A water jet tunneling method applicable to five-center circular arch tunnel structures

Abstract

This invention relates to a water jet tunneling method suitable for five-center circular arch tunnel structures, comprising the following steps: S1. Conducting a pre-experiment of jet cutting in the lower cutting zone of the tunnel face according to the tunnel design; S2. Measuring the cutting depth D under different jet parameters; S3. Determining the cutting parameters based on the cutting depth D, and designing a cutting path diagram based on the cutting parameters; S4. Performing cutting operations on the lower cutting zone according to the cutting path diagram; S5. Performing cutting operations on the upper cutting zone according to the cutting path diagram. This invention enables efficient, precise, safe, and reliable tunneling of five-center circular arch tunnel structures, and can improve construction quality, enhance adaptability, and reduce construction costs.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering technology, specifically to a water jet tunneling method for a five-center circular arch structure tunnel face. Background Technology

[0002] With the continuous expansion of tunnel construction scale in my country, tunnel types are becoming increasingly diversified. Among them, the five-center circular arch tunnel is widely used in various major tunnel projects due to its superior structural performance and ability to adapt to complex geological conditions. However, the excavation and construction of five-center circular arch tunnels faces many technical challenges, and existing excavation methods have many shortcomings, making it difficult to meet the increasing demands.

[0003] Traditional drill-and-blast excavation techniques for five-center arch tunnels suffer from severe over- and under-excavation, leading to substantial subsequent support work and increased costs. The process also generates significant noise and dust, negatively impacting worker health and the surrounding environment. Furthermore, considerable disturbance to the surrounding rock can cause instability, resulting in low construction safety. While shield tunneling enables continuous excavation, its high equipment operation and maintenance costs, poor adaptability to the unique cross-sectional shape of five-center arch tunnels, and significant limitations imposed by construction space constraints further exacerbate the problem. TBM (Tunnel Boring Machine) technology also presents challenges, including severe cutter wear, frequent cutter replacements, and difficult maintenance, significantly increasing construction costs. Moreover, TBMs are highly dependent on the construction environment and have poor adaptability to certain geological conditions, hindering their ability to fully realize their excavation efficiency.

[0004] In summary, existing tunneling methods all have certain limitations in the construction of five-center circular arch tunnels, making it difficult to meet the demands of efficient, precise, adaptable, low-cost, and safe tunnel and underground engineering construction. Therefore, there is an urgent need to develop a new tunneling technology for five-center circular arch tunnels to overcome the shortcomings of existing technologies, improve the construction quality and efficiency of five-center circular arch tunnels, reduce construction costs, ensure construction safety, and promote the further development of tunnel engineering.

[0005] For example, patent document CN113153336A discloses a high-pressure abrasive waterjet tunneling method. This method uses axial nozzles to spray abrasive waterjet to divide the tunnel face into a grid, and radial nozzles to spray abrasive waterjet to radially cut and peel off rock blocks from the bottom of the slots. Although this method can achieve hydraulic cutting and peeling of rock blocks at the tunnel face throughout the entire process, it still has the following drawbacks:

[0006] (1) During the tunnel excavation process, it is necessary to frequently switch or replace the nozzles, which makes the tunneling process complicated and is not conducive to continuous tunnel excavation;

[0007] (2) The groove cut by the axial nozzle may close under the action of ground stress, which will prevent the radial nozzle from entering the groove;

[0008] (3) When cutting a face with layered, weak interlayers or complex lithology using axial nozzle abrasive water jet, the depth of each groove varies greatly, and there may be a large number of repeated cutting paths.

[0009] For example, patent document CN117418850A discloses a bread-type jet tunneling method for hard rock tunnel faces. This method uses a camera to acquire images of the rock face, obtains the distribution characteristics of different rocks on the face based on color, and divides a virtual route map. Linear abrasive water jets are used to cut the tunnel face tracks, rotating abrasive water jets are used for drilling, and radial abrasive water jets rotate to cut and peel away the rock on the tunnel face. Although this method can achieve precise hydraulic cutting of the tunnel face in complex strata, it still has the following drawbacks:

[0010] (1) Dust and water mist generated during tunnel excavation can easily obscure the camera lens, making it difficult to guarantee the quality of the obtained rock sample images;

[0011] (2) Abrasive material tends to accumulate at the nozzle of the radial abrasive water jet emitter, causing nozzle blockage. Manual unblocking or nozzle replacement is required, which in turn affects the construction period. Summary of the Invention

[0012] The purpose of this invention is to provide a water jet tunneling method suitable for five-center circular arch tunnels, which can achieve efficient, accurate, safe and reliable tunneling of five-center circular arch tunnels, improve construction quality, enhance adaptability and reduce construction costs.

