A deep in-situ rock true triaxial preparation device containing internal stress

Abstract

The present application relates to the technical fields of deep rock in-situ simulation preparation, and discloses a deep in-situ rock true triaxial preparation device containing internal stress, which comprises a mold, the mold comprises a rectangular frame structure formed by connecting rigid plate A, rigid plate B, elastic plate A and elastic plate B in sequence, and further comprises a first axial compression device, the first axial compression device comprises a top plate, a first hydraulic cylinder and a first compression plate, the top plate is detachably connected to one end of the rectangular frame structure, the other end of the rectangular frame structure is detachably connected to a bottom plate, the first compression plate is slidably matched with the interior of the rectangular frame structure, the first hydraulic cylinder can drive the first compression plate to slide, the lower end and the upper end of the side of the rigid plate A close to the elastic plate B are respectively provided with a first grouting hole and a first back grouting hole, and the lower end and the upper end of the side of the rigid plate B close to the elastic plate A are respectively provided with a second grouting hole and a second back grouting hole; the device can prepare deep in-situ rock containing internal stress under different three-directional stress loading environments, and is beneficial to the in-depth study of deep mining theory.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of deep rock in-situ simulation preparation, in particular to a deep in-situ rock true triaxial preparation device containing internal stress. BACKGROUND

[0002] With the exhaustion of shallow resources, resource exploitation activities gradually develop to the deep, and compared with shallow resources, the geological conditions and stress environment of deep rock mass are more complex. Because the rock core will experience an instantaneous internal stress release process after being taken out from the deep, the rock will be damaged to a certain extent, making it difficult to reflect the occurrence environment and structural state of the deep engineering area. Even if the deep rock mass is taken out, it is also difficult to conduct in-situ physical and mechanical experimental research on the deep rock mass at the laboratory scale.

[0003] When preparing deep in-situ rock samples containing internal stress in the laboratory, the following steps are generally followed: first, determine the particle raw materials and mass fraction according to the composition of the rock mass to be tested, place the particle raw materials in the mold, and pre-embed strain gauges in the particle voids; then, apply axial pressure and confining pressure to the mold according to different stress loading paths; after the stress loading is stable, inject adhesive slurry into the mold, stop the injection when the voids are completely filled; then, keep the stress loading stable and keep the mold stationary for curing, and wait for the adhesive material to solidify. Currently, when preparing deep in-situ rock samples containing internal stress in the laboratory, stress loading is usually performed on a conventional triaxial testing machine to complete the preparation, and the prepared rock samples are cylindrical samples. The conventional triaxial testing machine is commonly known as a "pseudo-triaxial" testing machine, which can only load different values of axial pressure and confining pressure. From the perspective of three-dimensional stress, two stress values in the conventional triaxial testing machine are always equal, and it cannot achieve different loading paths of three-dimensional stress. The internal stress rock samples prepared have limitations. SUMMARY

[0004] The purpose of the present application is to provide a deep in-situ rock true triaxial preparation device containing internal stress, which can prepare internal stress deep in-situ rock samples under different three-dimensional stress loading environments, and the prepared rock samples can reflect more types of occurrence environment and stress path in deep engineering areas, which is beneficial to the in-depth study of deep mining theory.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] The utility model relates to a kind of containing internal stress deep in situ rock true triaxial preparation device, including mould, the mould includes rigid plate A, rigid plate B, elastic plate A, elastic plate B and first axial pressure device, the rigid plate A, rigid plate B, elastic plate A, elastic plate B are sequentially connected to form the rectangular frame structure of both ends opening, one end of the rectangular frame structure is detachably connected with bottom plate, the first axial pressure device includes top plate, first hydraulic cylinder, first pressing plate, the top plate is detachably connected in the rectangular frame structure far from bottom plate one end, the first hydraulic cylinder is fixedly connected with the top plate, the piston rod end of the first hydraulic cylinder is fixedly connected with the first pressing plate, the first pressing plate is slidably adapted with the rectangular frame structure inside, the rigid plate A is close to the first grouting hole of one corner of elastic plate B and bottom plate, the rigid plate A is close to the first return slurry hole of one corner of elastic plate B and top plate, the rigid plate B is close to the second grouting hole of one corner of elastic plate A and bottom plate, the rigid plate B is close to the second return slurry hole of one corner of elastic plate A and top plate, the sidewall of the first pressing plate is provided with first recess and second recess along the first pressing plate sliding direction, the first recess is adapted with the first return slurry hole, the second recess is adapted with the second return slurry hole.

