Device and method for rock breaking and tunneling based on abrasive air jet

Abstract

The present application belongs to the technical field of rock tunnel boring, and specifically discloses a tunnel boring device for breaking rock by using abrasive air jet, which comprises an air compressor, a high-pressure gas storage bottle, an abrasive tank, a rotary connecting body, a detachable conversion drill rod, an extendable arm, a hydraulic system, a slag removal system, a control room and the like. The present application uses mixed high-pressure abrasive air as medium, cuts grooves on the tunnel cross section through the rear laval nozzle of the detachable conversion drill rod, and then drills holes in the center of each grooved rock. After the drilling is completed, the rear nozzle is removed, a side-cutting conversion cover is replaced, and the drill bit is extended into the hole for rotary cutting of the rock mass. After the cutting is completed, the core bucket is controlled to shovel out the rock mass and place it on the conveyor belt for transportation, thereby realizing tunnel boring, improving the kinetic energy of the mixed abrasive gas, increasing the rock breaking rate, and improving the tunnel boring operation efficiency. The energy utilization rate is high, the problem of fast tool wear in hard rock boring is solved, and the tunnel boring cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of rock tunnel excavation technology, and particularly relates to a device and method for rock breaking tunneling based on abrasive air jet. Background Technology

[0002] Currently, tunnel boring methods are mainly divided into three types: drill-and-blast, shield tunneling, and tunneling machine (TBM) tunneling. Drill-and-blast first uses explosives to break the rock, then uses mechanical equipment to clean up the broken rock. However, this method suffers from low automation, poor safety, and environmental pollution. Shield tunneling uses a tunnel boring machine (TBM). Cutting tool wear is one of the most significant factors affecting tunneling efficiency and construction costs. Furthermore, opening the tunnel face for cutting tool replacement can easily lead to instability at the excavation face and tunnel collapse, increasing construction risks and costs. Additionally, the time spent on TBM cutting tool inspection, replacement, and cutterhead maintenance accounts for approximately 30% to 40% of the total tunneling time. TBM tunneling uses excavators and tunneling machines for excavation. It boasts advantages such as rapid construction, high quality, safety, economy, and environmental friendliness. However, this method suffers from problems such as the difficulty in producing the TBM's cutting head, rapid wear, and low energy utilization. Therefore, wear on the cutterhead of the tunnel boring machine and the cutting drill bit of the tunneling machine are the main problems inhibiting tunneling efficiency; in addition, the rock is highly fragmented and the newly added surface area is large during the tunneling process of these two methods, resulting in low energy utilization.

[0003] To improve rock-breaking efficiency, patent CN201910561800.3 discloses a "shield tunneling machine and its water jet combined with a cutting tool rock-breaking mechanism." This method first uses high-pressure water jets to cut annular slits in the rock, relieving local stress in the surrounding rock, and then uses cutting tools to break the rock. However, hard rock tunneling requires jet pressures exceeding 200 MPa, placing high demands on system equipment performance and safety, while tool wear is unavoidable. Patent CN202011011344.4 discloses a "different-shaped full-face tunneling machine suitable for hard rock strata," which uses drilling and splitting modules in each pane to enable simultaneous cutting by multiple units, resulting in high efficiency. However, this leads to high rock fragmentation and low energy utilization. Increasing the size of the broken rock blocks, improving energy utilization, and achieving bladeless rock-breaking technology are key to future tunnel excavation. Therefore, this invention proposes a rock-breaking tunneling device and method based on abrasive air jets. Summary of the Invention