[0013] The present invention discloses a water jet tunneling method applicable to a five-center circular arch structure tunnel, comprising:

[0014] S1. Based on the five-center circular arch tunnel structure, the semi-circular area of ​​the tunnel face is considered as the upper cutting zone, and the entire area below it is the lower cutting zone. According to the tunnel construction design, abrasive water jet pre-cutting experiments are conducted under different jet parameters. Abrasive is sprayed through nozzles to cut the outline of the lower cutting zone of the tunnel. Water jet is a flexible transmission method with strong adaptability, suitable for tunnel excavation in various complex environments. Moreover, operators can control it away from the working face, which improves construction safety. Water can adsorb dust to a large extent and wet the rock to a certain extent, effectively reducing noise and dust.

[0015] S2. After pre-cutting is completed and the rock has cooled, measure the cutting depth D under different jet parameters.

[0016] S3. Based on the cutting depth D obtained from the pre-cutting experiment, the cutting parameters are determined, and a cutting path diagram is designed based on these parameters. The cutting path diagram includes a first ring straight cut line, a first ring oblique cut line in the lower cutting zone, a second ring straight cut line in the lower cutting zone, a second ring oblique cut line in the lower cutting zone, a frustum segment line, an upper cutting zone outline line, a semi-circular inner parallel cut line, and a semi-circular outer straight cut line. The cutting methods include parallel cutting, straight cutting, and oblique cutting. By determining the parameters through the pre-cutting experiment and drawing the cutting path diagram, precise cutting of the tunnel face is achieved, improving excavation accuracy, effectively controlling over- and under-excavation phenomena, and reducing subsequent support costs.

[0017] S4. According to the cutting line diagram, the lower cutting area is cut. First, cutting is performed along the straight cutting line and the oblique cutting line of the first ring of the lower cutting area. After the cutting is completed, the rock in the first ring is stripped away. Next, cutting is performed along the straight cutting line and the oblique cutting line of the second ring of the lower cutting area. After the cutting is completed, the rock in the second ring is stripped away. Then, cutting is performed along the straight cutting line and the oblique cutting line of the second ring of the lower cutting area. After the cutting is completed, the rock in the extended cutting line is stripped away, and the lower cutting area forms a frustum. Finally, cutting is performed along the segment line of the frustum. After the cutting is completed, the rock in the frustum is stripped away. Thus, one excavation of the lower cutting area is completed, with a progress of [missing information]. D sin α Gravity-based rock stripping reduces the cutting distance of falling rock blocks, lowers construction costs, improves jet tunneling efficiency, and simplifies the process.

[0018] S5. Perform cutting operations on the upper cutting area according to the cutting line diagram. First, make a straight cut along the outline of the upper cutting area; second, make a parallel cut along the inner parallel cutting line of the semicircle; finally, make a straight cut along the outer straight cutting line of the semicircle. After each cutting operation, a long strip of rock will fall, with a height of [missing information]. D sin α Thus, the upper cutting zone has completed one excavation, with a progress of [missing information]. D sin α Repeat step S5 until the upper cutting area is completely cut.

[0019] Optionally, in step S1, during the pre-cutting experiment, the distance between the nozzle and the cutting target on the surface to be cut is 20mm-40mm, and the abrasive is a solid abrasive, such as ceramsite, garnet, or quartz sand, with a concentration of 20%-30%. Different combinations of jet pressure and nozzle movement speed are set to cut the overall contour of the cutting area.

[0020] Optionally, in step S2, after pre-cutting and rock cooling, pulsed ultrasonic waves are emitted into the rock cut using the transmitting end of an ultrasonic sensor. Simultaneously, a timer is initialized. Once the receiving end of the ultrasonic sensor collects the ultrasonic waves reflected back from the bottom interface of the rock block, the timer is turned off. The cutting depth D under different jet parameters is calculated based on the time interval. Using an ultrasonic sensor for non-contact measurement allows for rapid feedback of jet cutting results even when no one is present at the work site, reducing labor costs and improving construction safety and reliability.

