Device for simulating rock fracture morphology under different depth conditions and method of using the same

Abstract

The present invention discloses a device for simulating rock fracture morphology under conditions of different depths and a method for using the device, including an axial confining pressure simulation loading device, the axial confining pressure simulation loading device including an axial pressure simulation loading device and a confining pressure simulation loading device, the axial pressure simulation loading device including: a crossbeam, the crossbeam is installed on a crossbeam moving device, the crossbeam moving device controls the lifting of the crossbeam; a pressure head, the pressure head is arranged below the crossbeam, the pressure head is composed of an inner pressure head and a pressure head sleeve, the pressure head sleeve is embedded in the crossbeam, and the inner pressure head is slidably nested in the pressure head sleeve; an inner pressure head power device, the telescopic end of the inner pressure head power device is fixedly connected to the inner pressure head; the inner pressure head is a solid cylindrical structure, and the diameter of the inner pressure head is equal to the diameter of the sample. Before uniaxial force loading, the sample is first subjected to axial pressure and confining pressure simulation loading to simulate the natural stress state of the rock under conditions of different depths, thereby restoring the state of the rock before mining to the greatest extent and improving the accuracy of the test results.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical engineering and relates to a device for simulating rock fracture forms under conditions of different depths and a method for using the device. Background Art

[0002] Compressive strength is an important indicator for evaluating rock strength performance. Currently, rock compressive strength is mainly obtained through uniaxial compression tests. The rock samples used in the test are further mined or reshaped on the basis of natural rock blocks, and the samples will change from the original triaxial stress state to a stress-free state during the mining process. The various properties of the samples are bound to be different from the original rock, which will also have a certain impact on the test results, and thus the true strength characteristics of the rock cannot be obtained. In addition, today's microscopic testing is to take some damaged samples for sample preparation after the test, and then send them to an electron microscope for testing, which will take a lot of time, and human factors will cause certain disturbances to the samples. Summary of the invention

[0003] The purpose of the embodiments of the present invention is to provide a device for simulating rock fracture morphology under conditions of different depths and a method for using the device, so as to solve the problem that the true strength characteristics of the rock cannot be obtained when the compressive strength of the rock is determined by a uniaxial compression test, and the problem that the preparation of the destroyed sample after the uniaxial compression test for microscopic testing is time-consuming and human factors cause disturbances to the sample.

[0004] The technical solution adopted in the embodiment of the present invention is: a device for simulating rock fracture morphology under different depth conditions, including an axial confining pressure simulation loading device, the axial confining pressure simulation loading device includes an axial pressure simulation loading device and a confining pressure simulation loading device, and the axial pressure simulation loading device includes:

[0005] A crossbeam, which is mounted on a crossbeam moving device, and the crossbeam moving device controls the lifting of the crossbeam;

[0006] The pressure head is arranged under the cross beam, and the pressure head is composed of an inner pressure head and a pressure head sleeve. The pressure head sleeve is embedded in the cross beam, and the inner pressure head is slidably nested in the pressure head sleeve;

[0007] An internal pressure head power device, wherein the telescopic end of the internal pressure head power device is fixedly connected to the internal pressure head;

[0008] in:

[0009] The internal pressure head is a solid cylindrical structure, and the diameter of the internal pressure head is equal to the diameter of the sample.

[0010] Another technical solution adopted by the embodiment of the present invention is: a method for using a device for simulating rock fracture morphology under different depth conditions, comprising the following steps:

[0011] S1: Take the prepared sample and place it on a solid column;

[0012] S2: Go to the control console, turn on the display and the axial pressure simulation loading device, make the internal pressure head gradually approach the upper surface of the sample, turn on the servo mechanism of the confining pressure loading device to drive the composite constraint to move toward the specimen, and stop pressurizing when the inner surface of the composite constraint fits the side of the specimen. Clear the pressure when the servo mechanism drives the composite constraint to move toward the specimen on the operation interface of the console, input the axial pressure and confining pressure under the corresponding depth conditions, and start the axial pressure and confining pressure simulation loading. When the confining pressure sensor on the servo mechanism and the axial pressure measuring device detect that the confining pressure and axial pressure reach the set value, control the confining pressure and axial pressure to maintain the set value, and simulate the natural stress state of the rock under different depth conditions until the designed axial pressure and confining pressure simulation time is reached;

[0013] S3: Unload the axial pressure and confining pressure, so that the servo mechanism drives the composite constraint away from the specimen. After reaching the specified position, the movement of the composite constraint is stopped. The transparent constraint on the outer wall of each composite constraint is slid along the arc slide groove on the sliding device, so that all transparent constraints and rigid constraints form a closed enclosure. At the same time, the vertical displacement meter and the lateral displacement meter are installed on the specimen;