[0004] The purpose of this invention is to provide a simple-to-operate, adaptable to various cross-sectional shapes, and capable of rapid tunnel excavation device and method based on abrasive air jet rock breaking.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A device for rock breaking and tunneling based on abrasive air jet includes an air compressor, a high-pressure air cylinder connected to the air compressor's outlet pipeline, the outlet of the high-pressure air cylinder connected to the air inlet of an abrasive tank via a high-pressure pipeline, and the abrasive outlet of the abrasive tank connected to a detachable convertible drill rod via an abrasive ejection pipe. The detachable convertible drill rod is movably connected to a telescopic boom via a rotating connector. The telescopic boom's extension and retraction are controlled by a control room, and its pitch angle is controlled by a hydraulic system. The detachable convertible drill rod has a rear-mounted laval nozzle or a side-cutting conversion cover at its end. The air compressor, high-pressure air cylinder, abrasive tank, control room, hydraulic system, telescopic boom, and... The detachable drill rods are integrated into the top of the chassis, which is equipped with a slewing mechanism. The chassis is driven by tracks, drive wheels, and driven wheels. At the end of the chassis, where the detachable drill rods are located, there is a hydraulically controlled bucket. The telescopic boom has a pitch angle of ±60° to ±30° and a swing angle of ±45° to ±45°. The detachable drill rods are connected to the telescopic boom via a rotating connector. The detachable drill rods can rotate 360° horizontally and axially, offering flexible operation and eliminating blind spots during construction. The telescopic boom has a three-section telescopic structure with a travel of 2.5m, a working width of 16m, a height of 11m, and a maximum coverage area of ​​154m². 2 A hydraulic system is installed below the control room, which can raise or lower the control room for better observation of the construction face. The control room controls the telescopic arm, hydraulic system, rotary connector, and detachable drill rod to perform low-pressure abrasive air jet cutting according to a preset plan, cutting a Dmm×Lmm groove on the rock surface, dividing the tunnel cross-section into multiple squares with the same side length. The detachable drill rod and rear-mounted laval nozzle are assembled, and the detachable drill rod is converted into a front-spray drill bit. The front-spray drill bit is controlled by the control room to move to the center of each square rock block to perform low-pressure abrasive air jet rotary drilling. The drilling depth is slightly larger than the groove depth, and the drilling diameter is slightly larger than the drill bit to facilitate the drill bit's operation in the hole. The detachable drill rod and side-cutting conversion cover are assembled, and the detachable drill rod is converted into a side-spray drill bit. The control room controls the telescopic arm, hydraulic system, and rotary connector to extend the detachable drill rod into the borehole for cutting.

[0007] Furthermore, the abrasive hopper includes a hopper with two abrasive barrels arranged side-by-side at its bottom. Abrasive is fed between the hopper and the barrels via a feeding pipe. The feeding pipe is equipped with a vibrating feeder and a cylinder. A collection hopper is located at the bottom of the two barrels, and a horizontal screw feeder is installed at the discharge port of the collection hopper. The screw feeder is also driven by a motor, and its end connects to a gas pipeline from a high-pressure gas cylinder, leading to an abrasive ejection pipe. Both the hopper and the collection hopper have viewing windows for observing the remaining abrasive level and replenishing it as needed. The vibrating feeder is equipped with a vibrating rod and a motor to vibrate the abrasive inside the barrels, preventing abrasive accumulation. The cylinder feeds abrasive into the barrels... A certain pressure of gas is input, which, in conjunction with a vibrating feeder, enables a continuous supply of abrasive. A screw feeder equipped with a motor transports the abrasive from the collection hopper to the gas pipeline for pre-mixing with the low-pressure gas. One end of the abrasive ejector pipe is connected to the abrasive tank, and the other end is connected to a rotating connector and fixed to a detachable conversion drill rod. High-pressure air and abrasive are pre-mixed within the ejector pipe, and high-speed gas drives the particles to the laval nozzle. The laval nozzle has a circular inlet and a 4mm × 20mm rectangular outlet. The overall structure of the laval nozzle includes a converging section and an expanding section. Gas flows under high pressure into the converging section of the nozzle, passes through a narrow throat, and escapes from the expanding section. This architecture allows the airflow velocity to vary with the nozzle cross-sectional area, accelerating the airflow from subsonic to sonic speeds, and eventually to supersonic speeds. The gas jet in the converging section accelerates to sonic speeds, and further expands and accelerates to 700 m / s in the expanding section. The hypersonic air jet accelerates the abrasive to speeds exceeding 300 m / s.

[0008] Furthermore, the detachable convertible drill rod includes a drill rod connecting end located at the front end, on which a material inlet is provided. The end of the drill rod connecting end is connected to the main drill rod via a rotating buckle. The material inlet communicates with the inner cavity of the main drill rod. A spring is provided inside the front end of the main drill rod. The end of the spring is fixedly connected to the front end of a slidable laval structure tube located inside the main drill rod. A side-mounted laval nozzle is provided on the outer wall of the end of the main drill rod. A matching hole that mates with the side-mounted laval nozzle is provided on the slidable laval structure tube. The end of the main drill rod is movably connected to the rear laval nozzle via a threaded connecting section.