[0021] Optionally, in step S2, the ultrasonic sensor has a transmission power of 20-50W and a frequency of 20-40kHz.

[0022] Optionally, in step S3, the cutting parameters include the cutting depth of the abrasive waterjet. D and cutting angle α， The cutting angle α The angle between the nozzle and the working face, and the depth of a single excavation. D sin α Greater than 0.5 D Furthermore, it reserves the minimum length and cutting angle sufficient to allow the equipment to perform circumferential cutting of the frustum parallel to the working face. α satisfy, L To meet the minimum length required for the nozzle to cut parallel to the face of the tunnel.

[0023] The present invention has the following advantages:

[0024] 1. This invention benefits from the flexible transmission characteristics of water jets, making it highly adaptable and suitable for tunnel excavation in various complex environments. Furthermore, operators can make adjustments away from the working face, thus improving construction safety.

[0025] 2. By setting different jet parameters, this invention utilizes abrasive water jet technology to precisely cut the tunnel face, improving excavation accuracy, effectively controlling over-excavation and under-excavation, and reducing subsequent support costs.

[0026] 3. This invention utilizes an ultrasonic sensor to perform non-contact measurement of the jet cutting depth, enabling rapid feedback of jet cutting results even when no one is on the work surface, thus reducing labor costs and improving construction safety and reliability.

[0027] 4. This invention utilizes gravity to peel away rock blocks, which can reduce the cutting distance of the falling rock blocks, lower construction costs, and improve jet tunneling efficiency.

[0028] 5. This invention makes full use of the characteristics of the five-centered circular tunnel structure, and the process is simple. The semi-circular cylinder in the upper cutting area only needs to be cut twice to fall off naturally.

[0029] 6. The present invention adopts an abrasive water jet rock breaking method, which causes little disturbance to the surrounding rock. For tunnels with high ground stress, the jet cutting can achieve the effect of pressure relief and energy release, and realize active control of the deformation of the surrounding rock.

[0030] 7. This invention uses water as the main material for cutting and tunneling the working face throughout the entire process. Water can absorb dust to a large extent and wet the rocks to a certain extent, effectively reducing noise, reducing dust, and preventing rock splashes that could cause injury.

[0031] 8. Compared with the shield tunneling method and TBM method, the present invention has less equipment wear and tear. Only the nozzles, water pipes and some metal materials are damaged by abrasive erosion or water action. Moreover, the unit price of consumables is low, which greatly reduces the construction cost. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the jet tunneling method for a five-center circular tunnel as described in this embodiment of the invention.

[0033] Figure 2 This is a schematic diagram of the abrasive waterjet tunneling system in an embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram of the upper and lower cutting areas and the three cutting methods described in this invention.

[0035] Figure 4 This is a schematic diagram of the face cutting and falling ring and its cutting path as described in this invention.

[0036] Figure 5 This is a schematic diagram of the first round of cutting steps on the working face and the oblique view of the cross-section after cutting, as described in this invention.

[0037] Figure 6 This is a schematic diagram of the first round of cutting steps at the working face and the cross-section after cutting, as described in this invention, viewed from the left.

[0038] Reference numerals: 1. Abrasive jet generating system; 101. Water tank; 102. Water; 103. High-pressure water pipe; 104. Engine; 105. High-pressure pump; 106. Overflow valve; 107. Throttle valve; 108. Check valve; 109. Abrasive container; 110. Abrasive; 111. Mixing chamber; 112. Nozzle; 2. Remote control system; 201. Electronic pressure gauge; 202. Electronic flow meter; 203. Control box; 204. Computer; 205. Ultrasonic sensor; 206. Data cable; 3. Upper cutting zone; 301. Straight cutting line of upper cutting zone contour; 302. Semi-circular inner parallel cutting line; 303. Semi-circular outer straight cutting line; 4. Lower cutting zone; 401. First ring straight cut line in the lower cutting zone; 402. First ring oblique cut line in the lower cutting zone; 403. Second ring straight cut line in the lower cutting zone; 404. Second ring oblique cut line in the lower cutting zone; 405. Frustum ring cut line; 5. Parallel cut; 6. Straight cut; 7. Oblique cut; 8. First ring cutting rock; 9. Second ring cutting rock; 10. Extended cutting rock; 11. Frustum cutting rock; 12. Long strip-shaped rock block. Detailed Implementation

[0039] The following description, with reference to the accompanying drawings and preferred embodiments, illustrates the implementation of the technical solution of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are merely illustrative of the invention and not intended to limit the scope of protection of the invention.