[0014] S4: reset the internal pressure head, perform uniaxial force loading, start the crossbeam moving device to drive the crossbeam to slowly descend, stop when the pressure head descends above the surface of the specimen at a uniform speed, turn on the camera, set the loading rate on the uniaxial compression test system, start uniaxial force loading, and stop when the specimen is destroyed, and at the same time turn on the drying device in the base;

[0015] S5: Move the electric trolley along the track to the discharge port of the microscopic sample collection device. When the amount of microscopic samples in the electric trolley reaches a certain amount, move the electric trolley to the electron microscope to screen the preliminary finished products of the samples for microscopic inspection.

[0016] The beneficial effects of the embodiments of the present invention are:

[0017] 1. This embodiment realizes the macroscopic fracture morphology of rocks under different depth conditions of the model, and restores the state of the rocks before mining to the greatest extent, so that the rock compressive strength determined by the uniaxial compression test is closer to the real strength characteristics of the rocks, improves the accuracy of the test results, and solves the problem that the real strength characteristics of the rocks cannot be obtained when the rock compressive strength is determined by the uniaxial compression test at present;

[0018] 2. This embodiment uses a microscopic sample collection device and a drying device to realize timely collection and drying of microscopic samples during the loading process, shortening the time required for microscopic detection. By introducing an electric trolley to transport microscopic samples, the interference of human factors on the test is avoided to the greatest extent, further realizing instant microscopic detection, and solving the problem that the current microscopic detection using the destructive sample preparation after the uniaxial compression test is time-consuming and the sample is disturbed by human factors;

[0019] 3. This embodiment realizes servo confining pressure loading by pushing the composite constraint through the piston mechanism, which has the advantages of strong applicability, simple operation, and low labor consumption. After the axial pressure and confining pressure loading are completed to simulate the natural stress state of rock under different depth conditions, the rigid constraint and transparent constraint of the composite constraint can form a closed enclosure, which isolates and protects the test site while facilitating the observation and acquisition of the sample fracture characteristic diagram, and facilitating the analysis of the macroscopic destruction characteristics of the sample under different depth conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 Schematic diagram of the overall system of an embodiment of the present invention.

[0022] Figure 2 It is a schematic structural diagram of an axial pressure simulation loading device according to an embodiment of the present invention.

[0023] Figure 3 It is a schematic structural diagram of a confining pressure simulation loading device according to an embodiment of the present invention.

[0024] Figure 4 It is a front side schematic diagram of an axle confining pressure simulation loading device according to an embodiment of the present invention.

[0025] Figure 5 It is a rear side schematic view of the axial confining pressure simulation loading device according to an embodiment of the present invention.

[0026] Figure 6 It is a cross-sectional schematic diagram of a hollow base and a base according to an embodiment of the present invention.

[0027] Figure 7 1 is a schematic top view of a base according to an embodiment of the present invention.

[0028] Figure 8 Schematic diagram of a composite constraint structure according to an embodiment of the present invention.

[0029] Fig. 9 Schematic diagram of the structure of the sliding device according to an embodiment of the present invention.

[0030] Fig.10 Schematic diagram of the sliding of transparent constraints according to an embodiment of the present invention.

[0031] Fig.11 Schematic diagram of the structure of the vertical groove of the embodiment of the present invention.

[0032] In the figure, 1. control system, 2. axial confining pressure simulation loading device, 3. microscopic detection system, 4. crossbeam, 5. crossbeam moving device, 6. baffle, 7. pressure head, 8. internal pressure head power device, 9. axial pressure measuring device, 10. internal pressure head, 11. pressure head sleeve, 12 composite constraint, 13. infusion tube, 14. piston mechanism, 15. hollow base, 16. base, 17. solid column, 18. push rod, 19. camera, 20. annular chute, 21. crushed block discharge port, 22. 1. Crumb conveyor belt, 23. Electric trolley, 24. Powder discharge port, 25. Powder conveyor belt, 26. Track, 27. First filter, 28. Guide structure, 29. Second filter, 30. Third filter, 31. Conveyor belt, 32. Partition net, 33. Fan, 34. Heating wire, 35. Rigid constraint, 36. Transparent constraint, 37. Sliding device, 38. Push rod mounting point, 39. Circular arc slide, 40. Roller, 41. Vertical groove, 42. Sliding shaft, 43. Sleeve. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment provides a device for simulating rock fracture morphology under different depth conditions, such as Figure 1 As shown, it includes a control system 1, an axle confining pressure simulation loading device 2 and a microscopic detection system 3;