[0009] Furthermore, the rear laval nozzle includes a threaded connection end at the front end and a nozzle wall, with a converging section and an expanding section sequentially arranged inside the nozzle wall.

[0010] Furthermore, the side-cut conversion cover includes a protruding tube located at the center and an internal threaded connection section sleeved at the end of the protruding tube, with the internal threaded connection section being sleeved with a replacement cover wall.

[0011] Furthermore, a first valve is provided between the air compressor and the high-pressure gas cylinder, and a pressure gauge and a second valve are provided on the pipeline between the high-pressure gas cylinder and the outlet pipeline of the screw feeder.

[0012] A tunneling method based on an abrasive air jet rock-breaking tunneling device includes the following steps:

[0013] (1) Measure the cross-sectional area of ​​the tunnel, and divide the cross-section into multiple squares based on its shape to make a planning map;

[0014] (2) The operator drives the tunneling machine, stops it in the designated position, checks the air tightness of the pipeline and interface, and closes all valves after confirming that there are no problems. He opens the inlet valve of the high pressure storage cylinder, turns on the air compressor and sets the air compressor parameters. When the pressure is 8 MPa, the air compressor stops working. When the pressure is lower than 8 MPa, it automatically pressurizes. When the pressure of the high pressure cylinder reaches 8 MPa, the inlet valve of the abrasive tank is opened and the valve outlet pressure is adjusted to 2 MPa.

[0015] (3) Turn on the motor of the screw feeder of the abrasive tank; open the hopper to feed abrasive into the right abrasive barrel, and at the same time turn on the right vibrator and cylinder; control the feeding speed of the screw feeder through the motor, and observe the remaining abrasive through the window of the collection hopper. When the abrasive in the abrasive barrel is used up, open the valve on the left side of the hopper, the vibrator on the left side and the cylinder, switch the operation of the left abrasive barrel, and realize the cyclic operation of the abrasive barrels on both sides to ensure the continuous supply of abrasive;

[0016] (4) The operator, in conjunction with the planning diagram, controls the telescopic arm, hydraulic system, and detachable drill rod to perform low-pressure abrasive air jet grooving according to the preset plan, and cuts a groove of Dmm×Lmm on the rock surface;

[0017] (5) The operator controls the drill bit to move to the center of each square rock block to perform low-pressure abrasive air jet rotary drilling. The drilling depth is greater than the cutting depth and the drilling diameter is greater than the drill bit.

[0018] (6) After completing the grooving work, turn off the air inlet valve and the motor of the abrasive tank feeder, remove the rear laval nozzle from the detachable conversion drill rod, replace the side cutting conversion cover for assembly, and convert the detachable conversion drill rod into a side spray drill bit;

[0019] (7) The operator controls the drill bit to go deeper into the borehole, and opens the air inlet valve and the motor of the abrasive can feeder again to perform low-pressure abrasive air jet rotation cutting to cut off the rock block as a whole;

[0020] (8) The operator controls the core shovel to scoop up rock blocks and place them on the conveyor belt to realize the recycling of rock blocks. Repeat steps (1)-(8) to realize abrasive air jet rock breaking tunnel excavation.

[0021] The advantages of this invention are:

[0022] 1. Based on the gas jet theory and combined with the Laval nozzle structure, this device develops a low-pressure abrasive air jet rock-breaking drill bit structure, realizing two-stage acceleration of low-pressure abrasive air jet to obtain low-pressure supersonic air jet, which improves the efficiency of hard rock tunneling.

[0023] 2. This device utilizes a telescopic boom, hydraulic system, rotating shaft, and detachable drill rod to select different cutting methods according to different cross-sections, offering flexible operation and eliminating blind spots in construction;

[0024] 3. This device is equipped with a core-sampling bucket and a conveyor belt, which enables the recycling of intact rock blocks and reduces construction costs;

[0025] 4. The laval nozzle of this device is made of hard alloy, which reduces the wear of abrasive air on the inner wall of the laval nozzle, reduces the number of laval nozzle replacements, shortens the construction cycle, and reduces construction costs. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the abrasive air jet rock-breaking tunneling device of the present invention.

[0027] Figure 2 This is a schematic diagram of the detachable and convertible drill rod structure of the present invention.

