A mine roadway surrounding rock loose circle automatic measuring device and a use method thereof

Abstract

The application provides a mine roadway surrounding rock loose circle automatic measuring device and a use method thereof, and particularly relates to the technical field of surrounding rock detection. The device comprises a control box, a crawling hydraulic cylinder, two sound wave bidirectional probes and two sets of supporting and stabilizing mechanisms. The supporting and stabilizing mechanism comprises a stabilizing platform and four hole wall supporting legs, the four hole wall supporting legs are arranged at equal intervals along the outer wall of the stabilizing platform and each is provided with a supporting hydraulic cylinder. Each hole wall supporting leg is hinged to the stabilizing platform through a passive supporting arm and an active supporting arm. The telescopic rod of the supporting hydraulic cylinder is rotationally connected to the active supporting arm of the corresponding hole wall supporting leg, and the active supporting arm is pushed or pulled back to realize the close adhesion or separation of the hole wall supporting leg and the inner wall of the test hole. The two stabilizing platforms are connected to the two sound wave bidirectional probes respectively on the side away from the crawling hydraulic cylinder. The application can automatically complete the measurement without manual operation, uses the sound wave bidirectional probe, repeatedly detects and takes the average value, and the result is more accurate.

Description

Technical Field

[0001] This invention patent relates to the field of surrounding rock detection technology, specifically to an automatic measuring device for the loosening zone of surrounding rock in mine roadways and its usage method. Background Technology

[0002] The loosened zone of the surrounding rock in a tunnel refers to a ring-shaped fractured and loosened area formed around the tunnel after the excavation of an underground project. This is caused by the disruption of the original stress balance, resulting in stress redistribution in the rock mass around the tunnel, which leads to reduced strength, development of fissures, and damage to its integrity.

[0003] The loosening zone has the following important significance: (1) Direct basis for support design: The rock within the loosening zone has poor self-stabilizing ability and will gradually collapse over time; the support structure (such as anchor bolts and anchor cables) supports the surrounding rock of the roadway based on the "suspension theory", "composite beam" and "reinforced arch theory", combining the rock within the loosening zone with the internal stable rock mass into a whole; therefore, the thickness (range) of the loosening zone is the most critical factor in determining the support parameters (anchor bolt length, spacing, support form). (2) Assess the stability of the surrounding rock: The larger the loosening zone, the more unstable the surrounding rock, and the higher the risk of large deformation or roof fall and spalling. (3) Judge the rheological characteristics of the roadway (long-term deformation of the surrounding rock): The roadway with a large loosening zone often has more obvious convergence deformation (cross-sectional reduction) and a longer duration. At present, the most commonly used and classic method for measuring the loosening zone of the surrounding rock is the sonic wave test method.

[0004] However, this method requires drilling, is a point-based measurement, and involves a large workload. It also requires filling the holes with water, making it difficult to measure the top plate and sides. In particular, the test for the loose ring of the top plate requires sealing the water in the hole with a plug and manually pushing the instrument with a drill rod, which is very inconvenient. Poor sealing can also easily cause water leakage, affecting the test results. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides an automatic measuring device for the loosening zone of surrounding rock in mine roadways and its usage method, the specific technical solution of which is as follows: An automatic measuring device for the loosening zone of surrounding rock in a mine roadway includes a control box, a crawling hydraulic cylinder, two bidirectional acoustic probes, and two sets of identical support and stabilizing mechanisms arranged axially symmetrically on both sides of the crawling hydraulic cylinder. Each support and stabilizing mechanism includes a stabilizing platform and four borehole wall support legs. The four borehole wall support legs are evenly spaced along the outer circumference of the stabilizing platform, and each borehole wall support leg is correspondingly equipped with a support hydraulic cylinder. Each borehole wall support leg is hinged to the stabilizing platform via a passive support arm and an active support arm. The telescopic rod of the support hydraulic cylinder is rotatably connected to the active support arm of the corresponding borehole wall support leg. By pushing or pulling back the active support arm, the passive support arm is simultaneously extended or retracted, thereby achieving tight contact or separation between the borehole wall support leg and the inner wall of the test borehole. The side of each of the two stabilizing platforms furthest from the crawling hydraulic cylinder is connected to one of the two bidirectional acoustic probes via probe connecting rods.

[0006] Preferably, the outer side wall of the stabilizing platform has four support arm mounting slots evenly spaced around its circumference; each support arm mounting slot has a hydraulic cylinder mounting groove below it, and each hydraulic cylinder mounting groove has a supporting hydraulic cylinder installed in it; each hole wall support leg has a connecting groove along its length on the side wall near the stabilizing platform; and each active support arm has a through groove along its length in the middle.

