Friction measuring instrument and method for measuring friction angle of rock mass

Abstract

The invention discloses a friction measuring instrument and method for measuring the friction angle of rock mass, and relates to the technical field of rock mass mechanical testing, the friction measuring instrument comprises a shell, a telescopic air cylinder is arranged in the shell, the output end of the telescopic air cylinder is connected with one end of a telescopic unit, and the other end of the telescopic unit is connected with one end of an angle adjusting unit; the other end of the angle adjusting unit is connected with the friction unit, and an image acquisition unit is further arranged on the friction unit; a sensing unit is further arranged above the telescopic unit and on the friction unit; a leveling unit is arranged at the bottom of the shell. According to the friction measuring instrument and method for measuring the friction angle of the rock mass, the telescopic unit achieves stable and accurate telescopic movement of the friction unit through the telescopic rod, the movable guide rod, the sliding rail and other structures, and rock mass measuring requirements at different positions can be met; the angle adjusting unit adjusts the contact angle between the friction unit and the rock mass through worm and gear transmission and the locking effect of a locking piece, and the measurement requirement is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rock mass mechanics testing, and in particular to a friction measuring instrument and method for rock mass friction angle determination. BACKGROUND

[0002] The rock mass friction angle is an important parameter for characterizing the shear strength of rock joint surfaces, and plays a key role in slope stability, underground engineering design and geological disaster assessment. Traditional rock mass friction angle testing methods mostly use the tilt method or the direct shear method, which requires complex loading devices and manual data reading, resulting in large experimental errors, complicated operation, and inconvenience for use in field environments. Existing friction measuring devices usually cannot realize automatic pressure application, real-time force value monitoring and visual observation, and lack self-stabilizing support and leveling structures, resulting in measurement angle deviation and force dispersion. In addition, the normal force and friction force during the test are often measured by different devices, which has low system integration and a bulky structure, and is not conducive to rapid measurement on site. SUMMARY

[0003] The purpose of the present application is to provide a friction measuring instrument and method for rock mass friction angle determination to solve the problems raised in the background.

[0004] To achieve the above-mentioned purpose, the present application provides a friction measuring instrument for rock mass friction angle determination, comprising a shell, a telescopic cylinder is arranged inside the shell, the output end of the telescopic cylinder is connected with one end of a telescopic unit, the other end of the telescopic unit is connected with one end of an angle adjusting unit, the other end of the angle adjusting unit is connected with a friction unit, and an image acquisition unit is further arranged on the friction unit. A sensing unit is further arranged above the telescopic unit and on the friction unit. A leveling unit is arranged at the bottom of the shell.

[0005] Preferably, the telescopic unit comprises a telescopic rod fixedly connected with the output end of the telescopic cylinder at one end, and a moving guide rod is arranged at both ends of the telescopic rod, a sliding sleeve is slidably connected with the moving guide rod, the sliding sleeve is connected with a half ring sleeve through a connecting rod, and the half ring sleeve is arranged below the telescopic rod. One end of the moving guide rod is fixedly connected with a support platform, the support platform is arranged below the telescopic cylinder, the other end of the moving guide rod is fixedly connected with a support leg, and the support leg is fixedly arranged at the bottom of the shell. A slide rail is arranged below the telescopic rod, a sliding block is slidably connected with the slide rail, the sliding block is fixedly connected with the telescopic rod through a connecting rod, and limit blocks are arranged at both ends of the slide rail.

[0006] Preferably, the angle adjusting unit comprises an adjusting box fixedly connected with the telescopic rod, a fixed block is arranged in the adjusting box, the fixed block is penetrated by a connecting shaft, one end of the connecting shaft is rotatably connected to the wall of the adjusting box through a worm gear, the worm gear is drivingly connected with a worm arranged above the worm gear, one end of the worm is rotatably connected to the wall of the adjusting box, and the other end of the worm is fixedly connected with a rotating handle and penetrates out of the adjusting box. The other end of the connecting shaft is fixedly connected with a rotating head through a locking wheel, the rotating head is internally provided with a connecting cavity, an internal thread is formed in the inner wall of the rotating head, and the locking wheel is provided with a plurality of locking teeth in the circumferential direction.

