A method for controlling over-excavation and under-excavation in mechanized construction of large-section tunnels in complex geological conditions

Abstract

This invention belongs to the field of tunnel construction technology, specifically a method for controlling over- and under-excavation during mechanized construction of large-section tunnels in complex geological conditions. The method includes: S1: Erecting a positioning device inside the tunnel and adjusting the height of the arch frame to ensure its axis coincides with the tunnel axis; S2: Simultaneously emitting lasers from multiple laser emitters onto the tunnel face, creating multiple laser projection points at the edge of the face to mark the positions of edge blast holes; S3: Drilling multiple edge blast holes at the face, followed by drilling the remaining central blast holes, and then placing and detonating explosives inside each blast hole. This invention simplifies the positioning of edge blast holes by utilizing the convenience of laser positioning. By coordinating the shape of the arch frame with the designed excavation outline of the tunnel, the distance between each laser projection point and the designed excavation outline is equal, improving the positioning accuracy of edge blast holes and reducing over- and under-excavation problems after blasting.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction technology, specifically a method for controlling over-excavation and under-excavation in mechanized construction of large-section tunnels with complex geology. Background Technology

[0002] Over-excavation and under-excavation refer to the actual excavation of a section beyond the designed excavation outline, where over-excavation is defined as the portion outside the outline and under-excavation as the portion within it. Both over-excavation and under-excavation negatively impact the stability of the surrounding rock, especially in complex geological conditions, and can lead to tunnel collapse in severe cases.

[0003] A Chinese patent with publication number CN112577377A discloses a method for controlling over- and under-excavation in mechanized construction of large-section soft rock tunnels. This method primarily involves dynamically adjusting and determining the layout of blast holes, ensuring the drilling equipment is close to the surrounding rock surface, determining the location and angle of the blast holes, and then performing initial support followed by focused blasting. This effectively controls over- and under-excavation in mechanized construction of large-section soft rock tunnels, reduces blasting disturbance to the surrounding rock, accelerates the excavation speed, controls construction costs, and optimizes the over- and under-excavation values. It also effectively avoids the limitations imposed by the skill level of the workers on tunnel excavation.

[0004] In existing technologies, the over-excavation and under-excavation problems caused by drilling and blasting are largely due to inaccurate positioning of blast holes at the edge of the tunnel face. The existing positioning methods usually involve manual measurement and layout, and positioning of blast holes with steel rulers. The positioning accuracy is low, which leads to deviations in the positioning of edge blast holes. This easily results in over-excavation and under-excavation after blasting, and the operation process is also quite cumbersome.

[0005] Therefore, this invention provides a method for controlling over-excavation and under-excavation during mechanized construction of large-section tunnels in complex geological conditions. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by this invention to solve its technical problem is: a method for controlling over-excavation and under-excavation in mechanized construction of large-section tunnels in complex geological conditions, comprising the following steps:

[0008] S1: After the tunnel entrance is excavated, a positioning device is set up inside the tunnel, the height of the arch frame is adjusted, and the axis of the arch frame is kept coincident with the tunnel axis. Check whether the laser emitter can work normally.

[0009] S2: When determining the location of the edge blast holes, multiple laser emitters evenly distributed on one side of the arched frame simultaneously emit lasers toward the working face, thereby forming multiple laser projection points at the edge of the working face, thus marking the location of the edge blast holes;

[0010] S3: Based on the laser markings, drill multiple edge holes on the face of the tunnel using a drilling device, then drill the remaining central holes, and finally place explosives inside each hole and detonate them.

[0011] In existing technologies using the drill-and-blast method, over- and under-excavation problems are largely due to inaccurate positioning of blast holes at the tunnel face edges. Current positioning methods typically involve manual measurement and layout, using steel rulers to locate the blast holes, which has low accuracy, leading to deviations in edge hole positioning and making over- and under-excavation after blasting easy. Furthermore, the process is cumbersome. This invention addresses this by utilizing the convenience of laser positioning to simplify edge hole positioning, improving efficiency. By setting the shape of the arched frame to match the tunnel's designed excavation outline, the distance between each laser projection point and the designed excavation outline is equal, thereby improving the positioning accuracy of edge blast holes and reducing over- and under-excavation problems after blasting.

