A positioning drilling coring test device and method for a tunnel flexible net lining structure

Abstract

The application discloses a kind of tunnel flexible net lining structure's positioning drilling coring test device and method, including support, mould forming device, lifting drive device, longitudinal positioning device, transverse positioning device and drilling device;Mould forming device includes bottom plate and the side plate being set to bottom plate around, longitudinal positioning device is connected below support by lifting drive device, longitudinal positioning device includes two mutually parallel longitudinal sliding grooves, transverse positioning device includes transverse sliding plate, transverse sliding plate both ends are slidably arranged in two longitudinal sliding grooves, transverse screw rod is screw-connected on transverse sliding plate, and loading platform is slidably arranged on transverse sliding plate, and loading platform is screw-connected with transverse screw rod, drilling device includes drill bit, driving motor, sight distance camera and annular direct light.The application can obtain the sample of different flexible net drilling position in flexible net lining structure, solves the technical problem that individualized sampling cannot be carried out according to the internal net material distribution of test piece.

Description

Technical Field

[0001] This invention relates to the field of sampling device technology, and in particular to a positioning borehole core sampling test device and method for a flexible mesh lining structure in a tunnel. Background Technology

[0002] During the construction of railway tunnels, the stability of tunnel excavation is affected by complex geological environments. Among these, under high ground stress conditions, the dynamic instability induced by brittle hard rock after excavation unloading—known as rockburst—seriously affects the safe construction of tunnels and poses significant risks to life and property. To ensure tunnel excavation stability, rock support, as the most direct and effective rockburst prevention measure after underground cavern excavation, has received increasing attention. Flexible protective netting, as an emerging polymer material, is made from polymer filament fibers and advanced coating technology. It possesses high strength and high toughness, acting as a flexible buffer and energy release mechanism in rockburst protection, making it highly beneficial for preventing tunnel rockburst disasters.

[0003] However, the material characteristics of the flexible protective netting dictate that its warp and weft strips have a certain width, which to some extent hinders shotcreting. Furthermore, whether the coating technology of the flexible protective netting supports concrete adhesion are key areas requiring further research. Based on this, core drilling technology is used to obtain concrete-flexible protective netting-concrete flexible protective netting lining samples. Mechanical testing and analysis can be conducted on these samples to study the degree of integration of the flexible protective netting lining structure, providing a basis for the safe construction and operation of rockburst tunnels.

[0004] Existing technologies have enabled precise and portable concrete core drilling, but flexible mesh lining structures exhibit significant differences in sampling locations, specifically in two aspects:

[0005] ① Because the width of the flexible mesh strip is at least about 20mm and the mesh width is about 120mm, while the standard specimen for core sampling of concrete is 200mm, it can be seen that the specimen obtained by drilling may contain a cross-shaped flexible protective mesh, a grid-shaped mesh, or more mesh shapes. The different mesh arrangements will seriously affect the mechanical properties of the core sample.

[0006] ② The flexible net is fixed to the tunnel cross section by anchor bolts. However, the anchor bolts can only fix one point. The flexible net far from the anchor bolts will fall naturally due to gravity, resulting in a gap between the flexible net and the initial sprayed surface. Therefore, the degree of fit between the flexible net and the initial sprayed surface varies at different locations, which will seriously affect the performance of the core sample.

[0007] Existing technologies cannot penetrate concrete to locate the flexible mesh inside, and cannot perform personalized sampling based on the distribution of mesh material inside the specimen. Summary of the Invention

[0008] The purpose of this invention is to provide a positioning drilling core sampling test device and method for flexible mesh lining structures in tunnels, which can obtain samples from different drilling locations of the flexible mesh in the flexible mesh lining structure, and solve the technical problem of difficulty in performing personalized sampling based on the distribution of mesh material inside the specimen.