[0007] Preferably, a through opening is formed in the top end of the adjusting box, the top end of the fixed block is located in the through opening, the top end of the fixed block is provided with a locking piece, two shaft rods are symmetrically arranged on the two sides of the locking piece, the two shaft rods are rotatably connected with two plug-in blocks respectively, and the plug-in blocks are fixedly arranged at the top end of the fixed block. One end of the locking piece is fixedly connected with a moving column, the bottom end of the moving column is fixedly connected with an elastic element, the bottom end of the elastic element is fixed in a mounting groove arranged on the fixed block, a sleeve is arranged at the top end of the mounting groove, the sleeve is arranged outside the moving column, and the moving column slides up and down in the sleeve. The other end of the locking piece is provided with a locking block which is inserted into the locking teeth.

[0008] Preferably, the friction unit comprises a friction rod and a friction head, the friction head is clampedly connected with the friction rod, one side of the friction rod is provided with a connecting head, an external thread is arranged on the outer portion of the connecting head, and the friction rod and the rotating head are connected through the internal thread and the external thread.

[0009] Preferably, the image acquisition unit comprises a bent rod connected with the friction rod, a micro camera is connected to the bottom end of the bent rod, a protective cover is arranged on the outer portion of the micro camera, and the protective cover is connected with the bent rod.

[0010] Preferably, the sensing unit comprises a force sensor and a two-axis sensor, the two-axis sensor is arranged at the connection position of the friction head and the friction rod, the force sensor is arranged on the output end of an electric push rod and located above the telescopic rod, is used for applying and monitoring the normal force downward, and the electric push rod is arranged on the inner wall of the shell. The force sensor and the two-axis sensor are electrically connected with a controller, and the controller is arranged on the outer portion of the shell.

[0011] Preferably, the leveling unit comprises three supporting frames arranged at the lower end of the shell, the supporting frame comprises a sleeve-connected inner frame and outer frame, a fixing plate is arranged in the outer frame, mounting holes are formed in the fixing plate, guide sleeves are arranged in the mounting holes, the guide sleeves are penetrated by the lead screw, the top end of the lead screw is fixedly connected with a gear one, the gear one and a gear two are engagedly connected, the gear two is fixedly connected on a transmission shaft, one end of the transmission shaft is rotatably connected on the side wall of the outer frame, the other end of the transmission shaft is fixedly connected with a rotating wheel penetrating through the outer frame; The bottom end of the lead screw is rotatably connected on a strip plate, the strip plate is fixedly connected with one end of a fixing rod, the other end of the fixing rod is fixedly connected on the fixing plate. A lead screw pair is threadedly connected on the lead screw, the two ends of the lead screw pair are fixedly connected with auxiliary blocks, the auxiliary blocks are fixedly connected on the inner wall of the inner frame, the auxiliary blocks are penetrated by the guide rods and slide opposite to the guide rods. The bottom of the inner frame is fixedly connected with a foot.

[0012] Preferably, the top end of the shell is provided with a top cover, one side of the shell is provided with an exit opening, the exit opening is provided with a sealing plate, the outer side of the sealing plate is provided with a handle.

[0013] A method for a friction measuring instrument for rock mass friction angle measurement, comprising the following steps: Step S1, the measuring instrument is transported to the measurement site, and is placed in a position close to the rock mass and relatively flat, and the leveling unit is used to level the measuring instrument; Step S2, after leveling, the top cover at the top end of the shell is opened, the power supply box is started, all electrical elements in the measuring instrument are powered, and at the same time, the controller is started, and the measuring instrument is initialized and set; Step S3, the friction rod and the friction head are taken out from the tool box, the friction head is clamped to the friction rod, and the friction rod is connected with the rotating head; Step S4, the operator inputs a control instruction on the controller, the controller drives the telescopic cylinder to start working, the output end of the telescopic cylinder pushes the telescopic rod to extend, and the telescopic cylinder stops elongating after the telescopic rod extends to a predetermined position; Step S5, the angle of the friction unit is adjusted through the angle adjusting unit, after adjustment, the controller controls the electric push rod to drive the force sensor to move downward, so that the force sensor contacts with the telescopic rod and provides a normal force; Step S6, the telescopic cylinder is started through the controller, the output end of the telescopic cylinder drives the telescopic rod to do reciprocating motion, in the process that the friction head and the rock surface produce relative motion, the two-axis sensor collects the shear force between the friction head and the rock surface in real time, and converts the shear force signal into an electric signal and transmits to the controller; Step S7: During the friction test, the miniature camera continuously captures images of the friction head contacting and rubbing against the rock surface, and transmits the captured image data to the controller via a connecting cable. Step S8: The controller receives the force signals in two orthogonal directions collected by the biaxial sensor, and calculates the true normal force and shear force on the rock mass contact surface by combining the dip angle measured by the current friction unit. Then, it calculates the friction angle according to the preset formula, obtains the friction angle value of the rock mass, and displays the calculation result on the display screen of the controller. Step S9: After the test is completed, separate the friction rod from the rotating head, start the telescopic cylinder to reset through the controller, drive the telescopic unit to retract into the housing, install the sealing plate on the protrusion, and finally open the top cover to place the friction unit into the toolbox, then close the top cover and turn off the power box.

