Testing system and testing method for revealing the action mechanism of in-situ stress on large deformation of rock mass

Abstract

The present invention belongs to a in-situ stress testing system, and discloses a testing system and a testing method for revealing the action mechanism of in-situ stress in large-deformation rock masses, which includes a drill pipe, a drill bit, a plugging test head, and a water pump system; the drill bit or the plugging test head can be installed on the drill pipe; the plugging test head includes a connecting column mechanism, a pressure sensor, an image observation device, and a water injection head; the connecting column mechanism includes a connecting column and fixing disks respectively arranged at both ends thereof, and a front plugging head and a rear plugging head are respectively arranged on the two fixing disks; the two plugging heads form a top support and fixing relationship with the inner wall surface of the test hole by means of arc-shaped outer support members, and are further sealed by injecting water into and expanding the water injection expansion rubber ring; the water pump system is used for pressurizing and injecting water into the water injection expansion rubber ring and testing the water pressure fracturing value in the plugging test head. The advantages of the present invention are: a position top support and fixing relationship with the inner wall surface of the test hole is formed by means of arc-shaped outer support members, and the water injection and expansion sealing work of the water injection expansion rubber ring and the testing of the water pressure fracturing value are completed by using the same water pump system.

Description

Technical Field

[0001] The present invention belongs to a in-situ stress testing system, and particularly relates to a testing system and a testing method for revealing the action mechanism of in-situ stress of large deformation of rock mass. Background Art

[0002] Rock mass is a geological body that was in a relatively balanced state before human engineering and economic activities, and has undergone deformation and damage during the geological history process, with a certain material composition and structure and existing in a certain stress field. For rock mass, the stress field is both an organic part of the rock mass and its existing environment, but is generally treated as the existing environment. Gravity, temperature and tectonic movement are the main causes of in-situ stress, among which the horizontal tectonic movement has the greatest influence on the formation and characteristics of in-situ stress.

[0003] The hydraulic fracturing method is one of the recommended methods for measuring rock mechanics, and is currently the most reliable and direct method for measuring deep stress. This method is relatively simple to operate, the measured values are reliable, and multiple or repeated measurements can be carried out. It uses an expansion packer to seal a section of the borehole at a known depth, and then pressurizes the measured section by pumping in fluid. The horizontal principal stress value is determined using the recorded breakdown pressure, instantaneous shut-in pressure and reopening pressure. At present, the main drawback is that the sealing and anti-seepage of the expansion packer are difficult to achieve an ideal level and cannot adapt to rock mass under high pressure. Summary of the Invention

[0004] The purpose of the present invention is to provide a testing system and a testing method for revealing the action mechanism of in-situ stress of large deformation of rock mass according to the deficiencies of the above-mentioned prior art. The testing system realizes preliminary positioning and sealing on the rock mass wall surface of the test hole by setting a radially movable arc-shaped outer support on the plugging test head, and further realizes final sealing by injecting water into and expanding a water injection and expansion rubber ring preset in the groove of the arc-shaped outer support, so as to adapt to the fracturing test under high water pressure.

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

[0006] A testing system for revealing the action mechanism of in-situ stress of large deformation of rock mass, comprising a drill pipe, a drill bit, a plugging test head, a water pump system and a calculation and control terminal; wherein:

[0007] During the stage of drilling the test hole, the front end of the drill pipe is detachably installed with the drill bit to drill the test hole in the rock mass of the tunnel face; during the hydraulic fracturing test stage, the front end of the drill pipe is detachably installed with the plugging test head;

[0008] The plugging test head includes a front plugging head, a rear plugging head, a connecting column mechanism, a pressure sensor, an imaging observation device, and a water injection head; the connecting column mechanism includes a connecting column and a front fixing plate and a rear fixing plate respectively disposed at both ends of the connecting column; the front plugging head is disposed on the front fixing plate, and the rear plugging head is disposed on the rear fixing plate; the pressure sensor, the imaging observation device, and the water injection head are disposed on the connecting column;