[0007] Specifically, it further includes a workbench, the mould is installed on the workbench, the bottom plate is arranged downward, the workbench is provided with a second axial pressure device and a third axial pressure device, the second axial pressure device can apply positive pressure to the elastic plate A, and the third axial pressure device can apply positive pressure to the elastic plate B.

[0008] Specifically, the second axial pressure device includes a second hydraulic cylinder and a second pressing plate, the second hydraulic cylinder is fixedly installed on the workbench, the second pressing plate is fixedly connected with the piston rod end of the second hydraulic cylinder, and the second pressing plate is arranged opposite to the elastic plate A; the third axial pressure device includes a third hydraulic cylinder and a third pressing plate, the third hydraulic cylinder is fixedly installed on the workbench, the third pressing plate is fixedly connected with the piston rod end of the third hydraulic cylinder, and the third pressing plate is arranged opposite to the elastic plate B.

[0009] Specifically, the mould further includes a mounting frame, the mounting frame is fixedly sleeved at one end of the rectangular frame structure away from the top plate, and the mounting frame is detachably connected with the workbench.

[0010] Specifically, a rectangular hole is formed in the workbench, one end of the bottom plate is provided with a boss, the boss and the rectangular hole are adapted to the inner cavity section of the rectangular frame structure, the boss passes through the rectangular hole from bottom to top and extends into the rectangular frame structure, and four tension bolts are further included, the screw rod end of the tension bolts sequentially passes through the top plate, the mounting frame, the workbench, the bottom plate and is threadedly connected with a nut, and the four tension bolts are arranged at four corner positions outside the rectangular frame structure.

[0011] Specifically, the workbench is provided with a first force receiving plate and a second force receiving plate, the first force receiving plate can abut against the rigid plate A, and the second force receiving plate can abut against the rigid plate B.

[0012] Specifically, the workbench is provided with a first force receiving plate and a second force receiving plate, the first force receiving plate can abut against the rigid plate A, and the second force receiving plate can abut against the rigid plate B.

[0013] The beneficial effects of the present application are:

[0014] The device for preparing deep in-situ rock with internal stress in a true triaxial manner comprises a mold and a workbench, the mold comprises a bottom plate, a rectangular frame structure and a first axial compression device, the rectangular frame structure is formed by connecting and surrounding rigid plate A, rigid plate B, elastic plate A and elastic plate B in sequence, the bottom plate is detachably connected to one end of the rectangular frame structure, the first axial compression device comprises a top plate, a hydraulic cylinder and a first compression plate, the top plate is detachably connected to the other end of the rectangular frame structure, the first compression plate is in sliding fit with the inside of the rectangular frame structure, the first hydraulic cylinder is fixedly installed on the top plate, and the first hydraulic cylinder can drive the first compression plate to slide in the rectangular frame structure. When preparing the rock sample with internal stress, the granular raw material is placed in the mold, the second axial compression device provided on the workbench can apply a positive pressure (in the X-axis direction) to the elastic plate A, the third axial compression device can apply a positive pressure (in the Y-axis direction) to the elastic plate B, the elastic plate A and the elastic plate B are made of elastic materials with good ductility, and the positive pressure received from the outside can be transmitted to the granular raw material in the rectangular frame structure through a certain degree of deformation, so that two-way loading in the X-axis direction and the Y-axis direction is completed; the first hydraulic cylinder can drive the first compression plate to slide downward and directly act on the granular raw material to complete Z-direction loading. Therefore, the loading devices can load different three-way stresses on the granular raw material in the mold, and the rock sample prepared after grouting and curing can reflect more types of deep engineering area occurrence environment and stress path, which is beneficial to the in-depth study of deep mining theory.