[0014] Therefore, the present invention employs the aforementioned friction measuring instrument and method for determining the friction angle of rock mass. The telescopic unit, through structures such as a telescopic rod, a moving guide rod, and a slide rail, achieves stable and precise telescopic movement of the friction unit, ensuring adaptability to the measurement needs of rock masses at different locations. The angle adjustment unit, utilizing worm gear transmission and the locking action of a locking plate, can adjust the contact angle between the friction unit and the rock mass, meeting the measurement requirements under complex rock mass conditions. The leveling unit, with its support frame, lead screw, and gears, can quickly and effectively adjust the measuring instrument to a horizontal state, providing a fundamental guarantee for accurate measurement.

[0015] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of an embodiment of a friction measuring instrument and method for determining the friction angle of rock mass according to the present invention; Figure 2 This is a cross-sectional view of the casing of a friction measuring instrument and method for determining the friction angle of rock mass according to the present invention. Figure 1 ; Figure 3 This is a cross-sectional view of the casing of a friction measuring instrument and method for determining the friction angle of rock mass according to the present invention. Figure 2 ; Figure 4 for Figure 3 Enlarged schematic diagram of the structure at point A; Figure 5 This is a top partial structural cross-sectional view of a friction measuring instrument and method for determining the friction angle of rock mass according to the present invention. Figure 6 This is a schematic diagram of the friction unit of a friction measuring instrument and method for determining the friction angle of rock mass according to the present invention; Figure 7It is a structural schematic view of an angle locking unit of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Figure 8 It is a structural schematic view of a locking piece of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Figure 9 It is a structural schematic view of a leveling unit of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 1 is a structural schematic view of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 2 is a structural schematic view of an angle locking unit of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 3 is a structural schematic view of a locking piece of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 4 is a structural schematic view of a leveling unit of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 5 is a structural schematic view of a friction unit of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 6 is a structural schematic view of an image acquisition unit of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 7 is a structural schematic view of a force sensor of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 8 is a structural schematic view of a two-axis sensor of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 9 is a structural schematic view of an electric push rod of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 10 is a structural schematic view of a support frame of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 11 is a structural schematic view of an inner frame of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 12 is a structural schematic view of an outer frame of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 13 is a structural schematic view of a fixed plate of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 14 is a structural schematic view of a guide sleeve of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 15 is a structural schematic view of a screw rod of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 16 is a structural schematic view of a gear one of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 17 is a structural schematic view of a gear two of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 18 is a structural schematic view of a transmission shaft of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 19 is a structural schematic view of a rotating wheel of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 20 is a structural schematic view of a strip plate of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 21 is a structural schematic view of a fixed rod of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 22 is a structural schematic view of a screw rod pair of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 23 is a structural schematic view of an auxiliary block of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 24 is a structural schematic view of a foot shoe of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 25 is a structural schematic view of a controller of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 26 is a structural schematic view of a power supply box of a friction measuring instrument and method for rock mass friction angle determination according to the present application; Fig. 27 is a structural schematic view of a tool box of a friction measuring instrument and method for rock mass friction angle determination according to the present application. DETAILED DESCRIPTION

[0017] The technical solutions of the present application are further described below through the drawings and examples.

[0018] Unless otherwise defined, technical terms or scientific terms used in the present application shall have the ordinary meanings as understood by one of ordinary skill in the art to which this application pertains. The terms "first", "second", and similar terms do not imply any order, quantity, or importance, but are used to distinguish one element from another, and are used only to distinguish different components. The terms "include", "contain", and similar terms mean that the elements or objects before the term encompass the elements or objects listed after the term and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" or similar terms do not mean only physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0019] Embodiments Please refer to Figures 1-9 The present application provides a kind of for rock mass friction angle determination friction measuring instrument, including shell 1, retractable pneumatic cylinder 2 is arranged in shell 1, the output end of retractable pneumatic cylinder 2 is connected with one end of telescopic unit 3, the other end of telescopic unit 3 is connected with one end of angle adjusting unit 4, the other end of angle adjusting unit 4 is connected with friction unit 5, friction unit 5 is also provided with image acquisition unit 6.