[0012] Preferably, the positioning device in step S1 includes an arched frame; the shape of the arched frame matches the designed excavation outline of the tunnel, and the arched frame is composed of multiple arc-shaped I-beams connected together; a set of positioning cylinders are evenly distributed on one side of the arched frame; a laser emitter is installed inside the positioning cylinder, and the laser emitter is parallel to the axis of the arched frame; after the tunnel entrance is excavated, a positioning device is set up inside the tunnel, the height of the arched frame is adjusted, and the axis of the arched frame is made to coincide with the tunnel axis. When determining the position of the edge blast holes, multiple laser emitters evenly distributed on one side of the arched frame simultaneously emit lasers towards the tunnel face, thereby forming multiple laser projection points at the edge of the tunnel face, thus marking the position of the edge blast holes and improving the positioning accuracy of drilling and blasting excavation.

[0013] Preferably, the bottom ends of the arch frame are fixedly connected to bases; rollers are rotatably connected to the lower side of the bases via brackets; by setting the bases and rollers, the arch frame can be moved inside the tunnel, allowing it to move forward as the tunnel face advances, thereby improving the construction efficiency of tunnel excavation.

[0014] Preferably, a collision protection plate is fixedly connected inside the open end of the positioning cylinder, and the collision protection plate is made of transparent material; the laser emitter is located inside the cavity formed between the positioning cylinder and the collision protection plate; since the emitting end of the laser emitter always faces the working face, the rocks generated during the blasting process at the working face are easily splashed to the arch frame and impact the laser emitter, which can easily damage the laser emitter. By setting the collision protection plate, the splashed rocks can be blocked, preventing the rocks from directly impacting the laser emitter and extending the service life of the device.

[0015] Preferably, an air pump is installed on the upper side of the base; an air pipe is fixedly connected inside the arched frame, and the air pump is connected to the air pipe; an elastic corrugated pipe is fixedly connected to the inner side wall of the top of the positioning cylinder near the anti-collision plate, and the elastic corrugated pipe is connected to the air pipe through a conduit; a sponge block is fixedly connected to the bottom of the elastic corrugated pipe through a mounting plate; an elastic rope is fixedly connected between the positioning cylinder and the mounting plate; the anti-collision plate is located between the laser emitter and the sponge block, and the surface of the sponge block and the anti-collision plate are in close contact; during blasting operations at the working face, the flying rocks After impact, dirt or dust is easily left on the surface of the crash barrier. Therefore, after the blasting operation, air is supplied to the air pipe through an air pump. The gas is then transmitted to various parts of the arch frame through the air pipe and enters the interior of the elastic bellows through the conduit, causing the elastic bellows to extend downwards. This causes the sponge block to slide and rub against the surface of the crash barrier. By controlling the air pump to start and stop continuously, the sponge block can scrape up and down on the surface of the crash barrier, thereby wiping away the dirt on the surface of the crash barrier and avoiding the problem of dirt blocking the laser beam during subsequent use.

[0016] Preferably, a flexible hose is fixed inside the sponge block, and the hose is set in an inclined state; one end of the hose is connected to the elastic corrugated pipe, and the other end faces the anti-collision plate; by setting the hose in an inclined manner, as the elastic corrugated pipe extends downward, the airflow inside the elastic corrugated pipe will be sprayed outward through the hose simultaneously, thereby further blowing away the mud and dust on the surface of the anti-collision plate and improving the cleaning efficiency of the anti-collision plate.

[0017] Preferably, a guide shell is embedded and fixedly connected to the side of the sponge block near the anti-collision plate, and the cross-sectional shape of the guide shell is circular; the guide shell has an opening near the anti-collision plate; the middle of the hose is tangent to and connected to the guide shell; a rotating rod is rotatably connected inside the guide shell; a set of paddles are evenly distributed around the circumference of the rotating rod, and the airflow can push the paddles to rotate when passing through the inside of the hose; an elastic block is fixedly connected to the free end of the paddle; when the airflow passes through the hose, it passes through the guide shell and pushes the paddles to rotate, thereby causing multiple paddles to intermittently approach the anti-collision plate, and the elastic blocks at the ends of the paddles to bounce against the surface of the anti-collision plate, causing the anti-collision plate to produce slight vibrations, thereby causing the dirt and dust on the surface of the anti-collision plate to fall off quickly. Combined with the wiping of the sponge block, the cleaning efficiency of the anti-collision plate is further improved.

