Optical fiber sensing type rock and soil stress strain real-time monitor

Abstract

The invention discloses an optical fiber sensing type rock-soil stress strain real-time monitor, which belongs to the technical field of rock-soil engineering monitoring, and comprises an insertion cylinder, an FBG sensor, a mediator and an edge computer terminal, the top end of the insertion cylinder is provided with a positioning mechanism, the top of the positioning mechanism is provided with a gland for shielding a monitoring hole, and the bottom end of the insertion cylinder is fixedly provided with a conical head. According to the invention, the contact rods are uniformly hinged to the circumferential surface of the insertion cylinder at different horizontal heights, the FBG sensors are arranged on the contact rods in the length direction, and the extension mechanism is used in cooperation, so that multiple groups of contact rods can be directly contacted with the inner wall of the insertion hole in the use process, and the detection accuracy is improved. A point-surface contact mode is adopted to make direct contact with a monitoring surface, under the condition that rock-soil stress changes, the rock-soil stress can be directly transmitted to a contact rod, real-time monitoring is conducted through an FBG sensor, multi-channel parallel acquisition is conducted through a mediator, and finally data preprocessing, anomaly detection and local early warning are achieved through an edge computer terminal. And the monitoring precision in use is ensured.

Description

Technical Field

[0001] The present invention relates to a rock and soil stress and strain real-time monitor, in particular to an optical fiber sensing rock and soil stress and strain real-time monitor, belonging to the technical field of rock and soil engineering monitoring. Background Art

[0002] Fiber optic sensing technology is used in geotechnical engineering to monitor the stress and strain of soil or rock in real time, which is very important for geological disaster warning, engineering structure health monitoring, and other aspects. In the prior art, for example, the invention with application number 202211592278.3 discloses a geotechnical deformation monitor, system, and measurement method based on fiber optic sensors. In order to solve the shortcomings of ordinary displacement sensors, such as limited transmission distance, susceptibility to external magnetic field interference, poor stability, difficulty in long-term real-time monitoring, and susceptibility to complex and harsh field working environments, it is difficult to ensure measurement accuracy for displacement and deformation measurement, and there is no long-distance monitoring and data transmission function, which greatly limits the application of electrical sensors. By utilizing the working principle of Fabry-Perot interferometer fiber optic sensor and the transmission of first and second magnetic gears, real-time dynamic measurement of overlying rock and soil displacement can be achieved. The Fabry-Perot fiber optic sensing unit composed of optical fiber and metal plate reflective mirror reduces a series of measurement deviations caused by physical friction in traditional fiber optic geotechnical monitors and improves measurement accuracy.

[0003] Similar to the above application, there are still some deficiencies:

[0004] During the detection process, the baffle is fitted with the deformation area through surface contact for detection. However, during use, the contact effect between the baffle and the detection surface cannot be ensured, and after the deformation, a gear rack transmission method is adopted. There is a transmission gap between the gear and the rack, and small deformations cannot be effectively transmitted, which affects the monitoring effect during use. In addition, after the device is inserted into the detection point, it is inconvenient to fix it, and its practicality is low.

[0005] Therefore, a fiber optic sensing rock and soil stress and strain real-time monitoring instrument is designed to optimize the above problems. Summary of the Invention

[0006] The main purpose of the present invention is to provide a fiber optic sensing rock and soil stress and strain real-time monitor, which is evenly hinged and installed with contact rods on the circumferential surface of the plug at different levels, and FBG sensors are provided on the contact rods along the length direction, and then used in conjunction with an extension mechanism. During use, multiple groups of contact rods can be directly brought into contact with the inner wall of the jack, and direct contact with the monitoring surface is achieved in the form of point-to-surface contact. When the rock and soil stress changes, it can be directly transmitted to the contact rods, and real-time monitoring is performed using FBG sensors, and then multi-channel parallel acquisition is performed using a regulator. Finally, data preprocessing, anomaly detection and local early warning are achieved using an edge computer terminal, thereby ensuring monitoring accuracy during use. Through a hollow shell, an annular plate, a flat thread, an extrusion block, a through port, an adjustment rod, an adjustment block, a mounting groove, an insert, a tapered plug, an extrusion spring, The positioning mechanism composed of serrated grooves can quickly fix the insert sleeve after the insert sleeve is inserted into the detection hole, which makes it more convenient to use and improves the functionality of the device. The extension mechanism consists of an outer cylinder body, a first piston, a push rod, an inner cylinder body, a second piston, a limit baffle, a rectangular inner spiral tube, a screw, a one-way air intake valve, an exhaust pipe, a one-way exhaust valve, an air hole, a retaining ring, a second sealing ring, a connecting rod, a limit disk, and a reset spring. The top of the screw is connected to the adjusting rod. After the position of the insert sleeve is fixed, the continuous rotation of the adjusting rod can automatically expand multiple groups of contact rods outward at the same time, and the pneumatic extrusion can ensure the fit between the contact rod and the inner wall of the detection hole. In addition, after the monitoring is completed, the reverse rotation of the multiple adjusting rods can be used to shrink the contact rods and unlock the insert sleeve, which makes it more convenient to use and more practical.

