True triaxial rock-soil mass test device and test method therefor

Abstract

A true triaxial rock-soil mass test device and a test method therefor, the test device comprising a triaxial loading module, wherein the triaxial loading module comprises a triaxial servo loading syst

Description

[0001] The present disclosure relates to the technical field of mining engineering testing devices, and in particular, to a true triaxial testing device for rock and soil masses and a testing method therefor. BACKGROUND

[0002] With the development of economy, the requirement for the energy source is increasing. The mining depth of coal, which is a main energy source of China, has been increased gradually. The deeper the position of the rock mass, the greater the stress which the rock mass is subjected to, and stress concentration results in severe rock crushing. The grouting technology is a direct and effective means for reinforcing engineering and preventing seepage and leakage. The hydraulic fracturing technology is a powerful measure for pressure relief mining, gas extraction, and surrounding rock maintenance. Before specific construction, relevant tests need to be performed, so as to ensure safety and accuracy. In-situ tests are difficult to be performed due to limitations of equipment and the like, and performing laboratory tests on the rock mass at the deeper position is the most economical and reasonable means. An existing related first patent (Application Publication NO. CN115308043 A) provides a thermally variable testing system for splitting grouting, in which the formation temperature is simulated by heating the slurry and the rock block, and the main research is on the problem of splitting grouting. However, the current grouting method is mainly permeation grouting. The testing system cannot simultaneously perform grouting and pressurization on the clastic material, so that the testing object is relatively simple and has a certain limitation. Second patent (Patent Publication NO. CN11163817IB) provides a three-way loading rock splitting grouting system, which considers the splicing of regular small rock pieces into a large regular fractured rock mass, but the data show that most fractures are distributed unevenly and the rock mass is anisotropic, so that the influence of a wider range of clastic material grouting and stress environments on the grouting effect should be taken into consideration. Third patent (Patent Publication NO. CN109882183B) provides a grouting testing device for a water-rich loose fractured coal rock mass, but the triaxial pressurization method used is a false triaxial, which cannot better simulate the influence of the real condition of the formation and the confining pressure difference in the test on the diffusion range and the reinforcing effect of the grouting.

[0003] However, in terms of functionality, the current rock mass testing equipment is generally single triaxial grouting equipment or triaxial hydraulic fracturing equipment, and the testing equipment has a single functionality. With regard to the rock mass integrity, currently, many rock masses are integral standard testing specimens, and there are few testing equipment capable of performing neither triaxial hydraulic fracturing and grouting tests on the integral rock mass nor triaxial grouting tests on the clastic material, and the testing equipment has poor adaptability to the rock mass. With regard to the grouting equipment for the clastic material, most of the grouting equipment adopts the testing methods such as open and non-pressurized and false triaxial, resulting in a relatively large different between the tests and the engineering field, and the testing results with the reduced cogency. SUMMARY

[0004] The objective of the present disclosure is to provide a true triaxial testing device for rock and soil masses and a testing method therefor, so as to solve the problems described above existing in the prior art, and to be able to perform a triaxial grouting test and a triaxial hydraulic fracturing test, so that not only a true triaxial hydraulic fracturing test and a true triaxial grouting test can be performed on an integral rock mass, but also a true triaxial grouting test can be performed on a clastic material.

[0005] To achieve the above objective, the present disclosure provides the following solutions:

[0006] The present disclosure provides a true triaxial testing device for rock and soil masses, including: a triaxial loading module including a triaxial servo loading system and a triaxial bearing system, in which the triaxial servo loading system is configured for applying pressures in an X direction, a Y direction and a Z direction to the triaxial bearing system; a grouting module communicated with a grouting-fracturing pipe in the triaxial bearing system via a pipeline; a hydraulic fracturing module communicated with the grouting-fracturing pipe in the triaxial bearing system via a pipeline; and a data acquisition and analysis module communicated with an ultrasonic transmission sensor and an ultrasonic receiving sensor provided in the triaxial bearing system via a line.