[0020] Telescopic unit 3 includes one end and the output end of retractable pneumatic cylinder 2 fixed connection telescopic rod 31, both ends of telescopic rod 31 are provided with moving guide rod 32, sliding sleeve 33 is slidably connected on moving guide rod 32, half ring sleeve 34 is connected with sliding sleeve 33 by connecting rod 35, half ring sleeve 34 is set as half arc structure, is fixedly connected below telescopic rod 31. One end of moving guide rod 32 is fixedly connected on support platform 21, support platform 21 is arranged below retractable pneumatic cylinder 2, the other end of moving guide rod 32 is fixedly connected on support leg 36, support leg 36 is fixedly arranged in the bottom of shell 1, setting moving guide rod 32 plays a guiding role to telescopic rod 31, avoids its lateral swing in telescopic process. The lower portion of telescopic rod 31 is provided with slide rail 37, the slide rail 37 is slidably connected with sliding block 38, the sliding block 38 is fixedly connected with telescopic rod 31 by connecting rod 39, both ends of slide rail 37 are provided with limit block 310, and sliding block 38 and slide rail 37 play an auxiliary role, so that the movement of telescopic rod 31 is more stable.

[0021] The angle adjusting unit 4 comprises an adjusting box 41 fixedly connected with the telescopic rod 31, a fixed block 42 is arranged in the adjusting box 41, the fixed block 42 is penetrated by a connecting shaft, one end of the connecting shaft is rotatably connected to the wall of the adjusting box 41 through a worm wheel 43, the worm wheel 43 is in transmission connection with a worm 44 arranged above the worm wheel 43, one end of the worm 44 is rotatably connected to the wall of the adjusting box 41, the other end of the worm 44 penetrates through the adjusting box 41 and is fixedly connected with a rotating handle 45. The other end of the connecting shaft penetrates through a locking wheel 46 and is fixedly connected with a rotating head 47, the rotating head 47 is internally provided with a connecting cavity, an internal thread 48 is formed in the inner wall of the rotating head 47, and the locking wheel 46 is formed with a plurality of locking teeth 49 in the circumferential direction. As shown in Figure 8 , the rotating handle 45 is rotated to drive the worm 44 to rotate, and then the worm wheel 43 is rotated, and the rotating head 47 is also rotated through the transmission of the connecting shaft, the friction rod 51 connected with the rotating head 47 is rotated, and the angle of the friction head 52 is adjusted.

[0022] A through opening is formed in the top end of the adjusting box 41, and the top end of the fixed block 42 is located in the through opening. The top end of the fixed block 42 is provided with a locking piece 410, two shaft rods 411 are symmetrically arranged on the two sides of the locking piece 410, the two shaft rods 411 are rotatably connected with two plug-in blocks 412 respectively, and the plug-in blocks 412 are fixedly arranged at the top end of the fixed block 42. A moving column 413 is fixedly connected to one end below the locking piece 410, a resilient element 414 is fixedly connected to the bottom end of the moving column 413, the bottom end of the resilient element 414 is fixed in a mounting groove formed in the fixed block 42, a sleeve 415 is arranged at the top end of the mounting groove, the sleeve 415 is arranged outside the moving column 413, and the moving column 413 slides up and down in the sleeve 415. The other end of the locking piece 410 is provided with a locking block 416, and the locking block 416 is inserted into the locking teeth 49. As shown in Figure 8 , the locking piece 410 is pressed downward on the arc side, the shaft rod 411 of the rotating piece is rotated in the plug-in block 412, the locking block 416 on the other side is lifted from the locking teeth 49, the locking effect on the locking wheel 46 is released, and the angle is adjusted at this time; when the angle is adjusted, the side of the locking piece 410 is released, the locking block 416 is inserted into the locking teeth 49 again under the action of the reaction force of the resilient element 414, the locking wheel 46 is locked, and the angle cannot be changed at this time.

[0023] The friction unit 5 comprises the friction rod 51 and the friction head 52, and the friction head 52 is arranged in a circular table structure. The friction head 52 is connected with the friction rod 51 in a clamping mode, and a two-axis sensor 72 is arranged at the end of the friction rod 51, which is arranged between the friction head 52 and the friction rod 51 when the friction head 52 is connected with the friction rod 51 in a clamping mode, and the two-axis sensor 72 measures the shear force and the normal force at the same time. One side of the friction rod 51 is provided with a connecting head 53, the outside of the connecting head 53 is provided with an external thread, and the friction rod 51 and the rotating head 47 are connected through the internal thread 48 and the external thread.