[0007] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0008] The optical fiber sensing rock and soil stress and strain real-time monitor includes an insert, an FBG sensor, a regulator and an edge computer terminal. A positioning mechanism is provided at the top of the insert, a pressure cover is provided on the top of the positioning mechanism to block the monitoring hole, a conical head is fixed to the bottom of the insert, contact rods are evenly hingedly installed along the circumference on different horizontal surfaces of the outside of the insert, and the contact rods are inclined toward the bottom of the insert, FBG sensors are installed on the outside of the contact rods along the length direction, multiple groups of FBG sensors are connected in series through optical fibers, an extension mechanism is provided inside the insert for controlling the rotation of the contact rods in the vertical plane, the FBG sensors are connected to the regulator through an optical fiber link, and the output end of the regulator is electrically connected to the edge computer terminal through a wire.

[0009] Preferably, the shape of the gland is circular, and the outer diameter of the gland is larger than the diameter of the insert, and a first sealing ring is fixed to the bottom end of the gland.

[0010] Preferably: the positioning mechanism includes a hollow shell, an annular plate, a flat thread, an extrusion block, a through port and a rotating assembly. The hollow shell is fixed between the top of the insert and the bottom of the pressure cover. The inner bottom of the hollow shell is horizontally rotatably mounted with an annular plate. The top of the annular plate is provided with a flat thread. The outer side of the hollow shell is evenly slidably provided with an extrusion block, and the extrusion block is perpendicular to the cross-sectional direction of the hollow shell. The outer side of the hollow shell is provided with a through port that cooperates with the extrusion block, and the bottom of the extrusion block is provided with a thread that engages with the flat thread. The interior of the hollow shell is provided with a rotating assembly that controls the rotation of the annular plate.

[0011] Preferably: the rotating assembly includes an adjusting rod, an adjusting block and a connecting piece, the adjusting rod passes through the hollow shell and extends to the top of the pressure cover, a through hole larger than the outer diameter of the adjusting rod is opened on the hollow shell, the adjusting rod and the pressure cover are rotatably connected, the adjusting block is fixed to the top of the adjusting rod, the bottom end of the adjusting rod extends to the inside of the annular plate, and a connecting piece is provided between the outer side of the bottom end of the adjusting rod and the annular plate.

[0012] Preferably: the connecting piece includes a mounting groove, an insert block, a tapered plug, an extrusion spring and a serrated groove, the mounting groove is evenly arranged along the circumferential direction at the bottom end of the outer side of the adjusting rod, the inside of the adjusting rod is slidably provided with an insert block, the ends of the insert block are provided with a tapered plug, an extrusion spring is provided between the insert block and the inner end of the mounting groove, and the inner side of the annular plate is evenly provided with a serrated groove that cooperates with the tapered plug.

[0013] Preferably: the extension mechanism includes an outer cylinder body, a first piston, a push rod, an inflation component and an exhaust component, the outer cylinder body is evenly arranged on the circumferential surface of the insert cylinder, the first piston is slidably installed inside the outer cylinder body, and a push rod is hingedly installed between the outer side of the first piston and the inner side of the contact rod, the interior of the insert cylinder is provided with an inflation component for supplying air to the interior of the outer cylinder body, and the interior of the insert cylinder is provided with an exhaust component for deflating the interior of the outer cylinder body.

[0014] Preferably: the inflation component includes an inner cylinder body, a second piston, a rectangular inner coil, a screw, a one-way air intake valve, an exhaust pipe and a one-way exhaust valve, the inner cylinder body is vertically fixed to the inner bottom end of the insert tube, the inner part of the inner cylinder body is vertically slidably provided with a second piston, a rectangular inner coil is fixed at the middle position of the top end of the second piston, the rectangular inner coil slides vertically inside the inner cylinder body, the internal thread of the rectangular inner coil is installed with a screw, the top end of the screw is fixedly connected to the bottom end of the adjusting rod, the bottom end of the outer side of the inner cylinder body is installed with a one-way air intake valve, an exhaust pipe is installed between the bottom end of the outer cylinder body and the inner cylinder body, and the top end of the exhaust pipe is provided with a one-way exhaust valve.

[0015] Preferably, a limit baffle is horizontally fixed to the inner top end of the inner cylinder body, the rectangular inner spiral tube slides through the inside of the limit baffle, and a rectangular hole is opened on the limit baffle to match the rectangular inner spiral tube.