[0009] To achieve the above objectives, the present invention provides the following solution:

[0010] This invention provides a positioning drilling and core sampling test device for a flexible mesh lining structure in a tunnel, comprising a support, a mold forming device, a lifting drive device, a longitudinal positioning device, a transverse positioning device, and a drilling device;

[0011] The support is provided with a mold groove for installing the mold forming device; the mold forming device includes a base plate and side plates disposed around the base plate, and the mold forming device is used to be installed in the mold groove with the base plate facing upward;

[0012] The longitudinal positioning device is connected to the support below through the lifting drive device. The lifting drive device can drive the longitudinal positioning device to rise and fall. The longitudinal positioning device includes two parallel longitudinal slides, which are fixedly connected by a crossbeam. The transverse positioning device includes a transverse slide plate, which is slidably disposed at both ends in the two longitudinal slides. Each of the two longitudinal slides is provided with a longitudinal positioning bolt, and the transverse slide plate is provided with longitudinal positioning screw holes that cooperate with the longitudinal positioning bolts at both ends.

[0013] A transverse screw perpendicular to the longitudinal groove is threaded onto the transverse sliding plate. The transverse screw is connected to a rotating wheel. A mounting platform is slidably disposed on the transverse sliding plate along the direction of the transverse screw. The mounting platform is threadedly connected to the transverse screw. A transverse positioning bolt is provided on the mounting platform. A transverse groove is provided on the transverse sliding plate. The transverse positioning bolt can pass through the transverse groove and be threaded into a transverse positioning screw hole on the lower end face of the mounting platform to fasten the mounting platform to the transverse sliding plate.

[0014] The drilling device includes a drill bit, a drive motor, a line-of-sight camera, and a ring-shaped direct light. The drill bit is mounted on the mounting platform and driven by the drive motor. The drill bit faces the mold forming device. The line-of-sight camera and the ring-shaped direct light are disposed inside the drill bit.

[0015] Preferably, each end of the transverse slide plate is fixedly connected to a long screw, and the end of each long screw away from the transverse slide plate passes through the end face of the longitudinal slide groove and is threaded with a self-tightening nut.

[0016] Preferably, the transverse slide plate has lateral grooves on both sides, the mounting platform has lateral bosses on both sides that are slidably connected to the lateral grooves, the transverse slide plate has a central groove in the middle, and the drill bit extends through the central groove toward the direction of the mold forming device.

[0017] Preferably, the drilling device further includes a water supply system, which includes a water tank, a water pipeline, and a water pump. The water pipeline is connected to the water tank and is used to supply cooling water to the drill bit. The water pump is installed on the water pipeline.

[0018] Preferably, the support around the mold groove is provided with mold pins for fixing the mold forming device in the mold groove.

[0019] Preferably, a load-bearing structural column is fixed at each of the four corners of the bottom of the support.

[0020] Preferably, the lifting drive device is a hydraulic lifting rod, and a hydraulic lifting rod is provided at each end of the longitudinal slide groove. One end of the hydraulic lifting rod is connected to the bottom surface of the support, and the other end is connected to the longitudinal slide groove.

[0021] This invention also provides a method for positioning borehole coring test of a tunnel flexible mesh lining structure, based on the above-described positioning borehole coring test device for a tunnel flexible mesh lining structure, comprising the following steps:

[0022] (1) Apply a preliminary sprayed concrete layer at the bottom of the mold forming device, then lay and fix the flexible protective net, place the mold forming device in the mold groove, turn on the viewing distance camera and the ring direct light, observe the position of the light illumination which is the drilling position, and use this as a guide to first start the longitudinal fixation of the drilling position. According to the combination structure of the longitudinal positioning device and the transverse positioning device, perform the preliminary fixation and final fixation of the longitudinal position of the transverse positioning device on the longitudinal positioning device, then perform the preliminary fixation and final fixation of the transverse position of the drilling device on the transverse positioning device, take a photo of the sampling point, accurately read the unbonded distance between the flexible protective net and the preliminary sprayed concrete layer, and finally turn off the electronic equipment.

[0023] (2) After the drilling device is fixed in position, remove the mold forming device and apply a sprayed concrete layer on the upper part of the flexible protective net. After the specimen is cured, place the mold forming device in the mold groove again, start the lifting drive device and drive motor, and start drilling and core taking of the specimen at the positioning point. Finally, obtain the core sample. After the core taking is completed, turn off the lifting drive device and drive motor, remove the mold forming device, take out the remaining specimen, clean and store each part of the device.