[0024] The image acquisition unit 6 comprises a bent rod 61 connected to the friction rod 51. In this embodiment, the bent rod 61 is made of a metal shaped hose, which can adjust the position of the miniature camera 62, so that the line of sight of the miniature camera 62 is not blocked, and is more suitable for different rock masses. The bottom end of the bent rod 61 is connected with the miniature camera 62, and the miniature camera 62 is externally provided with a protective cover (not shown in the figure), which is connected to the bent rod 61. The miniature camera 62 is connected with the controller 9 through a link cable for image transmission. The image acquisition unit 6 is installed at the rear of the friction rod 51 and keeps a certain distance from the friction head 52. The miniature camera 62 is arranged along the axis direction parallel to the friction rod 51 and is located at a position about 30°-45° above the friction head 52, so as to ensure that the miniature camera 62 can always clearly shoot the friction contact surface when the friction head 52 adjusts the angle. Through this design, the miniature camera 62 can adapt to the friction head 52 of different angles, and can always cover and record the friction process of the rock surface regardless of the inclination of the friction head 52.

[0025] The upper part of the telescopic unit 3 and the friction unit 5 are also provided with a sensing unit. The sensing unit comprises a force sensor 71 and a two-axis sensor 72. The two-axis sensor 72 is arranged at the connection between the friction head 52 and the friction rod 51, and the force sensor 71 is arranged on the output end of the electric push rod 73 and located above the telescopic rod 31 for applying and monitoring the normal force downward. The electric push rod 73 is arranged on the inner wall of the shell 1. The force sensor 71 and the two-axis sensor 72 are electrically connected with the controller 9. The controller 9 is arranged outside the shell 1. In addition to being connected with the force sensor 71 and the two-axis sensor 72, the controller 9 is also electrically connected with the telescopic cylinder 2 and the electric push rod 73. The controller 9 controls the telescopic cylinder 2 to extend by a predetermined distance, so that the telescopic rod 31 extends outside the shell 1 for convenient measurement, and the telescopic cylinder 2 drives the telescopic rod 31 to make reciprocating motion within the predetermined distance, so that the friction head 52 continuously rubs with the rock mass; the controller 9 can also control the electric push rod 73 to extend, drive the force sensor 71 to move downward to contact with the telescopic rod 31, and apply a predetermined normal force to the telescopic rod 31 through the electric push rod 73. The above control process is a mature existing technology in the art, and therefore the principle and circuit diagram are not described in detail here.

[0026] The bottom of the shell 1 is provided with a leveling unit for finding the horizontal balance state when measuring the friction angle, and compensating the influence caused by the surface part of the rock mass. The leveling unit comprises three support frames 81 arranged at the lower end of the shell 1, which are distributed in the form of an isosceles triangle, and are adjusted one by one. The outer surface of the inner frame 82 is further provided with a scale ring to assist observation and adjustment. The support frame 81 comprises a sleeve-connected inner frame 82 and an outer frame 83. The outer frame 83 is provided with a fixed plate 84, and the fixed plate 84 is provided with a mounting hole. A guide sleeve 85 is arranged in the mounting hole, and the guide sleeve 85 is penetrated by a lead screw 86. The top end of the lead screw 86 is fixedly connected with a gear one 87. The gear one 87 and a gear two 88 are engagedly connected. The gear two 88 is fixedly connected with a transmission shaft 89. One end of the transmission shaft 89 is rotatably connected with the side wall of the outer frame 83. The other end of the transmission shaft 89 is fixedly connected with a rotating wheel 810 through the outer frame 83. The bottom end of the lead screw 86 is rotatably connected with a strip plate 811. The strip plate 811 is fixedly connected with one end of a fixed rod 812. The other end of the fixed rod 812 is fixedly connected with the fixed plate 84. A screw pair 813 is threadedly connected with the lead screw 86. The two ends of the screw pair 813 are fixedly connected with auxiliary blocks 814. The auxiliary blocks 814 are fixedly connected with the inner wall of the inner frame 82, and are penetrated by a guide rod and slide opposite to the guide rod. The bottom of the inner frame 82 is fixedly connected with a foot 815 for supporting on the rock.