[0016] Preferably: the exhaust assembly includes an air hole, a retaining ring, a second sealing ring, a connecting rod, a limit plate and a return spring. The air hole is opened at the end of the outer cylinder body and is connected to the inside of the insert tube. The retaining ring is evenly slidably arranged inside the insert tube. The outer side of the retaining ring is provided with a second sealing ring. The outer side of the second sealing ring is in contact with the inner wall of the insert tube. A connecting rod is fixed between the retaining rings. A limit plate is horizontally arranged at the top of the insert tube, and the limit plate is located at the top of the rectangular inner spiral tube. The bottom of the limit plate is fixedly connected to the retaining ring. A return spring is provided between the top of the limit plate and the bottom of the hollow shell, and the screw passes through the limit plate and the return spring.

[0017] Preferably, the top end of the rectangular inner coil is circular, the outer diameter of the top end of the rectangular inner coil is larger than the inner diameter of the limiting disk, and the top end of the rectangular inner coil is parallel to the limiting disk.

[0018] The beneficial effects of the present invention are:

[0019] The fiber-optic sensing rock and soil stress and strain real-time monitor provided by the present invention has contact rods evenly hingedly mounted on the circumferential surface of an insert at different levels, and FBG sensors are provided on the contact rods along their length. This is then used in conjunction with an extension mechanism. During use, multiple sets of contact rods can be brought into direct contact with the inner wall of the insert, achieving point-to-surface contact with the monitoring surface. Changes in rock and soil stress can be directly transmitted to the contact rods, monitored in real time using FBG sensors, and then collected in parallel using a multi-channel regulator. Finally, an edge computer terminal is used to implement data preprocessing, anomaly detection, and local early warning, thereby ensuring monitoring accuracy during use.

[0020] The positioning mechanism composed of the hollow shell, annular plate, flat thread, extrusion block, through port, adjustment rod, adjustment block, mounting slot, insert block, tapered plug, extrusion spring, and serrated groove can quickly fix the insert tube after it is inserted into the detection hole, making it more convenient to use and improving the functionality of the device.

[0021] Through the extension mechanism consisting of an outer cylinder body, a first piston, a push rod, an inner cylinder body, a second piston, a limit baffle, a rectangular inner spiral tube, a screw, a one-way air inlet valve, an exhaust pipe, a one-way exhaust valve, an air hole, a retaining ring, a second sealing ring, a connecting rod, a limit plate, and a reset spring, the top end of the screw is connected to the adjusting rod. After the position of the insert cylinder is fixed, the continuous rotation of the adjusting rod can automatically expand multiple groups of contact rods outward at the same time, and the pneumatic extrusion method can ensure the fit between the contact rod and the inner wall of the detection hole. In addition, after the monitoring is completed, the reverse rotation of the multiple adjusting rods can be used to shrink the contact rods and unlock the insert cylinder, which is more convenient to use and more practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1This is a front view of a preferred embodiment of the optical fiber sensing rock and soil stress and strain real-time monitoring device of the present invention;

[0023] Figure 2 This is a cross-sectional view of the interior of the insert tube in the initial state of a preferred embodiment of the optical fiber sensing rock and soil stress and strain real-time monitoring device of the present invention;

[0024] Figure 3 This is a cross-sectional view of the interior of the insert tube of a preferred embodiment of the optical fiber sensing rock and soil stress and strain real-time monitoring device of the present invention in use;

[0025] Figure 4 An exploded view of a positioning mechanism in a preferred embodiment of the optical fiber sensing rock and soil stress and strain real-time monitoring device of the present invention;

[0026] Figure 5 This is a structural diagram of an annular plate in a preferred embodiment of the optical fiber sensing rock and soil stress and strain real-time monitoring device of the present invention;

[0027] Figure 6 This is a preferred embodiment of the optical fiber sensing rock and soil stress and strain real-time monitoring instrument of the present invention. Figure 2 Enlarged view of point A in the middle;

[0028] Figure 7 This is a partial structural diagram of the outer part of the inner cylinder of a preferred embodiment of the optical fiber sensing rock and soil stress and strain real-time monitoring device of the present invention;

[0029] Figure 8 This is a cross-sectional view of the inner cylinder of a preferred embodiment of the optical fiber sensing rock and soil stress and strain real-time monitoring device of the present invention.

[0030] In the figure: 1. Insertion tube;

[0031] 2. Positioning mechanism; 201. Hollow housing; 202. Annular plate; 203. Flat thread; 204. Extrusion block; 205. Through port; 206. Adjustment rod; 207. Adjustment block; 208. Mounting slot; 209. Insertion block; 210. Conical plug; 211. Extrusion spring; 212. Sawtooth groove;

[0032] 3. Gland; 301. First sealing ring;

[0033] 4. Conical head; 5. Contact rod; 6. FBG sensor;

[0034] 7. Extension mechanism; 701. Outer cylinder; 702. First piston; 703. Push rod; 704. Inner cylinder; 705. Second piston; 706. Stop plate; 707. Rectangular inner solenoid; 708. Screw; 709. One-way air inlet valve; 710. Exhaust pipe; 711. One-way exhaust valve; 712. Air hole; 713. Retaining ring; 714. Second sealing ring; 715. Connecting rod; 716. Stop plate; 717. Return spring;

