Roadway stress monitoring device and monitoring method thereof

Abstract

The application discloses a roadway stress monitoring device and a monitoring method thereof, which comprises a portal frame. According to the application, a plurality of pressure applying rods are driven to move by hydraulic pressure, and a base plate and an anchor rod stress sensor are sequentially pushed to be sleeved on corresponding anchor rods until the pressure applying rods abut against the corresponding anchor rod stress sensors and the corresponding anchor rod end portions and cannot continue to move, then a solenoid valve is closed, and then when the anchor rod position moves, the pressure applying rods change the pressure applying pressure on the anchor rod stress sensors through the change of the hydraulic pressure in the closed liquid delivery pipe, so that the anchor rod stress can be monitored by observing the degree change of the anchor rod stress sensor. Since the assembly of parts can be carried out simultaneously with anchor rod construction, and when the anchor rod is spliced, a plurality of anchor rod stress sensors can be quickly installed in place at one time, and there is no need to climb, so that the installation efficiency and safety of the anchor rod stress monitoring device are improved.

Description

Technical Field

[0001] This invention relates to the field of tunnel technology, and in particular to a tunnel stress monitoring device and its monitoring method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] In underground engineering projects such as mining and tunnel excavation, the stability of roadways directly affects the safety of workers and the smooth progress of the project. Rock bolts, as a key support method, are widely used for roadway reinforcement. By drilling holes in the surrounding rock and inserting rock bolts, the tensile strength of the bolts resists the deformation of the surrounding rock, thereby effectively maintaining the stability of the roadway.

[0004] Currently, after the anchor bolts are installed, it is necessary to install anchor bolt stress sensors at the anchor bolt locations to monitor the stress state of the anchor bolts and meet the stress monitoring requirements of the roadway. However, this process has several shortcomings: 1. Risks of working at height: In the installation of anchor bolts at the top of some tunnels or at high places, operators need to work at height, which increases the safety risks such as falls; 2. Low installation efficiency: The installation of anchor stress sensors at each anchor bolt requires a lot of time and manpower. Especially in large-scale tunnel support projects, the accumulated time and manpower costs are considerable, which seriously restricts the progress of the project. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned shortcomings by providing a roadway stress monitoring device and its monitoring method, thereby improving the installation efficiency and safety of anchor bolt stress monitoring devices.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a roadway stress monitoring device, comprising: A gantry frame, the gantry frame comprising a crossbeam and two columns respectively disposed at both ends of the crossbeam along its length; Multiple stress monitoring mechanisms are detachably mounted on a gantry frame. Each stress monitoring mechanism includes a detachable guide frame mounted on the gantry frame. The guide frame is equipped with a pad and an anchor stress sensor that can move towards or away from the tunnel wall and can be fitted onto the anchor bolt. The anchor stress sensor is detachably mounted on the side of the pad away from the tunnel wall. The stress monitoring mechanism also includes an infusion pipe with a solenoid valve at one end and a pressure rod at the other end located on the side of the anchor stress sensor away from the pad. The pressure rod can be hydraulically pushed to move towards the anchor stress sensor and can abut against the corresponding anchor stress sensor and the end of the corresponding anchor bolt.

[0007] Furthermore, both the crossbeam and the column are composed of a back plate and two side plates disposed on the side of the back plate near the tunnel wall, with the two side plates located on both sides of the width direction of the corresponding back plate. The guide frame includes two guide plates that abut against two side plates and are located between the two side plates. A connecting plate is provided between the two guide plates. A threaded sleeve that penetrates the back plate is provided on the side of the connecting plate near the back plate. A strip hole is provided on the back plate for the threaded sleeve to move along the length direction of the back plate. The stress monitoring mechanism also includes a nut head fixedly installed at the end of the infusion tube away from the solenoid valve, and the nut head is threadedly connected to the threaded sleeve.

[0008] Furthermore, the pad includes a plate body located between two corresponding guide plates. The plate body is provided with a first through hole for the anchor rod to pass through. Two L-shaped hook plates are provided on the side of the plate body away from the tunnel wall. The two L-shaped hook plates are respectively inserted into the corresponding guide plates. The guide plates are provided with sliding grooves for the L-shaped hook plates to slide. When the plate body moves to contact the tunnel wall, the L-shaped hook plates are located in the sliding grooves.