[0009] The front plugging head and the rear plugging head have the same structure; the front plugging head includes a rotating disk, a central rotating shaft, a driving mechanism, an arc-shaped guide groove, a radial follower stud, a sliding block, and a sliding groove. The central rotating shaft is disposed at the center of the rotating disk and is driven to rotate by the driving mechanism. The number of the arc-shaped guide grooves is three and they are evenly distributed on the rotating disk at equal angles. The trajectory of the arc-shaped guide groove has a change from near to far in the radial distance from the central rotating shaft; the sliding groove is arranged radially and fixed on the front fixing plate. The sliding block is arranged behind the rotating disk and is slidably assembled on the sliding groove. The radial follower stud is inserted into the arc-shaped guide groove and the lower end thereof is connected to the radial inner end of the sliding block. An arc-shaped outer support member is arranged at the radial outer end of the sliding block, and a water injection expansion rubber ring is embedded in the outer groove of the arc-shaped outer support member;

[0010] The water pump system includes a water storage tank, a booster water pump, and a pump water pipeline; the water inlet of the booster water pump is connected to the water storage tank, and the water outlet of the booster water pump is connected to the pump water pipeline; the pump water pipeline includes a main pump water pipe and three pump water branch pipes branched from the main pump water pipe. The three pump water branch pipes are respectively connected to the water injection head, the water injection expansion rubber ring on the front plugging head, and the water injection expansion rubber ring on the rear plugging head;

[0011] The calculation and control terminal is connected to control the booster water pump, the pressure sensor, and the imaging observation device.

[0012] The driving mechanism includes an electric telescopic rod mechanism and a straight rack. The electric telescopic rod mechanism is fixed on the front fixing plate. The teeth on the straight rack are engaged with the circular gear at the rear end of the central rotating shaft. The electric telescopic rod mechanism drives the straight rack to make a reciprocating motion to drive the circular gear and the central rotating shaft to rotate.

[0013] The number of the sliding blocks on the front plug is the same as that of the arc-shaped guide grooves, both being three groups. The three arc-shaped outer braces on the radially outer ends of the three groups of sliding blocks jointly enclose to form an annular outer brace at the minimum radial stroke. When each arc-shaped outer brace moves radially outward along with the sliding block and abuts against the inner wall surface of the test hole, water is injected into the water injection expansion rubber ring through the water pump branch pipe to be pressurized and expanded to abut against the inner wall of the test hole to form a completely closed seal.

[0014] A rotary support is arranged at the central position of the front fixing disk and is connected to the rear end of the central rotating shaft. The rear end of the central rotating shaft rotates on the rotary support and is axially limited.

[0015] A protective cover is sleeved on the front end of the central rotating shaft of the front plug. The center of the protective cover has a sleeve tube which is correspondingly sleeved on the front end of the central rotating shaft to form a clearance fit. A protective ring extends backward from the outer edge of the protective cover. Three guide rails are arranged on the protective cover and respectively correspond to the positions where the radial follower studs are arranged. The guide rails are in a slope shape within the radial movement path of the radial follower studs. The slope shape of the guide rails means that they extend from high to low in the radial direction so as to enable the whole protective cover to move radially outward from the inside along with the radial follower studs. Under the guidance of the guide rails, the protective cover gradually extends upward.

[0016] A rotary support is arranged at the central position of the rear fixing disk and is connected to one end of the central rotating shaft of the rear plug. The end of the central rotating shaft of the rear plug rotates on the rotary support and is axially limited.

[0017] A limiting ring groove is formed in the other end of the central rotating shaft of the rear plug. A limiting inner convex ring is arranged at the front end of the drill rod. By assembling the limiting inner convex ring of the drill rod into the limiting ring groove, the relative rotation and axial limitation between the central rotating shaft of the rear plug and the drill rod are realized.

