A multi-dimensional monitoring borehole stress meter

Abstract

The present application relates to a kind of multi-dimensional monitoring borehole stress meter and its monitoring method, belong to the technical field of mine pressure safety detection.The borehole stress meter includes angle sensor, multi-dimensional stress monitoring module and one-way hydraulic cylinder, stress monitoring module includes base and jacking mechanism, the base is two half symmetrical cylindrical rigid structure, built-in jacking mechanism, spring steel plate is fixed on the surface of base, force grating is installed on each spring steel plate;The rear end of base is connected with one-way hydraulic cylinder to push jacking mechanism, push jacking mechanism in the cavity of base, so that the diameter of sensor increases.The end of the borehole stress meter designed in the present application is provided with angle sensor for monitoring the orientation of sensor, can realize 360 degree orientation detection function;Multi-dimensional stress monitoring module is used to monitor the direction, size and fine position along the axial direction of surrounding rock stress, monitoring data is more comprehensive, application is more accurate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mine safety detection, and particularly relates to a multi-dimensional monitoring borehole stress meter. BACKGROUND

[0002] In daily mining operations of coal mines, the mining of coal bodies inevitably causes the redistribution of rock stress fields, and the new stress field distribution state has an extremely important influence on the stability of roadways and stope, especially for deep mining mines, the impact ground pressure caused by the high concentration of surrounding rock stress field occurs from time to time. Impact ground pressure is a dynamic phenomenon characterized by sudden, sharp and violent destruction of coal and rock bodies around the mine roadway and stope due to the release of deformation energy, which is essentially caused by the sudden release of a large amount of elastic energy. The problem of impact ground pressure is essentially a stress problem of coal and rock bodies, so for the monitoring of impact ground pressure, "stress" is the most reliable physical quantity. As a monitoring device for the stress change of mine roadway surrounding rock, the existing borehole stress meter has been widely used in the prior art, and the existing borehole stress meter basically adopts the structure of a hydraulic oil pillow, and the stress change of surrounding rock is monitored by monitoring the compression of the oil pillow by the ground pressure change, but the existing stress meter can only obtain the stress change, and cannot accurately monitor the source direction of the stress, and cannot accurately judge the possible accidents caused by the stress change. SUMMARY

[0003] To solve the problems in the prior art, the present application designs a multi-dimensional monitoring borehole stress meter to solve the deficiencies of the existing borehole stress meter in application and achieve the purpose of multi-dimensional accurate identification of stress change.

[0004] The technical scheme adopted by the present application is: the borehole stress meter comprises an angle sensor, a multi-dimensional stress monitoring module and a one-way hydraulic cylinder, the multi-dimensional stress monitoring module comprises a base and a jacking mechanism, the inside of the base is a cavity, and the cavity is formed by butt joint of two base plates in the form of a semicircular cylinder, a plurality of spring steel plates are fixed on each base plate in the axial direction, a force grating is arranged on each spring steel plate in the length direction of the spring steel plate, a deformation gap is left between the bottom surface of the spring steel plate and the base plate, the rear end of the base is connected with the one-way hydraulic cylinder, a lead-in optical fiber groove is opened in the front end of the base, a lead-out optical fiber groove is opened in the rear end of the base, the angle sensor is connected to the front end surface of the base of the multi-dimensional stress monitoring module, the jacking mechanism is arranged in the internal cavity of the base, the jacking mechanism jacks up the two base plates of the base outward so that they are in full contact with the borehole wall, and the piston rod of the one-way hydraulic cylinder is connected with the jacking mechanism to provide jacking force for the jacking mechanism.

[0005] Further, the jacking mechanism comprises a jacking plate and a jacking rod, the jacking plate is in a cylindrical shape, has a wedge-shaped cavity inside, is arranged in the cavity of the base in the axial direction, is formed by butt joint of two half-cylindrical groove plates, the two groove plates are respectively fixed in the inner cavities of the two base plates of the base, the inner side of the groove plate is a wedge-shaped slope, a plurality of rows of clamping grooves are arranged on the wedge-shaped slope in the axial direction, the jacking rod comprises a wedge-shaped block, the wedge-shaped block is matched with the wedge-shaped cavity inside the jacking plate, the front end of the wedge-shaped block is inserted into the wedge-shaped cavity of the jacking plate, the outer side of the wedge-shaped block is provided with a reverse tooth matched with the clamping groove, the rear end of the jacking rod is connected with a one-way hydraulic cylinder, the one-way hydraulic cylinder pushes the jacking rod forward, the wedge-shaped block is pushed forward into the wedge-shaped cavity of the jacking plate, the two groove plates are pushed outward, and the reverse tooth on the outer side of the wedge-shaped block is clamped into the clamping groove of the groove plate.