[0024] Preferably, when multiple core drilling operations are performed on the same flexible mesh lining structure mold, the transverse and longitudinal coordinates of different positions are recorded by performing multiple beam positioning and imaging operations. Then, multiple core drilling operations are performed. Before each drilling operation, the transverse and longitudinal positions of the drilling device are fixed according to the transverse and longitudinal coordinates of different sampling points. After each sampling operation, the fixing of the transverse and longitudinal positions is released before fixing the next position.

[0025] The present invention achieves the following technical effects compared to the prior art:

[0026] This invention provides a positioning drilling and core sampling test device and method for flexible mesh lining structures in tunnels. It is used to obtain samples from different drilling locations of the flexible mesh in the lining structure. A vertical beam of the same diameter as the borehole is used for positioning guidance. The fabrication of the flexible mesh lining structure mold is divided into two stages: the first stage exposes the flexible mesh to facilitate obtaining the core sampling location; the second stage forms a complete specimen for core sampling. This invention employs a bottom-up drilling method to simulate the situation where the flexible mesh sags from the tunnel arch, resulting in poor adhesion to the initial sprayed surface. The structural forming mold can restore the sag state of the flexible mesh, and a line-of-sight camera can accurately acquire the mesh adhesion at the drilling location. The drilling position is fixed in two steps, using longitudinal and transverse positioning devices to fix the position of the drilling device and avoid machine vibration during drilling. The drilling equipment of this invention is equipped with a mounting platform, which can mount the commonly used power unit and water supply system of the core drilling machine, enabling the synchronous movement of these devices with the drill bit. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of the positioning borehole coring test device for the flexible mesh lining structure of the tunnel provided by the present invention;

[0029] Figure 2 This is a schematic diagram of the structure when the support and the mold forming device are separated in this invention;

[0030] Figure 3 This is a schematic diagram showing the structural connection between the longitudinal positioning device and the transverse sliding plate in this invention;

[0031] Figure 4 This is a schematic diagram of the structural connection between the transverse sliding plate and the mounting platform in this invention;

[0032] Figure 5This is a schematic diagram showing the structural connection between the drilling device and the mounting platform in this invention;

[0033] Figure 6 This is a schematic diagram of the flexible mesh support structure, positioning, and core sampling in this invention.

[0034] In the diagram: 1-Support, 101-Mold Groove, 102-Mold Pin, 103-Bearing Structure Column, 2-Mold Forming Device, 201-Base Plate, 202-Side Plate, 3-Lifting Drive Device, 4-Longitudinal Positioning Device, 401-Longitudinal Slide, 402-Crossbeam, 403-Longitudinal Positioning Bolt, 5-Transverse Positioning Device, 501-Transverse Slide Plate, 502-Longitudinal Positioning Screw Hole, 503-Transverse Screw, 504-Roller, 505-Transverse Slide, 506-Long Screw, 507-Self-Tightening Nut, 508-Side Groove, 50 9-Central groove, 6-Drilling device, 601-Drill bit, 602-Drive motor, 603-Line-of-sight camera, 604-Ring direct light, 605-Water tank, 606-Water pipeline, 607-Water pump, 7-Mounting platform, 701-Horizontal positioning bolt, 702-Horizontal positioning screw hole, 703-Side boss, 704-Horizontal threaded round hole, 705-Upper plane round hole, 8-Initial shotcrete layer, 9-Flexible protective net, 10-Re-shotcrete layer, 11-Photograph of sampling point, 12-Anchor bolt and gasket, 13-Core sample. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] The purpose of this invention is to provide a positioning drilling core sampling test device and method for a flexible mesh lining structure in a tunnel, so as to solve the problems existing in the prior art, obtain samples from different flexible mesh drilling locations in the flexible mesh lining structure, and solve the technical problem of difficulty in performing personalized sampling based on the distribution of mesh material inside the specimen.

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] like Figures 1-6 As shown, this embodiment provides a positioning drilling core sampling test device for a tunnel flexible mesh lining structure, including a support 1, a mold forming device 2, a lifting drive device 3, a longitudinal positioning device 4, a transverse positioning device 5, and a drilling device 6.

[0039] The support 1 is provided with a mold groove 101 for installing a mold forming device 2; the mold forming device 2 includes a base plate 201 and side plates 202 disposed around the base plate 201, and the mold forming device 2 is installed in the mold groove 101 with the base plate 201 facing upward.