[0018] A test method for a test system related to any of the test systems for revealing the mechanism of in-situ stress action of large rock mass deformation, the test method comprising the following steps:

[0019] S1: Install a drill bit at the front end of the drill rod and drill obliquely upward on the tunnel face to form a test hole in the rock mass;

[0020] S2: After completing the drilling of the test hole, remove the drill bit from the drill pipe, install a plugging test head at the front end of the drill pipe, and then push the drill pipe and the plugging test head into the designated depth of the test hole. After pushing into place, control the arc-shaped outer support on the front plugging head to move radially until it forms a top support contact with the inner wall surface of the test hole, and control the arc-shaped outer support on the rear plugging head to move radially until it also forms a top support contact with the inner wall surface of the test hole.

[0021] S3: Use a booster water pump to pressurize and pump the water in the water storage tank through the pump water pipeline. The pump water pipeline pumps water to three pump water branch pipes respectively. Two of the pump water branch pipes inject water into the water injection expansion rubber rings on the front plugging head and the rear plugging head respectively to expand and fill the gaps to form a complete seal. The remaining one pump water branch pipe injects water into the cavity of the plugging test head through the water injection head and continuously pressurizes until cracks occur on the inner wall surface of the test hole surrounded by the plugging test head. Record the occurrence time of the cracks through an image observation device and record the pressure value when the cracks occur through a pressure sensor.

[0022] The advantages of the present invention are:

[0023] (1) Form a position top support fixation and preliminary seal between the arc-shaped outer support and the inner wall surface of the test hole rock mass, and further realize the final seal between the arc-shaped outer support and the inner wall surface of the test hole rock mass by injecting water into the water injection expansion rubber ring preset in the groove of the arc-shaped outer support, so as to adapt to the high water pressure fracture test.

[0024] (2) The same water pump system can be used to complete the water injection expansion sealing work of the water injection expansion rubber ring and the test of the water pressure fracture value in the cavity of the plugging test head.

[0025] (3) A protective cover is sleeved on the front plugging head. Before working, the protective cover can cover the components on the front plugging head to prevent them from being collided during the process of extending into the test hole, and can rise synchronously when the arc-shaped outer support expands outward to avoid blocking the moving path of the arc-shaped outer support. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of installing a drill bit on the drill pipe and drilling a test hole on the tunnel face in the present invention;

[0027] Figure 2 It is a schematic diagram of conducting a water pressure fracture test on the drill pipe installed with a plugging test head to obtain the in-situ stress value in the present invention;

[0028] Figure 3 It is a schematic diagram of the plugging test head in the present invention;

[0029] Figure 4Schematic diagram of the front end face of the front plugging head in the present invention (the protective cover is omitted);

[0030] Figure 5 Schematic diagram of the rotation of the rotating disk on the front plugging head in the present invention to drive the radial follower stud and the associated sliding block and arc-shaped outer support member to move radially outward;

[0031] Figure 6 Schematic diagram of the further water injection and expansion of the water injection expansion rubber ring by the arc-shaped outer support member on the front plugging head after moving radially outward to fit and seal with the inner wall surface of the test hole;

[0032] Figure 7 Schematic diagram of the rear end face of the front plugging head in the present invention;

[0033] Figure 8 For the present invention Figure 7 Cross-sectional view A0A;

[0034] Figure 9 Schematic diagram of the process of the protective cover provided on the front plugging head being lifted under the drive of the radial follower stud;

[0035] Figure 10 Schematic diagram of the process of the water injection expansion rubber ring expanding and sealing in the present invention.

[0036] As Figures 1-10 , the respective markings in the figure are:

[0037] Tunnel 1, heading face 2, drill pipe 3, drill bit 4, plugging test head 5, water storage tank 6, booster pump 7, calculation and control terminal 8, pump water pipeline 9;

[0038] Front plugging head 51, rotating disk 511, first central rotating shaft 512, arc-shaped guide groove 513, radial follower stud 514, sliding block 515, sliding groove 516, arc-shaped outer support member 517, water injection expansion rubber ring 518, electric telescopic rod mechanism 519a, straight rack 519b;

[0039] Rear plugging head 52, second central rotating shaft 521;