[0009] Furthermore, the pad also includes a positioning sleeve disposed on the side of the plate away from the roadway wall, the positioning sleeve being sleeved with the anchor stress sensor, the anchor stress sensor having a second through hole for the anchor to pass through.

[0010] Furthermore, the pressure rod includes an outer pressure rod inserted into the threaded sleeve and dynamically sealed with the threaded sleeve. The end of the outer pressure rod near the anchor stress sensor is provided with a slot for the anchor rod to be inserted. When the outer pressure rod is hydraulically pushed to push the anchor stress sensor, so that the plate abuts against the tunnel wall, one end of the outer pressure rod is located in the threaded sleeve. An inner pressure rod is provided inside the outer pressure rod, penetrating the outer pressure rod and inserted into the slot at one end. The inner pressure rod can be hydraulically pushed to move along the axial direction of the outer pressure rod, and the inner pressure rod and the outer pressure rod are dynamically sealed.

[0011] Furthermore, the gantry also includes an L-shaped bracket that is detachably connected to the crossbeam and adjacent columns. The L-shaped bracket is connected to the crossbeam via a bolt and nut assembly. The L-shaped bracket is provided with multiple mounting holes for installing the bolt and nut assembly. The distance between the two columns is different when the bolt and nut assembly is in different mounting holes.

[0012] Furthermore, it also includes a transfer assembly located at the end of the column away from the crossbeam. The transfer assembly includes a rotatable trolley located at the end of the column away from the crossbeam. The trolley is used to move within the tunnel. Both ends of the trolley along its length are threaded with fixing pins that can be inserted into the tunnel. A diagonal brace is rotatably mounted on the trolley. The end of the diagonal brace away from the trolley is detachably connected to the corresponding column.

[0013] A method for monitoring roadway stress, comprising any one of the roadway stress monitoring devices described in any one of the claims, wherein the method is as follows: S1. Install anchor bolts at the corresponding locations in the roadway according to the construction drawings; S2. Select beams and columns that are compatible with the size of the tunnel, lay them flat on the ground, and assemble them into a gantry frame using L-shaped brackets. Ensure that the distance between the two columns is minimized. Then, according to the anchor bolt construction points, install the corresponding multiple stress monitoring mechanisms on the beams and columns in advance. S3. Lift the gantry frame away from the transfer component manually or by a transport trolley, and move the gantry frame to the corresponding anchor bolt. S4. After the gantry frame is moved into place, adjust the splicing position of the L-shaped bracket and the crossbeam to increase the distance between the two columns and make it as close as possible to the tunnel wall. Then, insert the fixing pin into the tunnel and rotate the gantry frame ninety degrees manually or with hoisting equipment to make the gantry frame stand upright. Align each stress monitoring mechanism with the corresponding anchor rod. Then, connect the gantry frame with the diagonal brace to restrict the gantry frame from continuing to rotate. S5. The hydraulic equipment is connected to the solenoid valves of each stress monitoring mechanism. When the solenoid valves are open, the hydraulic equipment injects liquid into each delivery pipe, pushing the inner pressure rod to abut against the anchor rod and simultaneously pushing the outer pressure rod to abut against the anchor rod stress sensor. This causes the pad and the anchor rod stress sensor to be sequentially fitted onto the corresponding anchor rod. After the pad and the anchor rod stress sensor are obstructed by the tunnel wall and cannot move, the pressure on the anchor rod stress sensor from the outer pressure rod is observed. When the pressure reaches the preset value, the corresponding solenoid valve is closed. This process continues until all anchor rod stress sensors reach the preset value, at which point the connection between the hydraulic equipment and the solenoid valve is disconnected. S6. When the anchor bolt moves into the roadway, the original positions of the anchor bolt and the inner pressure rod change. Under the hydraulic pressure inside the infusion pipe, the inner pressure rod tends to move closer to the anchor bolt, while the outer pressure rod is driven to move away from the anchor bolt stress sensor, causing the value monitored by the anchor bolt stress sensor to decrease. Conversely, when the anchor bolt moves out of the roadway, the value monitored by the anchor bolt stress sensor increases. By monitoring the stress on the anchor bolt during the support process through the corresponding changes in the values, the stress on the roadway can be monitored.