[0040] The longitudinal positioning device 4 is connected to the support 1 below by the lifting drive device 3. The lifting drive device 3 can drive the longitudinal positioning device 4 to rise and fall. The longitudinal positioning device 4 includes two parallel longitudinal slides 401, which are fixedly connected by a crossbeam 402. The transverse positioning device 5 includes a transverse slide plate 501, which is slidably disposed in the two longitudinal slides 401 at both ends. Each of the two longitudinal slides 401 is provided with a longitudinal positioning bolt 403. The transverse slide plate 501 is provided with longitudinal positioning screw holes 502 at both ends that cooperate with the longitudinal positioning bolts 403.

[0041] A transverse screw 503 perpendicular to the longitudinal slide groove 401 is threaded onto the transverse slide plate 501. The transverse screw 503 is connected to the rotating wheel 504. A mounting platform 7 is slidably mounted on the transverse slide plate 501 along the direction of the transverse screw 503. The mounting platform 7 is threadedly connected to the transverse screw 503. A transverse positioning bolt 701 is provided on the mounting platform 7. A transverse slide groove 505 is provided on the transverse slide plate 501. The transverse positioning bolt 701 can pass through the transverse slide groove 505 and be threaded into the transverse positioning screw hole 702 on the lower end face of the mounting platform 7 to fasten the mounting platform 7 to the transverse slide plate 501.

[0042] The drilling device 6 includes a drill bit 601, a drive motor 602, a line-of-sight camera 603, and a ring direct light 604. The drill bit 601 is mounted on the mounting platform 7 and driven by the drive motor 602. The drill bit 601 faces the mold forming device 2. The line-of-sight camera 603 and the ring direct light 604 are disposed inside the drill bit 601.

[0043] In this embodiment, at both ends of the transverse slide plate 501, a long screw 506 is fixedly connected to each side. The end of each long screw 506 away from the transverse slide plate 501 passes through the end face of the longitudinal slide groove 401 and is threaded with a self-tightening nut 507.

[0044] In this embodiment, the two sides of the transverse slide plate 501 are provided with lateral grooves 508, the two sides of the mounting platform 7 are provided with lateral bosses 703 that are slidably connected to the lateral grooves 508, the middle of the transverse slide plate 501 is provided with a central groove 509, and the drill bit 601 extends through the central groove 509 toward the direction close to the mold forming device 2.

[0045] In this embodiment, the drilling device 6 also includes a water supply system, which includes a water tank 605, a water supply pipe 606 and a water pump 607. The water supply pipe 606 is connected to the water tank 605 and is used to provide cooling water to the drill bit 601. The water pump 607 is installed on the water supply pipe 606.

[0046] In this embodiment, mold pins 102 are provided on the supports 1 around the mold groove 101 to fix the mold forming device 2 in the mold groove 101.

[0047] In this embodiment, a load-bearing structural column 103 is fixed at each of the four corners of the bottom of the support 1.

[0048] In this embodiment, the lifting drive device 3 is a hydraulic lifting rod. A hydraulic lifting rod is provided at each end of the longitudinal slide groove 401. One end of the hydraulic lifting rod is connected to the bottom surface of the support 1, and the other end is connected to the longitudinal slide groove 401.

[0049] Because the adhesion between the flexible mesh and the initial sprayed surface is worst at the tunnel arch, this invention uses the flexible mesh lining structure at the tunnel arch as the core sampling object, and the entire device uses a bottom-up core sampling method. The device is based on support 1, and the entire device is built on the load-bearing structural column 103. The upper end of the hydraulic lifting rod is directly connected to support 1. The hydraulic lifting rod 2 consists of three nested cylindrical steel pipes, and its lower end is connected to the positioning device, realizing the hydraulically controlled lifting of the entire device.