[0018] Preferably, a baffle is fixed to the inner side wall of the top of the positioning cylinder near the sponge block, and the sponge block is located between the anti-collision plate and the baffle. By setting the baffle to shield the sponge block and the elastic corrugated pipe, the problem of flying stones hitting the sponge block and the elastic corrugated pipe and causing them to deform and be damaged is avoided, thereby extending the service life of the sponge block and the elastic corrugated pipe.

[0019] Preferably, a magnetic block is fixedly connected to the side of the baffle near the sponge block; a groove is formed inside the sponge block; a movable ball is slidably connected inside the groove, and the movable ball is made of iron; a spring is fixedly connected between the movable ball and the side wall of the groove; a metal block is fixedly connected to the end of the groove away from the spring; when the elastic rope pulls the sponge block back to the top of the positioning cylinder, the magnetic block attracts the movable ball, which in turn causes the movable ball to slide inside the groove and hit the metal block, thereby causing the sponge block to shake, shaking off the impurities adsorbed during the wiping process, so that the sponge block maintains a certain self-cleaning ability and improves the cleaning efficiency of the subsequent sponge block on the anti-collision plate.

[0020] Preferably, a pair of elastic plates are fixed to the side wall surface of the chute between the movable ball and the metal block. By setting a pair of elastic plates inside the chute, the movable ball will squeeze the elastic plates when sliding inside the chute, and the elastic plates will deform and store energy. When the movable ball passes the middle of the elastic plate, the movable ball will be subjected to the combined action of magnetic force and elastic plate rebound force, thereby increasing the impact force of the movable ball on the metal block, increasing the shaking amplitude of the sponge block, and further shaking off the impurities inside the sponge block.

[0021] The beneficial effects of this invention are as follows:

[0022] 1. The present invention provides a method for controlling over- and under-excavation during mechanized construction of large-section tunnels in complex geological conditions. By utilizing the convenience of laser positioning, the method simplifies the positioning of edge blast holes, improves work efficiency, and ensures that the shape of the arch frame matches the designed excavation outline of the tunnel, making the distance between each laser projection point and the designed excavation outline equal. This improves the positioning accuracy of edge blast holes and reduces over- and under-excavation problems after blasting.

[0023] 2. The method for controlling over-excavation and under-excavation in mechanized construction of large-section tunnels with complex geology described in this invention, by setting a base and rollers, facilitates the movement of the arch frame inside the tunnel, enabling the arch frame to move forward as the tunnel face advances, thereby improving the construction efficiency of tunnel excavation. Attached Figure Description

[0024] The invention will now be further described with reference to the accompanying drawings.

[0025] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0026] Figure 2 This is a perspective view of the present invention;

[0027] Figure 3 This is a cross-sectional view of the arched frame in this invention;

[0028] Figure 4 yes Figure 3 Enlarged view of a portion of point A in the middle;

[0029] Figure 5 yes Figure 4 Enlarged view of a section at point B in the middle;

[0030] Figure 6 This is a cross-sectional view of the groove in this invention;

[0031] In the diagram: 1. Arch frame; 2. Positioning cylinder; 3. Laser emitter; 4. Base; 5. Roller; 6. Anti-collision plate; 7. Air pump; 8. Air pipe; 9. Elastic corrugated pipe; 10. Conduit; 11. Sponge block; 12. Elastic rope; 13. Hose; 14. Guide shell; 15. Rotating rod; 16. Paddle; 17. Elastic block; 18. Baffle; 19. Magnetic block; 20. Slide groove; 21. Movable ball; 22. Metal block; 23. Elastic sheet. Detailed Implementation

[0032] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0033] like Figure 1 As shown, a method for controlling over-excavation and under-excavation during mechanized construction of large-section tunnels in complex geological conditions includes the following steps:

[0034] S1: After the tunnel entrance is excavated, a positioning device is set up inside the tunnel, the height of the arch frame 1 is adjusted, and the axis of the arch frame 1 is kept coincident with the tunnel axis. Check whether the laser emitter 3 can work normally.