[0027] When leveling, the rotating wheel 810 is rotated clockwise, the lead screw 86 is driven to rotate through the transmission of the gear two 88 and the gear one 87, and then the screw pair 813 moves upward on the lead screw 86, at this time, the length of the inner frame 82 and the outer frame 83 is shortened, and the height of the measuring instrument is lowered. Conversely, the rotating wheel 810 is counterclockwise rotated, the lead screw 86 is driven to rotate through the transmission of the gear two 88 and the gear one 87, and then the screw pair 813 moves downward on the lead screw 86, at this time, the length of the inner frame 82 and the outer frame 83 is increased, and the height of the measuring instrument is increased. In the adjustment process, the fixed rod 812 plays an auxiliary role, so that the screw pair 813 moves stably on the lead screw 86.

[0028] The top end of the shell 1 is provided with a top cover 11, which is connected with the shell 1 by using the existing technology such as clamping or lock buckle connection. One side of the shell 1 is provided with an extension outlet 12, and the extension outlet 12 is provided with a sealing plate 13. The outer side of the sealing plate 13 is provided with a handle 14. The sealing plate 13 is pulled out of the extension outlet 12 by pulling the handle 14, so that the extension rod 31 can be extended. The inside of the shell 1 is further provided with a power box 91 and a tool box 92. The tool box 92 is used for placing the friction rod 51 and the friction head 52. The power box 91 is used for power supply of the electrical elements.

[0029] A method for determining the friction angle of rock mass, comprising the following steps: Step S1, the measuring instrument is transported to the measurement site and placed in a relatively flat position close to the rock mass, and the leveling unit is used to level the measuring instrument.

[0030] Step S2, after leveling, open the top cover 11 at the top end of the shell 1, open the power supply box 91 to power all electrical elements in the measuring instrument. At the same time, start the controller 9 to initialize the settings of the measuring instrument.

[0031] Step S3, take the friction rod 51 and the friction head 52 from the tool box 92, according to the characteristics of the rock mass and the measurement requirements, the friction head 52 is clamped to the friction rod 51, and then the friction rod 51 is connected with the rotating head 47.

[0032] Step S4, the operator inputs control instructions on the controller 9, the controller 9 drives the telescopic cylinder 2 to start working, the output end of the telescopic cylinder 2 pushes the telescopic rod 31 to extend, and the telescopic cylinder 2 stops extending after extending to the predetermined position.

[0033] Step S5, adjust the angle of the friction unit 5 through the angle adjusting unit 4, after adjustment, loosen one side of the locking piece 410, under the action of the counterforce of the elastic element 414, the locking block 416 reinserts into the locking tooth 49 to lock the locking wheel 46, at this time the angle cannot be changed. The controller 9 controls the electric push rod 73 to be in the initial position (the force sensor 71 is not in contact with the telescopic rod 31, and there is no external force), at this time the controller 9 reads the output signal of the force sensor 71 and records it as a zero point reference value, and completes the calibration. After calibration, the controller 9 controls the electric push rod 73 to move downward, so that the force sensor 71 is in contact with the telescopic rod 31, and the normal force is provided after calibration. In this process, the force sensor 71 senses the force applied by the electric push rod 73 on the friction rod 51 in real time, that is, the normal force, and converts the sensed force signal into an electric signal and transmits it to the controller 9, to ensure that the application of the normal force meets the measurement requirements.

[0034] Step S6, start the telescopic cylinder 2 through the controller 9 to make the output end of the telescopic cylinder 2 drive the telescopic rod 31 to do reciprocating motion, in the process of relative motion between the friction head 52 and the rock surface, the two-axis sensor 72 collects the shear force between the friction head 52 and the rock surface in real time, and converts the shear force signal into an electric signal and transmits it to the controller 9.

[0035] Step S7, during the friction test, the miniature camera 62 continuously shoots the picture of the friction between the friction head 52 and the rock surface, and transmits the shot image data to the controller 9 through the connection cable.

[0036] Step S8, the controller 9 receives the two orthogonal direction force signals collected by the two-axis sensor 72, and combines the inclination angle measured by the current friction unit 5 to calculate the real normal force and shear force on the rock mass contact surface, and then calculates the friction angle according to the preset formula, obtains the friction angle value of the rock mass, and displays the calculation result on the display screen of the controller. The preset formula for calculating the friction angle is as follows: ; ; ; wherein, is the measured inclination angle, is the friction angle, is the shear force, is the normal force.