[0006] Further, the connecting end of the one-way hydraulic cylinder and the base is provided with an annular groove, the rear side ends of the two base plates constituting the base are respectively provided with semicircular annular clamping plates, the clamping plates of the rear side ends of the two base plates are respectively inserted into the annular grooves of the one-way hydraulic cylinder, and the length of the limited connection of the clamping plate and the groove is greater than the jacking displacement distance of the base plate, after the base plate is jacked up, the clamping plate cannot be pulled out of the groove.

[0007] Further, the angle sensor comprises a shell and a sensitive element inside the shell, the shell comprises a conical cover plate, a cylinder body and a bottom plate, the cover plate is connected to the top end of the cylinder body, the bottom plate is connected to the bottom end of the cylinder body, the bottom plate is provided with an optical cable routing hole, the bottom plate is connected and fixed with the front end surface of one of the base plates of the base, the optical cable routing hole corresponds to the lead-in optical fiber groove on the base, and the sensitive element is connected in the cylinder body.

[0008] Further, the sensitive element comprises a temperature measuring grating and two elastic beams arranged at a fixed angle on the same plane, one end of the two elastic beams is connected to a weight, and the other end is fixed on the cylinder body through a supporting plate, the elastic beams are pasted with angle measuring gratings along the length direction, the cylinder body is provided with lead hole corresponding to the two elastic beams, the lead lines at the ends of the two elastic beams are respectively pulled out from the two lead holes of the cylinder body, and are respectively pulled into the base through the optical cable routing hole on the bottom plate and the lead-in optical fiber groove on the base plate.

[0009] Further, the outer side of the multi-dimensional stress monitoring module is covered with a flexible sheath, the two ends of the flexible sheath are respectively connected with the bottom plate of the angle sensor and the one-way hydraulic cylinder, the surface of the cylinder body of the one-way hydraulic cylinder is provided with four through grooves in the axial direction, and thin-walled pipes are arranged in the four through grooves, and the signal cables of the multi-dimensional stress monitoring module and the angle sensor are located in the flexible sheath and are pulled out from the four thin-walled pipes through the lead-out optical fiber groove at the rear end of the base.

[0010] Further, four spring steel plates are connected to each base plate of the multi-dimensional stress monitoring module, the thickness of the four spring steel plates gradually changes, the surface of the spring steel plates is grooved along the central axis, the force grating is pasted in the groove as a sensor element, and the two ends of the four spring steel plates are fixed on the base plate through screws and are uniformly arranged in the circumferential direction.

[0011] Further, two jacking plates are arranged in the interior of the base in the axial direction, the jacking rod comprises two wedge-shaped blocks which are connected through a connecting rod.

[0012] Compared with the prior art, the multi-dimensional monitoring borehole stress gauge has the following advantages: first, the angle sensor is fixed at the front end of the borehole stress gauge, and the azimuth angle monitored by the angle sensor determines the azimuth of the multi-dimensional stress sensing module; second, the multi-dimensional stress sensing module is provided with a plurality of spring steel plates which are arranged in the circumferential direction and are provided with gratings, the spring steel plates are designed to have gradually changing thickness, so that the position of stress occurrence can be monitored; and third, the base of the multi-dimensional stress monitoring module is formed by butt joint of two base plates and is provided with a jacking mechanism, so that the sensor on the base can be in full contact with the borehole wall during application, the reverse tooth is arranged on the outside of the wedge-shaped block of the jacking mechanism, the reverse tooth will not retreat after jacking, the position of the base is stable, and the detection data is real and reliable. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a structural schematic diagram of the multi-dimensional monitoring borehole stress gauge.

[0014] Figure 2 is a schematic diagram of the multi-dimensional monitoring borehole stress gauge without a flexible sheath.

[0015] Figure 3 is a sectional view of the multi-dimensional monitoring borehole stress gauge.

[0016] Figure 4 is a structural schematic diagram of the base plate.

[0017] Figure 5 is a structural schematic diagram of the jacking rod.