[0050] The longitudinal positioning device 4 is first connected to the hydraulic lifting rod. The longitudinal positioning device 4 mainly consists of two longitudinal slides 401, which are connected by two columnar crossbeams 402 to enhance the stability of the device during use. The transverse positioning device 5 mainly consists of a rectangular plate (transverse slide plate 501). The two ends of the transverse slide plate 501 extend into the two longitudinal slides 401, and each end has a threaded circular hole (longitudinal positioning screw hole 502). When the transverse slide plate 501 slides along the longitudinal slides 401 to the designated position, the longitudinal positioning bolt 403 passes through the longitudinal slides 401 and is fixed into the end longitudinal positioning screw hole 502, thus initially fixing the transverse positioning device 5 in the longitudinal position. Next, to make the longitudinal fixation more secure, a long screw 506 is provided on each side of both ends of the transverse slide plate 501. The long screw 506 passes through the longitudinal slide groove 401 along the longitudinal direction. As the transverse slide plate 501 slides, the exposed end of the long screw 506 changes from short to long. After the transverse slide plate 501 is initially fixed, the self-tightening nut 507 is tightened to achieve the final fixation of the transverse positioning device 5 in the longitudinal direction.

[0051] The transverse positioning device 5 has two transverse sliding grooves 505, two lateral grooves 508, and a central groove 509. The three work together to enable the drilling device 6 to be mounted on the transverse positioning device 5. The main components of the drilling device 6 are connected to the mounting platform 7. The two lateral bosses 703 are respectively embedded in the two lateral grooves 508. The drill bit 601 passes through the central groove 509, thereby enabling the drilling device 6 to slide on the transverse positioning device 5. The transverse positioning device 5 has a transverse screw 503 that can rotate along the axis at its center. One end of the transverse screw 503 is connected to a rotating wheel 504. The mounting platform 7 has a through transverse threaded hole 704 at its center. The transverse screw 503 passes through the transverse threaded hole 704 and is threadedly connected to the transverse threaded hole 704. This enables the rotating wheel 504 to rotate in conjunction with the transverse screw 503, thus advancing the drilling device 6 forward or backward. When the drilling device 6 moves to the designated position in the transverse direction, the rotation of the rotating wheel 504 stops, thus initially fixing the drilling device 6 in the transverse position. Next, to make the lateral fixation more secure, the two ends of the mounting platform 7 are respectively provided with an upper flat circular hole 705 and a lower flat threaded circular hole (lateral positioning screw hole 702). After the drilling device 6 is initially fixed, the lateral positioning bolt 701 is used to pass through the upper flat circular hole 705 and the lateral sliding groove 505 and fixed into the lower flat threaded circular hole (lateral positioning screw hole 702) to achieve the final lateral fixation of the drilling device 6.

[0052] The drilling device 6 provides two functions: precise positioning and core drilling, both powered by electricity. First, the drill bit 601 has a hollow internal structure, with a line-of-sight camera 603 and a ring-shaped direct-light 604 at its top. The beam of light can illuminate the flexible protective netting 9 of the specimen along the drill bit 601. As lateral and longitudinal positioning proceeds, the beam guides the selection of the desired drilling location. After the location is determined, the line-of-sight camera 603 can take a photograph 11 of the sampling point and read the distance between the flexible protective netting 9 and the initial shotcrete layer 8 in the photograph to measure the degree of adhesion. Core drilling is performed by the drill bit 601, which is controlled by a hydraulic lifting rod to gradually drill upwards to extract the specimen. The rotation power of the drill bit 601 is provided by a drive motor 602. During drilling, a water supply system provides water to cool the drill bit 601. The water supply system includes a water tank 605, a water pipe 606, and a water pump 607.

[0053] The mold forming device 2 consists of a base plate 201 and side plates 202. The bottom of the mold is a layer of initial sprayed concrete 8, with a layer of flexible protective netting 9 laid in the middle. The flexible protective netting 9 is fixed at the four corners by anchor rods and gaskets 12. At this time, the mold forming device 2 can be placed into the mold groove 101 for drilling beam positioning and taking a photograph 11 of the sampling point. Then, the mold forming device 2 is removed, a layer of re-sprayed concrete 10 is applied, and after curing, the specimen can be put back, the four mold pins 102 are closed, and drilling is performed to obtain a core sample 13.