[0035] S2: When determining the location of the edge blast holes, multiple laser emitters 3 evenly distributed on one side of the arch frame 1 simultaneously emit lasers toward the working face, thereby forming multiple laser projection points at the edge of the working face, thus marking the location of the edge blast holes.

[0036] S3: Based on the laser markings, drill multiple edge holes on the face of the tunnel using a drilling device, then drill the remaining central holes, and finally place explosives inside each hole and detonate them.

[0037] In existing technologies using the drill-and-blast method, over-excavation and under-excavation problems are largely due to inaccurate positioning of blast holes at the tunnel face edges. Current positioning methods typically involve manual measurement and layout, using steel rulers to locate the blast holes, which has low accuracy, leading to deviations in edge blast hole positioning and making over-excavation and under-excavation more likely after blasting. Furthermore, the operation process is cumbersome. This invention addresses this by utilizing the convenience of laser positioning to simplify the positioning of edge blast holes, improving work efficiency. By setting the shape of the arched frame 1 to match the designed excavation outline of the tunnel, the distance between each laser projection point and the designed excavation outline is equal, thereby improving the positioning accuracy of the edge blast holes and reducing over-excavation and under-excavation problems after blasting.

[0038] Example 1

[0039] like Figures 2 to 5 As shown, the positioning device in step S1 includes an arched frame 1; the shape of the arched frame 1 matches the design excavation outline of the tunnel, and the arched frame 1 is composed of multiple arc-shaped I-beams connected together; a set of positioning cylinders 2 are evenly distributed on one side of the arched frame 1; a laser emitter 3 is installed inside the positioning cylinder 2, and the laser emitter 3 is parallel to the axis of the arched frame 1; after the tunnel entrance is excavated, a positioning device is set up inside the tunnel, the height of the arched frame 1 is adjusted, and the axis of the arched frame 1 is made to coincide with the tunnel axis. When determining the position of the edge blast holes, multiple laser emitters 3 evenly distributed on one side of the arched frame 1 simultaneously emit lasers to the tunnel face, thereby forming multiple laser projection points at the edge of the tunnel face, thus marking the position of the edge blast holes and improving the positioning accuracy of drilling and blasting excavation.

[0040] The bottom ends of the arch frame 1 are fixedly connected to the base 4; the lower side of the base 4 is rotatably connected to the roller 5 through the bracket; by setting the base 4 and the roller 5, the arch frame 1 can move inside the tunnel, so that the arch frame 1 can move forward with the advancement of the tunnel face, thereby improving the construction efficiency of tunnel excavation.

[0041] The positioning cylinder 2 has an anti-collision plate 6 fixedly connected inside its open end, and the anti-collision plate 6 is made of transparent material; the laser emitter 3 is located inside the cavity formed between the positioning cylinder 2 and the anti-collision plate 6; since the emitting end of the laser emitter 3 always faces the working face, the stones generated during the blasting process at the working face are easily splashed to the arch frame 1 and impact the laser emitter 3, which can easily damage the laser emitter 3. By setting the anti-collision plate 6, the splashed stones can be blocked, preventing the stones from directly impacting the laser emitter 3 and extending the service life of the device.

[0042] An air pump 7 is installed on the upper side of the base 4; an air pipe 8 is fixedly connected inside the arched frame 1, and the air pump 7 is connected to the air pipe 8; an elastic corrugated pipe 9 is fixedly connected to the inner side wall of the top of the positioning cylinder 2 near the anti-collision plate 6, and the elastic corrugated pipe 9 is connected to the air pipe 8 through a conduit 10; a sponge block 11 is fixedly connected to the bottom of the elastic corrugated pipe 9 through a mounting plate; an elastic rope 12 is fixedly connected between the positioning cylinder 2 and the mounting plate; the anti-collision plate 6 is located between the laser emitter 3 and the sponge block 11, and the surface of the sponge block 11 is in contact with the surface of the anti-collision plate 6; during blasting operations at the working face, the flying debris... After stones hit the surface of the crash barrier 6, they easily leave dirt or dust on the surface of the crash barrier 6. Therefore, after the blasting operation, air is supplied to the air pipe 8 through the air pump 7. The gas is then transmitted to various parts of the arch frame 1 through the air pipe 8. The gas also enters the interior of the elastic bellows 9 through the conduit 10, causing the elastic bellows 9 to extend downwards. This causes the sponge block 11 to slide and rub against the surface of the crash barrier 6. By controlling the air pump 7 to start and stop continuously, the sponge block 11 can be scraped up and down on the surface of the crash barrier 6, thereby wiping away the stains on the surface of the crash barrier 6 and avoiding the problem of the stains blocking the laser beam during subsequent use.