[0014] The beneficial effects of this invention are reflected in: This invention utilizes hydraulically driven multiple pressure rods to sequentially push a pad and anchor stress sensor onto the corresponding anchor rod. The process continues until the pressure rod abuts against the corresponding anchor stress sensor and the end of the corresponding anchor rod, preventing further movement. At this point, the solenoid valve closes. Subsequently, when the anchor rod shifts position, changes in the hydraulic pressure within the sealed infusion pipe alter the pressure applied by the pressure rod to the anchor stress sensor. By observing the changes in the sensor readings, anchor stress can be monitored. Furthermore, because component assembly can be performed concurrently with anchor rod construction, and multiple anchor stress sensors can be quickly installed in one go without requiring work at height, this invention improves the installation efficiency and safety of the anchor stress monitoring device. Attached Figure Description

[0015] Figure 1 This is a perspective view of the present invention; Figure 2 for Figure 1 A magnified view of a portion at point A shown; Figure 3 for Figure 1 A magnified view of a portion of point B is shown below; Figure 4 This is a schematic diagram of the gantry frame of the present invention in a horizontal position; Figure 5 for Figure 4 A magnified view of a portion at point C is shown below; Figure 6 This is a partial exploded view of the stress monitoring mechanism of the present invention; Figure 7 This is a structural view of the transfer component of the present invention.

[0016] In the picture: 1. Gantry frame; 11. Crossbeam; 12. Column; 13. L-shaped support; 2. Stress monitoring mechanism; 21. Guide frame; 211. Guide plate; 212. Connecting plate; 213. Screw sleeve; 22. Washer plate; 221. Plate body; 222. L-shaped hook plate; 223. Positioning sleeve; 23. Anchor bolt stress sensor; 24. Infusion tube; 25. Solenoid valve; 26. Pressure rod; 261. External pressure rod; 262. Internal pressure rod; 27. Nut head; 3. Transfer component; 31. Moving trolley; 32. Fixing pin; 33. Diagonal brace. Detailed Implementation

[0017] 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 a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. 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.

[0018] Please see Figure 1-7 This invention discloses a tunnel stress monitoring device, comprising: Gantry 1, gantry 1 includes a crossbeam 11 and two columns 12 respectively disposed at both ends of the crossbeam 11 along its length; Multiple stress monitoring mechanisms 2 are detachably mounted on the gantry frame 1. Each stress monitoring mechanism 2 includes a guide frame 21 detachably mounted on the gantry frame 1. The guide frame 21 is equipped with a pad 22 that can move towards or away from the tunnel wall and can be fitted onto the anchor bolt, and an anchor bolt stress sensor 23. The anchor bolt stress sensor 23 is detachably mounted on the side of the pad 22 away from the tunnel wall. The stress monitoring mechanism 2 also includes an infusion pipe 24. One end of the infusion pipe 24 is equipped with a solenoid valve 25, and the other end is equipped with a pressure rod 26 located on the side of the anchor bolt stress sensor 23 away from the pad 22. The pressure rod 26 can be hydraulically pushed to move towards the side of the anchor bolt stress sensor 23 and can abut against the corresponding anchor bolt stress sensor 23 and the corresponding anchor bolt end.

[0019] This invention involves installing stress monitoring mechanisms 2 at corresponding positions on the gantry frame 1 according to the installation locations of the anchor bolts. After multiple anchor bolts within a cross-section are installed, the operator can move the gantry frame 1 with the stress monitoring mechanisms 2 installed to that cross-section. Once each stress monitoring mechanism 2 is aligned with the anchor bolt, a hydraulic device is connected to the solenoid valve 25 of each stress monitoring mechanism 2. This hydraulically drives multiple pressure rods 26 to move, sequentially pushing the pad 22 and anchor bolt stress sensor 23 onto the corresponding anchor bolt until the pressure rod 26 is aligned with the corresponding anchor bolt stress sensor 23 and the end of the corresponding anchor bolt. After the anchor bolt stops moving, the solenoid valve 25 closes. Then, when the anchor bolt position moves, the change in hydraulic pressure within the sealed infusion pipe 24 alters the pressure applied by the pressure rod 26 to the anchor bolt stress sensor 23. By observing the change in the reading of the anchor bolt stress sensor 23, the anchor bolt stress can be monitored. Since the component assembly can be carried out simultaneously with the anchor bolt construction, and multiple anchor bolt stress sensors 23 can be quickly installed at once during the splicing with the anchor bolt without the need for working at height, the installation efficiency and safety of the anchor bolt stress monitoring device are improved.