[0040] like Figures 1 to 6 As shown, a water jet tunneling method suitable for a five-center circular arch structure tunnel includes the following steps:

[0041] S1. Based on the five-center circular arch tunnel structure, the semi-circular area of ​​the tunnel face is regarded as the upper cutting zone 3, and the entire area below it is the lower cutting zone 4. According to the tunnel construction design, abrasive water jet pre-cutting experiments under different jet parameters are carried out. Abrasive 110 is sprayed using nozzle 112 to cut the outline of the lower cutting zone 4 of the tunnel.

[0042] During the preliminary experiment of abrasive waterjet cutting, different jet parameters were first set through the remote control system 2, and then the abrasive jet generation system 1 was started through the control box 203. Abrasive 110 was sprayed through the nozzle 112 to cut the outline of the cutting area 4 under the tunnel.

[0043] Water jetting is a flexible transmission method with strong adaptability, suitable for tunnel excavation in various complex environments. Operators can control it from away from the working face, which improves construction safety. Water can adsorb dust to a large extent and wet the rock to a certain extent, effectively reducing noise and dust.

[0044] S2. After pre-cutting is completed and the rock has cooled, measure the cutting depth D under different jet parameters, specifically:

[0045] The ultrasonic sensor 205 emits pulsed ultrasonic waves towards the rock cut, while a timer is initialized. Once the receiving end of the ultrasonic sensor 205 collects the ultrasonic waves reflected back from the bottom interface of the rock, the timer is turned off. The cutting depth D under different jet parameters is calculated based on the time interval. Using an ultrasonic sensor for non-contact measurement allows for rapid feedback of jet cutting results even when no one is at the work site, reducing labor costs and improving construction safety and reliability.

[0046] S3. Based on the cutting depth D obtained from the pre-cutting experiment, determine the cutting parameters and design the cutting path diagram based on the cutting parameters. (See [reference]) Figure 4 The cutting path diagram includes a first ring straight cut line 401, a first ring oblique cut line 402 in the lower cutting area, a second ring straight cut line 403 in the lower cutting area, a second ring oblique cut line 404 in the lower cutting area, a frustum segment line 405, an upper cutting area contour line 301, a semi-circular inner parallel cut line 302, and a semi-circular outer straight cut line 303. The cutting methods include three types: parallel cut 5, straight cut 6, and oblique cut 7. (See attached diagram.) Figure 3 .

[0047] By determining various parameters through pre-cutting experiments and drawing cutting route diagrams, precise cutting of the tunnel face was achieved, which improved excavation accuracy, effectively controlled over- and under-excavation phenomena, and reduced subsequent support costs.

[0048] S4. Perform cutting operations on the lower cutting area 4 according to the cutting line diagram, specifically as follows:

[0049] like Figures 3 to 6 As shown, cutting is first performed along the straight cutting line 401 and the oblique cutting line 402 of the first ring of the lower cutting zone, respectively. After the cutting operation is completed, the rock 8 of the first ring is peeled off (see...). Figure 5 and Figure 6 (I)); then, cutting is carried out along the straight cutting line 403 and the oblique cutting line 404 of the second ring of the lower cutting zone, respectively. After the cutting operation is completed, the rock 9 of the second ring is peeled off (see Figure 5 and Figure 6(II)); Further cutting is then performed along the straight cutting line 403 and the oblique cutting line 404 of the second ring of the lower cutting zone, respectively. After the cutting operation is completed, the extended cutting rock 10 is peeled off (see...). Figure 5 and Figure 6 (III)), the lower cutting zone 4 forms a frustum; finally, cutting is carried out along the frustum segment line 405. After the cutting operation is completed, the frustum-cut rock 11 peels off (see Figure 5 and Figure 6 (Ⅳ)), at this point, the lower cutting zone 4 has completed one excavation, with a progress of Dsinα.

[0050] Gravity stripping of rocks reduces the cutting distance of falling rock blocks, lowers construction costs, improves jet tunneling efficiency, and simplifies the process.