[0007] Optionally, the triaxial bearing system includes a cubic structure enclosed by a plurality of pressure bearing plates, a triaxial pressure bearing cavity is formed in the triaxial bearing system, and the pressure bearing plates are fixed to positioning grooves inside a square shaping frame; a grouting-fracturing orifice is provided at a center of a pressure bearing plate of the pressure bearing plates in a X-axis direction, and a grouting-fracturing pipe penetrates through the grouting-fracturing orifice; a feed inlet is provided on a pressure bearing plate of the pressure bearing plates in a Z-axis direction, and a sealing plug is fixedly and hermetically provided at the feed inlet; the triaxial servo loading system includes an X-axis oil cylinder, a Y-axis oil cylinder and a Z-axis oil cylinder, in which the X-axis oil cylinder, the Y-axis oil cylinder and the Z-axis oil cylinder are respectively externally communicated with an X-axis servo loading pump, a Y-axis servo loading pump and a Z-axis servo loading pump via pipelines, and the X-axis servo loading pump, the Y-axis servo loading pump and the Z-axis servo loading pump are externally communicated with a main oil pump via a pipeline; a base is provided at a bottom of the triaxial bearing system, and a longitudinal limitation frame is sleeves the triaxial bearing system, the longitudinal limitation frame includes a top plate horizontally arranged at a top of the triaxial bearing system, and vertical plates are fixedly provided at two ends of the top plate, a bottom of each of the vertical plates is fixedly arranged on the base, and a lateral limitation frame with a rectangular cross section sleeves the triaxial bearing system, a bottom of the lateral limitation frame is connected to the base via a lifting support; the X-axis oil cylinder is fixed on the lateral limitation frame, the Y-axis oil cylinder and the Z-axis oil cylinder are fixed on the longitudinal limitation frame, and an upper surface of the base is provided with a groove.

[0008] Optionally, the grouting module includes a slurry mixing-stirring tank; a pre-embedded grouting-fracturing pipe is provided inside the triaxial pressure bearing cavity, the pre-embedded grouting-fracturing pipe is connected to one end of the grouting-fracturing pipe via a first switch, and one end of the grouting-fracturing pipe away from the first switch is communicated with the slurry mixing-stirring tank via a pipeline and a second switch; the slurry mixing-stirring tank is communicated with a high-pressure air storage pump via a pipeline and a third switch.

[0009] Optionally, the hydraulic fracturing module includes a pressure-bearing water storage tank; the end of the grouting-fracturing pipe away from the first switch is communicated with the pressure-bearing water storage tank via a pipeline and the second switch; the pressure-bearing water storage tank is communicated with the high-pressure air storage pump via a pipeline and the third switch; the second switch and the third switch are both three-way switches; each of the second switch and the third switch has a three-speed knob, in which a middle state of the three-speed knob is a closed state; a fracturing line communicated with the pressure-bearing water storage tank is opened as the three-speed knob is turned to left, and a grouting line communicated with the slurry mixing-stirring tank is opened as the three-speed knob is turned to right; an electronic flowmeter is provided at an outlet of the second switch, and a pressure stabilizing valve is provided at an outlet of the third switch.

[0010] Optionally, the data acquisition and analysis module includes an ultrasonic probe, an ultrasonic transceiver, a flow meter, an operating system and a data storage centre; in which an array of the ultrasonic probe is embedded into a pressure bearing plate of the pressure bearing plates in a Y-axial direction in the triaxial pressure bearing cavity, data of the ultrasonic transmission sensor and the ultrasonic receiving sensor are transmitted to a data processing centre via a line, and the processed data is transmitted to the data storage centre via a line; the operating system is able to control pressures of the X-axis servo loading pump, the Y-axis servo loading pump and the Z-axis servo loading pump, acquire ultrasonic data to form an image, set an injection pressure, and acquire data of accumulated injection flow.