[0054] A method for positioning borehole coring test of a flexible mesh lining structure in tunnels, based on the aforementioned positioning borehole coring test device for flexible mesh lining structures in tunnels, includes the following steps:

[0055] (1) Apply a preliminary sprayed concrete layer 8 at the bottom of the mold forming device 2, then lay and fix the flexible protective net 9, place the mold forming device 2 in the mold groove 101, turn on the viewing distance camera 603 and the ring direct light 604, observe the position illuminated by the light which is the drilling position, and use this as a guide to first fix the longitudinal position of the drilling position. According to the combination structure of the longitudinal positioning device 4 and the transverse positioning device 5, perform the preliminary and final fixation of the longitudinal position of the transverse positioning device on the longitudinal positioning device, then perform the preliminary and final fixation of the transverse position of the drilling device 6 on the transverse positioning device, take a photo of the sampling point, accurately read the non-adhesion distance between the flexible protective net 9 and the preliminary sprayed concrete layer 8, and finally turn off the electronic equipment.

[0056] (2) After the drilling device 6 is fixed in position, the mold forming device 2 is removed, and a sprayed concrete layer 10 is applied on the upper part of the flexible protective net 9. After the specimen is cured, the mold forming device 2 is placed in the mold groove 101 again, the lifting drive device 3 and the drive motor 602 are started, and the specimen at the positioning point is drilled and cored. Finally, the cored sample is obtained. After the cored sample is taken, the lifting drive device 3 and the drive motor 602 are turned off, the mold forming device 2 is removed, the remaining specimens are taken out, and each part of the device is cleaned and stored.

[0057] In this embodiment, when multiple core drilling operations are performed on the same flexible mesh lining structure mold, the horizontal and vertical coordinates of different positions are recorded by performing multiple beam positioning and imaging operations. Then, multiple core drilling operations are performed. Before each drilling operation, the horizontal and vertical positions of the drilling device 6 are fixed according to the horizontal and vertical coordinates of different sampling points. After each sampling operation, the horizontal and vertical positions are released and the next position is fixed.

[0058] The positioning drilling and coring test device for flexible mesh lining structures in tunnels provided by this invention offers two functions: drilling positioning and drilling coring. The positioning function cleverly utilizes the hollow cylindrical nature of the drill bit, modifying it into a light illumination tube. The location where the beam forms is the drilling position, and the vertical beam characteristic makes positioning precise and convenient. Additionally, a line-of-sight camera is installed inside the drill bit, which can capture the distance between the flexible mesh at the sampling point and the initial sprayed surface in the vertical direction. Furthermore, the device strengthens the fixation between components after positioning, effectively preventing vibration and displacement between components during drilling. This test device has the advantages of being scientifically effective, simple in structure, and easy to operate.

[0059] The positioning drilling and core sampling method for flexible mesh lining structures in tunnels provided by this invention fully utilizes the layered characteristics of the flexible mesh lining structure, completing the positioning drilling and core sampling in stages. Positioning is performed after the flexible mesh is laid, and core sampling is conducted after the lining structure has fully cured. The entire process consumes no additional energy and supports multiple core samplings using the same mold. This core sampling method has the advantages of being well-organized, ingeniously designed, and rationally effective.

[0060] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A positioning borehole core sampling test device for a flexible mesh lining structure in a tunnel, characterized in that: It includes supports, mold forming devices, lifting drive devices, longitudinal positioning devices, transverse positioning devices, and drilling devices; The support is provided with a mold groove for installing the mold forming device; the mold forming device includes a base plate and side plates disposed around the base plate, and the mold forming device is used to be installed in the mold groove with the base plate facing upward; The longitudinal positioning device is connected to the support below through the lifting drive device. The lifting drive device can drive the longitudinal positioning device to rise and fall. The longitudinal positioning device includes two parallel longitudinal slides, which are fixedly connected by a crossbeam. The transverse positioning device includes a transverse slide plate, which is slidably disposed at both ends in the two longitudinal slides. Each of the two longitudinal slides is provided with a longitudinal positioning bolt, and the transverse slide plate is provided with longitudinal positioning screw holes that cooperate with the longitudinal positioning bolts at both ends. A transverse screw perpendicular to the longitudinal groove is threaded onto the transverse sliding plate. The transverse screw is connected to a rotating wheel. A mounting platform is slidably disposed on the transverse sliding plate along the direction of the transverse screw. The mounting platform is threadedly connected to the transverse screw. A transverse positioning bolt is provided on the mounting platform. A transverse groove is provided on the transverse sliding plate. The transverse positioning bolt can pass through the transverse groove and be threaded into a transverse positioning screw hole on the lower end face of the mounting platform to fasten the mounting platform to the transverse sliding plate. The drilling device includes a drill bit, a drive motor, a line-of-sight camera, and a ring-shaped direct light. The drill bit is mounted on the mounting platform and driven by the drive motor. The drill bit faces the mold forming device. The line-of-sight camera and the ring-shaped direct light are disposed inside the drill bit.