[0020] It should be noted that this roadway stress monitoring device is applicable to flat-roofed roadways, and multiple anchor bolts corresponding to this roadway stress monitoring device must be located in the same cross section and inserted perpendicular to the roadway.

[0021] In one embodiment, both the crossbeam 11 and the column 12 are composed of a back plate and two side plates disposed on the side of the back plate near the tunnel wall, with the two side plates located on both sides of the width direction of the corresponding back plate. The guide frame 21 includes two guide plates 211 that abut against two side plates and are located between the two side plates. A connecting plate 212 is provided between the two guide plates 211. A threaded sleeve 213 that penetrates the back plate is provided on the side of the connecting plate 212 near the back plate. A strip hole is provided on the back plate for the threaded sleeve 213 to move along the length direction of the back plate. The stress monitoring mechanism 2 also includes a nut head 27 fixedly installed at the end of the infusion tube 24 away from the solenoid valve 25, and the nut head 27 is threadedly connected to the threaded sleeve 213.

[0022] This design allows the guide frame 21 to be installed by first inserting the threaded sleeve 213 into the slotted hole, then sliding it up and down along the slotted hole to the desired position, and then threading the nut head 27 on the infusion tube 24 to the threaded sleeve 213. After tightening, the nut head 27 cooperates with the connecting plate 212 to clamp on the back plate, and the installation and fixation of the guide frame 21 is completed by friction.

[0023] It should be noted that, in order to prevent the guide frame 21 from moving after installation, a rubber friction layer can be added to the side of the back plate that contacts the connecting plate 212 to increase the friction resistance after clamping. In order to prevent the air in the infusion tube 24 from not being able to be discharged during injection and affecting the subsequent detection accuracy, a one-way exhaust valve for venting internal air is provided on the infusion tube 24.

[0024] In practice, after the infusion pipe 24 is installed, the oil supply pipe needs to be connected to the end of the corresponding solenoid valve 25 and the oil supply pipe needs to be fixed to the gantry 1 to facilitate subsequent connection with the hydraulic equipment on the ground.

[0025] In one embodiment, the pad 22 includes a plate body 221 located between two corresponding guide plates 211. The plate body 221 is provided with a first through hole for the anchor rod to pass through. Two L-shaped hook plates 222 are provided on the side of the plate body 221 away from the tunnel wall. The two L-shaped hook plates 222 are respectively inserted into the corresponding guide plates 211. The guide plates 211 are provided with a sliding groove for the L-shaped hook plates 222 to slide. When the plate body 221 moves to contact the tunnel wall, the L-shaped hook plates 222 are located in the sliding groove.

[0026] This design allows the pad 22 to maintain its set position and move under the guidance of the guide frame 21 when it is pushed towards the tunnel wall, ensuring that it can be accurately fitted onto the corresponding anchor rod.

[0027] In one embodiment, the pad 22 further includes a positioning sleeve 223 disposed on the side of the plate 221 away from the roadway wall. The positioning sleeve 223 is sleeved with the anchor stress sensor 23, and the anchor stress sensor 23 has a second through hole for the anchor to pass through.

[0028] This design allows the anchor stress sensor 23 to be installed first inside the positioning sleeve 223, and then installed together with the pad 22 onto the guide frame 21. After the pad 22 moves to its limit position closer to the guide frame 21, the anchor stress sensor 23 inside the positioning sleeve 223 will be restricted from moving under the clamping of the pad 22 and the pressure rod 26. This does not affect the normal movement of the pad 22, anchor stress sensor 23 and pressure rod 26, and also improves installation efficiency.

[0029] It should be noted that, in order to prevent the anchor stress sensor 23 from coming loose during the transfer from the assembly position to the monitoring position, the L-shaped hook plate 222 is provided with a rubber resistance layer on the contact surface with the chute to increase its movement resistance.

[0030] In practice, the diameters of the first and second perforations are larger than the diameter of the anchor rod, ensuring that when the anchor rod deviates due to construction accuracy, the pad 22 and the anchor rod stress sensor 23 can also be fitted onto the corresponding anchor rod to achieve the monitoring effect.