[0007] Preferably, one end of each passive support arm is rotatably connected to the inner wall of the support arm mounting groove at the corresponding position via a first rotating shaft, and the other end is rotatably connected to the inner wall of the connecting groove of the corresponding hole wall support leg via a fifth rotating shaft; one end of each active support arm is rotatably connected to the inner wall of the support arm mounting groove at the corresponding position via a second rotating shaft, and the other end is rotatably connected to the inner wall of the connecting groove of the corresponding hole wall support leg via a fourth rotating shaft; wherein, each passive support arm is arranged parallel above its corresponding active support arm.

[0008] Preferably, each of the supporting hydraulic cylinders is hinged to the inner wall of the hydraulic cylinder mounting groove at its location via a third rotating shaft, and the other end of its telescopic rod is rotatably connected to the inner wall of the active support arm through groove at the corresponding location via a sixth rotating shaft.

[0009] Preferably, the cylinder body of the crawling hydraulic cylinder is mounted on one of the stable platforms away from its corresponding bidirectional acoustic probe, and the crawling thrust rod of the crawling hydraulic cylinder is connected to the other stable platform away from its corresponding bidirectional acoustic probe; the control box is set on the stable platform away from the crawling thrust rod, and the control box contains a controller and a power supply battery.

[0010] Preferably, the length of the crawling thrust rod is 0.5 to 1.0 m; and the capacity of the power supply battery is 10,000 to 20,000 mAh.

[0011] More preferably, the outer side wall of each of the hole wall support legs, avoiding the connecting groove, is fitted with a rubber anti-slip sleeve.

[0012] Furthermore, preferably, the bidirectional acoustic probe includes a built-in battery, a wireless receiver, an amplification module, a data storage module, and a Bluetooth communication module.

[0013] More preferably, the wireless receiver, amplification module, data receiving module, data storage module, and Bluetooth communication module are all electrically connected to the controller; The data receiving module is electrically connected to the customer terminal equipment.

[0014] A method for using an automatic measuring device for the loosening zone of surrounding rock in a mine roadway, employing the aforementioned automatic measuring device for the loosening zone of surrounding rock in a mine roadway, specifically includes the following steps: S1. Place the entire device into the test hole, with the crawling thrust rod facing the bottom of the hole; S2. Fill the test hole with water and seal it; S3. Set the number of tests for the test hole and the single test distance S, where the value of S ranges from 0.5 to 1.0 m; S4. During initial startup, all the support hydraulic cylinders of the two sets of support stabilization mechanisms extend and push outward the active support arm, while simultaneously driving the passive support arm to unfold, so that the support legs of each hole wall are in close contact with the hole wall of the test hole. S5. By switching the transmission or reception working state of the two bidirectional acoustic probes, two sets of acoustic wave propagation times are obtained and the corresponding wave velocities are calculated. The two sets of data are then averaged. S6. Keep the support legs of each hole wall close to the hole opening and the hole wall of the test hole in close contact. Control the extension rods of the four support hydraulic cylinders of the support stabilization mechanism close to the bottom of the hole to retract and pull the active support arm inward. At the same time, drive the passive support arm to retract, so that the four hole wall support legs on it are disengaged from the hole wall of the test hole. S7. According to the set single test distance, control the crawling thrust rod of the crawling hydraulic cylinder to extend and push into the hole, drive the support and stabilizing mechanism near the bottom of the hole to the set position, and control the four hole wall support legs on it to fit tightly against the hole wall of the test hole again. S8. Keep the support legs of each hole wall close to the bottom of the hole in close contact with the hole wall of the test hole. Control the extension rods of the four support hydraulic cylinders of the support stabilization mechanism close to the hole opening to retract and pull the active support arm inward. At the same time, drive the passive support arm to retract, so that the four hole wall support legs on it are disengaged from the hole wall of the test hole. S9. Control the decompression of the crawling hydraulic cylinder, so that the crawling thrust rod retracts, driving the cylinder body of the crawling hydraulic cylinder to move to one side of the hole, thereby driving the support and stabilizing mechanism near the hole opening to reach the set position and controlling the four hole wall support legs on it to fit tightly against the hole wall of the test hole again. S10. Repeat the test method in step S5 to complete the test of the current spacing; S11. Repeat steps S6-S10 to complete the testing of all spacings in the test hole in sequence, and move in the opposite direction to the opening of the test hole to end. S12. Based on all the mean-processed wave velocity data above, plot the wave velocity-hole depth relationship curve; where the hole depth corresponding to the inflection point where the wave velocity changes from low to high value is the boundary of the loosened zone of the surrounding rock.