[0037] The inside of the fixed block 42 is provided with a cavity for accommodating an ultra-miniature absolute rotary encoder mounted on the connecting shaft, the output shaft of which is coaxially connected with the connecting shaft for measuring the inclination angle of the connecting shaft. The ultra-miniature absolute rotary encoder is electrically connected with the controller, and the measured inclination angle is transmitted to the controller 9 for calculation. The ultra-miniature absolute rotary encoder used in the embodiment is model JEPSUN F11HE-S5E2H15F, which is a mature prior art, and its working principle and circuit connection are not repeated here. The calculation chip built-in the controller 9 quickly processes data to obtain the friction angle value of the rock mass, and displays the calculation result on the display screen of the controller 9, which is convenient for the operator to read.

[0038] Step S9, after the test is completed, the friction rod 51 is separated from the rotating head 47, the telescopic cylinder 2 is started to reset through the controller 9, the telescopic unit 3 is retracted into the shell, the sealing plate 13 is installed on the stretching port 12, finally the top cover 11 is opened to place the friction unit 5 into the tool box, and then the top cover 11 is closed, and the power box 91 is turned off.

[0039] Therefore, the friction measuring instrument and method for measuring the friction angle of rock mass are adopted, the telescopic unit realizes stable and accurate telescopic movement of the friction unit through the telescopic rod, the moving guide rod and the slide rail, and can adapt to the rock mass measurement requirements at different positions; the angle adjusting unit can adjust the contact angle of the friction unit and the rock mass by using the worm and gear transmission and the locking effect of the locking piece, and meets the measurement requirements under complex rock mass conditions; the support frame, screw rod and gear of the leveling unit can quickly and effectively adjust the measuring instrument to the horizontal state, and provide a basic guarantee for accurate measurement.

[0040] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A friction measuring instrument for determining the friction angle of rock mass, characterized in that: The device includes a housing, inside which a telescopic cylinder is installed. The output end of the telescopic cylinder is connected to one end of a telescopic unit, the other end of the telescopic unit is connected to one end of an angle adjustment unit, the other end of the angle adjustment unit is connected to a friction unit, and an image acquisition unit is also installed on the friction unit. A sensing unit is also provided above the telescopic unit and on the friction unit; A leveling unit is provided at the bottom of the housing.

2. The friction measuring instrument for determining the friction angle of rock mass according to claim 1, characterized in that: The telescopic unit includes a telescopic rod with one end fixedly connected to the output end of the telescopic cylinder. Both ends of the telescopic rod are provided with movable guide rods. A sliding sleeve is slidably connected to the movable guide rod. The sliding sleeve is connected to a semi-ring sleeve through a connecting rod. The semi-ring sleeve is located below the telescopic rod. One end of the movable guide rod is fixedly connected to the support platform, which is located below the telescopic cylinder; the other end of the movable guide rod is fixedly connected to the support leg, which is fixedly located at the bottom of the housing. A slide rail is provided below the telescopic rod, and a slider is slidably connected to the slide rail. The slider is fixedly connected to the telescopic rod through a connecting rod, and limit blocks are provided at both ends of the slide rail.

3. The friction measuring instrument for determining the friction angle of rock mass according to claim 2, characterized in that: The angle adjustment unit includes an adjustment box fixedly connected to the telescopic rod. A fixing block is provided inside the adjustment box. The fixing block is penetrated by a connecting shaft. One end of the connecting shaft passes through a worm gear and is rotatably connected to the wall of the adjustment box. The worm gear is connected to a worm gear located above it. One end of the worm gear is rotatably connected to the wall of the adjustment box, and the other end of the worm gear passes through the adjustment box and is fixedly connected to a rotating handle. The other end of the connecting shaft passes through the locking wheel and is fixedly connected to the rotating head. The rotating head has a connecting cavity inside, and an internal thread is provided on the inner wall of the rotating head. The locking wheel has several locking teeth along the circumferential direction.

4. A friction measuring instrument for determining the friction angle of rock mass according to claim 3, characterized in that: The top of the regulating box has an opening, the top of the fixing block is located inside the opening, the top of the fixing block is provided with a locking piece, and two shafts are symmetrically arranged on both sides of the locking piece. The two shafts are rotatably connected to two plug-in blocks respectively, and the plug-in blocks are fixedly installed on the top of the fixing block. A movable column is fixedly connected to one end of the locking piece. An elastic element is fixedly connected to the bottom end of the movable column. The bottom end of the elastic element is fixed in the mounting groove. The mounting groove is opened on the fixing block. A sleeve is provided at the top end of the mounting groove. The sleeve is located outside the movable column. The movable column slides up and down inside the sleeve. A locking block is provided at the other end of the locking piece, and the locking block is inserted into the locking tooth.