[0031] In one embodiment, the pressure rod 26 includes an outer pressure rod 261 that is inserted into the threaded sleeve 213 and dynamically sealed with the threaded sleeve 213. The outer pressure rod 261 has a slot for inserting the anchor rod at one end near the anchor stress sensor 23. When the outer pressure rod 261 is hydraulically pushed against the anchor stress sensor 23, causing the plate 221 to abut against the tunnel wall, one end of the outer pressure rod 261 is located in the threaded sleeve 213. An inner pressure rod 262 is provided inside the outer pressure rod 261, penetrating the outer pressure rod 261 and inserted into the slot at one end. The inner pressure rod 262 can be hydraulically pushed and moved axially along the outer pressure rod 261, and the inner pressure rod 262 and the outer pressure rod 261 are dynamically sealed.

[0032] This design allows the inner pressure rod 262 and the outer pressure rod 261 to move separately when the pressure rod 26 is hydraulically pushed, so that they can stably abut against the anchor stress sensor 23 and the anchor rod, which can accommodate some anchor rod installation errors caused by construction.

[0033] In one embodiment, the gantry frame 1 further includes an L-shaped bracket 13 that is detachably connected to the crossbeam 11 and the adjacent column 12. The L-shaped bracket 13 is connected to the crossbeam 11 by a bolt and nut assembly. The L-shaped bracket 13 is provided with a plurality of mounting holes for the bolt and nut assembly to be installed. The distance between the two columns 12 is different when the bolt and nut assembly is in different mounting holes.

[0034] This design allows the gantry frame 1 to avoid collisions and interference with the pre-installed gantry frame 1 when it moves in the tunnel by reducing the distance between the two columns 12.

[0035] In one embodiment, a transfer assembly 3 is also provided at the end of the column 12 away from the crossbeam 11. The transfer assembly 3 includes a movable trolley 31 rotatably provided at the end of the column 12 away from the crossbeam 11. The movable trolley 31 is used to move in the tunnel. Both ends of the movable trolley 31 are threaded with fixing pins 32 that can be inserted into the tunnel. A diagonal brace 33 is rotatably provided on the movable trolley 31. The end of the diagonal brace 33 away from the movable trolley 31 is detachably connected to the corresponding column 12.

[0036] This design allows workers to install the corresponding stress monitoring mechanism 2 on the gantry 1, which is in a flat position. After installation, the gantry 1 can be moved to the corresponding location using a trolley 31. Then, the gantry 1 can be flipped up and erected, and supported and fixed by the diagonal brace 33, thus completing the transfer of the gantry 1.

[0037] A method for monitoring roadway stress, comprising any one of the roadway stress monitoring devices, wherein the method is as follows: S1. Install anchor bolts at the corresponding locations in the roadway according to the construction drawings; S2. Select beams 11 and columns 12 that are compatible with the size of the tunnel, lay them flat on the ground, and assemble them into a gantry frame 1 using L-shaped brackets 13. Ensure that the distance between the two columns 12 is minimized. Then, according to the anchor bolt construction points, install multiple stress monitoring mechanisms 2 on the beams 11 and columns 12 respectively in advance. S3. Lift the gantry frame 1 away from the transfer component 3 by hand or by a transport trolley, and push the gantry frame 1 to the corresponding anchor bolt. S4. After the gantry frame 1 is moved into place, adjust the splicing position of the L-shaped bracket 13 and the crossbeam 11 to increase the distance between the two columns 12 and make them as close as possible to the tunnel wall. Then, insert the fixing pin 32 into the tunnel and rotate the gantry frame 1 ninety degrees manually or with hoisting equipment to make the gantry frame 1 stand upright. Align each stress monitoring mechanism 2 with the corresponding anchor rod. Then, connect the gantry frame 1 with the diagonal brace 33 to restrict the gantry frame 1 from continuing to rotate. S5. The hydraulic equipment is connected to the solenoid valves 25 of each stress monitoring mechanism 2. When the solenoid valves 25 are open, the hydraulic equipment injects liquid into each delivery pipe 24, pushing the inner pressure rod 262 to abut against the anchor rod, and at the same time pushing the outer pressure rod 261 to abut against the anchor rod stress sensor 23, so that the pad 22 and the anchor rod stress sensor 23 are sequentially fitted onto the corresponding anchor rod. After the pad 22 and the anchor rod stress sensor 23 are blocked by the tunnel wall and cannot move, the pressure of the anchor rod stress sensor 23 on the outer pressure rod 261 is observed. When the pressure reaches the preset value, the corresponding solenoid valve 25 is controlled to close. After all the anchor rod stress sensors 23 have reached the preset value, the connection between the hydraulic equipment and the solenoid valves 25 is cut off. S6. When the anchor bolt moves into the roadway, the original positions of the anchor bolt and the inner pressure rod 262 change. Under the hydraulic pressure inside the infusion pipe 24, the inner pressure rod 262 tends to move closer to the anchor bolt, while the outer pressure rod 261 is driven to move away from the anchor bolt stress sensor 23, causing the value monitored by the anchor bolt stress sensor 23 to decrease. Conversely, when the anchor bolt moves out of the roadway, the value monitored by the anchor bolt stress sensor 23 increases. By monitoring the stress on the anchor bolt during the support process through the corresponding changes in the values, the stress on the roadway can be monitored.