[0043] A flexible hose 13 is fixedly connected inside the sponge block 11, and the flexible hose 13 is set in an inclined state; one end of the flexible hose 13 is connected to the elastic corrugated pipe 9, and the other end faces the anti-collision plate 6; by setting the flexible hose 13, as the elastic corrugated pipe 9 extends downward, the airflow inside the elastic corrugated pipe 9 will be sprayed outward through the flexible hose 13 simultaneously, thereby further blowing away the mud and dust on the surface of the anti-collision plate 6 and improving the cleaning efficiency of the anti-collision plate 6.

[0044] A guide shell 14 is embedded and fixedly connected to the side of the sponge block 11 near the anti-collision plate 6, and the cross-sectional shape of the guide shell 14 is circular. The guide shell 14 has an opening near the anti-collision plate 6. The middle part of the hose 13 is tangent to the guide shell 14 and is interconnected with it. A rotating rod 15 is rotatably connected inside the guide shell 14. A set of paddles 16 are evenly distributed around the circumference of the rotating rod 15, and the airflow can push the paddles 16 to rotate when passing through the inside of the hose 13. An elastic block 17 is fixedly connected to the free end of the paddle 16. When the airflow passes through the hose 13, it will pass through the guide shell 14 and push the paddles 16 to rotate. Then, multiple paddles 16 intermittently approach the anti-collision plate 6 and bounce on the surface of the anti-collision plate 6 through the elastic block 17 at the end of the paddle 16, causing the anti-collision plate 6 to generate a small vibration, thereby causing the dirt and dust on the surface of the anti-collision plate 6 to fall off quickly. Combined with the wiping of the sponge block 11, the cleaning efficiency of the anti-collision plate 6 is further improved.

[0045] A baffle 18 is fixed to the inner side wall of the top of the positioning cylinder 2 near the position of the sponge block 11, and the sponge block 11 is located between the anti-collision plate 6 and the baffle 18. By setting the baffle 18 to shield the sponge block 11 and the elastic corrugated pipe 9, the problem of flying stones hitting the sponge block 11 and the elastic corrugated pipe 9 and causing them to deform and be damaged is avoided, thereby extending the service life of the sponge block 11 and the elastic corrugated pipe 9.

[0046] A magnetic block 19 is fixedly attached to the side of the baffle 18 near the sponge block 11; a groove 20 is formed inside the sponge block 11; a movable ball 21 is slidably connected inside the groove 20, and the movable ball 21 is made of iron; a spring is fixedly attached between the movable ball 21 and the side wall of the groove 20; a metal block 22 is fixedly attached to the end of the groove 20 away from the spring; when the elastic rope 12 pulls the sponge block 11 back to the top of the positioning cylinder 2, the magnetic block 19 attracts the movable ball 21, thereby causing the movable ball 21 to slide inside the groove 20 and hit the metal block 22, thereby causing the sponge block 11 to shake, shaking off the impurities adsorbed during the wiping process, so that the sponge block 11 maintains a certain self-cleaning ability and improves the cleaning efficiency of the subsequent cleaning of the anti-collision plate 6 by the sponge block 11.

[0047] Example 2

[0048] like Figure 6 As shown in the comparative embodiment one, another embodiment of the present invention is as follows: a pair of elastic plates 23 are fixedly connected to the side wall surface of the groove 20 between the movable ball 21 and the metal block 22; by setting a pair of elastic plates 23 inside the groove 20, the movable ball 21 will squeeze the elastic plates 23 when sliding inside the groove 20, and cause the elastic plates 23 to deform and store energy. When the movable ball 21 passes the middle of the elastic plate 23, the movable ball 21 will be subjected to the combined action of magnetic force and elastic plate 23 rebound force, thereby increasing the impact force of the movable ball 21 on the metal block 22, increasing the shaking amplitude of the sponge block 11, and further shaking off the impurities inside the sponge block 11.