[0015] The first grouting hole is arranged at an angle close to the elastic plate B and the bottom plate of the rigid plate A, the first back grouting hole is arranged at an angle close to the elastic plate B and the top plate of the rigid plate A, the second grouting hole is arranged at an angle close to the elastic plate A and the bottom plate of the rigid plate B, and the second back grouting hole is arranged at an angle close to the elastic plate A and the top plate of the rigid plate B. The side wall of the first pressing plate is provided with a first groove and a second groove along the sliding direction of the first pressing plate, the first groove is matched with the first back grouting hole, and the second groove is matched with the second back grouting hole. After the particle raw material in the mold is loaded as described above, the adhesive slurry needs to be injected, and the rock sample is prepared after curing. The above is a specific design for realizing the grouting process. The first grouting hole, the first back grouting hole, the second grouting hole and the second back grouting hole are arranged on the non-deformed rigid plate A and the rigid plate B, and the shape and position of each hole remain unchanged during the stress loading process, which is beneficial to the connection of the grouting pipe (back grouting pipe) and the plugging of the plug. When grouting, grouting from bottom to top is beneficial to ensure that the adhesive slurry is fully injected; the two grouting holes and the two back grouting holes are located at positions close to the two ends of the diagonal line of the rectangular frame structure section, and the simultaneous grouting of the two grouting holes is also beneficial to ensure that the adhesive slurry is fully injected; the first groove and the second groove arranged on the first pressing plate are beneficial to ensure that the adhesive slurry injected can flow out of the two back grouting holes when the first pressing plate has a certain displacement during the Z-direction loading process.

[0016] The side walls of the rectangular frame structure of the mold are respectively composed of the rigid plate A, the rigid plate B, the elastic plate A and the elastic plate B, and the rigid plate A, the rigid plate B, the elastic plate A and the elastic plate B are sequentially connected to ensure the sealing performance of the side edges, so as to ensure the sealing of the lower part of the mold to avoid the leakage of the adhesive slurry when the rock sample is prepared, and realize the true triaxial three-direction loading process. The elastic plate A and the elastic plate B are provided with elastic force, and after the rock sample is prepared, the second shaft pressing device and the third shaft pressing device are loosened, and the elastic plate A and the elastic plate B have a tendency of elastic recovery. After the bottom plate is disassembled, the rock sample can be pushed out downward by using the first hydraulic cylinder, so that the mold is quickly demolded. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a whole structure schematic diagram of the true triaxial preparation device for deep in-situ rock containing internal stress of the application;

[0018] Figure 2 It is a structure schematic diagram of the mold in the true triaxial preparation device for deep in-situ rock containing internal stress of the application;

[0019] Figure 3 It is Figure 2 It is an exploded view of the mold shown in the figure;

[0020] Figure 4 It is a structure schematic diagram of the workbench part after the mold is removed in the true triaxial preparation device for deep in-situ rock containing internal stress of the application;

[0021] In the diagram, 1-rigid plate A, 2-rigid plate B, 3-elastic plate A, 4-elastic plate B, 5-bottom plate, 6-top plate, 7-first hydraulic cylinder, 8-first pressure plate, 9-first grouting hole, 10-first grout return hole, 11-second grouting hole, 12-second grout return hole, 13-first groove, 14-second groove, 15-workbench, 16-second hydraulic cylinder, 17-second pressure plate, 18-third hydraulic cylinder, 19-third pressure plate, 20-mounting frame, 21-rectangular hole, 22-bore, 23-tensioning bolt, 24-nut, 25-first bearing plate, 26-second bearing plate, 27-first tightening screw, 28-second tightening screw. Detailed Implementation

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0023] like Figures 1 to 4 As shown, a true triaxial preparation device for deep in-situ rock containing internal stress includes a mold. The mold structure is as follows: Figure 2 , Figure 3 As shown, the structure includes a rigid plate A1, a rigid plate B2, an elastic plate A3, an elastic plate B4, and a first axial pressing device. The rigid plates A1, B2, A3, and B4 are sequentially connected to form a rectangular frame structure with openings at both ends. One end of the rectangular frame structure is detachably connected to a base plate 5. The first axial pressing device includes a top plate 6, a first hydraulic cylinder 7, and a first pressure plate 8. The top plate 6 is detachably connected to the end of the rectangular frame structure away from the base plate 5. The first hydraulic cylinder 7 is fixedly connected to the top plate 6, and the piston rod end of the first hydraulic cylinder 7 is fixedly connected to the first pressure plate 8. The first pressure plate 8 is slidably adapted to the interior of the rectangular frame structure. A first grouting hole 9 is provided on a rigid plate A1 near a corner of the elastic plate B4 and the bottom plate 5. A first return grouting hole 10 is provided on a rigid plate A1 near a corner of the elastic plate B4 and the top plate 6. A second grouting hole 11 is provided on a rigid plate B2 near a corner of the elastic plate A3 and the bottom plate 5. A second return grouting hole 12 is provided on a rigid plate B2 near a corner of the elastic plate A3 and the top plate 6. A first groove 13 and a second groove 14 are provided on the side wall of the first pressure plate along the sliding direction of the first pressure plate. The first groove 13 is adapted to the first return grouting hole 10, and the second groove 14 is adapted to the second return grouting hole 12.