[0015] The beneficial effects of this invention are: 1. This invention has a simple structure and is easy to operate. It can automatically complete the measurement without manual operation. 2. This invention uses a bidirectional acoustic probe, repeatedly detecting and averaging the results, which is more accurate; 3. This invention is applicable to the roof, sides, and bottom of surrounding rock, with a wide range of applications. It is particularly suitable for roof areas where installation is difficult: first, the device is placed into a test hole in the roof. Then, a rubber plug with two through holes is used. A steel pipe extending to the bottom of one hole is inserted for venting, and a water injection pipe is inserted into the other hole. When water begins to flow from the vent pipe, the hole is full. Water is added while the pipe is pulled out. Finally, the through holes are sealed with a small plug, resulting in better stability. Attached Figure Description

[0016] The accompanying drawings constituting this invention are provided to further understand this application and do not constitute an undue limitation of this application.

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 A structural diagram showing the supporting and stabilizing mechanism; Figure 3 for Figure 2 Cross-sectional view; Figure 4 This is a schematic diagram of the structure of the hole wall support leg; Figure 5 Two working state diagrams to support the stabilizing mechanism; among them, Figure 5 (a) is a schematic diagram of the hole wall support leg in the retracted state; Figure 5 (b) is a schematic diagram of the hole wall support leg in the deployed state; Figure 6 This is a diagram illustrating the upward movement of the device within the test hole according to the present invention. Figure 7This is a schematic diagram of the operation of the present invention inside a test hole in surrounding rock; In the diagram, 1-stabilized platform; 2-support arm mounting slot; 201-first rotating shaft; 202-second rotating shaft; 3-hydraulic cylinder mounting slot; 301-third rotating shaft; 4-hole wall support leg; 5-passive support arm; 6-support hydraulic cylinder; 7-active support arm; 8-fourth rotating shaft; 9-fifth rotating shaft; 10-sixth rotating shaft; 11-crawling thrust rod; 12-crawling hydraulic cylinder; 13-probe connecting rod; 14-sonic bidirectional probe; 15-control box; 16-test hole; 17-surrounding rock. Detailed Implementation

[0018] The specific implementation of the automatic measuring device for loosening zone of surrounding rock in mine roadways and its usage method provided by the present invention will be further described with reference to the accompanying drawings and embodiments.

[0019] like Figure 1 As shown, an automatic measuring device for the loosening zone of surrounding rock in a mine roadway includes a control box 15, a crawling hydraulic cylinder 12, two bidirectional acoustic probes 14, and two sets of identical and axially symmetrically arranged support and stabilizing mechanisms on both sides of the crawling hydraulic cylinder 12. The support and stabilizing mechanism includes a stabilizing platform 1 and four borehole wall support legs 4. Preferably, the four borehole wall support legs 4 are evenly spaced along the outer circumference of the stabilizing platform 1, and each borehole wall support leg 4 is correspondingly equipped with a support hydraulic cylinder 6. Each borehole wall support leg 4 is hinged to the stabilizing platform 1 via a passive support arm 5 and an active support arm 7. The telescopic rod of the support hydraulic cylinder 6 is rotatably connected to the active support arm 7 of the corresponding borehole wall support leg 4. By pushing or pulling back the active support arm 7, the passive support arm 5 is simultaneously extended or retracted, so as to achieve tight contact or disengagement between each borehole wall support leg 4 and the inner wall of the test hole 16.

[0020] Preferably, the sides of the two stabilizing platforms 1 furthest from the crawling hydraulic cylinder 12 are each connected to two bidirectional acoustic probes 14 via probe connecting rods 13. Each bidirectional acoustic probe 14 includes a built-in battery, a wireless receiver, an amplification module, a data storage module, and a Bluetooth communication module (the bidirectional acoustic probe 14 is known prior art, and its specific internal structure is omitted in the accompanying drawings).

[0021] Preferably, the cylinder body of the crawling hydraulic cylinder 12 is mounted on one of the stable platforms 1 on the side away from its corresponding bidirectional acoustic probe 14, and the crawling thrust rod 11 of the crawling hydraulic cylinder 12 is connected to the other stable platform 1 on the side away from its corresponding bidirectional acoustic probe 14. The control box 15 is located on the stable platform 1 on the side away from the crawling thrust rod 11, and the control box 15 contains a controller and a power supply battery (not shown in the figure) to realize the control, coordination and power supply of various devices in the device.

