted according to the contour design requirements. The jet pump group is turned on to output premixed abrasive water jet. The drill bit's double-sided jets are used to perform transverse cutting of the drill hole on the face, forming continuous and regular prefabricated cracks at the outer contour of the face.

[0063] Collaborative blasting: Using pre-fabricated fissures as blasting boundaries as guidance, explosives are placed at predetermined locations on the working face and blasting is carried out. The pre-fabricated fissures can constrain the propagation range of the explosive energy, preventing the explosive energy from spreading irregularly to the periphery of the working face, and effectively controlling and reducing over-excavation and under-excavation around the working face.

[0064] By using a coordinated drilling-cutting-blasting operation, the forming accuracy of the tunnel face's outer contour is improved, significantly reducing subsequent construction costs caused by over- or under-excavation. At the same time, the integrated drilling and cutting operation improves overall construction efficiency and meets the needs of continuous tunnel construction.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art without creative effort within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pre-mixed abrasive waterjet drilling and cutting device for precision blasting excavation of tunnels, characterized in that, This includes a trolley, an abrasive jet supply system, and a collaborative control system, among which: The trolley is equipped with several supports, and several valve blocks are mounted on the supports. Each valve block is equipped with a jet drill bit, and a rotating mechanism is mounted on the valve block to adjust the setting angle of the jet drill bit. The valve block is connected to the abrasive jet supply system via pipelines; After the contour hole drilling is completed, a jet drill bit is used to cut the rock mass on one or both sides of the hole laterally according to the contour design requirements. The jet drill bit includes several groups, each group including a single nozzle or two nozzles arranged side by side. The single nozzle is used to cut the upper and lower sides of the drill hole simultaneously, and the two nozzles are used to cut different sides of adjacent drill holes. The collaborative control system is used to control the jet drill bit, the abrasive jet supply system, and the rotating mechanism to control the drilling parameters and achieve drilling and cutting.

2. The pre-mixed abrasive waterjet drilling and cutting device for precision blasting excavation of tunnels as described in claim 1, characterized in that, The jet drill bit includes a T-shaped nozzle with two cutting surfaces, a horizontal one and a vertical one, and the T-shaped nozzle is connected to a valve block via a high-pressure pipeline.

3. The pre-mixed abrasive waterjet drilling and cutting device for precision blasting excavation of tunnels as described in claim 1, characterized in that, The jet drill bit includes an L-shaped nozzle, which comprises two horizontally spaced nozzles. Each nozzle is connected to a valve block via a high-pressure pipeline. The two nozzles have a spacing greater than a set value and are used to cut one side of two adjacent boreholes respectively.

4. The pre-mixed abrasive waterjet drilling and cutting device for precision blasting excavation of tunnels as described in claim 1, characterized in that, The trolley includes several layers for housing the motor and power system, and a support rod is provided at the top of the trolley.

5. The pre-mixed abrasive waterjet drilling and cutting device for precision blasting excavation of tunnels as described in claim 1, characterized in that, It also includes a moving mechanism on which the abrasive jet supply system is mounted, so that the abrasive jet supply system moves with the drilling rig.

6. The pre-mixed abrasive waterjet drilling and cutting device for precision blasting excavation of tunnels as described in claim 1, characterized in that, The drilling parameters include drilling depth, retraction speed, jet pressure, abrasive concentration, and cutting angle. The collaborative control system is used to control the drilling parameters according to the preset contour surface cutting path.

7. An abrasive jet cutting system for tunnel excavation, characterized in that, Includes the drilling and cutting device and rock drill as described in any one of claims 1-6, wherein the rock drill is provided with a water jet mechanism; Using a rock drill, peripheral holes are drilled along the designed positions on the outer contour of the tunnel face to complete the contour hole drilling operation; After the contour hole drilling is completed, the jet drill bit of the drilling and cutting device is used to cut the rock mass on one or both sides of the hole laterally according to the contour design requirements. Drilling and cutting operations are completed sequentially along the outer contour of the working face for each peripheral eye. The cutting gaps between adjacent drill holes are interconnected, eventually forming a complete closed contour gap.

8. The abrasive jet cutting system for tunnel excavation as described in claim 7, characterized in that, The rock drill is detachably equipped with a direct-jet drill bit at its end. The direct-jet drill bit is equipped with several water jet nozzles and is connected to the rotation center via a drill rod.

9. The abrasive jet cutting system for tunnel excavation as described in claim 8, characterized in that, The direct-injection drill bit adopts a straight jet structure with the jet direction forward, and is used for mechanized drilling of the contour hole of the working face. The end of the direct-injection drill bit is equipped with a single nozzle or annular multi-nozzle structure. The direct-injection drill bit and the drill rod adopt a quick-connect structure, and the internal flow channel of the direct-injection drill bit is lined with a wear-resistant material.

10. A method of operation based on the system according to any one of claims 7-9, characterized in that, Includes the following steps: Using a rock drill, peripheral holes are drilled along the designed location of the outer contour of the tunnel face. During the drilling stage, a direct-jet drill bit is used with the jet direction forward to complete the contour hole drilling operation. After the contour hole drilling is completed, the jet drill bit of the drilling and cutting device is used to cut the rock mass on one or both sides of the hole laterally according to the contour design requirements. Drilling and cutting operations are completed sequentially along the outer contour of the working face for each peripheral eye. The cutting gaps between adjacent drill holes are interconnected, eventually forming a complete closed contour gap. Directional blasting is carried out at a predetermined position on the tunnel face, using the closed contour crack as the blasting boundary.

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