[0024] The aforementioned mold can be used to prepare deep in-situ rocks with internal stress under true triaxial conditions, such as... Figure 1 As shown, a worktable 15 is also provided during implementation, and a second axial pressing device and a third axial pressing device are provided on the worktable 15. The preparation process includes the following steps:

[0025] S1, connect one end of the rectangular frame structure surrounded by the base plate 5, rigid plate A1, rigid plate B2, elastic plate A3 and elastic plate B4, and install the whole in the workbench 15 with the base plate 5 facing down.

[0026] S2, put the granular raw material into the rectangular frame structure, and pre-embed 8 corner point strain gauges and a center strain gauge in the gap of the granular raw material. The eight corner point stress gauges are distributed to enclose a simulated cube, and each side of the simulated cube is parallel to each inner wall surface of the rectangular frame structure. The center stress gauge is located at the geometric center of the simulated cube.

[0027] S3, install the top plate 6 at the top end of the rectangular frame structure.

[0028] S4, the piston rod of the first hydraulic cylinder 7 is extended, driving the first pressing plate 8 to slide downward in the rectangular frame structure, loading the granular material in the rectangular frame structure with a force in the downward direction (Z-axis direction). The second shaft pressing device on the workbench 15 applies a positive pressure (X-axis direction) to the elastic plate A3, and the third shaft pressing device applies a positive pressure (Y-axis direction) to the elastic plate B4. The elastic plate A3 and the elastic plate B4 are made of elastic materials with good ductility, which can deform when subjected to pressure, and transmit the positive pressure from the outside to the granular raw material in the rectangular frame structure. Each corner point strain gauge and center strain gauge detects the loading force at its location in real time, and when the set value is reached, the first hydraulic cylinder 7, the second shaft pressing device and the third shaft pressing device stop loading.

[0029] S5, connect the grouting pipe and the back grouting pipe, inject the adhesive material into the rectangular frame structure from the first grouting hole 9 and the second grouting hole 11 until the adhesive material flows out from the first back grouting hole 10 and the second back grouting hole 12, and then use the plug to close each grouting hole and back grouting hole.

[0030] S6, maintain the loading force of each shaft pressing device, and maintain until the adhesive material is completely solidified.

[0031] S7, unload the second shaft pressing device and the third shaft pressing device, take out the entire mold, remove the base plate 5, and then fix the rectangular frame structure. The piston rod of the first hydraulic cylinder 7 is extended, and the first pressing plate 8 pushes out the rock sample solidified in the rectangular frame structure, completing demolding.

[0032] As can be seen from the above, the deep in-situ rock true triaxial preparation device with internal stress can prepare deep in-situ rock with internal stress under different three-directional stress loading environments. The prepared rock sample can reflect more types of deep engineering area occurrence environment and stress path, which is conducive to the in-depth study of deep mining theory.

[0033] In the foregoing specific design: since the rock sample undergoes the grouting process of adhesive slurry during preparation, the lower part of the mold is required to have reliable sealing performance to prevent slurry leakage, and since the three-way stress loading is required to be directly transmitted to the inside of the rock sample, the rectangular frame structure of the mold is connected in sequence by rigid plate A1, rigid plate B2, elastic plate A3 and elastic plate B4 to ensure the sealing of the side edge part, the rigid plate A1 and the rigid plate B2 provide the reaction force, and the elastic plate A3 and the elastic plate B4 can be deformed when subjected to pressure, so as to transmit the two-way loading stress in the X-axis direction and the Y-axis direction to the material inside the rectangular frame structure, and the loading force in the Z-axis direction is directly pressed on the material by the first pressing plate 8; thus, during the preparation of the rock sample, the lower part of the mold is not only sealed, but also true triaxial three-way loading is realized. Since the elastic plate A3 and the elastic plate B4 are deformed to a certain extent during the above loading process, it is relatively difficult to demold after the rock sample is solidified and formed, and the elastic plate A3 and the elastic plate B4 are selected to have a tendency to rebound outward after the second shaft pressing device and the third shaft pressing device are unloaded, which is beneficial to make the demolding process more convenient; and in the foregoing implementation steps, as can be seen from step S7, the rock sample prepared can be pushed out in the form of the piston rod of the first hydraulic cylinder 7 extending out, so that the demolding process is more convenient, and in addition, in the demolding step, the first pressing plate 8 slides through the entire rectangular frame structure inside, which is also beneficial to correct the rectangular frame structure, assist the elastic plate A3 and the elastic plate B4 to reset, and facilitate the next use. In the design of the grouting process, the first grouting hole 9, the first back grouting hole 10, the second grouting hole 11 and the second back grouting hole 12 are opened on the non-deformed rigid plate A1 and the rigid plate B2, and the shape and position of each hole remain unchanged during the stress loading process, which is beneficial to the connection of the grouting pipe (back grouting pipe) and the plugging of the plug; when grouting, the downward grouting mode is beneficial to ensure that the adhesive slurry is filled; the two grouting holes and the two back grouting holes are located near the positions of the opposite corners of the cross section of the rectangular frame structure, and the simultaneous grouting of the two grouting holes is also beneficial to ensure that the adhesive slurry is filled; the first recess 13 and the second recess 14 provided on the first pressing plate 8 are beneficial to ensure that when the first pressing plate 8 has a certain displacement during Z-direction loading, the adhesive slurry injected can also flow out from the two back grouting holes, and in specific implementation, the top of the above-mentioned first recess 13 and second recess 14 can be designed as a closed structure to avoid excessive injection of slurry from the position of the first pressing plate 8 upward.