[0040] Connecting column mechanism 53, connecting column 531, front fixing disk 532, rear fixing disk 533;

[0041] Protective cover 54, cover plate 541, sleeved cylinder 542, guide rail 543, protective ring 544;

[0042] Pressure sensor 55;

[0043] Imaging observation device 56;

[0044] Water injection head 57. Detailed implementation manners

[0045] The features of the present invention and other related features will be further described in detail below in conjunction with the accompanying drawings through embodiments for the understanding of those skilled in the same industry:

[0046] Embodiment: As Figures 1-10 shown, this embodiment specifically relates to a test system and a test method for revealing the mechanism of in-situ stress action in large deformation of rock masses. The test system includes a drill pipe 3, a drill bit 4, a plugging test head 5, a water pump system, and a calculation and control terminal 8.

[0047] As Figure 1 , 2 shown, in the stage of drilling a test hole, the front end of the drill pipe 3 is detachably installed with the drill bit 4 to drill a test hole in the rock mass of the working face 2 of the tunnel 1; in the stage of hydraulic fracturing test, the front end of the drill pipe 3 is detachably installed with the plugging test head 5.

[0048] As Figures 1-10 shown, the plugging test head 5 includes a front plugging head 51, a rear plugging head 52, a connecting column mechanism 53, a pressure sensor 55, an image observation device 56, and a water injection head 57; the connecting column mechanism 53 includes a connecting column 531 and a front fixing disk 532 and a rear fixing disk 533 respectively arranged at both ends of the connecting column 531. The diameters of the front fixing disk 532 and the rear fixing disk 533 should ensure that they are smaller than the aperture of the test hole; the front plugging head 51 is arranged on the front fixing disk 532, and the rear plugging head 52 is arranged on the rear fixing disk 533; the pressure sensor 55, the image observation device 56, and the water injection head 57 are all arranged at different positions on the connecting column 531. It should be noted that a test cavity of the plugging test head 5 is formed under the enclosure of the front plugging head 51 and the rear plugging head 52.

[0049] As Figures 1-10 shown, the front plugging head 51 includes a rotating disk 511, a first central rotating shaft 512, a driving mechanism, an arc-shaped guide groove 513, a radial follower stud 514, a sliding block 515, and a sliding groove 516. The first central rotating shaft 512 is fixedly arranged at the center of the rotating disk 511 and is driven to rotate (reciprocating rotation) by the driving mechanism. The number of the arc-shaped guide grooves 513 is three groups and they are evenly distributed at equal angles on the rotating disk 511. The trajectory of the arc-shaped guide groove 513 has a change from near to far in the radial distance from the first central rotating shaft 512; the sliding groove 516 is arranged radially and fixed on the front fixing disk 532. The sliding block 515 is arranged behind the rotating disk 511 and is slidably assembled on the sliding groove 516. The radial follower stud 514 is inserted into the arc-shaped guide groove 513 and the lower end is connected to the radial inner end of the sliding block 515. An arc-shaped outer support member 517 is arranged at the radial outer end of the sliding block 515, and a water injection expansion rubber ring 518 is embedded in the outer groove of the arc-shaped outer support member 517.

[0050] As Figures 1-10As shown in the figure, the driving mechanism includes an electric telescopic rod mechanism 519a and a straight rack 519b. The electric telescopic rod mechanism 519a is fixed on the front fixed disk 532. The teeth on the straight rack 519b are meshed with the circular gear on the rear end of the first central rotating shaft 512. The electric telescopic rod mechanism 519a drives the straight rack 519b to reciprocate, so as to drive the circular gear and the first central rotating shaft 512 to rotate. The first central rotating shaft 512 can drive the rotating disk 511 to rotate synchronously.