[0035] 8. Regulator; 9. Edge computer terminal. DETAILED DESCRIPTION

[0036] In order to make the technical solution of the present invention more clear and specific to those skilled in the art, the present invention is described in further detail below with reference to embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0037] like Figures 1-8 As shown, this embodiment provides a fiber optic sensing rock and soil stress and strain real-time monitoring instrument, including an insert tube 1, an FBG sensor 6, a regulator 8 and an edge computer terminal 9. A positioning mechanism 2 is provided at the top of the insert tube 1, and a pressure cover 3 is provided on the top of the positioning mechanism 2 to block the monitoring hole. A conical head 4 is fixed to the bottom end of the insert tube 1. Contact rods 5 are evenly hingedly installed along the circumferential direction on different horizontal surfaces on the outside of the insert tube 1, and the contact rods 5 are inclined toward the bottom end of the insert tube 1.

[0038] An FBG sensor 6 is installed along the length of the outer side of the contact rod 5. The FBG sensor 6 is adhered to the contact rod 5 with a high-temperature and high-pressure resistant epoxy resin adhesive. The two ends of the sensor are fixed to the end face of the contact rod 5 by optical fiber fastening clamps to prevent the sensor from directly contacting the rock and soil. The pigtails of multiple groups of FBG sensors 6 are converged into the optical fiber groove on the inner wall of the insert 1 through the micro-through hole inside the contact rod 5. The groove is filled with waterproof sealant to prevent the optical fiber from being pulled and broken during the extension of the insert 1.

[0039] Multiple groups of FBG sensors 6 are connected in series via optical fibers. An extension mechanism 7 for controlling the rotation of the contact rod 5 on a vertical plane is provided inside the insert 1. The FBG sensors 6 are connected to a regulator 8 via an optical fiber link.

[0040] The moderator 8 uses a wavelength demodulator, supports 8-16 channels of parallel acquisition, has a wavelength resolution of ≤1pm, a sampling frequency of ≥100Hz, and a built-in temperature compensation module, which can automatically calibrate the effect of ambient temperature on the FBG sensor 6;

[0041] The output end of the regulator 8 is electrically connected to the edge computer terminal 9 via a wire;

[0042] The edge computer terminal 9 uses an embedded industrial computer (such as Advantech UNO-2483G), equipped with an Intel i5 processor, 8GB memory, a 128GB solid-state drive, an integrated 4G / 5G communication module, and supports optical fiber and wireless dual-link data transmission.

[0043] The overall working principle is as follows: when in use, a geological drill is used to open a vertical hole at the monitoring point with a diameter 20 mm larger than the insert 1. The hole depth is determined according to the monitoring requirements. After cleaning the hole, a small amount of bentonite slurry is injected to protect the wall. Then, the insert 1 is inserted into the interior of the monitoring hole. The bottom end of the conical head 4 contacts the bottom end of the monitoring hole. Then, the positioning mechanism 2 is used to fix the position of the insert 1, and the top of the monitoring hole is shielded and sealed using the pressure cover 3. After the insert 1 is fixed, the extension mechanism 7 is used to expand the contact rod 5 outward, and the bottom end of the contact rod 5 contacts the inner wall of the monitoring hole. When all the contact rods 5 are in contact with the inner wall of the monitoring hole, the FBG sensor 6 is used to monitor the stress and strain in real time. The regulator 8 collects the data of the FBG sensor 6 and transmits it to the inside of the edge computer terminal 9. Finally, the edge computer terminal 9 is used to implement data preprocessing, anomaly detection and local early warning, thereby ensuring the monitoring accuracy during use.

[0044] Data processing algorithm:

[0045] Preprocessing: The original wavelength signal is subjected to sliding average filtering (window size N = 100) to remove high-frequency noise. Strain calculation: Based on the FBG wavelength drift formula Δλ = λ0(1-pe)Δε (λ0 is the center wavelength, pe is the effective elastic-optical coefficient), the strain value of each contact rod 5 is calculated in real time. Anomaly detection: A dynamic threshold method based on historical data (3σ principle) is used in combination with machine learning algorithms (such as isolation forest) to identify sudden stress mutation events. Local warning: When the strain value exceeds the warning threshold (such as ±1000με) for three consecutive sampling cycles, a buzzer alarm is triggered and a warning signal is sent to the remote server.

[0046] In this embodiment, the shape of the gland 3 is circular, and the outer diameter of the gland 3 is larger than the diameter of the insert 1 . A first sealing ring 301 is fixed to the bottom end of the gland 3 .

[0047] Partial working principle: The first sealing ring 301 is made of ethylene propylene diene monomer (EPDM) with a hardness of 60±5 Shore A, a sealing ring compression rate of 20%, and a waterproof grade of IP67, which can ensure the sealing effect on the top of the monitoring hole and reduce external interference.