[0036] The axial confining pressure simulation loading device 2 comprises an axial pressure simulation loading device and a confining pressure simulation loading device, wherein:

[0037] Axial compression simulation loading device, such as Figure 2~3 As shown, including:

[0038] A crossbeam 4, which is mounted on a crossbeam moving device 5, and the crossbeam moving device 5 controls the lifting of the crossbeam 4;

[0039] The pressure head 7 is arranged below the cross beam 4. The pressure head 7 is composed of an inner pressure head 10 and a pressure head sleeve 11. The pressure head sleeve 11 is embedded in the cross beam 4, and the inner pressure head 10 is slidably nested in the pressure head sleeve 11;

[0040] The inner pressure head power device 8 is fixedly connected to the cross beam 4 or the pressure head sleeve 11. The specific installation position is not limited, as long as the inner pressure head power device 8 can drive the inner pressure head 10 to move up and down in the pressure head sleeve 11; the telescopic end of the inner pressure head power device 8 is fixedly connected to the inner pressure head 10;

[0041] in:

[0042] The internal pressure head 10 is a solid cylindrical structure, the diameter of the internal pressure head 10 is equal to the diameter of the sample, and an axial pressure measuring device 9 is arranged on the top of the internal pressure head 10 .

[0043] In some embodiments, the beam moving device 5 is composed of rigid columns, rigid beams and a lifting power device at the four corners of the top of the base 16. The beam 4 is placed in a groove on the rigid beam and fits therein. The rigid beam can be welded to the rigid column as a whole. The rigid column is fixedly connected to a power lifting device (similar to an electric jack) in the base 16, which can drive the rigid column to move downward or upward, thereby realizing the downward or upward movement of the beam 4.

[0044] In some embodiments, the confining pressure simulation loading device includes at least two composite constraints 12 and a servo mechanism, wherein:

[0045] Each composite constraint 12 is fixedly connected to the power end of the corresponding servo mechanism, and the servo mechanism works to drive the composite constraint 12 to move;

[0046] At least two composite constraints 12 can be moved and assembled into a cylindrical cavity covering the side wall of the specimen under the drive of the corresponding servo mechanism.

[0047] In some embodiments, the confining pressure simulation loading device includes two composite constraints 12, the composite constraints 12 are semi-cylindrical structures, and the two composite constraints 12 are arranged opposite to each other to form a cylindrical structure to wrap the test piece, such as Fig.10 shown.

[0048] In some embodiments, the composite constraint 12 includes a rigid constraint 35 and a transparent constraint 36 , wherein the transparent constraint 36 forms an outer surface of the composite constraint 12 and the rigid constraint 35 forms an inner surface of the composite constraint 12 ;

[0049] The transparent constraint 36 is slidably connected to the rigid constraint 35. The rigid constraints 35 of at least two composite constraints 12 and the transparent constraint 36 after sliding out along the predetermined slideway on the rigid constraint 35 form a closed enclosure with an inscribed circle diameter greater than the diameter of the specimen.

[0050] In some embodiments, a circular arc groove 39 is provided on the outside of the rigid constraint 35 of the composite constraint 12, such as Figure 8 As shown, the transparent constraint 36 of the composite constraint 12 slides in the arc slide groove 39 via the sliding device 37 .

[0051] In some embodiments, the height of the transparent constraint 36 and the arc groove 39 is less than the height of the rigid constraint 35, and the power end of the servo mechanism is connected to the outer surface of the rigid constraint 35, such as Figure 8 As shown, a push rod mounting point 38 located outside the arc groove 39 is provided on the rigid constraint 35 , and the push rod 18 of the piston mechanism 14 is fixed at the push rod mounting point 38 .

[0052] In some embodiments, Figures 8 and 9 As shown, the sliding device 37 includes a vertical groove 41, one end of the transparent constraint 36 is inserted into the vertical groove 41 of the sliding device 37, and rollers 40 are installed at the top and bottom of the vertical groove 41, and the rollers 40 slide in the arc groove 39. When the composite constraint 12 reaches the specified position, the tester pushes the vertical groove 41 respectively, so that it slides in the arc groove 39 through the roller 40, thereby driving the transparent constraint 36 to move. When the vertical groove 41 slides to the end of the arc groove 39 through the roller 40, the transparent constraint 36 and the rigid constraint 35 can form a closed enclosure, as shown in FIG. Fig.10 shown.

[0053] In some embodiments, the height of the composite constraint 12 is equal to the height of the specimen, and at least two sets of servo mechanisms are provided on each composite constraint 12, and at least two sets of servo mechanisms are evenly distributed on the composite constraint 12 so that the specimen is subjected to uniform force as a whole, thereby ensuring the confining pressure simulation loading effect.