[0034] In specific implementation, the second shaft pressing device and the third shaft pressing device can select a variety of pressure loading structures, and in the present embodiment, as Figure 1 、 Figure 4As shown, the second axial pressing device comprises a second hydraulic cylinder 16 and a second pressing plate 17, the second hydraulic cylinder 16 is fixedly installed on the workbench 15, the second pressing plate 17 is fixedly connected with the end of the piston rod of the second hydraulic cylinder 16, the second pressing plate 17 is arranged opposite to the elastic plate A3, the piston rod of the second hydraulic cylinder 16 can drive the second pressing plate 17 to press the elastic plate A3 when the piston rod of the second hydraulic cylinder 16 is extended, so as to realize the stress loading process in the X-axis direction; the third axial pressing device comprises a third hydraulic cylinder 18 and a third pressing plate 19, the third hydraulic cylinder 18 is fixedly installed on the workbench 15, the third pressing plate 19 is fixedly connected with the end of the piston rod of the third hydraulic cylinder 18, the third pressing plate 19 is arranged opposite to the elastic plate B4, and the third hydraulic cylinder 18 can drive to complete the stress loading process in the Y-axis direction.

[0035] In specific implementation, the mold further comprises a mounting frame 20, the mounting frame 20 is fixedly sleeved at one end of the rectangular frame structure away from the top plate 6, and the mold is detachably connected with the workbench 15 through the mounting frame 20. Specifically, a rectangular hole 21 is formed in the workbench 15, and a boss 22 is arranged at one end of the bottom plate 5, the boss 22 and the rectangular hole 21 are adapted to the inner cavity section of the rectangular frame structure, and the boss 22 extends into the rectangular frame structure after passing through the rectangular hole 21 from bottom to top. Four tension bolts 23 are further arranged, the screw ends of the four tension bolts 23 pass through the top plate 6, the mounting frame 20, the workbench 15 and the bottom plate 5 in sequence and are threadedly connected with nuts 24, and the four tension bolts 23 are arranged at four corner positions outside the rectangular frame structure. The four tension bolts 23 enable the mold to be fixedly installed on the workbench 15, and the mold as a whole has a mouse cage structure so as to keep the mold as a whole relatively stable during the loading process in the X-axis direction and the Y-axis direction. Meanwhile, when demolding is needed after curing, the nuts 24 can be loosened first to take down the bottom plate 5, then the nuts 24 are tightened to fix the rectangular frame structure and the workbench 15, and the piston rod of the first hydraulic cylinder 7 is driven to extend to directly push out the rock sample downward, and the operation is also relatively convenient.

[0036] Further, the first force bearing plate 25 and the second force bearing plate 26 are further arranged on the workbench 15, the first force bearing plate 25 can abut against the rigid plate A1, the second force bearing plate 26 can abut against the rigid plate B2, the first force bearing plate 25 and the second force bearing plate 26 can respectively strengthen the force bearing capacity of the rigid plate A1 and the rigid plate B2, and can be applicable to greater loading force in the X-axis direction or the Y-axis direction.