[0038] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0039] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0040] Additionally, "multiple" refers to two or more.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tunnel stress monitoring device, characterized in that, include: The gantry frame (1) includes a crossbeam (11) and two columns (12) respectively disposed at both ends of the crossbeam (11) along its length. Multiple stress monitoring mechanisms (2) are detachably mounted on the gantry (1). Each stress monitoring mechanism (2) includes a guide frame (21) detachably mounted on the gantry (1). The guide frame (21) is provided with a pad (22) that can move towards or away from the roadway wall and can be fitted onto the anchor bolt and an anchor bolt stress sensor (23). The anchor bolt stress sensor (23) is detachably mounted on the side of the pad (22) away from the roadway wall. The stress monitoring mechanism (2) also includes an infusion pipe (24). One end of the infusion pipe (24) is provided with a solenoid valve (25), and the other end is provided with a pressure rod (26) located on the side of the anchor bolt stress sensor (23) away from the pad (22). The pressure rod (26) can be hydraulically pushed to move towards the side of the anchor bolt stress sensor (23) and can abut against the corresponding anchor bolt stress sensor (23) and the corresponding anchor bolt end.

2. The roadway stress monitoring device according to claim 1, characterized in that: The crossbeam (11) and the column (12) are both composed of a back plate and two side plates set on the side of the back plate near the roadway wall, and the two side plates are respectively located on both sides of the width direction of the corresponding back plate; The guide frame (21) includes two guide plates (211) that abut against two side plates and are located between the two side plates respectively. A connecting plate (212) is provided between the two guide plates (211). A threaded sleeve (213) is provided on the side of the connecting plate (212) near the back plate and penetrates the back plate. A strip hole is provided on the back plate for the threaded sleeve (213) to move along the length direction of the back plate. The stress monitoring mechanism (2) also includes a nut head (27) fixedly installed at the end of the infusion tube (24) away from the solenoid valve (25), and the nut head (27) is threadedly connected to the screw sleeve (213).

3. The tunnel stress monitoring device according to claim 2, characterized in that: The pad (22) includes a plate (221) located between two corresponding guide plates (211). The plate (221) is provided with a first through hole for the anchor rod to pass through. Two L-shaped hook plates (222) are provided on the side of the plate (221) away from the roadway wall. The two L-shaped hook plates (222) are respectively inserted into the corresponding guide plates (211). The guide plates (211) are provided with a sliding groove for the L-shaped hook plates (222) to slide. When the plate (221) moves to contact the roadway wall, the L-shaped hook plates (222) are located in the sliding groove.

4. The roadway stress monitoring device according to claim 3, characterized in that: The pad (22) also includes a positioning sleeve (223) disposed on the side of the plate (221) away from the roadway wall. The positioning sleeve (223) is sleeved with the anchor stress sensor (23), and the anchor stress sensor (23) has a second through hole for the anchor to pass through.