[0049] Working principle: After the tunnel entrance is excavated, a positioning device is set up inside the tunnel. The height of the arch frame 1 is adjusted to ensure that its axis coincides with the tunnel axis. When determining the position of the edge blast holes, multiple laser emitters 3 evenly distributed on one side of the arch frame 1 simultaneously emit lasers towards the tunnel face, thereby forming multiple laser projection points at the edge of the tunnel face, thus marking the position of the edge blast holes and improving the positioning accuracy of drilling and blasting excavation. By setting up a base 4 and rollers 5, the arch frame 1 can be moved easily inside the tunnel, allowing it to move forward as the tunnel face advances, improving the construction efficiency of tunnel excavation. Since the emitting end of the laser emitter 3 is always facing the tunnel face, rocks generated during blasting at the tunnel face are easily splashed onto the arch frame. At the arch frame 1, flying stones can easily collide with the laser emitter 3, causing damage. By installing a crash barrier 6, flying stones can be blocked, preventing direct impact on the laser emitter 3 and extending the lifespan of the device. During blasting operations at the working face, flying stones can leave dirt or dust on the surface of the crash barrier 6 after impact. Therefore, after blasting, air is supplied to the air pipe 8 via the air pump 7, and the gas is then transmitted to various parts of the arch frame 1 through the air pipe 8. The gas also enters the elastic bellows 9 through the conduit 10, causing the elastic bellows 9 to extend downwards, which in turn causes the sponge block 11 to slide and rub against the surface of the crash barrier 6. By controlling the continuous starting and stopping of the air pump 7, the sponge block 11 can slide and rub against the surface of the crash barrier 6. The surface is scraped up and down to remove dirt from the surface of the crash barrier 6, preventing the dirt from blocking the laser beam during subsequent use. By using an inclined flexible hose 13, as the elastic bellows 9 extends downwards, the airflow inside the bellows 9 is simultaneously ejected outwards through the hose 13, further blowing away dirt and dust from the surface of the crash barrier 6, improving cleaning efficiency. As the airflow passes through the hose 13, it passes through the guide shell 14 and pushes the paddles 16 to rotate. Multiple paddles 16 then intermittently approach the crash barrier 6, and the elastic blocks 17 at the ends of the paddles 16 strike the surface of the crash barrier 6, causing it to vibrate slightly. This causes the dirt and dust on the surface of the crash barrier 6 to fall off quickly, complementing the wiping action of the sponge block 11. This further improves the cleaning efficiency of the anti-collision plate 6; by setting baffles 18 to shield the sponge block 11 and the elastic corrugated pipe 9, the problem of flying stones hitting the sponge block 11 and the elastic corrugated pipe 9 and causing them to deform and be damaged is avoided, thereby extending the service life of the sponge block 11 and the elastic corrugated pipe 9; when the elastic rope 12 pulls the sponge block 11 back to the top of the positioning cylinder 2, the magnetic block 19 attracts the movable ball 21, which in turn causes the movable ball 21 to slide inside the slide groove 20 and hit the metal block 22, thereby causing the sponge block 11 to shake, shaking off the impurities adsorbed by the sponge block 11 during the wiping process, so that the sponge block 11 maintains a certain self-cleaning ability, and improving the subsequent cleaning efficiency of the sponge block 11 on the anti-collision plate 6;By setting a pair of elastic plates 23 inside the slide groove 20, the movable ball 21 squeezes the elastic plates 23 as it slides inside the slide groove 20, causing the elastic plates 23 to deform and store energy. When the movable ball 21 passes the middle of the elastic plate 23, it is subjected to the combined action of magnetic force and the rebound force of the elastic plate 23, thereby increasing the impact force of the movable ball 21 on the metal block 22, increasing the shaking amplitude of the sponge block 11, and further shaking off impurities inside the sponge block 11.