[0037] Further, the first and second jacking screws 27 and 28 are threadedly connected to the workbench 15, and the first and second force receiving plates 25 and 26 are slidably connected to the workbench 15. The two force receiving plates are slid rearward to facilitate the placement and installation of the mold on the workbench 15. After the mold is installed, the first jacking screw 27 is tightened to press the first force receiving plate 25 against the rigid plate A1, and the second jacking screw 28 is tightened to press the second force receiving plate 26 against the rigid plate B2.

[0038] The above description is merely preferred embodiments of the present application, and it is understood that the present application is not limited to the forms disclosed herein but is susceptible to various modifications and alternative forms, all of which are intended to be included within the scope of the application as described herein and / or as pointed out in the attached claims. It is intended that the application be construed as including all such modifications and alterations in light of the above teachings.

Claims

1. A device for preparing deep in-situ rock true triaxial with internal stress, characterized in that, Including a mold, the mold includes rigid plate A, rigid plate B, elastic plate A, elastic plate B and first shaft pressing device, The rigid plate A, rigid plate B, elastic plate A, elastic plate B are sequentially connected to form a rectangular frame structure with both ends open, one end of the rectangular frame structure is detachably connected with a bottom plate, The first shaft pressing device includes a top plate, a first hydraulic cylinder and a first pressing plate, the top plate is detachably connected to one end of the rectangular frame structure away from the bottom plate, the first hydraulic cylinder is fixedly connected with the top plate, the piston rod end of the first hydraulic cylinder is fixedly connected with the first pressing plate, and the first pressing plate is in sliding fit with the inside of the rectangular frame structure; The rigid plate A is provided with a first grouting hole at a corner close to the elastic plate B and the bottom plate, the rigid plate A is provided with a first back grouting hole at a corner close to the elastic plate B and the top plate, the rigid plate B is provided with a second grouting hole at a corner close to the elastic plate A and the bottom plate, and the rigid plate B is provided with a second back grouting hole at a corner close to the elastic plate A and the top plate, the side wall of the first pressing plate is provided with a first groove and a second groove along the sliding direction of the first pressing plate, the first groove is matched with the first back grouting hole, and the second groove is matched with the second back grouting hole; It also includes a workbench, the mold is installed on the workbench, the bottom plate is arranged downward, the workbench is provided with a second shaft pressing device and a third shaft pressing device, the second shaft pressing device applies positive pressure to the elastic plate A, and the third shaft pressing device applies positive pressure to the elastic plate B.

2. The device for preparing a deep in-situ rock true triaxial specimen with internal stress according to claim 1, characterized in that, The second shaft pressing device includes a second hydraulic cylinder and a second pressing plate, the second hydraulic cylinder is fixedly installed on the workbench, the second pressing plate is fixedly connected with the piston rod end of the second hydraulic cylinder, and the second pressing plate is arranged opposite to the elastic plate A; the third shaft pressing device includes a third hydraulic cylinder and a third pressing plate, the third hydraulic cylinder is fixedly installed on the workbench, the third pressing plate is fixedly connected with the piston rod end of the third hydraulic cylinder, and the third pressing plate is arranged opposite to the elastic plate B.

3. The device according to claim 1, wherein, The mold further includes a mounting frame, the mounting frame is fixedly sleeved at one end of the rectangular frame structure away from the top plate, and the mounting frame is detachably connected with the workbench.

4. The device according to claim 3, wherein, A rectangular hole is formed in the workbench, one end of the bottom plate is provided with a boss, the boss and the rectangular hole are matched with the inner cavity section of the rectangular frame structure, and the boss penetrates through the rectangular hole from bottom to top and extends into the rectangular frame structure; It also includes four tensioning bolts, the screw rod ends of the tensioning bolts sequentially penetrate through the top plate, the mounting frame, the workbench and the bottom plate and are threadedly connected with nuts, and the four tensioning bolts are arranged at four corner positions outside the rectangular frame structure.

5. The internal stress containing deep in-situ rock true triaxial preparation device according to claim 1, characterized in that, The workbench is provided with a first force bearing plate and a second force bearing plate, the first force bearing plate abuts against the rigid plate A, and the second force bearing plate abuts against the rigid plate B.

6. A device for preparing a deep in-situ rock true triaxial specimen with internal stress according to claim 5, characterized in that, The first and second force receiving plates are in sliding connection with the workbench, and the first and second force receiving plates are pressed against the rigid plates A and B by the end portions of the first and second jacking screws, respectively.

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