[0028] Figure 3 This is a schematic diagram of the rear-mounted laval nozzle structure of the present invention.

[0029] Figure 4 This is a schematic diagram of the side-cut conversion cover structure of the present invention.

[0030] Figure 5 This is a schematic diagram of the abrasive tank structure of the present invention.

[0031] Figure 6 This is a schematic diagram of the rock-breaking plan in an embodiment of the present invention. Detailed Implementation

[0032] As shown in the figure, a device for rock breaking and tunneling based on abrasive air jet includes an air compressor 1, a high-pressure air cylinder 3 connected to the outlet pipeline of the air compressor, the outlet of the high-pressure air cylinder being connected to the air inlet of an abrasive tank 6 via a high-pressure pipeline, and the abrasive outlet of the abrasive tank being connected to a detachable convertible drill rod 11 via an abrasive ejection pipe. The detachable convertible drill rod 11 is movably connected to a telescopic arm 9 via a rotating connector 10. The telescopic arm 9 is controlled to extend and swing by a control room 7 and its pitch angle is controlled by a hydraulic system 8. The end of the detachable convertible drill rod 11 is equipped with a rear-mounted laval nozzle 12 or a side-cutting conversion cover. The air compressor, high-pressure air cylinder, abrasive tank, control room, and hydraulic system are all included. The system, telescopic boom, and detachable drill rod are all integrated on the top of the chassis. The chassis is equipped with a slewing mechanism 17, and the bottom of the chassis is driven by tracks 16, drive wheels 15, and driven wheels. At the end of the chassis, the detachable drill rod is located at its base, and a hydraulically controlled bucket 13 is also provided. The telescopic boom has a pitch angle of ±60° to ±30° and a swing angle of ±45° to ±45°. The detachable drill rod is connected to the telescopic boom via a rotating connector, allowing for 360° horizontal and axial rotation, providing flexible operation and eliminating blind spots during construction. The telescopic boom is a three-section telescopic structure with a travel of 2.5m, a working width of 16m, a height of 11m, and a maximum coverage area of ​​154m². 2A hydraulic system is installed below the control room, which can raise or lower the control room for better observation of the construction face. The control room controls the telescopic boom, hydraulic system, rotating connector, and detachable drill rod to perform low-pressure abrasive air jet cutting according to a preset plan, cutting Dmm×Lmm grooves on the rock surface and dividing the tunnel cross-section into multiple squares with equal sides. The detachable drill rod and rear-mounted laval nozzle are assembled together. The detachable drill rod is converted into a front-jet drill bit, which is controlled by the control room to move to the center of each square rock block to perform low-pressure abrasive air jet swirling. The drilling depth is slightly greater than the grooving depth, and the borehole diameter is slightly larger than the drill bit to facilitate drill bit operation within the hole. A detachable convertible drill rod and a side-cutting convertible cover are assembled, allowing the detachable convertible drill rod to be converted into a side-spraying drill bit. The control room controls the telescopic arm, hydraulic system, and rotating connector to extend the detachable convertible drill rod into the borehole for cutting. The abrasive hopper 6 includes a hopper 35 with two abrasive barrels 39 arranged side-by-side at the bottom. A feeding pipe transports abrasive between the hopper and the abrasive barrels. The feeding pipe is equipped with a vibrating feeder 37 and a cylinder 38. The bottoms of the two abrasive barrels... The unit is equipped with a collection hopper 40, and a horizontal screw feeder 42 is installed at the discharge port of the collection hopper. The screw feeder is also driven by a motor 41, and the end of the screw feeder merges with a gas pipeline from a high-pressure gas cylinder to an abrasive ejection pipeline. Both the hopper and the collection hopper are equipped with viewing windows 36 for observing the remaining abrasive and replenishing it in time. The vibrating feeder is equipped with a vibrating rod and a motor to vibrate the abrasive in the abrasive barrel and prevent abrasive accumulation. A cylinder inputs gas at a certain pressure into the abrasive barrel, which, together with the vibrating feeder, achieves a continuous supply of abrasive. The screw feeder is equipped with a motor. It is used to transport the abrasive in the collection hopper to the gas pipeline for pre-mixing with low-pressure gas. One end of the abrasive ejector pipe is connected to the abrasive tank, and the other end is connected to the rotating connector and fixed to the detachable conversion drill rod. High-pressure air and abrasive are pre-mixed in the ejector pipe, and high-speed gas drives the particles to the laval nozzle. The laval nozzle has a circular inlet and a rectangular outlet of 4mm×20mm. The overall structure of the laval nozzle includes a converging section 29 and an expanding section 30. Gas flows into the converging section of the nozzle under high pressure, passes through the narrow throat, and escapes from the expanding section.This architecture allows the airflow velocity to vary with the nozzle cross-sectional area, accelerating the airflow from subsonic to sonic speeds, and ultimately to supersonic speeds. The converging section of the gas jet accelerates to sonic speeds, and the expanding section further expands and accelerates the gas jet to 700 m / s. The hypersonic air jet accelerates the abrasive to speeds exceeding 300 m / s. The detachable drill rod includes a drill rod connecting end 18 at the front end, with a material inlet 19. The end of the drill rod connecting end is connected to the main drill rod 23 via a rotating buckle 20. The material inlet communicates with the inner cavity of the main drill rod. A spring 21 is installed inside the front end of the main drill rod. The end of the spring is fixedly connected to the front end of a slidable laval structure tube 22 located inside the main drill rod. A side-mounted laval nozzle 24 is provided on the outer wall of the end of the main drill rod. A matching hole 25 for the side-mounted laval nozzle is provided on the slidable laval structure tube. The end of the main drill rod is movably connected to a rear laval nozzle through a threaded connection section 26. The rear laval nozzle includes a threaded connection end 28 at the front end and a nozzle wall 31. A converging section 29 and an expanding section 30 are sequentially provided inside the nozzle wall. The side-cutting conversion cover includes a protruding tube 32 located in the center and an internal threaded connection section 33 sleeved on the end of the protruding tube. A replacement cover wall 34 is provided outside the internal threaded connection section. A first valve 2 is provided between the air compressor and the high-pressure gas cylinder. A pressure gauge 4 and a second valve 5 are provided on the pipeline between the high-pressure gas cylinder and the outlet pipeline of the screw feeder.