[0051] As Figures 1-10 As shown in the figure, the number of sliding blocks 515 on the front plug 51 is the same as that of the arc-shaped guide grooves 513, both being three groups. The three arc-shaped outer support members 517 on the radially outer ends of the three groups of sliding blocks 515 jointly enclose a ring-shaped outer support member at the minimum radial stroke, and the arc-shaped outer support members 517 are in contact with each other; when each arc-shaped outer support member 517 moves radially outward with the sliding block 515 and abuts against the inner wall surface of the test hole, water is injected into the water injection expansion rubber ring 518 through the water pump branch pipe to be pressurized and expanded to abut against the inner wall of the test hole to form a completely closed seal.

[0052] It should be noted that the structures of the front plug 51 and the rear plug 52 are the same, so the structure of the rear plug 52 will not be described in detail. The main difference between the two is the connection structure between the second central rotating shaft 521 in the rear plug 52 and the front end of the drill pipe 3. A rotating support is arranged at the central position of the rear fixed disk 533 and is connected to one end of the second central rotating shaft 521 of the rear plug 52. The end of the second central rotating shaft 521 rotates on the rotating support and is axially limited. A limiting ring groove is provided at the other end of the second central rotating shaft 521 of the rear plug 52, and a limiting inner convex ring is provided at the front end of the drill pipe 3. By assembling the limiting inner convex ring of the drill pipe 3 into the limiting ring groove, the relative rotation and axial limit between the second central rotating shaft 521 of the rear plug 52 and the drill pipe 3 are realized.

[0053] In addition, in order to provide protection during the process of inserting the plugging test head 5 into the test hole, a protective cover 54 is further provided at the front end of the first central rotating shaft 512 of the front plugging head 51. A sleeve 542 is provided at the center of the cover plate 541 of the protective cover 54 and is correspondingly sleeved on the front end of the first central rotating shaft 512 to form a clearance fit. A protective ring 544 extends backward from the outer edge of the cover plate 541. Three guide rails 543 are provided on the cover plate 541 and respectively correspond to the positions where the radially follower studs 514 are arranged. The guide rails 543 are in a slope shape within the radial movement path of the radially follower studs 514. The slope shape of the guide rails 543 means that they extend from high to low in the radial direction from inside to outside, so as to enable the overall protective cover 54 to move radially from inside to outside along with the radially follower studs 514. Under the guidance of the guide rails 543, the protective cover 54 is gradually pushed upward to make way for the radial outward movement of the arc-shaped outer support member 517. A rotating support is provided at the central position of the front fixing plate 532 and is connected to the rear end of the first central rotating shaft 512. The rear end of the first central rotating shaft 512 rotates on the rotating support and is axially limited.

[0054] As Figures 2-9 shown, the water pump system includes a water storage tank 6, a booster water pump 7, and a pump water pipeline 9; the water inlet of the booster water pump 7 is connected to the water storage tank 6, and the water outlet of the booster water pump 7 is connected to the pump water pipeline 9; the pump water pipeline 9 includes a main pump water pipe and three branched pump water pipes branched from the main pump water pipe, and the three branched pump water pipes are respectively connected to the injection head 57, the injection expansion rubber ring 518 on the front plugging head 51, and the injection expansion rubber ring on the rear plugging head 52. In addition, the calculation control terminal 8 is connected to control the booster water pump 7, the pressure sensor 55, and the image observation device 56.

[0055] As Figures 1-10 shown, the test method of the test system for revealing the test system of the large deformation in-situ stress action mechanism of rock mass in this embodiment includes the following steps:

[0056] S1: Install a drill bit 4 at the front end of the drill pipe 3 and drill obliquely upward on the tunnel face 2 of the tunnel 1 to form a test hole in the rock mass.

[0057] S2: After the drilling of the test hole is completed, remove the drill bit 4 from the front end of the drill pipe 3, install the plugging test head 5 at the front end of the drill pipe 3, and then push the drill pipe 3 and the plugging test head 5 into the designated depth of the test hole; after pushing and positioning, control the arc-shaped outer support member 517 on the front plugging head 51 to move radially until it forms a top support contact with the inner wall surface of the test hole, and control the arc-shaped outer support member 517 on the rear plugging head 52 to move radially until it also forms a top support contact with the inner wall surface of the test hole, so as to form a preliminary fixed position and preliminary seal.