[0054] In some embodiments, two sets of servo mechanisms are provided on each composite constraint 12, and the two sets of servo mechanisms are provided corresponding to the bottom and the top of the specimen one by one, so that the specimen is subjected to uniform force as a whole, thereby ensuring the confining pressure simulation loading effect.

[0055] In some embodiments, the servo mechanism is mounted on the baffle 6 , and the baffle 6 is mounted on the base 16 .

[0056] In some embodiments, the servo mechanism uses a piston mechanism 14, such as Figure 3 As shown, the piston mechanism 14 is composed of a slide groove and a push rod 18. One end of the push rod 18 is placed in the slide groove, and the other end is fixedly connected to the composite constraint 12. The push rod slide groove is connected to the pressurizing device (oil pump, air pump) through the infusion tube 13. When the pressurizing device acts on the push rod 18 to move, the composite constraint 12 can be driven to move. A confining pressure sensor is provided on the servo mechanism.

[0057] It is worth noting that since the transparent constraint 36 and the arc groove 39 are both arc-shaped structures, the transparent constraint 36 must constantly change its angle when moving along the arc groove 39. Therefore, in some embodiments, the vertical groove 41 adopts a hinge structure, such as Fig.11 As shown, the vertical groove 41 is composed of a sliding shaft 42 and a sleeve 43, the roller 40 is arranged at the top and bottom of the sliding shaft 42, the sleeve 43 is sleeved on the sliding shaft 42 and can rotate around the sliding shaft 42, and the transparent constraint 36 is installed in the installation groove of the sleeve 43. In addition, in order to ensure the stability of the closed enclosure formed by the transparent constraint 36 and the rigid constraint 35, a card slot matching the sleeve 43 can be set at the end of the arc slide groove 39. When the vertical groove 41 slides to the end of the arc slide groove 39 through the roller 40, the sleeve 43 is inserted into the corresponding card slot to fix the position of the vertical groove 41.

[0058] In some embodiments, Figures 3-5 As shown, the device for simulating rock fracture morphology under different depth conditions includes a hollow base 15 arranged below the specimen, a solid column 17 is arranged in the hollow base 15, the specimen is placed on the solid column 17, and the solid column 17 is fixedly connected to the base 16 so as to transmit the axial force borne by the specimen to the base 16.

[0059] In some embodiments, the pressure head sleeve 11 and the hollow base 15 are made of steel plates of equal thickness.

[0060] In some embodiments, a microscopic sample collection device is disposed in the hollow base 15, such as Figures 5 and 6 As shown, the microscopic sample collection device comprises:

[0061] The first filter screen 27, the guide structure 28, the second filter screen 29 and the third filter screen 30 are arranged in sequence from top to bottom in the hollow base 15, wherein:

[0062] The mesh apertures of the first filter screen 27, the second filter screen 29 and the third filter screen 30 decrease from top to bottom; the first filter screen 27 is horizontally arranged on the top of the hollow base 15; the guide structure 28 is a structure of an inverted figure eight with a vertical section that is symmetrical about the solid column 17, so that the sample fragments and powder can fall into the middle of the second filter screen 29 at the lower layer;

[0063] The guide structure 28 is composed of two guide plates, wherein the top of one guide plate is wrapped around the solid column 17 and fixedly connected to the side wall of the solid column 17, and the top of the other guide plate is wrapped around the inner wall of the hollow base 15 and fixedly connected to the inner wall of the hollow base 15; the second filter screen 29 and the third filter screen 30 are both truncated cone structures with a certain inclination angle at the bottom, the top of the second filter screen 29 and the third filter screen 30 are fixedly connected to the side wall of the solid column 17, and the bottom of the second filter screen 29 and the third filter screen 30 are respectively fixedly connected to the corresponding conveyor belts 31, and the inclined conveyor belts 31 are installed on the inner wall of the hollow base 15 and are arranged in a circle so as to transport microscopic samples (sample fragments and powder) through the two conveyor belts 31.

[0064] In some embodiments, the mesh size of the first filter 27 is set to 10 mm, the opening width of the guide structure 28 is set to 50 mm, the mesh size of the second filter 29 is set to 0.5 mm, the mesh size of the third filter 30 is set to 0.075 mm, and the mesh size of the partition 32 is 0.045 mm. The first filter 27, the guide structure 28, the second filter 29 and the third filter 30 are installed on the inner wall of the hollow base 15 by screw plug connection.

[0065] In some embodiments, the first filter screen 27 is flush with the top of the solid column 17 .