[0018] In the drawings, 1 is an angle sensor, 2 is a multi-dimensional stress monitoring module, 3 is a one-way hydraulic cylinder, 4 is a flexible sheath, 5 is a base, 6 is a jacking plate, 7 is a jacking rod, 8 is a thin-walled tube, 11 is a cover plate, 12 is a cylinder body, 13 is a bottom plate, 14 is an elastic beam, 15 is a supporting plate, 16 is a lead hole, 17 is a weight, 18 is an optical cable routing hole, 51 is a base plate, 52 is a spring steel plate, 53 is a clamping plate, 54 is a lead-in optical fiber groove, 55 is a lead-out optical fiber groove, 31 is an annular groove, 32 is a U-shaped clamping joint, 33 is a through groove, 61 is a groove plate, 62 is a clamping groove, 71 is a wedge-shaped block, 72 is a connecting rod, and 73 is a reverse tooth. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The technical solutions in the embodiments of the present invention will be clearly and completely described. The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] like Figures 1 to 5 As shown, this invention patent designs an embodiment of a multi-dimensional monitoring borehole stress gauge. In this embodiment, the borehole stress gauge includes an angle sensor 1, a multi-dimensional stress monitoring module 2, and a one-way hydraulic cylinder 3. The multi-dimensional stress monitoring module 2 includes a base 5 and a lifting mechanism. The rear end of the base 5 is connected to the one-way hydraulic cylinder 3, and the angle sensor 1 is connected to the front end face of the base 5. The base 5 has a hollow interior with a smaller outer diameter in the middle and a larger outer diameter at both ends. The two ends are connecting seats, forming a regular octagon, with screw holes on each side. The base 5 is formed by joining two semi-cylindrical base plates 51. Each base plate 51 has four spring steel plates 52 fixed axially. The two ends of the spring steel plates 52 are fixed to the screw holes of the connecting seats on both sides by screws. Each spring steel plate 52 has a force-measuring grating arranged along its length, and a deformation gap is left between the bottom surface of the spring steel plate 52 and the base plate 51. The thickness of the spring steel plate 52 gradually changes, and grooves are engraved along the central axis on the surface of the spring steel plate 52. The force measuring grating is attached to the groove as a sensor element. The front end of the base plate 51 has multiple fiber optic inlet grooves 54 along the axial direction, and the rear end has multiple fiber optic outlet grooves 55 along the axial direction.

[0021] The jacking mechanism is arranged in the inner cavity of the base 5, and the jacking mechanism jacks up the two base plates 51 of the base 5 outwardly so that the two base plates 51 can be in full contact with the wall of the borehole. The piston rod of the one-way hydraulic cylinder 3 is connected to the jacking mechanism to provide jacking power for the jacking mechanism. The jacking mechanism comprises two jacking plates 6 and a jacking rod 7. The jacking plate 6 is in a cylindrical shape and has a wedge-shaped cavity in the inside. The two jacking plates 6 are arranged in the cavity in the inside of the base 5 along the axial direction. The jacking plate 6 is formed by butt joint of two half-cylindrical groove plates 61. The two groove plates 61 are respectively fixed in the inner cavities of the two base plates 51 of the base and are connected to the base plates 51 to avoid relative deflection during use. The inner side of the groove plate 61 is a wedge-shaped slope. After the two groove plates 61 are closed, a wedge-shaped cavity is formed. A plurality of clamping grooves 62 are arranged on the wedge-shaped slope of the inner side of the groove plate 61 along the axial direction. The jacking rod 7 comprises two wedge-shaped blocks 71. The wedge-shaped blocks 71 are matched with the wedge-shaped cavities in the inside of the jacking plates 6. The two wedge-shaped blocks 71 are connected by a connecting rod 72. The two wedge-shaped blocks 71 are respectively inserted into the wedge-shaped cavities of the two jacking plates 6. The upper and lower sides of the wedge-shaped block 71 are respectively provided with reverse teeth 73 matched with the clamping grooves 62. The wedge-shaped block 71 at the rear end of the jacking rod 7 is connected to the piston rod of the one-way hydraulic cylinder 3. The one-way hydraulic cylinder 3 pushes the jacking rod forward. The two wedge-shaped blocks 71 are respectively jacked into the wedge-shaped cavities of the two jacking plates 6. The two groove plates 61 of the two jacking plates 6 are respectively jacked outwardly. Thus, the two base plates 51 are jacked outwardly. The outer diameter of the multi-dimensional stress monitoring module 2 is expanded. The multi-dimensional stress monitoring module 2 is in full contact with the wall of the borehole. The reverse teeth 73 outside the wedge-shaped block 71 are clamped into the clamping grooves 62 of the groove plate 61 after insertion. The positioning is completed. The jacking rod 71 is prevented from retreating to maintain the expansion state of the multi-dimensional stress monitoring module 2.