[0048] In this embodiment, the positioning mechanism 2 includes a hollow shell 201, an annular plate 202, a flat thread 203, an extrusion block 204, a through port 205 and a rotating assembly. The hollow shell 201 is fixed between the top of the insert 1 and the bottom of the pressure cover 3. The inner bottom of the hollow shell 201 is horizontally rotatably installed with an annular plate 202. The top of the annular plate 202 is provided with a flat thread 203. The outer side of the hollow shell 201 is evenly slidably provided with an extrusion block 204, and the extrusion block 204 is perpendicular to the cross-sectional direction of the hollow shell 201. The outer side of the hollow shell 201 is provided with a through port 205 that cooperates with the extrusion block 204. The bottom of the extrusion block 204 is provided with a thread that engages with the flat thread 203. The interior of the hollow shell 201 is provided with a rotating assembly that controls the rotation of the annular plate 202.

[0049] Local working principle: When positioning the insert 1, first use the rotating assembly to control the rotation of the annular plate 202. Since the top of the annular plate 202 is engaged with the extrusion block 204 through the flat thread 203, during the rotation of the annular plate 202, the outward movement of multiple groups of extrusion blocks 204 can be synchronously controlled to make the outer end of the extrusion block 204 contact the inner wall of the monitoring hole to complete the fixation of the insert 1. When the device is disassembled, it is only necessary to reversely control the annular plate 202 to release the fixation of the insert 1.

[0050] In this embodiment, the rotating assembly includes an adjusting rod 206, an adjusting block 207 and a connecting piece. The adjusting rod 206 passes through the hollow shell 201 and extends to the top of the pressure cover 3. A through hole larger than the outer diameter of the adjusting rod 206 is opened on the hollow shell 201. The adjusting rod 206 is rotatably connected to the pressure cover 3. The adjusting block 207 is fixed to the top of the adjusting rod 206. The bottom end of the adjusting rod 206 extends to the inside of the annular plate 202. A connecting piece is provided between the outer side of the bottom end of the adjusting rod 206 and the annular plate 202.

[0051] Partial working principle: When controlling the rotation of the annular plate 202, since the bottom end of the adjusting rod 206 is connected to the annular plate 202 through a connecting piece, the rotation of the annular plate 202 can be driven by rotating the adjusting rod 206, and the use of the adjusting block 207 can be manually adjusted, which is more practical.

[0052] In this embodiment, the connecting part includes a mounting groove 208, an insert block 209, a tapered plug 210, an extrusion spring 211 and a serrated groove 212. The mounting groove 208 is evenly arranged along the circumferential direction at the bottom end of the outer side of the adjusting rod 206. The inside of the adjusting rod 206 is slidably provided with an insert block 209, and the end of the insert block 209 is provided with a tapered plug 210. An extrusion spring 211 is provided between the insert block 209 and the inner end of the mounting groove 208. The inner side of the annular plate 202 is evenly provided with a serrated groove 212 that cooperates with the tapered plug 210.

[0053] Partial working principle: In the initial state, the extrusion spring 211 applies a thrust to the plug block 209, inserting the tapered plug 210 into the inside of the serrated groove 212. During the fixing process of the insert 1, the adjustment rod 206 rotates, and the tapered plug 210 applies a thrust to the hypotenuse of the serrated groove 212. The rotational resistance of the annular plate 202 is less than the thrust applied by the tapered plug 210. Therefore, the annular plate 202 can rotate horizontally until the extrusion block 204 contacts the inner wall of the monitoring hole. After that, the rotational resistance of the annular plate 202 increases, and the adjustment rod 206 then presses the annular plate 202 through the tapered plug 210. When the thrust is applied, the extrusion spring 211 will be pushed, the extrusion spring 211 will be compressed, and the plug block 209 will be squeezed into the inside of the installation groove 208. At this time, the tapered plug 210 at the end of the plug block 209 will move inside the different serrated grooves 212, and a "clicking" sound will be emitted, indicating that the fixation is completed. When the insert tube 1 is removed, the adjustment rod 206 is controlled to rotate in the reverse direction. The resistance of the annular plate 202 during the reverse rotation is less than the thrust applied to the annular plate 202 by the tapered plug 210. Therefore, the annular plate 202 can rotate in the reverse direction, controlling the retraction and reset of the extrusion block 204 to release the locked state.

[0054] In this embodiment, the extension mechanism 7 includes an outer cylinder body 701, a first piston 702, a push rod 703, an inflation component and an exhaust component. The outer cylinder body 701 is evenly arranged on the circumferential surface of the insert tube 1. The first piston 702 is slidably installed inside the outer cylinder body 701. The push rod 703 is hingedly installed between the outer side of the first piston 702 and the inner side of the contact rod 5. The interior of the insert tube 1 is provided with an inflation component for supplying air to the interior of the outer cylinder body 701, and the interior of the insert tube 1 is provided with an exhaust component for deflating the interior of the outer cylinder body 701.