[0066] In some embodiments, a fragment discharge port 21 and a powder discharge port 24 are provided on the side of the hollow base 15. Figure 5 As shown, the fragment discharge port 21 is located above the powder discharge port 24, the fragment discharge port 21 is connected to the bottom of the inclined conveyor belt 31 connected to the second filter screen 29, the powder discharge port 24 is connected to the bottom of the inclined conveyor belt 31 connected to the third filter screen 30, the microscopic detection samples on the second filter screen 29 and the third filter screen 30 are discharged from the fragment discharge port 21 and the powder discharge port 24, and then transmitted to the conveying device through the fragment conveyor belt 22 connected to the fragment discharge port 21 and the powder conveyor belt 25 connected to the powder discharge port 24.

[0067] In some embodiments, a camera 19 and an annular slide 20 are provided on the base 16. Figure 4 As shown, the annular groove 20 is arranged on the outside of the solid column 17, and a fixed rod is slidably connected in the annular groove 20. The camera 19 is installed on the fixed rod, so that the camera 19 is arranged on the side of the sample through the fixed rod slidably connected to the annular groove 20. When the fixed rod moves in the annular groove 20, the camera 19 can be driven to move on the side of the sample, so as to facilitate the shooting of characteristic images of the sample after rupture from different angles.

[0068] In some embodiments, the base 16 is provided with a drying device distributed on the top of the base 16 and below the microscopic sample collecting device. A plurality of evenly distributed drying devices may be provided in the base 16, such as Figure 6-7 As shown, four drying devices are provided. A groove is provided at the top of the base 16, a solid column 17 is fixed in the groove, and the drying device is installed in the groove and outside the solid column 17. Each drying device includes a partition 32, a fan 33, and an electric heating wire 34 arranged from top to bottom. The mesh aperture of the partition 32 is smaller than the third filter 30, and the partition 32 is fixed at the top of the groove provided on the base 16. The electric heating wire 34 heats the air, and the fan 33 provides appropriate wind force, thereby forming an upward hot air flow. The hot air flows out of the base 16 through the partition 32 and reaches the hollow base 15, drying the microscopic sample in the hollow base 15, so that the moisture in the microscopic sample can be taken away to the greatest extent. The function of the partition 32 is to ensure that the hot air flow flows from the base 16 into the hollow base 15 while preventing the microscopic sample residue from falling into the drying device and affecting the operation of the equipment.

[0069] In some embodiments, the control system 1 includes a data analysis and processing system, a control console and a display. The data analysis and processing system is mainly responsible for analyzing and processing the peak strength of the axial displacement, radial displacement, axial pressure, confining pressure, and uniaxial compression failure of the sample generated during the test, and transmitting them to the display; the control console is electrically connected to the crossbeam moving device 5, the internal pressure head power device 8, the servo mechanism, the camera 19, and the electric trolley 23 (such as wireless communication connection). The control console is mainly responsible for controlling the crossbeam moving device 5, the internal pressure head power device 8, the servo mechanism, the camera 19, the electric trolley 23 and other equipment. A central processing unit is provided inside the control console, and the operating instructions of the test personnel are processed by the central processing unit, and then the central processing unit decodes the corresponding instructions and generates corresponding operation control signals, so that the crossbeam moving device 5, the internal pressure head power device 8, the servo mechanism, the camera 19, the electric trolley 23 and other equipment perform the specified actions.

[0070] In some embodiments, the microscopic detection system 3 includes a conveying device and an electron microscope. The conveying device is composed of an electric trolley 23 and a track 26. The electric trolley 23 is connected to the fragment conveyor belt 22 and the powder conveyor belt 25 to receive the microscopic detection samples conveyed by the fragment conveyor belt 22 and the powder conveyor belt 25. The electric trolley 23 moves on the track 26 to immediately deliver the microscopic detection samples to the electron microscope for microscopic detection. The electric trolley 23 is composed of two storage boxes arranged up and down. The two storage boxes arranged up and down are connected to the fragment conveyor belt 22 and the powder conveyor belt 25 respectively, and receive the fragment microscopic detection samples and the powder microscopic detection samples respectively. A camera can be set at the parking place of the electric trolley 23 to monitor whether the number of microscopic samples in the electric trolley 23 meets the required number requirements for the test.