[0022] The front end of the cylinder body of the one-way hydraulic cylinder 3 is provided with an annular groove 31 at the connection with the base 5. The rear side ends of the two base plates 51 of the base 5 are respectively provided with semicircular annular clamping plates 53 inwardly. The clamping plates 53 of the rear side ends of the two base plates 51 are respectively inserted into the annular groove 31 of the one-way hydraulic cylinder 3. The limited connection length of the clamping plate 53 and the annular groove 31 is greater than the jacking displacement distance of the base plate 51. That is, the clamping plate 53 always remains in the annular groove 31 after the base plate 51 is jacked up. The rear end of the cylinder body of the one-way hydraulic cylinder 3 is connected with a U-shaped clamping joint 32 to facilitate butt joint of the hydraulic oil pipe. In addition, four through grooves 33 are formed on the outer side of the cylinder body along the axial direction. Thin-walled pipes 8 are respectively arranged in the four through grooves 33.

[0023] The angle sensor 1 comprises a shell and a sensitive element inside the shell, the shell comprises a conical cover plate 11, a barrel 12 and a bottom plate 13, the cover plate 11 is connected to the top end of the barrel 12, the bottom plate 13 is connected to the bottom end of the barrel 12, the bottom plate 13 is fixedly connected with the front end face of one of the base plates 51 of the base 5, two optical cable routing holes 18 are formed in the bottom plate 13, the optical cable routing holes 18 are matched with the lead-in optical fiber grooves 52 on the base plate 5, and the sensitive element is connected in the barrel 12. The sensitive element comprises a side temperature grating and two elastic beams 14 arranged at a fixed angle in the same plane, one end of the two elastic beams 14 is commonly connected to a weight 17, and the other end is fixed on the barrel through a supporting plate 15 respectively, and an angle measuring grating is adhered on the elastic beam 14 in the length direction. Corresponding to the two angle measuring gratings, lead holes 16 are formed in the barrel 12, the lead lines at the ends of the two angle measuring gratings are respectively led out from the two lead holes 16 on the barrel 12, and are respectively led into the base 5 through the optical cable routing holes 18 on the bottom plate 13 and the lead-in optical fiber grooves 54 on the base plate.

[0024] The outside of the multi-dimensional stress monitoring module 2 is covered with a flexible sheath 4, the two ends of the flexible sheath 4 are connected with the bottom plate 13 of the angle sensor 1 and the cylinder body of the single hydraulic cylinder 3 respectively, the signal cables of the multi-dimensional stress monitoring module and the angle sensor are covered in the flexible sheath 4, extend in the axial direction, and are respectively led out from the four thin-walled pipes 8 through the lead-out optical fiber grooves 55 at the rear end of the base 5.

[0025] The multi-dimensional monitoring borehole stress meter provided by the application is used as follows: first, a 5-10m deep borehole is drilled at a place to be monitored such as a roadway, and then the borehole stress meter is inserted into the borehole, after reaching the monitoring position, the hydraulic pump is started, the single hydraulic cylinder pushes the jacking rod forward into the jacking plate, the two base plates constituting the base are relatively moved, the borehole wall is clamped, and the jacking degree of the base plate is controlled by the pressure provided by the hydraulic cylinder. After the signal line is connected, the monitoring can be carried out, and the monitoring process of the borehole stress meter comprises a position monitoring process of the sensor and a size and position monitoring process of the surrounding rock stress of the borehole, wherein the position monitoring process of the sensor is realized by the angle sensor, because the position of the borehole stress meter changes with the drilling angle of the borehole after being put into the borehole, at this time, the weight in the angle sensor always points to the center of the earth under the action of gravity, the two elastic beams of the sensitive element are bent and deformed due to the action of gravity, the bending angle of the angle measuring grating adhered on the elastic beam changes, the angle measuring grating is bent, the detection wavelength is shifted, and the bending angle of the angle measuring grating can be calculated by the wavelength shift amount through the strain sensor technology commonly used in the prior art, so that the position of the whole sensor is deduced.

[0026] The above merely describes the preferred embodiments of the present application and cannot be used to limit the scope of the present application, that is, any simple equivalent changes or modifications made according to the claims and the description of the present application shall still fall within the scope of the present application.