[0055] Partial working principle: After the insert 1 is fixed, the inflation assembly is used to inflate the interior of the outer cylinder 701. The gas pushes the first piston 702 outward. The first piston 702 uses the push rod 703 to expand the contact rod 5 outward and contact the inner wall of the monitoring hole. The pressure inside multiple groups of outer cylinders 701 is the same, which can ensure the contact effect of multiple groups of contact rods 5 with the inner wall of the monitoring hole. After the device is used, the exhaust assembly is used to discharge the gas inside the outer cylinder 701 to reduce the pressure inside the outer cylinder 701, and then the insert 1 is pulled out. The contact rod 5 will not hinder the removal of the insert 1. After the insert 1 is completely pulled out, the contact rod 5 is pressed again to reset and restore to the initial state for secondary use and carrying.

[0056] In this embodiment, the inflation component includes an inner cylinder body 704, a second piston 705, a rectangular inner coil 707, a screw 708, a one-way air inlet valve 709, an exhaust pipe 710 and a one-way exhaust valve 711. The inner cylinder body 704 is vertically fixed to the inner bottom end of the insert 1. The inner part of the inner cylinder body 704 is provided with a second piston 705 for vertical sliding. The second piston 705 is made of polyformaldehyde and is coated with a molybdenum disulfide anti-friction layer on the surface. A rectangular inner coil 707 is fixed at the middle position of the top of the second piston 705. The rectangular inner coil 707 slides vertically inside the inner cylinder body 704. The inner thread of the rectangular inner coil 707 is installed with Screw 708, the top end of screw 708 is fixedly connected to the bottom end of adjusting rod 206, and a one-way air intake valve 709 is installed at the bottom end of the outer side of inner cylinder 704. The one-way air intake valve 709 adopts a diaphragm one-way valve with an opening pressure of ≤5kPa to ensure that outside air can easily enter. An exhaust pipe 710 is installed between the bottom end of outer cylinder 701 and inner cylinder 704, and a one-way exhaust valve 711 is provided at the top end of exhaust pipe 710. The one-way exhaust valve 711 is spring-loaded and the opening pressure is set to 100-150kPa to ensure that the contact rod 5 fits the inner wall of the monitoring hole with a constant thrust (about 5-8N / rod).

[0057] Partial working principle: in the process of rotating the adjusting rod 206 to fix the insert tube 1, the adjusting rod 206 will drive the screw 708 to rotate. Since the rectangular inner screw tube 707 is limited and can only move along the length direction of the inner cylinder body 704, the rotation of the adjusting rod 206 controls the rectangular inner screw tube 707 to drive the second piston 705 to move downward, and supply air to the interior of the outer cylinder body 701. Before the insert tube 1 is fixed, due to the existence of the exhaust component, the outer cylinder body 701 is in an open state, and the gas entering will be discharged, which will not cause the internal pressure of the outer cylinder body 701 to increase, and the contact rod 5 will not move. Only when the insert tube 1 is fixed, the outer cylinder body 701 is in an open state, and the gas entering will be discharged, which will not cause the internal pressure of the outer cylinder body 701 to increase, and the contact rod 5 will not move. After the tube 1 is fixed, the end of the outer cylinder 701 will be blocked, and the gas injected from the inner cylinder 704 will increase the air pressure inside the outer cylinder 701, causing the contact rod 5 to expand outward. When the device is taken out, the reverse rotation of the adjusting rod 206 will drive the second piston 705 to move upward inside the inner cylinder 704, and the gas inside the insert tube 1 will enter the interior of the inner cylinder 704, which will not hinder the rotation of the adjusting rod 206. Moreover, when the adjusting rod 206 rotates in the opposite direction, the exhaust component will connect the outer cylinder 701 with the inner cylinder 704 again to reduce the air pressure inside the outer cylinder 701, making it easier to remove the device.

[0058] In this embodiment, a limit baffle 706 is horizontally fixed to the inner top of the inner cylinder body 704, and the rectangular inner screw tube 707 slides through the inside of the limit baffle 706. The limit baffle 706 is provided with a rectangular hole that cooperates with the rectangular inner screw tube 707.

[0059] Partial working principle: The use of the limit baffle 706 can ensure that the rectangular inner screw tube 707 can only move in a straight line during the rotation of the screw rod 708.