[0071] Example 2

[0072] This embodiment provides a method for using a device for simulating rock fracture morphology under different depth conditions, which is specifically performed according to the following steps:

[0073] S1: Place the prepared sample on the solid column 17 and connect the push rod slide groove of the piston mechanism 14 with the infusion tube 13;

[0074] S2: Go to the control console, turn on the display and the axial pressure simulation loading device, make the internal pressure head 10 gradually approach the upper surface of the sample, turn on the servo mechanism of the confining pressure loading device to drive the composite constraint 12 to move toward the specimen, and stop pressurizing when the inner surface of the composite constraint 12 fits the side of the specimen. Clear the pressure when the servo mechanism, i.e., the piston mechanism 14, drives the composite constraint 12 to move toward the specimen on the operation interface of the control console, input the axial pressure and confining pressure under the corresponding depth conditions, and the rigid constraint 35 starts confining pressure loading under the action of the push rod 18. The internal pressure head 10 moves downward under the action of the internal pressure head power device 8 to perform axial pressure loading. When the confining pressure sensor on the servo mechanism and the axial pressure measuring device 9 detect that the confining pressure and axial pressure reach the set value, stop increasing the axial pressure and confining pressure, and maintain the confining pressure and axial pressure near the set value, with an error not exceeding 0.5% of the set value, to simulate the natural stress state of rock under different depth conditions. The axial pressure and confining pressure simulation time is determined according to the specific test;

[0075] S3: After the axial pressure and confining pressure simulation is completed, the axial pressure and confining pressure are unloaded, so that the servo mechanism drives the composite constraint 12 away from the specimen. After reaching the specified position, the movement of the composite constraint 12 is stopped, and the transparent constraint 36 on the outer wall of each composite constraint 12 is slid along the arc slide groove 39 on the sliding device 37, so that all transparent constraints 36 and rigid constraints 35 form a closed enclosure, and at the same time, the vertical displacement meter and the lateral displacement meter are installed on the specimen;

[0076] S4: reset the internal pressure head 10, perform uniaxial force loading, start the crossbeam moving device 5 to drive the crossbeam 4 to slowly descend, and stop when the pressure head 7 descends above the surface of the specimen at a uniform speed, turn on the camera 19, set the loading rate on the uniaxial compression test system, start uniaxial force loading, and stop when the specimen is destroyed, and at the same time turn on the drying device in the base 16;

[0077] S5: Move the electric trolley 23 along the track 26 to the discharge port of the microscopic sample collection device (the discharge end of the fragment conveyor belt 22 and the powder conveyor belt 25). When the microscopic sample in the electric trolley 23 reaches a certain amount, move the electric trolley 23 to the electron microscope to screen the sample pre-finished products for microscopic inspection.

[0078] The designated position in step S3 refers to the transparent constraint 36 of the outer wall of the sliding composite constraint 12 at the position, so that the transparent constraint 36 and the rigid constraint 35 form a closed enclosure with an inscribed circle diameter greater than the diameter of the specimen. The transparent constraint 36 can be made of a light, light-transmitting material, such as a transparent PVC plastic plate or a transparent PVC soft plastic plate.

[0079] Transparency constraint 36 has the following functions:

[0080] 1. It is convenient to obtain the sample fracture characteristic diagram through the camera 19 during the uniaxial compression test and analyze the macroscopic failure characteristics of the sample under different depth conditions;

[0081] 2. During uniaxial compression, the flying fragments can be blocked and allowed to rebound and fall into the microscopic sample collection device.

[0082] The use of the pressure head 7 to apply pressure can ensure that the specimen is subjected to uniform force even if a slight deviation occurs during the loading process. Since the size of the internal pressure head 10 is the same as the size of the specimen, if the internal pressure head 10 is used for loading during the loading process, the specimen may be subjected to uneven force, thereby distorting the specimen results.