[0022] It is worth noting that the length of the crawling thrust rod 11 is 0.5 to 1.0 m; and the capacity of the power supply battery is 10,000 to 20,000 mAh.

[0023] like Figures 2-4 As shown, the outer side wall of the stable platform 1 is provided with four support arm mounting slots 2 at equal intervals around the perimeter; each support arm mounting slot 2 is provided with a hydraulic cylinder mounting groove 3 below it, wherein a support hydraulic cylinder 6 is installed in each hydraulic cylinder mounting groove 3.

[0024] Preferably, each of the hole wall support legs 4 has a connecting groove on the side wall near the stable platform 1 along its length; each of the active support arms 7 has a through groove in the middle along its length.

[0025] During installation, one end of each passive support arm 5 is rotatably connected to the inner wall of the corresponding support arm mounting groove 2 via a first rotating shaft 201, and the other end is rotatably connected to the inner wall of the connecting groove of the corresponding hole wall support leg 4 via a fifth rotating shaft 9. One end of each active support arm 7 is rotatably connected to the inner wall of the corresponding support arm mounting groove 2 via a second rotating shaft 202, and the other end is rotatably connected to the inner wall of the connecting groove of the corresponding hole wall support leg 4 via a fourth rotating shaft 8. Each passive support arm 5 is arranged parallel above its corresponding active support arm 7, forming an umbrella-like rib mechanism to improve the stability of the hole wall support leg 4.

[0026] Preferably, each supporting hydraulic cylinder 6 is hinged to the inner wall of the hydraulic cylinder mounting groove 3 at its location via a third rotating shaft 301, and the other end of its telescopic rod is rotatably connected to the inner wall of the through groove of the corresponding active support arm 7 via a sixth rotating shaft 10.

[0027] More preferably, in order to ensure the grip between the support mechanism and the inner wall of the test hole 15 during crawling, the outer side wall of each hole wall support leg 4, avoiding the connecting groove, is fitted with a rubber anti-slip sleeve.

[0028] It is worth emphasizing that the hydraulic control system, wireless receiver, amplification module, data receiving module, data storage module, and Bluetooth communication module of the supporting hydraulic cylinder 6 and crawling hydraulic cylinder 12 are all electrically connected to the controller; the data receiving module is electrically connected to the customer terminal equipment (including but not limited to terminal computers, etc.) to realize data reception and transmission.

[0029] The detailed usage method and working principle of this invention are described below: A method for using an automatic measuring device for the loosening zone of surrounding rock in a mine roadway, employing the aforementioned automatic measuring device for the loosening zone of surrounding rock in a mine roadway, specifically includes the following steps: S1. Place the entire device into the test hole 16 to be tested, and place one side of the crawling thrust rod 11 towards the bottom of the test hole 16; S2. Fill the test hole 16 with water and seal it. Specifically: After the device is placed into the test hole 16, find a rubber soft plug with two through holes. Insert a steel pipe that can reach the bottom of the test hole 16 into one of the through holes for venting, and insert a water injection pipe into the other through hole. When water starts to come out from the vent pipe side, it is considered that the hole is full of water. Continue to inject water while pulling out the pipe. Finally, use a small plug to block the through hole to complete the seal. S3. Set the number of tests and the single test distance S for test hole 16, where the value of S ranges from 0.5 to 1.0 m; S4. During initial startup, the telescopic rods of all the support hydraulic cylinders 6 of the two sets of support stabilization mechanisms extend and push outward the active support arm 7, while driving the passive support arm 5 to unfold, so that the support legs 4 of each hole wall are in close contact with the hole wall of the test hole 16. S5. By switching the transmission or reception working state of the two bidirectional acoustic probes 14, two sets of acoustic wave propagation times are obtained and the corresponding wave velocities are calculated. The two sets of data are then averaged. S6. Keep the support legs 4 of each hole wall close to the hole wall on the side near the test hole 16 opening, and at the same time control the extension rods of the four support hydraulic cylinders 6 of the support stabilization mechanism near the bottom of the hole to retract and pull the active support arm 7 inward, while driving the passive support arm 5 to retract, so that the four hole wall support legs 4 on it are separated from the hole wall of the test hole 16. S7. According to the set single test distance S, control the crawling thrust rod 11 of the crawling hydraulic cylinder 12 to extend and push it into the hole, drive the support and stabilizing mechanism near the bottom of the hole to the set position and control the four hole wall support legs 4 on it to fit tightly against the hole wall of the test hole again. S8. Keep the support legs 4 of each hole wall close to the bottom of the test hole 16 in close contact with the hole wall, while controlling the telescopic rods of the four support hydraulic cylinders 6 of the support stabilization mechanism close to the hole opening to retract and pull the active support arm 7 inward, while driving the passive support arm 5 to retract, so that the four hole wall support legs 4 on it are separated from the hole wall of the test hole 16. S9. Control the decompression of the crawling hydraulic cylinder 12, causing the crawling thrust rod 11 to retract, which in turn moves the cylinder body of the crawling hydraulic cylinder 12 towards the inside of the hole. This, in turn, moves the support and stabilizing mechanism near the hole opening to the set position and controls the four hole wall support legs 4 on it to once again tightly fit against the hole wall of 16, thus completing one position movement of the test point. Figures 5-7 As shown; S10. Repeat the test method in step S5 to complete the test of the current spacing; S11. Repeat steps S6-S10 to test all the spacings in the test hole 16 in sequence, and then move in the opposite direction to the opening of the test hole 16 to finish. S12. Based on all the wave velocity data after mean processing, draw the wave velocity-hole depth relationship curve; where the hole depth corresponding to the inflection point where the wave velocity changes from low to high value is the boundary of the loosened zone of the surrounding rock 17.