[0060] In this embodiment, the exhaust assembly includes an air hole 712, a retaining ring 713, a second sealing ring 714, a connecting rod 715, a limit plate 716 and a return spring 717. The air hole 712 is opened at the end of the outer cylinder 701 and is connected to the interior of the insert 1. The retaining ring 713 is evenly slidably arranged inside the insert 1. The outer side of the retaining ring 713 is provided with a second sealing ring 714. The second sealing ring 714 is made of fluororubber, which is temperature-resistant from -20°C to 150°C, has an O-shaped cross-section (diameter 3mm), and is installed in the annular groove on the outer side of the retaining ring 713. The outer side of the second sealing ring 714 is in contact with the inner wall of the insert tube 1, and a connecting rod 715 is fixed between the retaining ring 713. A limit plate 716 is horizontally arranged at the top of the insert tube 1, and the limit plate 716 is located at the top of the rectangular inner screw tube 707. The bottom of the limit plate 716 is fixedly connected to the retaining ring 713. A return spring 717 is provided between the top of the limit plate 716 and the bottom of the hollow shell 201, and the screw 708 passes through the limit plate 716 and the return spring 717.

[0061] Partial working principle: In the initial state, the top of the rectangular inner screw 707 contacts the limit plate 716, the reset spring 717 is in a compressed state, and the second sealing ring 714 on the retaining ring 713 does not block the air hole 712. When the adjusting rod 206 is rotated and fixed, the rectangular inner screw 707 will also move down, and the reset spring 717 will reset, pushing the retaining ring 713 to move down. When the device is fixed, as the adjusting rod 206 continues to rotate, the retaining ring 713 moves down and the second sealing ring 714 blocks the air hole 712, and the inner cylinder body 704 enters the outer cylinder The gas inside the body 701 will not continue to be discharged, and the contact rod 5 can be expanded outward. When the device is dismantled, the adjustment rod 206 moves in the opposite direction to release the lock on the insert 1. At the same time, the rectangular inner screw 707 rises. When the rectangular inner screw 707 contacts the limit plate 716, it will drive the retaining ring 713 and the second sealing ring 714 to move upward, release the blockage of the air hole 712, and relieve the pressure on the outer cylinder 701 until the limit plate 716 returns to its initial position. Then the insert 1 is pulled out. During the withdrawal process, the contact rod 5 retracts under the action of rock and soil pressure or its own gravity.

[0062] In this embodiment, the top of the rectangular inner coil 707 is circular, and the outer diameter of the top of the rectangular inner coil 707 is larger than the inner diameter of the limiting plate 716 . The top of the rectangular inner coil 707 is parallel to the limiting plate 716 .

[0063] Partial working principle: The rectangular inner screw tube 707 can stably control the upward movement of the limit plate 716 during the upward movement, and can stably block the limit plate 716 in the initial state.

[0064] The above is only a further embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and concepts of the present invention within the scope disclosed by the present invention, which fall within the scope of protection of the present invention.

Claims

1. A fiber optic sensing rock and soil stress and strain real-time monitoring instrument, comprising an insert (1), an FBG sensor (6), a regulator (8) and an edge computer terminal (9), characterized in that: The top of the insert (1) is provided with a positioning mechanism (2), the top of the positioning mechanism (2) is provided with a pressure cover (3) for covering the monitoring hole, the bottom of the insert (1) is fixed with a conical head (4), and contact rods (5) are evenly hingedly installed along the circumference on different horizontal surfaces outside the insert (1), and the contact rods (5) are inclined toward the bottom of the insert (1), and FBG sensors (6) are installed on the outside of the contact rods (5) along the length direction, and multiple groups of FBG sensors (6) are connected in series through optical fibers. The inside of the insert (1) is provided with an extension mechanism (7) for controlling the rotation of the contact rods (5) on the vertical plane, and the FBG sensors (6) are connected to the regulator (8) through an optical fiber link, and the output end of the regulator (8) is electrically connected to the edge computer terminal (9) through a wire.

2. The optical fiber sensing rock and soil stress and strain real-time monitoring device according to claim 1, characterized in that: The shape of the pressure cover (3) is circular, and the outer diameter of the pressure cover (3) is larger than the diameter of the insert (1). A first sealing ring (301) is fixed to the bottom end of the pressure cover (3).

3. The optical fiber sensing rock and soil stress and strain real-time monitoring device according to claim 1, characterized in that: The positioning mechanism (2) comprises a hollow shell (201), an annular plate (202), a flat thread (203), an extrusion block (204), a through-port (205) and a rotating assembly. The hollow shell (201) is fixed between the top of the insert (1) and the bottom of the pressure cover (3). The inner bottom of the hollow shell (201) is horizontally rotatably mounted with an annular plate (202). The top of the annular plate (202) is provided with a flat thread (203). The outer side of the hollow shell (201) is evenly slidably provided with an extrusion block (204), and the extrusion block (204) is perpendicular to the cross-sectional direction of the hollow shell (201). The outer side of the hollow shell (201) is provided with a through-port (205) that cooperates with the extrusion block (204). The bottom of the extrusion block (204) is provided with a thread that meshes with the flat thread (203). The interior of the hollow shell (201) is provided with a rotating assembly that controls the rotation of the annular plate (202).