[0083] This embodiment can simulate the natural stress state of rock under different depth conditions before conducting a uniaxial compression test, so that the rock sample can restore its initial characteristics before mining as much as possible, and can obtain the true strength characteristics of the rock to the greatest extent, and obtain the fracture characteristic diagram of the rock under different depth conditions, which improves the accuracy of the test results to a certain extent. At the same time, when conducting a uniaxial compression test, some of the fallen fragments and powder are collected synchronously, dried and classified, saving the time required for microscopic detection, thereby achieving an instant microscopic effect, and realizing instant microscopic detection, avoiding interference with the test caused by human factors. The piston mechanism 14 pushes the composite constraint 12 to achieve confining pressure loading, which can simplify the conventional confining pressure loading procedure and improve the test efficiency.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A device for simulating rock fracture morphology under conditions of different depths, comprising an axial confining pressure simulation loading device (2), the axial confining pressure simulation loading device (2) comprising an axial pressure simulation loading device and a confining pressure simulation loading device, characterized in that: The axial pressure simulation loading device includes: A crossbeam (4), wherein the crossbeam (4) is mounted on a crossbeam moving device (5), and the crossbeam moving device (5) controls the lifting and lowering of the crossbeam (4); A pressure head (7), the pressure head (7) being arranged below the cross beam (4), the pressure head (7) being composed of an inner pressure head (10) and a pressure head sleeve (11), the pressure head sleeve (11) being embedded in the cross beam (4), and the inner pressure head (10) being slidably nested in the pressure head sleeve (11); An internal pressure head power device (8), wherein the telescopic end of the internal pressure head power device (8) is fixedly connected to the internal pressure head (10); in: The internal pressure head (10) is a solid cylindrical structure, and the diameter of the internal pressure head (10) is equal to the diameter of the sample; The confining pressure simulation loading device comprises at least two composite constraints (12) and a servo mechanism, wherein: Each composite constraint (12) is fixedly connected to the power end of the corresponding servo mechanism, and the servo mechanism works to drive the composite constraint (12) to move; At least two composite constraints (12) can be moved and assembled into a cylindrical cavity covering the side wall of the specimen under the drive of the corresponding servo mechanism; The composite constraint (12) includes a rigid constraint (35) and a transparent constraint (36), wherein the transparent constraint (36) forms an outer surface of the composite constraint (12), and the rigid constraint (35) forms an inner surface of the composite constraint (12); The transparent constraint (36) is connected to the rigid constraint (35) by sliding; The rigid constraints (35) of at least two composite constraints (12) and the transparent constraints (36) that slide out along the predetermined slideway on the rigid constraints (35) form a closed enclosure with an inscribed circle having a diameter greater than the diameter of the specimen; Each composite constraint (12) is connected to at least two sets of servo mechanisms, and at least two sets of servo mechanisms are evenly distributed on the composite constraint (12); An arc groove (39) is arranged outside the rigid constraint (35) of the composite constraint (12), and the transparent constraint (36) of the composite constraint (12) slides in the arc groove (39) via a sliding device (37); The height of the transparent constraint (36) and the arc slide groove (39) is less than the height of the rigid constraint (35), and the power end of the servo mechanism is connected to the outer surface of the rigid constraint (35); The sliding device (37) includes a vertical groove (41), the transparent constraint (36) is inserted into the vertical groove (41) of the sliding device (37), and rollers (40) are installed at the top and bottom of the vertical groove (41), and the rollers (40) slide in the arc sliding groove (39); The vertical groove (41) is a hinge structure, which is composed of a sliding shaft (42) and a sleeve (43). The rollers (40) are arranged at the top and bottom of the sliding shaft (42). The sleeve (43) is sleeved on the sliding shaft (42) and can rotate around the sliding shaft (42). The transparent constraint (36) is installed in the installation groove of the sleeve (43).

2. The device for simulating rock fracture morphology under different depth conditions according to claim 1, characterized in that: It also includes a hollow base (15) disposed below the test piece, a solid column (17) disposed in the hollow base (15), and the test piece is placed on the solid column (17); A microscopic sample collecting device is arranged in the hollow base (15), and the microscopic sample collecting device comprises: A first filter screen (27), a guide structure (28), a second filter screen (29) and a third filter screen (30) are arranged in sequence from top to bottom in the hollow base (15), wherein: The mesh sizes of the first filter screen (27), the second filter screen (29) and the third filter screen (30) decrease in sequence from top to bottom; The first filter screen (27) is horizontally arranged on the top of the hollow base (15); The guide structure (28) is a structure having a vertical cross-section in the shape of an inverted figure eight and being symmetrical about the solid column (17). The guide structure (28) is composed of two guide plates, wherein the top of one guide plate is wound around the solid column (17) and fixedly connected to the side wall of the solid column (17), and the top of the other guide plate is wound around the inner wall of the hollow base (15) and fixedly connected to the inner wall of the hollow base (15). The second filter screen (29) and the third filter screen (30) are both truncated cone structures with a certain inclination angle at the bottom. The tops of the second filter screen (29) and the third filter screen (30) are fixedly connected to the side wall of the solid column (17). The bottoms of the second filter screen (29) and the third filter screen (30) are respectively fixedly connected to corresponding conveyor belts (31). The inclined conveyor belt (31) is installed on the inner wall of the hollow base (15) and is arranged in a circle.