[0058] S3: The water in the water storage tank 6 is pressurized and pumped through the pump water pipeline 9 by the booster pump 7. The pump water pipeline 9 pumps water to three pump water branch pipes respectively. Two of the pump water branch pipes inject water into and expand the water injection expansion rubber rings 518 on the front plug 51 and the water injection expansion rubber rings on the rear plug 52 respectively to fill the gaps and form a complete seal. The remaining one pump water branch pipe injects water into the cavity of the plugging test head 5 through the water injection head 57 and continuously pressurizes until cracks occur on the inner wall surface of the test hole enclosed by the plugging test head 5. The imaging observation device 56 records the occurrence time of the cracks and the pressure sensor 55 records the pressure value at the time of crack occurrence.

[0059] The beneficial effects of the present invention are as follows:

[0060] (1) The arc-shaped outer support member is used to form position support fixation and preliminary sealing with the inner wall surface of the test hole rock mass, and further, the water injection expansion rubber ring preset in the groove of the arc-shaped outer support member is injected with water to expand to achieve the final sealing with the inner wall surface of the test hole rock mass, adapting to the high water pressure fracture test;

[0061] (2) The same water pump system can be used to complete the water injection and expansion sealing work of the water injection expansion rubber ring and the test of the water pressure fracture value in the cavity of the plugging test head;

[0062] (3) A protective cover is sleeved on the front plug. Before working, the protective cover can cover the components on the front plug to prevent them from being collided during the process of extending into the test hole, and can rise synchronously when the arc-shaped outer support member expands outward to avoid blocking the moving path of the arc-shaped outer support member.

Claims

1. A test system for revealing the mechanism of in-situ stress action on large deformation of rock mass, characterized in that The described test system includes a drill pipe, a drill bit, a plugging test head, a water pump system, and a calculation and control terminal; where: In the stage of drilling a test hole, the front end of the drill pipe is detachably installed with the drill bit to drill the test hole in the rock mass of the tunnel face; in the stage of hydraulic fracturing test, the front end of the drill pipe is detachably installed with the plugging test head; The plugging test head includes a front plugging head, a rear plugging head, a connecting column mechanism, a pressure sensor, an image observation device, and a water injection head; the connecting column mechanism includes a connecting column and a front fixing plate and a rear fixing plate respectively arranged at both ends of the connecting column; the front plugging head is arranged on the front fixing plate, and the rear plugging head is arranged on the rear fixing plate; the pressure sensor, the image observation device, and the water injection head are arranged on the connecting column; The structures of the front plugging head and the rear plugging head are the same; the front plugging head includes a rotating disk, a central rotating shaft, a driving mechanism, an arc-shaped guide groove, a radial follower stud, a sliding block, and a sliding groove. The central rotating shaft is arranged at the center of the rotating disk and is driven to rotate by the driving mechanism. The number of the arc-shaped guide grooves is three and they are evenly distributed at equal angles on the rotating disk. The trajectory of the arc-shaped guide groove has a change from near to far in the radial distance from the central rotating shaft; the sliding groove is arranged radially and fixed on the front fixing plate. The sliding block is arranged behind the rotating disk and is slidably assembled on the sliding groove. The radial follower stud is inserted into the arc-shaped guide groove and the lower end is connected to the radial inner end of the sliding block. An arc-shaped outer support member is arranged at the radial outer end of the sliding block, and a water injection and expansion rubber ring is embedded in the outer groove of the arc-shaped outer support member; the arc-shaped outer support member moves radially until it forms a top support contact with the inner wall surface of the test hole; The water pump system includes a water storage tank, a booster water pump, and a pump water pipeline; the water inlet of the booster water pump is connected to the water storage tank, and the water outlet of the booster water pump is connected to the pump water pipeline; the pump water pipeline includes a main pump water pipe and three pump water branch pipes branched from the main pump water pipe. The three pump water branch pipes are respectively connected to the water injection head, the water injection and expansion rubber ring on the front plugging head, and the water injection and expansion rubber ring on the rear plugging head; The calculation and control terminal is connected to control the booster water pump, the pressure sensor, and the image observation device; The driving mechanism includes an electric telescopic rod mechanism and a straight rack. The electric telescopic rod mechanism is fixed on the front fixing plate. The teeth on the straight rack are meshed with the circular gear at the rear end of the central rotating shaft. The electric telescopic rod mechanism drives the straight rack to make a reciprocating motion to drive the circular gear and the central rotating shaft to rotate; A rotating support is arranged at the central position of the front fixing plate and is connected to the rear end of the central rotating shaft. The rear end of the central rotating shaft rotates on the rotating support and is axially limited; A protective cover is sleeved on the front end of the central rotating shaft of the front plugging head. The center of the protective cover has a sleeving cylinder which is correspondingly sleeved on the front end of the central rotating shaft to form a clearance fit. A protective ring extends backward on the outer edge of the protective cover. Three guide rails are arranged on the protective cover and respectively correspond to the arrangement positions of the radial follower studs. The guide rails are in a slope shape within the radial movement path of the radial follower studs. The slope shape of the guide rails means that they extend from high to low in the radial direction, so as to enable the whole protective cover to move radially from the inside to the outside along with the radial follower studs, and the protective cover is gradually pushed upward under the guidance of the guide rails. The number of the sliding blocks on the front plugging head is the same as that of the arc-shaped guide grooves, both being three groups. Three arc-shaped outer support members on the radially outer ends of the three groups of sliding blocks jointly enclose a ring-shaped outer support member at the minimum radial stroke. When each arc-shaped outer support member moves radially outward along with the sliding block and abuts against the inner wall surface of the test hole, water is injected into the water injection expansion rubber ring through the water pump branch pipe to be pressurized and expanded to abut against the inner wall of the test hole to form a completely closed seal.