[0033] A tunneling method based on an abrasive air jet rock-breaking tunneling device includes the following steps:

[0034] (1) Measure the cross-sectional area of ​​the tunnel, and divide the cross-section into multiple squares based on its shape to make a planning map;

[0035] (2) The operator drives the tunneling machine, stops it in the designated position, checks the air tightness of the pipeline and interface, and closes all valves after confirming that there are no problems. He opens the inlet valve of the high pressure storage cylinder, turns on the air compressor and sets the air compressor parameters. When the pressure is 8 MPa, the air compressor stops working. When the pressure is lower than 8 MPa, it automatically pressurizes. When the pressure of the high pressure cylinder reaches 8 MPa, the inlet valve of the abrasive tank is opened and the valve outlet pressure is adjusted to 2 MPa.

[0036] (3) Turn on the motor of the screw feeder of the abrasive tank; open the hopper to feed abrasive into the right abrasive barrel, and at the same time turn on the right vibrator and cylinder; control the feeding speed of the screw feeder through the motor, and observe the remaining abrasive through the window of the collection hopper. When the abrasive in the abrasive barrel is used up, open the valve on the left side of the hopper, the vibrator on the left side and the cylinder, switch the operation of the left abrasive barrel, and realize the cyclic operation of the abrasive barrels on both sides to ensure the continuous supply of abrasive;

[0037] (4) The operator, in conjunction with the planning diagram, controls the telescopic arm, hydraulic system and detachable drill rod to perform low-pressure abrasive air jet grooving according to the preset plan, and cuts a groove 43 of Dmm×Lmm on the rock surface;

[0038] (5) The operator controls the drill bit to move to the center of each square rock block to perform low-pressure abrasive air jet rotary drilling. The drilling depth is greater than the cutting depth and the drilling diameter is greater than the drill bit.

[0039] (6) After completing the grooving work, turn off the air inlet valve and the motor of the abrasive tank feeder, remove the rear laval nozzle from the detachable conversion drill rod, replace the side cutting conversion cover for assembly, and convert the detachable conversion drill rod into a side spray drill bit;

[0040] (7) The operator controls the drill bit to go deeper into the borehole, and opens the air inlet valve and the motor of the abrasive can feeder again to perform low-pressure abrasive air jet rotation cutting to cut off the rock block as a whole;

[0041] (8) The operator controls the core-sampling bucket to scoop up rock blocks and place them on the conveyor belt to realize the recycling of rock blocks. Repeat steps (1)-(8) to realize abrasive air jet rock breaking tunnel excavation.