3. The device for simulating rock fracture morphology under different depth conditions according to claim 2, characterized in that: It also includes a base (16), the hollow base (15) is fixed on the base (16), and the solid column (17) is fixed inside the base (16); At least two drying devices are arranged on the base (16), and the at least two drying devices are evenly distributed on the top of the base (16); A groove is formed at the top of the base (16), a solid column (17) is fixed in the groove, and a drying device is installed in the groove and outside the solid column (17). Each drying device comprises a partition net (32), a heating wire (34) and a fan (33) arranged from top to bottom. The partition net (32) is fixed at the top of the groove formed on the base (16), and the mesh aperture of the partition net (32) is smaller than the mesh aperture of the third filter net (30).

4. The device for simulating rock fracture morphology under different depth conditions according to claim 2, characterized in that: An annular slide groove (20) and a camera (19) are provided on the base (16), wherein: The annular slide groove (20) is arranged outside the hollow base (15), a fixing rod is slidably connected in the annular slide groove (20), and the camera (19) is mounted on the fixing rod; A fragment discharge port (21) and a powder discharge port (24) are provided on the side of the hollow base (15); the fragment discharge port (21) is located above the powder discharge port (24); the fragment discharge port (21) is connected to the bottom of an inclined conveyor belt (31) connected to the second filter screen (29); and the powder discharge port (24) is connected to the bottom of an inclined conveyor belt (31) connected to the third filter screen (30); The equipment for simulating rock fracture morphology under different depth conditions also includes a microscopic detection system, which includes a transmission device and an electron microscope; The conveying device is composed of an electric trolley (23) and a track (26); the electric trolley (23) is connected to a fragment conveyor belt (22) and a powder conveyor belt (25); the fragment conveyor belt (22) is connected to a fragment discharge port (21); and the powder conveyor belt (25) is connected to a powder discharge port (24); The control system (1) includes a data analysis and processing system, a control console and a display, wherein: Data analysis and processing system, used to analyze and process the peak intensity of the axial displacement, radial displacement, axial pressure, confining pressure, and uniaxial compression failure of the specimen generated during the test, and transmit them to the display; The control console is electrically connected to the crossbeam moving device (5), the internal pressure head power device (8), the servo mechanism, the camera (19), and the electric trolley (23), and controls the crossbeam moving device (5), the internal pressure head power device (8), the servo mechanism, the camera (19), and the electric trolley (23).

5. The method for using the device for simulating rock fracture morphology under different depth conditions according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: Take the prepared sample and place it on the solid column (17); S2: Go to the control console, turn on the display and the axial pressure simulation loading device, make the internal pressure head (10) gradually approach the upper surface of the sample, turn on the servo mechanism of the confining pressure loading device to drive the composite constraint (12) to move toward the specimen, and stop pressurizing when the inner surface of the composite constraint (12) fits the side of the specimen. Clear the pressure when the servo mechanism drives the composite constraint (12) to move toward the specimen on the operation interface of the control console, input the axial pressure and confining pressure under the corresponding depth conditions, and start the axial pressure and confining pressure simulation loading. When the confining pressure sensor on the servo mechanism and the axial pressure measuring device (9) detect that the confining pressure and axial pressure reach the set value, control the confining pressure and axial pressure to maintain the set value, simulate the natural stress state of the rock under different depth conditions, until the designed axial pressure and confining pressure simulation time is reached; S3: Unloading the axial pressure and the confining pressure, so that the servo mechanism drives the composite constraint (12) away from the specimen, and stops the movement of the composite constraint (12) after reaching the specified position, and slides the transparent constraint (36) on the outer wall of each composite constraint (12) along the arc slide groove (39) on the sliding device (37), so that all the transparent constraints (36) and the rigid constraints (35) form a closed enclosure, and at the same time, the vertical displacement meter and the lateral displacement meter are installed on the specimen; S4: the internal pressure head (10) is reset, uniaxial force loading is performed, the crossbeam moving device (5) is started to drive the crossbeam (4) to slowly descend, the pressure head (7) stops when it descends above the surface of the specimen at a uniform speed, the camera (19) is turned on, the loading rate is set on the uniaxial compression test system, the uniaxial force loading is started, and the sample is stopped when it is destroyed, and the drying device in the base (16) is turned on at the same time; S5: Move the electric trolley (23) along the track (26) to the discharge port of the microscopic sample collection device. When the microscopic samples in the electric trolley (23) reach a certain amount, move the electric trolley (23) to the electron microscope to screen the sample pre-finished products and perform microscopic inspection.

6. The method for using the device for simulating rock fracture morphology under different depth conditions according to claim 5 is characterized in that: The designated position in step S3 refers to sliding the transparent constraint (36) of the outer wall of the composite constraint (12) at the position so that the transparent constraint (36) and the rigid constraint (35) form a closed enclosure with an inscribed circle having a diameter greater than the diameter of the specimen; The transparent restraint (36) is made of a light material with good light transmittance.

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