2. The test system for revealing the ground stress action mechanism of large deformation of rock mass according to claim 1, wherein A rotary support is arranged at the center of the rear fixed disk and is connected to one end of the central rotating shaft of the rear plugging head. The end of the central rotating shaft of the rear plugging head rotates on the rotary support and is axially limited.

3. The test system for revealing the in-situ stress action mechanism of large rock mass deformation according to claim 2, characterized in that A limiting ring groove is opened at the other end of the central rotating shaft of the rear plugging head. A limiting inner convex ring is arranged at the front end of the drill pipe. By assembling the limiting inner convex ring of the drill pipe into the limiting ring groove, the relative rotation and axial limitation between the central rotating shaft of the rear plugging head and the drill pipe are realized.

4. A testing method for a testing system related to the mechanism of in-situ stress action revealing large deformation of rock masses as described in any one of claims 1-3, characterized in that The test method includes the following steps: S1: Install a drill bit at the front end of the drill pipe and drill obliquely upward on the tunnel face to form a test hole in the rock mass. S2: After the drilling of the test hole is completed, remove the drill bit from the drill pipe, install a plugging test head at the front end of the drill pipe, and then push the drill pipe and the plugging test head into the specified depth of the test hole. After being pushed in place, control the arc-shaped outer support member on the front plugging head to move radially until it abuts against the inner wall surface of the test hole, and control the arc-shaped outer support member on the rear plugging head to move radially until it also abuts against the inner wall surface of the test hole. S3: Use a booster water pump to pressurize and pump the water in the water storage tank through the pump water pipeline. The pump water pipeline pumps water to three water pump branch pipes respectively. Two of the water pump branch pipes respectively inject water into the water injection expansion rubber rings on the front plugging head and the rear plugging head to be expanded to fill the gaps to form a completely sealed state. The remaining one water pump branch pipe injects water into the cavity of the plugging test head through a water injection head and continuously pressurizes until cracks occur on the inner wall surface of the test hole enclosed by the plugging test head. Record the occurrence time of the cracks through an image observation device and record the pressure value at the time of crack occurrence through a pressure sensor.

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