[0050] The terms "front," "back," "left," "right," "top," and "bottom" all refer to the figures in the accompanying drawings. Figure 1 Based on the perspective of the observer, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0051] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling overbreak and underbreak in the mechanized construction of a large-section tunnel in complex geology, characterized in that: The method comprises the following steps: S1: after the tunnel entrance is excavated, a positioning device is arranged inside the tunnel, the height of the arch-shaped frame (1) is adjusted, the axis of the arch-shaped frame (1) is kept coincident with the axis of the tunnel, and it is checked whether the laser emitter (3) can work normally; S2: when the position of the edge blast hole is determined, the multiple laser emitters (3) on one side of the arch-shaped frame (1) emit laser light to the tunnel face at the same time, thereby forming multiple laser projection points at the edge position of the tunnel face, so as to mark the position of the edge blast hole; S3: according to the position marked by the laser, multiple edge blast holes are drilled on the tunnel face by the drilling device, then the remaining middle blast holes are drilled, and then explosives are arranged in the blast holes and detonated; The positioning device in step S1 comprises an arch-shaped frame (1); the shape of the arch-shaped frame (1) is matched with the designed excavation contour line of the tunnel, and the arch-shaped frame (1) is combined and fixed by multiple arc-shaped I-beams; a group of positioning cylinders (2) are uniformly distributed on one side of the arch-shaped frame (1); a laser emitter (3) is arranged in the positioning cylinder (2), and the laser emitter (3) is kept parallel to the axis of the arch-shaped frame (1); Both ends of the bottom of the arch-shaped frame (1) are fixedly connected with a base (4); a roller (5) is rotatably connected to the lower side of the base (4) through a support; A collision-proof plate (6) is fixedly connected to the opening end of the positioning cylinder (2), and the collision-proof plate (6) is made of transparent material; the laser emitter (3) is arranged in the cavity formed between the positioning cylinder (2) and the collision-proof plate (6); A gas pump (7) is arranged on the upper side of the base (4); a gas pipe (8) is fixedly connected in the arch-shaped frame (1), and the gas pump (7) is in communication with the gas pipe (8); an elastic bellows (9) is fixedly connected to the inner side wall of the top of the positioning cylinder (2) near the collision-proof plate (6), and the elastic bellows (9) is in communication with the gas pipe (8) through a conduit (10); a sponge block (11) is fixedly connected to the bottom of the elastic bellows (9) through a mounting plate; an elastic rope (12) is fixedly connected between the positioning cylinder (2) and the mounting plate; the collision-proof plate (6) is located between the laser emitter (3) and the sponge block (11), and the sponge block (11) and the surface of the collision-proof plate (6) are attached to each other; A hose (13) is fixedly connected in the sponge block (11), and the hose (13) is arranged in an inclined state; one end of the hose (13) is in communication with the elastic bellows (9), and the other end faces the collision-proof plate (6); A guide shell (14) is embeddedly fixedly connected to one side of the sponge block (11) near the collision-proof plate (6), and the cross-sectional shape of the guide shell (14) is circular; an opening is arranged on the guide shell (14) near the collision-proof plate (6); the middle of the hose (13) is tangent to the guide shell (14) and in communication with each other; a rotating rod (15) is rotatably connected in the guide shell (14); a group of push pieces (16) are uniformly distributed on the surface of the rotating rod (15), and the airflow passing through the inside of the hose (13) can drive the push pieces (16) to rotate; an elastic block (17) is fixedly connected to the free end of the push piece (16).

2. The method according to claim 1, characterized in that: The inner side wall of the top of the positioning cylinder (2) is fixedly connected with a baffle (18) near the sponge block (11), and the sponge block (11) is located between the anti-collision plate (6) and the baffle (18).

3. The method according to claim 2, wherein the method is characterized in that: The side of the baffle (18) near the sponge block (11) is fixedly connected with a magnetic block (19); the inside of the sponge block (11) is provided with a sliding groove (20); the inside of the sliding groove (20) is slidably connected with a movable ball (21), and the material of the movable ball (21) is iron; the movable ball (21) and the side wall of the sliding groove (20) are fixedly connected with a spring; the end of the sliding groove (20) away from the spring is fixedly connected with a metal block (22).

4. The method according to claim 3, characterized in that: A pair of elastic sheets (23) are fixedly connected between the side wall surface of the sliding groove (20) between the movable ball (21) and the metal block (22).

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