[0042] In practical use, the air compressor is turned on and its parameters are set. When the pressure reaches 8 MPa, the air compressor stops working. When the pressure is lower than 8 MPa, it automatically pressurizes. When the high-pressure cylinder pressure reaches 8 MPa, the second valve 5 is opened, and the valve outlet pressure is adjusted to 2 MPa. The motor of the screw feeder is turned on, and the hopper 35 is opened to feed abrasive into the right-side abrasive barrel 39. At the same time, the right-side vibrating feeder 37 and cylinder 38 are turned on. The feeding speed of the screw feeder 42 is controlled by the motor 41, and the remaining abrasive is observed through the viewing window 36 of the collection hopper 40. When the abrasive in the right-side abrasive barrel of the hopper is exhausted, the valve on the left side of the hopper and the left-side vibrating feeder 37 and cylinder 38 are opened to switch the operation of the left-side abrasive barrel, realizing the cyclic operation of the abrasive barrels on both sides to ensure continuous abrasive supply. The control room 7 controls the telescopic arm 9, hydraulic system 8, rotating connector 10, and detachable conversion drill rod 11 to perform low-pressure abrasive air jet cutting according to the preset plan to unload the local stress of the surrounding rock. After the grooving is completed, the control room 7 controls the telescopic arm 9, hydraulic system 8, and rotating connector 10 to move the detachable convertible drill rod 11 to the center of each square rock block for low-pressure abrasive air jet rotary drilling. The drilling depth is slightly greater than the grooving depth, and the drilling diameter is slightly larger than the drill bit. After drilling is completed, the abrasive tank 6 and valve 5 are closed in sequence. The telescopic arm 9 and hydraulic system 8 are controlled to retract the detachable convertible drill rod 11, the rotating connector 10 is closed, the rear laval nozzle 12 is removed from the detachable convertible drill rod 11, and the side-cutting conversion cover is replaced, so that the subsequent low-pressure abrasive air jet is ejected from the side laval nozzle 21 of the detachable convertible drill rod 11. After the detachable drill rod is fitted with a side-cutting conversion cover, the control room 7 controls the telescopic arm 9, hydraulic system 8, and rotating connector 10 to extend the detachable drill rod 11 into the borehole. Then, the abrasive tank 6, valve 5, and rotating connector 10 are opened in sequence, causing the detachable drill rod 11 to rotate and cut, resulting in the overall removal of the rock block. The control room 7 then controls the telescopic arm 9, hydraulic system 8, and core bucket 13 to scoop the rock block onto the conveyor belt 14 for transport, thus achieving the recycling of the rock block.

Claims

1. A device for rock breaking and tunneling based on abrasive air jet, characterized in that: The system includes a detachable convertible drill rod, a rear-mounted laval nozzle, a side-cutting conversion cover, and an air compressor. A high-pressure gas cylinder is connected to the air compressor's outlet pipe. The outlet of the high-pressure gas cylinder is connected to the air inlet of an abrasive canister via a high-pressure pipe. The abrasive outlet of the abrasive canister is connected to the detachable convertible drill rod via an abrasive ejection pipe. The detachable convertible drill rod is movably connected to a telescopic boom via a rotating connector. The telescopic boom's extension and retraction are controlled by a control room, and its pitch angle is controlled by a hydraulic system. The end of the detachable convertible drill rod is equipped with either a rear-mounted laval nozzle or a side-cutting conversion cover. The rear-mounted laval nozzle can be removed from the detachable convertible drill rod, and the side-cutting conversion cover can be replaced for reassembly, converting the detachable convertible drill rod into a side-spray drill bit. The air compressor, high-pressure gas cylinder, abrasive canister, control room, hydraulic system, telescopic boom, and detachable convertible drill rod are all integrated into the top of the chassis. The chassis is equipped with a slewing mechanism, and the bottom of the chassis is driven by tracks, drive wheels, and driven wheels. The bottom of the detachable convertible drill rod is also equipped with a... The bucket is controlled by a hydraulic arm; the detachable convertible drill rod includes a drill rod connecting end at the front end, a material inlet on the drill rod connecting end, and the end of the drill rod connecting end is connected to the main drill rod via a rotating buckle. The material inlet communicates with the inner cavity of the main drill rod. A spring is provided inside the front end of the main drill rod, and the end of the spring is fixedly connected to the front end of a slidable laval structure tube located inside the main drill rod. A side-mounted laval nozzle is provided on the outer wall of the end of the main drill rod. A matching hole for the side-mounted laval nozzle is provided on the slidable laval structure tube. The end of the main drill rod is movably connected to a rear laval nozzle via a threaded connecting section; the rear laval nozzle includes a threaded connecting end at the front end and a nozzle wall. A converging section and an expanding section are provided sequentially inside the nozzle wall. The laval nozzle inlet is a circular structure, and the outlet is a rectangular structure of 4mm×20mm; the side-cutting conversion cover includes a protruding tube located in the center and an internal threaded connecting section sleeved on the end of the protruding tube. A replacement cover wall is sleeved on the internal threaded connecting section.