5. The tunnel stress monitoring device according to claim 2, characterized in that: The pressure rod (26) includes an outer pressure rod (261) that is inserted into the threaded sleeve (213) and dynamically sealed with the threaded sleeve (213). The outer pressure rod (261) has a slot for inserting the anchor rod at one end near the anchor stress sensor (23). When the outer pressure rod (261) is hydraulically pushed against the anchor stress sensor (23) so that the plate (221) abuts against the tunnel wall, one end of the outer pressure rod (261) is located in the threaded sleeve (213). An inner pressure rod (262) is provided inside the outer pressure rod (261) that passes through the outer pressure rod (261) and is inserted into the slot at one end. The inner pressure rod (262) can be hydraulically pushed and moved axially along the outer pressure rod (261), and the inner pressure rod (262) and the outer pressure rod (261) are dynamically sealed.

6. The roadway stress monitoring device according to claim 1, characterized in that: The gantry (1) also includes an L-shaped bracket (13) that is detachably connected to the crossbeam (11) and the adjacent column (12). The L-shaped bracket (13) is connected to the crossbeam (11) by a bolt and nut assembly. The L-shaped bracket (13) is provided with a plurality of mounting holes for the bolt and nut assembly to be installed. The distance between the two columns (12) is different when the bolt and nut assembly is in different mounting holes.

7. The roadway stress monitoring device according to claim 1, characterized in that: It also includes a transfer assembly (3) set at the end of the column (12) away from the crossbeam (11). The transfer assembly (3) includes a rotatable trolley (31) set at the end of the column (12) away from the crossbeam (11). The trolley (31) is used to move in the tunnel. Both ends of the trolley (31) in the length direction are threaded with fixing pins (32) that can be inserted into the tunnel. A diagonal brace (33) is rotatably set on the trolley (31). The end of the diagonal brace (33) away from the trolley (31) is detachably connected to the corresponding column (12).

8. A method for monitoring roadway stress, characterized in that: The method includes a roadway stress monitoring device as described in any one of claims 1-7, wherein the method is as follows: S1. Install anchor bolts at the corresponding locations in the roadway according to the construction drawings; S2. Select beams (11) and columns (12) that are compatible with the size of the tunnel, lay them flat on the ground, and assemble them into a gantry frame (1) using an L-shaped bracket (13). Ensure that the distance between the two columns (12) is minimized. Then, according to the anchor bolt construction point, install multiple stress monitoring mechanisms (2) on the beams (11) and columns (12) respectively. S3. Lift the gantry (1) away from the transfer assembly (3) by hand or by a trolley, and push the gantry (1) to the corresponding anchor. S4. After the gantry (1) is moved into place, adjust the splicing position of the L-shaped bracket (13) and the crossbeam (11) to increase the distance between the two columns (12) and make them as close as possible to the roadway wall. Then insert the fixing pin (32) into the roadway and rotate the gantry (1) ninety degrees manually or with hoisting equipment to make the gantry (1) stand upright and align each stress monitoring mechanism (2) with the corresponding anchor rod. Then connect the gantry (1) with the diagonal brace (33) to restrict the gantry (1) from continuing to rotate. S5. The hydraulic equipment is connected to the solenoid valves (25) of each stress monitoring mechanism (2). When the solenoid valve (25) is in the open state, the hydraulic equipment is used to inject liquid into each infusion pipe (24) to push the inner pressure rod (262) to abut against the anchor rod, and at the same time push the outer pressure rod (261) to abut against the anchor rod stress sensor (23), so that the pad (22) and the anchor rod stress sensor (23) are successively fitted onto the corresponding anchor rod. After the pad (22) and the anchor rod stress sensor (23) are blocked by the roadway wall and cannot move, the pressure of the anchor rod stress sensor (23) under the outer pressure rod (261) is observed. When the pressure reaches the preset value, the corresponding solenoid valve (25) is controlled to close. After all the anchor rod stress sensors (23) reach the preset value, the connection between the hydraulic equipment and the solenoid valve (25) is cut off. S6. When the anchor bolt moves into the roadway, the original positions of the anchor bolt and the inner pressure rod (262) change. Under the hydraulic action inside the infusion pipe (24), the inner pressure rod (262) tends to move closer to the anchor bolt, while the outer pressure rod (261) is driven to move away from the anchor bolt stress sensor (23), causing the value monitored by the anchor bolt stress sensor (23) to decrease. Conversely, when the anchor bolt moves out of the roadway, the value monitored by the anchor bolt stress sensor (23) increases. By monitoring the stress of the anchor bolt during the support process through the change of the corresponding number, the stress of the roadway can be monitored.

Images