Claims

1. A multi-dimensional monitoring borehole stress gauge, characterized in that, The borehole stress gauge includes an angle sensor, a multi-dimensional stress monitoring module, and a one-way hydraulic cylinder. The multi-dimensional stress monitoring module includes a base and a lifting mechanism. The base has an internal cavity and is formed by two semi-cylindrical base plates joined together. Each base plate has multiple spring steel plates fixed axially, and each spring steel plate has a force-measuring grating along its length. A deformation gap is left between the bottom surface of the spring steel plate and the base plate. The rear end of the base is connected to the one-way hydraulic cylinder, the front end of the base has an inlet fiber optic groove, and the rear end of the base has an outlet fiber optic groove. The angle sensor is connected to the front end face of the base of the multi-dimensional stress monitoring module. The lifting mechanism is set in the internal cavity of the base. The lifting mechanism pushes the two base plates of the base outward to make them fully contact the borehole wall. The piston rod of the one-way hydraulic cylinder is connected to the lifting mechanism to provide lifting force. The lifting mechanism includes a lifting plate and a lifting rod. The lifting plate is cylindrical with a wedge-shaped cavity inside, and is axially disposed in the cavity of the base. The lifting plate is formed by joining two semi-cylindrical slotted plates. The two slotted plates are respectively fixed in the inner cavities of the two base plates of the base. The inner side of the slotted plate is a wedge-shaped inclined surface, and multiple rings of slots are arranged axially on the wedge-shaped inclined surface. The lifting rod includes a wedge-shaped block, which is adapted to the wedge-shaped cavity inside the lifting plate. Its front end is inserted into the wedge-shaped cavity of the lifting plate. The outer side of the wedge-shaped block is provided with reverse teeth adapted to the slots. The rear end of the lifting rod is connected to a one-way hydraulic cylinder. The one-way hydraulic cylinder pushes the lifting rod forward, and the wedge-shaped block is pushed forward into the wedge-shaped cavity of the lifting plate, pushing the two slotted plates outward. The reverse teeth on the outer side of the wedge-shaped block engage with the slots of the slotted plates. Each base plate of the multidimensional stress monitoring module is connected to eight spring steel plates with varying thicknesses. The surfaces of the spring steel plates are grooved along the central axis, and force-measuring gratings are attached to the grooves as sensor elements. The two ends of the eight spring steel plates are fixed to the base plate with screws and are evenly arranged circumferentially.

2. The borehole stress gauge for multidimensional monitoring according to claim 1, characterized in that, The connection end between the one-way hydraulic cylinder and the base is provided with an annular groove. Correspondingly, the rear ends of the two base plates constituting the base are respectively provided with semi-circular retaining plates. The retaining plates at the rear ends of the two base plates are respectively inserted into the annular groove of the one-way hydraulic cylinder, and the limited connection length between the retaining plate and the groove is greater than the lifting displacement distance of the base plate. After the base plate is lifted, the retaining plate will not fall out of the groove.

3. The borehole stress gauge for multidimensional monitoring according to claim 2, characterized in that, The angle sensor includes a housing and a sensitive element inside. The housing includes a conical cover plate, a cylindrical body, and a base plate. The cover plate is connected to the top of the cylindrical body, and the base plate is connected to the bottom of the cylindrical body. The base plate has an optical cable routing hole. The base plate is connected and fixed to the front end face of one of the base plates of the base. The optical cable routing hole corresponds to the optical fiber inlet groove on the base. The sensitive element is connected inside the cylindrical body.

4. A multi-dimensional monitoring borehole stress gauge according to claim 3, characterized in that, The sensitive element includes a temperature measuring grating and two elastic beams located on the same plane at a fixed angle. One end of the two elastic beams is connected to a weight, and the other end is fixed to the cylinder by a support plate. An angle measuring grating is attached to the elastic beam along its length. The cylinder has lead wire holes corresponding to the two angle measuring gratings. The lead wires at the ends of the two angle measuring gratings pass through the two lead wire holes on the cylinder and pass through the optical cable routing holes on the bottom plate and the optical fiber inlet groove on the base plate to enter the base.

5. A multi-dimensional monitoring borehole stress gauge according to claim 4, characterized in that, The multidimensional stress monitoring module is covered with a flexible sheath. The two ends of the flexible sheath are connected to the base plate of the angle sensor and the one-way hydraulic cylinder, respectively. The cylinder body surface of the one-way hydraulic cylinder is provided with four through grooves along the axial direction. Thin-walled tubes are respectively arranged in the four through grooves. The signal cables of the multidimensional stress monitoring module and the angle sensor are located in the flexible sheath and pass through the fiber optic cable outlet groove at the rear end of the base and through the four thin-walled tubes.

6. A multi-dimensional monitoring borehole stress gauge according to claim 5, characterized in that, The base has two axially separated lifting plates inside. The lifting rod includes two wedge-shaped blocks connected by a connecting rod. The two wedge-shaped blocks are respectively inserted into the wedge-shaped cavities of the two lifting plates.

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