[0030] This invention can automatically complete the measurement without manual operation, and uses a bidirectional acoustic probe to repeatedly measure and average the results, resulting in more accurate values. This invention is applicable to the roof, sides, and floor of surrounding rock, making it widely applicable.

[0031] In this invention, terms such as "upper," "lower," "bottom," and "top" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are merely used to facilitate the description of the structural relationships of the various components or elements of this invention and do not specifically refer to any particular component or element in this invention, nor should they be construed as limiting the invention. Terms such as "connected" and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of the above terms in this invention based on the specific circumstances, and they should not be construed as limiting the invention.

[0032] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. An automatic measuring device for the loosening zone of surrounding rock in a mine roadway, characterized in that, It includes a control box, a crawling hydraulic cylinder, two bidirectional acoustic probes, and two sets of identical support and stabilizing mechanisms arranged symmetrically on both sides of the crawling hydraulic cylinder. The supporting and stabilizing mechanism includes a stabilizing platform and four hole wall support legs. The four hole wall support legs are arranged at equal intervals along the outer circumference of the stabilizing platform, and each hole wall support leg is equipped with a corresponding support hydraulic cylinder. Each of the hole wall support legs is hinged to the stable platform via a passive support arm and an active support arm; the telescopic rod of the support hydraulic cylinder is rotatably connected to the active support arm of the corresponding hole wall support leg, and by pushing or pulling back the active support arm, the passive support arm is driven to expand or retract synchronously, so as to achieve close contact or separation between the hole wall support leg and the inner wall of the test hole. The two stabilized platforms, on the side furthest from the crawling hydraulic cylinder, are each connected to one of the two bidirectional acoustic probes via probe connecting rods.

2. The automatic measuring device for the loosening zone of surrounding rock in a mine roadway according to claim 1, characterized in that, The outer wall of the stable platform is provided with four support arm mounting slots at equal intervals around its circumference. Below each of the support arm mounting slots is a hydraulic cylinder mounting groove, and a support hydraulic cylinder is installed in each of the hydraulic cylinder mounting grooves. Each of the aforementioned hole wall support legs has a connecting groove along its length on the side wall near the stable platform; each of the aforementioned active support arms has a through groove along its length in the middle.

3. The automatic measuring device for the loosening zone of surrounding rock in a mine roadway according to claim 2, characterized in that, One end of each passive support arm is rotatably connected to the inner wall of the support arm mounting groove at the corresponding position via a first rotating shaft, and the other end is rotatably connected to the inner wall of the connecting groove of the corresponding hole wall support leg via a fifth rotating shaft. One end of each active support arm is rotatably connected to the inner wall of the support arm mounting groove at the corresponding position via a second pivot, and the other end is rotatably connected to the inner wall of the connecting groove of the corresponding hole wall support leg via a fourth pivot; wherein, each passive support arm is arranged parallel above its corresponding active support arm.