[0051] S5. Perform cutting operations on the upper cutting area 3 according to the cutting line diagram, specifically as follows:

[0052] like Figures 3 to 6 As shown, first, a straight cut 6 is made along the upper cutting area outline line 301; second, a parallel cut 5 is made along the inner parallel cut line 302 of the semicircle; finally, a straight cut 6 is made along the outer straight cut line 303 of the semicircle; after each cutting operation, a long strip-shaped rock block 12 falls off, with a height of Dsinα (see...). Figure 5 and Figure 6 (V) Thus, the upper cutting zone 3 has completed one excavation, with a depth of Dsinα. Repeat the above steps until the upper cutting zone 3 is completely cut (see [reference]). Figure 5 and Figure 6 (VI) in the middle.

[0053] After the cutting operations in the upper cutting zone 3 and the lower cutting zone 4 are completed, the excavation of the five-center circular arch tunnel section is finished.

[0054] This water jet tunneling method, applicable to five-center circular arch tunnels, enables efficient, precise, safe, and reliable tunneling of such tunnels. It also improves construction quality, enhances adaptability, reduces construction costs, and promotes the further development of tunnel engineering.

[0055] like Figure 1As shown, in one possible embodiment, the abrasive jet generating system 1 includes a water tank 101, water 102, a high-pressure water pipe 103, an engine 104, a high-pressure pump 105, an overflow valve 106, a throttle valve 107, a check valve 108, an abrasive tank 109, abrasive 110, a mixing chamber 111, and a nozzle 112, wherein: the engine 104 drives the high-pressure pump 105 to supply water from the water tank 101 to the mixing chamber 111 through the high-pressure water pipe 103. The overflow valve 106 is used to drain excess water back into the water tank 101. The throttle valve 107 is used to change the throttling cross-section to control the water flow rate. The check valve 108 is used to prevent water backflow. The abrasive tank 109 is used to temporarily store the abrasive 110, which is used to mix with water to increase the jet's rock-breaking ability. The mixing chamber 111 is used to mix water and abrasive. Nozzle 112 is used to eject water and abrasive from mixing chamber 111. All components within the system are connected via high-pressure water pipe 103 for transporting water, abrasive, or a mixture of water and abrasive. This system is simple in composition, low in material and equipment costs, and has minimal wear and tear, effectively reducing construction costs. Nozzles, water pipes, and some metal materials are worn down by abrasive corrosion or the action of water, and the unit price of consumables is inexpensive, significantly reducing construction costs.

[0056] like Figure 1 As shown, in one possible embodiment, the remote control system 2 includes an electronic pressure gauge 201, an electronic flow meter 202, a control box 203, a computer 204, an ultrasonic sensor 205, and a data cable 206. The electronic pressure gauge 201 and the electronic flow meter 202 are respectively installed on the high-pressure water pipe 103, positioned between a throttle valve 107 and a one-way valve 108, to monitor the pressure and flow rate of the water in the high-pressure pipe 103. The computer 204 is connected to the electronic pressure gauge 201 and the electronic flow meter 202 via the data cable to receive the detection data. The computer 204 is connected to the ultrasonic sensor 205 via the data cable 206 to receive data from the ultrasonic sensor 205. The computer 204 is connected to the control box 203 via the data cable 206 for remote control. The control box 203 is connected to the engine 104 via the data cable 206 to start the engine 104 and transmit data. This system has a simple composition, low material and equipment costs, and low losses, effectively reducing construction costs.

[0057] like Figure 1 As shown, in one possible embodiment, the abrasive 110 is composed of commonly used solid abrasives such as ceramsite, garnet, or quartz sand, with a concentration of 20%-30%.

[0058] like Figure 1 As shown, in one possible embodiment, the distance between the nozzle 112 and the cutting target of the surface being cut is 20mm-40mm.

[0059] like Figure 1As shown, in one possible embodiment, in S2, the ultrasonic sensor 205 has a transmission power of 20-50 W and a frequency of 20 kHz-40 kHz.

[0060] like Figure 3 As shown, in one possible embodiment, the cutting parameters include the cutting depth of the abrasive waterjet. D and cutting angle α Cutting angle α The angle between the nozzle and the working face, and the depth of a single excavation. D sin α Greater than 0.5 D Furthermore, it reserves the minimum length and cutting angle sufficient to allow the equipment to perform circumferential cutting of the frustum parallel to the working face. α satisfy, L To meet the minimum length required for the nozzle to cut parallel to the face of the tunnel.