2. The device for rock breaking and tunneling based on abrasive air jet as described in claim 1, characterized in that: The abrasive hopper includes a hopper with two abrasive barrels arranged side by side at the bottom of the hopper. The abrasive is conveyed between the hopper and the abrasive barrels through a feeding pipe. The feeding pipe is equipped with a vibrating feeder and a cylinder. A collection hopper is located at the bottom of the two abrasive barrels. A horizontal screw feeder is located at the discharge port of the collection hopper. The screw feeder is also driven by a motor, and the end of the screw feeder merges with a gas pipeline from a high-pressure gas cylinder to an abrasive ejection pipeline.

3. The device for rock breaking and tunneling based on abrasive air jet as described in claim 2, characterized in that: A first valve is provided between the air compressor and the high-pressure gas cylinder, and a pressure gauge and a second valve are provided on the pipeline between the high-pressure gas cylinder and the outlet pipeline of the screw feeder.

4. The tunneling method based on the abrasive air jet rock-breaking tunneling device as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Measure the cross-sectional area of ​​the tunnel, and divide the cross-section into multiple squares based on its shape to make a planning map; (2) The operator drives the tunneling machine, stops it in the designated position, checks the air tightness of the pipeline and interface, and closes all valves after confirming that there are no problems. He opens the inlet valve of the high pressure storage cylinder, turns on the air compressor and sets the air compressor parameters. When the pressure is 8 MPa, the air compressor stops working. When the pressure is lower than 8 MPa, it automatically pressurizes. When the pressure of the high pressure cylinder reaches 8 MPa, the inlet valve of the abrasive tank is opened and the valve outlet pressure is adjusted to 2 MPa. (3) Turn on the motor of the screw feeder of the abrasive tank; open the hopper to feed abrasive into the right abrasive barrel, and at the same time turn on the right vibrator and cylinder; control the feeding speed of the screw feeder through the motor, and observe the remaining abrasive through the window of the collection hopper. When the abrasive in the abrasive barrel is used up, open the valve on the left side of the hopper, the vibrator on the left side and the cylinder, switch the operation of the left abrasive barrel, and realize the cyclic operation of the abrasive barrels on both sides to ensure the continuous supply of abrasive; (4) The operator, in conjunction with the planning diagram, controls the telescopic arm, hydraulic system, and detachable drill rod to perform low-pressure abrasive air jet grooving according to the preset plan, and cuts a groove of Dmm×Lmm on the rock surface; (5) The operator controls the drill bit to move to the center of each square rock block to perform low-pressure abrasive air jet rotary drilling. The drilling depth is greater than the cutting depth and the drilling diameter is greater than the drill bit. (6) After completing the grooving work, turn off the air inlet valve and the motor of the abrasive tank feeder, remove the rear laval nozzle from the detachable conversion drill rod, replace the side cutting conversion cover for assembly, and convert the detachable conversion drill rod into a side spray drill bit; (7) The operator controls the drill bit to go deeper into the borehole, and opens the air inlet valve and the motor of the abrasive can feeder again to perform low-pressure abrasive air jet rotation cutting to cut off the rock block as a whole; (8) The operator controls the core shovel to scoop up rock blocks and place them on the conveyor belt to realize the recycling of rock blocks. Repeat steps (1)-(8) to realize abrasive air jet rock breaking tunnel excavation.

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