5. A friction measuring instrument for determining the friction angle of rock mass according to claim 4, characterized in that: The friction unit includes a friction rod and a friction head. The friction head is snapped into the friction rod. A connector is provided on one side of the friction rod. The connector is provided with an external thread. The friction rod and the rotating head are connected by the internal thread and the external thread.

6. A friction measuring instrument for determining the friction angle of rock mass according to claim 5, characterized in that: The image acquisition unit includes a curved rod connected to the friction rod, a miniature camera connected to the bottom end of the curved rod, and a protective cover provided on the outside of the miniature camera, which is connected to the curved rod.

7. A friction measuring instrument for determining the friction angle of rock mass according to claim 6, characterized in that: The sensing unit includes a force sensor and a biaxial sensor. The biaxial sensor is located at the connection between the friction head and the friction rod. The force sensor is located at the output end of the electric push rod and above the telescopic rod. It is used to apply downward force and monitor the normal force. The electric push rod is located on the inner wall of the housing. Both the force sensor and the biaxial sensor are electrically connected to the controller, which is located outside the housing.

8. A friction measuring instrument for determining the friction angle of rock mass according to claim 7, characterized in that: The leveling unit includes three support frames disposed at the lower end of the housing. Each support frame includes an inner frame and an outer frame that are sleeved together. A fixing plate is disposed inside the outer frame. An installation hole is provided on the fixing plate. A guide sleeve is disposed inside the installation hole. A lead screw passes through the guide sleeve. A gear one is fixedly connected to the top end of the lead screw. Gear one and gear two are meshed together. Gear two is fixedly connected to a drive shaft. One end of the drive shaft is rotatably connected to the side wall of the outer frame. The other end of the drive shaft passes through the outer frame and is fixedly connected to a rotating wheel. The bottom end of the lead screw is rotatably connected to the strip plate, the strip plate is fixedly connected to one end of the fixed rod, and the other end of the fixed rod is fixedly connected to the fixed plate; A lead screw pair is threaded onto the lead screw, and auxiliary blocks are fixedly connected to both ends of the lead screw pair. The auxiliary blocks are fixedly connected to the inner wall of the inner frame, and the auxiliary blocks are passed through by the guide rod and slide relative to the guide rod. The bottom of the inner frame is fixedly connected with feet.

9. A friction measuring instrument for determining the friction angle of rock mass according to claim 8, characterized in that: The top of the housing is provided with a top cover, and an opening is provided on one side of the housing. A sealing plate is provided inside the opening, and a handle is provided on the outside of the sealing plate.

10. A method for using a friction measuring instrument for determining the friction angle of rock mass according to any one of claims 1-9, characterized in that, Includes the following steps: Step S1: Move the measuring instrument to the measurement site and place it in a relatively flat location close to the rock mass, and use the leveling unit to level the measuring instrument; Step S2: After leveling, open the top cover of the housing, turn on the power supply box to supply power to all electrical components inside the measuring instrument, and at the same time, start the controller to initialize the measuring instrument. Step S3: Take out the friction rod and friction head from the toolbox, attach the friction head to the friction rod, and then connect the friction rod to the rotating head; Step S4: The operator inputs control commands on the controller, and the controller drives the telescopic cylinder to start working. The output end of the telescopic cylinder pushes the telescopic rod to extend. After extending to the predetermined position, the telescopic cylinder stops extending. Step S5: Adjust the angle of the friction unit through the angle adjustment unit. After adjustment, the controller controls the electric push rod to move the power sensor downward, so that the force sensor contacts the telescopic rod and provides normal force. Step S6: Start the telescopic cylinder through the controller, so that the output end of the telescopic cylinder drives the telescopic rod to reciprocate. During the relative motion between the friction head and the rock surface, the two-axis sensor collects the shear force between the friction head and the rock surface in real time and converts the shear force signal into an electrical signal and transmits it to the controller. Step S7: During the friction test, the miniature camera continuously captures images of the friction head contacting and rubbing against the rock surface, and transmits the captured image data to the controller via a connecting cable. Step S8: The controller receives the force signals in two orthogonal directions collected by the biaxial sensor, and calculates the true normal force and shear force on the rock mass contact surface by combining the dip angle measured by the current friction unit. Then, it calculates the friction angle according to the preset formula, obtains the friction angle value of the rock mass, and displays the calculation result on the display screen of the controller. Step S9: After the test is completed, separate the friction rod from the rotating head, start the telescopic cylinder to reset through the controller, drive the telescopic unit to retract into the housing, install the sealing plate on the protrusion, and finally open the top cover to place the friction unit into the toolbox, then close the top cover and turn off the power box.

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