2. The positioning borehole core sampling test device for tunnel flexible mesh lining structure according to claim 1, characterized in that: At both ends of the transverse slide plate, a long screw is fixedly connected to each side. The end of each long screw away from the transverse slide plate passes through the end face of the longitudinal slide groove and is threaded with a self-tightening nut.

3. The positioning borehole core sampling test device for tunnel flexible mesh lining structure according to claim 1, characterized in that: The transverse slide plate has lateral grooves on both sides, and the mounting platform has lateral bosses on both sides that are slidably connected to the lateral grooves. The transverse slide plate has a central groove in the middle, and the drill bit extends through the central groove toward the direction of the mold forming device.

4. The positioning borehole core sampling test device for tunnel flexible mesh lining structure according to claim 1, characterized in that: The drilling device also includes a water supply system, which includes a water tank, a water pipeline, and a water pump. The water pipeline is connected to the water tank and is used to supply cooling water to the drill bit. The water pump is installed on the water pipeline.

5. The positioning borehole core sampling test device for tunnel flexible mesh lining structure according to claim 1, characterized in that: The support around the mold groove is provided with mold pins for fixing the mold forming device in the mold groove.

6. The positioning borehole core sampling test device for tunnel flexible mesh lining structure according to claim 1, characterized in that: Each of the four corners of the bottom of the support is fixed with a load-bearing structural column.

7. The positioning borehole core sampling test device for tunnel flexible mesh lining structure according to claim 1, characterized in that: The lifting drive device is a hydraulic lifting rod. Each end of the longitudinal slide is provided with a hydraulic lifting rod. One end of the hydraulic lifting rod is connected to the bottom surface of the support, and the other end is connected to the longitudinal slide.

8. A method for positioning borehole core sampling test of a flexible mesh lining structure for tunnels, characterized in that, The positioning borehole coring test device for the tunnel flexible mesh lining structure according to any one of claims 1 to 7 includes the following steps: (1) Apply a preliminary sprayed concrete layer at the bottom of the mold forming device, then lay and fix the flexible protective net, place the mold forming device in the mold groove, turn on the viewing distance camera and the ring direct light, observe the position of the light illumination which is the drilling position, and use this as a guide to first start the longitudinal fixation of the drilling position. According to the combination structure of the longitudinal positioning device and the transverse positioning device, perform the preliminary fixation and final fixation of the longitudinal position of the transverse positioning device on the longitudinal positioning device, then perform the preliminary fixation and final fixation of the transverse position of the drilling device on the transverse positioning device, take a photo of the sampling point, accurately read the unbonded distance between the flexible protective net and the preliminary sprayed concrete layer, and finally turn off the electronic equipment. (2) After the drilling device is fixed in position, remove the mold forming device and apply a sprayed concrete layer on the upper part of the flexible protective net. After the specimen is cured, place the mold forming device in the mold groove again, start the lifting drive device and drive motor, and start drilling and core taking of the specimen at the positioning point. Finally, obtain the core sample. After the core taking is completed, turn off the lifting drive device and drive motor, remove the mold forming device, take out the remaining specimen, clean and store each part of the device.

9. The method for positioning borehole core sampling test of the flexible mesh lining structure of a tunnel according to claim 8, characterized in that: When drilling and core sampling is performed on the same flexible mesh lining structure mold multiple times, the horizontal and vertical coordinates of different positions are recorded by multiple beam positioning and shooting. Then, multiple drilling and core sampling are performed. Before each drilling, the horizontal and vertical positions of the drilling device are fixed according to the horizontal and vertical coordinates of different sampling points. After each sampling is completed, the horizontal and vertical positions are released and the next position is fixed.

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