4. The automatic measuring device for the loosening zone of surrounding rock in a mine roadway according to claim 3, characterized in that, Each of the aforementioned support hydraulic cylinders is hinged to the inner wall of the hydraulic cylinder mounting groove at its location via a third rotating shaft, and the other end of its telescopic rod is rotatably connected to the inner wall of the active support arm through groove at the corresponding location via a sixth rotating shaft.

5. The automatic measuring device for the loosening zone of surrounding rock in a mine roadway according to claim 4, characterized in that, The cylinder body of the crawling hydraulic cylinder is mounted on one of the stable platforms away from its corresponding bidirectional acoustic probe, and the crawling thrust rod of the crawling hydraulic cylinder is connected to the other stable platform away from its corresponding bidirectional acoustic probe. The control box is mounted on a stable platform away from the crawling thrust rod, and contains a controller and a power supply battery.

6. The automatic measuring device for the loosening zone of surrounding rock in a mine roadway according to claim 5, characterized in that, The length of the crawling thrust rod is 0.5 to 1.0 m; The capacity of the power supply battery is 10,000 to 20,000 mAh.

7. The automatic measuring device for the loosening zone of surrounding rock in a mine roadway according to claim 6, characterized in that, The outer wall of each of the hole wall support legs, avoiding the connecting groove, is fitted with a rubber anti-slip sleeve.

8. The automatic measuring device for the loosening zone of surrounding rock in a mine roadway according to claim 6, characterized in that, The bidirectional acoustic probe includes a built-in battery, a wireless receiver, an amplification module, a data storage module, and a Bluetooth communication module.

9. The automatic measuring device for the loosening zone of surrounding rock in a mine roadway according to claim 8, characterized in that, The wireless receiver, amplification module, data receiving module, data storage module, and Bluetooth communication module are all electrically connected to the controller. The data receiving module is electrically connected to the customer terminal equipment.

10. A method of using an automatic measuring device for the loosening zone of surrounding rock in a mine roadway, comprising the automatic measuring device for the loosening zone of surrounding rock in a mine roadway as described in any one of claims 6-9, characterized in that, Specifically, the following steps are included: S1. Place the entire device into the test hole, with the crawling thrust rod facing the bottom of the hole; S2. Fill the test hole with water and seal it; S3. Set the number of tests for the test hole and the single test distance S, where the value of S ranges from 0.5 to 1.0 m; S4. During initial startup, all the support hydraulic cylinders of the two sets of support stabilization mechanisms extend and push outward the active support arm, while simultaneously driving the passive support arm to unfold, so that the support legs of each hole wall are in close contact with the hole wall of the test hole. S5. By switching the transmission or reception working state of the two bidirectional acoustic probes, two sets of acoustic wave propagation times are obtained and the corresponding wave velocities are calculated. The two sets of data are then averaged. S6. Keep the support legs of each hole wall close to the hole opening and the hole wall of the test hole in close contact. Control the extension rods of the four support hydraulic cylinders of the support stabilization mechanism close to the bottom of the hole to retract and pull the active support arm inward. At the same time, drive the passive support arm to retract, so that the four hole wall support legs on it are disengaged from the hole wall of the test hole. S7. According to the set single test distance, control the crawling thrust rod of the crawling hydraulic cylinder to extend and push into the hole, drive the support and stabilizing mechanism near the bottom of the hole to the set position, and control the four hole wall support legs on it to fit tightly against the hole wall of the test hole again. S8. Keep the support legs of each hole wall close to the bottom of the hole in close contact with the hole wall of the test hole. Control the extension rods of the four support hydraulic cylinders of the support stabilization mechanism close to the hole opening to retract and pull the active support arm inward. At the same time, drive the passive support arm to retract, so that the four hole wall support legs on it are disengaged from the hole wall of the test hole. S9. Control the decompression of the crawling hydraulic cylinder, so that the crawling thrust rod retracts, driving the cylinder body of the crawling hydraulic cylinder to move to one side of the hole, thereby driving the support and stabilizing mechanism near the hole opening to reach the set position and controlling the four hole wall support legs on it to fit tightly against the hole wall of the test hole again. S10. Repeat the test method in step S5 to complete the test of the current spacing; S11. Repeat steps S6-S10 to complete the testing of all spacings in the test hole in sequence, and move in the opposite direction to the opening of the test hole to end. S12. Based on all the mean-processed wave velocity data above, plot the wave velocity-hole depth relationship curve; where the hole depth corresponding to the inflection point where the wave velocity changes from low to high value is the boundary of the loosened zone of the surrounding rock.

Images