[0061] like Figure 3 As shown, in one possible embodiment, the straight cut 6 is when the nozzle 112 cuts perpendicular to the working face, and the oblique cut 7 is when the nozzle 112 forms an angle with the working face. α Perform the cutting. Parallel cutting is performed with nozzle 112 parallel to the working face.

[0062] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A water jet tunneling method suitable for a five-center arched tunnel structure, characterized in that, Includes the following steps: S1. Based on the five-center circular arch tunnel structure, the semi-circular area of ​​the tunnel face is regarded as the upper cutting area (3), and the entire area below it is the lower cutting area (4). According to the tunnel construction design, abrasive water jet pre-cutting experiments under different jet parameters are carried out. Abrasive (110) is sprayed using nozzle (112) to cut the outline of the lower cutting area of ​​the tunnel. S2. After pre-cutting is completed and the rock has cooled, measure the cutting depth D under different jet parameters; S3. Based on the cutting depth D obtained from the pre-cutting experiment, determine the cutting parameters and design the cutting path diagram based on the cutting parameters. The cutting path diagram includes the first ring straight cutting path (401), the first ring oblique cutting path in the lower cutting area (402), the second ring straight cutting path in the lower cutting area (403), the second ring oblique cutting path in the lower cutting area (404), the frustum link path (405), the upper cutting area contour path (301), the semi-circular inner parallel cutting path (302), and the semi-circular outer straight cutting path (303). S4. According to the cutting line diagram, the lower cutting area (4) is cut. First, cut along the first ring straight cutting line (401) and the first ring oblique cutting line (402) of the lower cutting area respectively; then cut along the second ring straight cutting line (403) and the second ring oblique cutting line (404) of the lower cutting area respectively; then extend the cut along the second ring straight cutting line (403) and the second ring oblique cutting line (404) of the lower cutting area respectively. At this time, the lower cutting area (4) forms a frustum; finally, cut along the frustum link line (405). After the cutting operation is completed, the lower cutting area (4) completes one excavation, with a depth of [missing information]. D sin α ; S5. Cut the upper cutting area (3) according to the cutting line diagram. First, cut straight along the outline line (301) of the upper cutting area; then cut parallel along the inner parallel cutting line (302) of the semicircle; finally cut straight along the outer straight cutting line (303) of the semicircle. Thus, the upper cutting area (3) completes one excavation with a depth of Dsinα. Repeat S5 until the upper cutting area (3) is cut.

2. The water jet tunneling method for a five-center arched tunnel structure according to claim 1, characterized in that, In step S1, during the pre-cutting experiment, the distance between the nozzle (112) and the cutting target of the cut surface is 20-40mm; the abrasive is a solid abrasive, which is ceramsite, garnet or quartz sand, with a concentration of 20%-30%, and different jet pressures and different nozzle moving speeds are set to cut the overall contour of the cutting area (4).

3. The water jet tunneling method for a five-center arched tunnel structure according to claim 1, characterized in that, In S2, after the pre-cutting is completed and the rock is cooled, the transmitting end of the ultrasonic sensor (205) emits pulsed ultrasonic waves to the rock cut. At the same time, the timer is initialized. When the receiving end of the ultrasonic sensor (205) collects the ultrasonic waves reflected back from the bottom interface of the rock, the timer is turned off. The cutting depth D under different jet parameters is calculated according to the interval time.

4. The water jet tunneling method for a five-center arched tunnel structure according to claim 3, characterized in that, In step S2, the ultrasonic sensor (205) has a transmission power of 20-50W and a frequency of 20-40kHz.

5. The water jet tunneling method for a five-center arched tunnel structure according to claim 1, characterized in that, In step S3, the cutting parameters include the cutting depth of the abrasive waterjet. D and cutting angle α， The cutting angle α The angle between the nozzle and the working face, and the depth of a single excavation. D sin α Greater than 0.5 D Furthermore, it reserves the minimum length and cutting angle sufficient to allow the equipment to perform circumferential cutting of the frustum parallel to the working face. α satisfy, L To meet the minimum length required for the nozzle to cut parallel to the face of the tunnel.

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