4. The optical fiber sensing rock and soil stress and strain real-time monitoring device according to claim 3, characterized in that: The rotating assembly comprises an adjusting rod (206), an adjusting block (207) and a connecting piece. The adjusting rod (206) passes through the hollow shell (201) and extends to the top of the pressure cover (3). A through hole larger than the outer diameter of the adjusting rod (206) is provided on the hollow shell (201). The adjusting rod (206) and the pressure cover (3) are rotatably connected. The adjusting block (207) is fixed to the top of the adjusting rod (206). The bottom end of the adjusting rod (206) extends to the inside of the annular plate (202). A connecting piece is provided between the outer side of the bottom end of the adjusting rod (206) and the annular plate (202).

5. The optical fiber sensing rock and soil stress and strain real-time monitoring device according to claim 4, characterized in that: The connecting piece comprises a mounting groove (208), an insert block (209), a tapered plug (210), an extrusion spring (211) and a sawtooth groove (212). The mounting groove (208) is evenly arranged at the bottom end of the outer side of the adjusting rod (206) along the circumferential direction. The adjusting rod (206) is slidably provided with an insert block (209). The end of the insert block (209) is provided with a tapered plug (210). An extrusion spring (211) is provided between the insert block (209) and the inner end of the mounting groove (208). The inner side of the annular plate (202) is evenly provided with a sawtooth groove (212) matched with the tapered plug (210).

6. The optical fiber sensing rock and soil stress and strain real-time monitoring device according to claim 5, characterized in that: The extension mechanism (7) comprises an outer cylinder (701), a first piston (702), a push rod (703), an inflation assembly and an exhaust assembly. The outer cylinder (701) is evenly arranged on the circumferential surface of the insert cylinder (1). The first piston (702) is slidably mounted inside the outer cylinder (701). The push rod (703) is hingedly mounted between the outer side of the first piston (702) and the inner side of the contact rod (5). The interior of the insert cylinder (1) is provided with an inflation assembly for supplying air to the interior of the outer cylinder (701). The interior of the insert cylinder (1) is provided with an exhaust assembly for deflating the interior of the outer cylinder (701).

7. The optical fiber sensing rock and soil stress and strain real-time monitoring device according to claim 6, characterized in that: The inflation assembly includes an inner cylinder (704), a second piston (705), a rectangular inner spiral tube (707), a screw (708), a one-way air inlet valve (709), an exhaust pipe (710) and a one-way exhaust valve (711). The inner cylinder (704) is vertically fixed to the inner bottom end of the insert (1). The second piston (705) is vertically slidably provided inside the inner cylinder (704). A rectangular inner spiral tube (707) is fixed at the middle position of the top end of the second piston (705). (707) slides vertically inside the inner cylinder (704), the inner thread of the rectangular inner screw tube (707) is installed with a screw rod (708), the top end of the screw rod (708) is fixedly connected to the bottom end of the adjustment rod (206), a one-way air intake valve (709) is installed at the bottom end of the outer side of the inner cylinder (704), an exhaust pipe (710) is installed between the bottom ends of the outer cylinder (701) and the inner cylinder (704), and a one-way exhaust valve (711) is provided at the top end of the exhaust pipe (710).

8. The optical fiber sensing rock and soil stress and strain real-time monitoring device according to claim 7, characterized in that: A limit baffle (706) is horizontally fixed to the inner top of the inner cylinder body (704), and the rectangular inner screw tube (707) slides through the inside of the limit baffle (706). The limit baffle (706) is provided with a rectangular hole that matches the rectangular inner screw tube (707).

9. The optical fiber sensing rock and soil stress and strain real-time monitoring device according to claim 7 or 8, characterized in that: The exhaust assembly includes an air hole (712), a retaining ring (713), a second sealing ring (714), a connecting rod (715), a limiting plate (716) and a reset spring (717). The air hole (712) is opened at the end of the outer cylinder (701) and is connected to the inside of the insert (1). The retaining ring (713) is evenly slidably arranged inside the insert (1). The outer side of the retaining ring (713) is provided with a second sealing ring (714). The outer side of the second sealing ring (714) is in contact with the inner side of the insert (1). The wall is fitted, a connecting rod (715) is fixed between the retaining ring (713), a limit plate (716) is horizontally arranged on the top of the insert cylinder (1), and the limit plate (716) is located at the top of the rectangular inner screw tube (707), the bottom of the limit plate (716) is fixedly connected to the retaining ring (713), a return spring (717) is provided between the top of the limit plate (716) and the bottom of the hollow shell (201), and the screw (708) passes through the limit plate (716) and the return spring (717).

10. The optical fiber sensing rock and soil stress and strain real-time monitoring device according to claim 9, characterized in that: The top of the rectangular inner spiral tube (707) is circular, and the outer diameter of the top of the rectangular inner spiral tube (707) is larger than the inner diameter of the limiting plate (716). The top of the rectangular inner spiral tube (707) is parallel to the limiting plate (716).

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