[0011] Optionally, the sealing plug includes a thread, a hexagonal groove, a sealing ring, and a rigid sealing plug; the hexagonal groove is provided at a top of the rigid sealing plug, the thread is formed on an upper part of an outer wall of the rigid sealing plug, two circles of grooves are formed on a lower part of the outer wall of the rigid sealing plug, the sealing ring is arranged in each of the two circles of grooves, and a hexagonal tension wrench is able to be clamped inside the hexagonal groove.

[0012] Optionally, the hexagonal tension wrench includes a rigid main body, a rotating handle is fixedly connected to an upper part of the rigid main body, a hexagonal protrusion is fixedly provided at a bottom of the rigid main body, and the hexagonal protrusion is able to be clamped into the hexagonal groove.

[0013] The present discourse further provides a testing method for a true triaxial testing device for rock and soil masses, including a grouting testing method for clastic materials, in which the grouting testing method for clastic materials includes following steps:

[0014] SI, preparing clastic materials fitting a practical field, detecting operating conditions of a testing device to ensure that the testing device is able to operate stably and safely;

[0015] S2, unscrewing and taking out a sealing plug sealing a feed inlet at a top by means of a hexagonal tension wrench; at the same time, fixing a pre-embedded grouting-fracturing pipe onto a grouting-fracturing orifice via a screw, and externally connecting the pre-embedded grouting-fracturing pipe to a first switch and a grouting-fracturing pipe; loading each of pressure bearing plates on six sides of a triaxial pressure bearing cavity into an initial position thereof, keeping the triaxial pressure bearing cavity sealed, thereby ensuring that the clastic materials are not be squeezed out during a process of being pressurized;

[0016] S3, feeding the prepared clastic materials into the triaxial pressure bearing cavity through the feed inlet until the clastic materials fill the whole triaxial pressure bearing cavity, and then tightening the sealing plug by means of the hexagonal tension wrench to block the feed inlet, so as to seal an interior of the triaxial pressure bearing cavity;

[0017] S4, preparing a required slurry in a slurry mixing-stirring tank in a pre-set slurry ratio, sealing the slurry mixing-stirring tank after the preparing step is completed, and the slurry mixing-stirring tank keeps running during the preparing step;

[0018] S5, loading a pressure applied on each of the pressure bearing plates to a pre-set pressure, activating a high-pressure gas storage pump, in which a gas storage pressure of the high-pressure gas storage pump is greater than a pre-set grouting pressure, turning a third switch to right to pass a high-pressure gas through the slurry mixing-stirring tank, turning a second switch to right, starting a grouting test, and at the same time, activating a data acquisition and analysis module to acquire data during the grouting test;

[0019] S6, finishing the grouting test after a flow rate of slurry drops to a set range, closing the first switch, turning off the data acquisition and analysis module, sequentially closing the high-pressure gas storage pump, the third switch, the slurry mixing-stirring tank and the second switch, dismounting the grouting-fracturing pipe, cleaning pipelines and the grouting-stirring tank;

[0020] S7, after maintaining the grouted clastic materials in the triaxial pressure bearing cavity for a required period of time, unloading the pressure applied on each of the pressure bearing plates, retracting pressure bearing plates in an X-axis direction and a Y-axis direction, moving a lateral limitation frame into a groove of a base by means of a lifting support, and taking out the reinforced clastic materials;

[0021] S8, after taking out the reinforced clastic materials, cleaning the triaxial pressure bearing cavity, and resetting the testing device to an original state thereof for a next test.

[0022] The testing method further includes a hydraulic fracturing testing method for integral rock masses, in which the hydraulic fracturing testing method for integral rock masses includes the following steps:

[0023] SI, preparing an integral rock mass or a similar rock mass fitting the practical field, detecting operating conditions of the testing device to ensure that the testing device is able to operate stably and safely, lowering a lateral limitation frame to facilitate loading of a testing specimen;

[0024] S2, drilling a drilling hole in a centre of the integral rock mass, fixing a pre-embedded grouting-fracturing pipe in the drilling hole via epoxy resin glue; alternatively, directly embedding the pre-embedded grouting-fracturing pipe in the similar rock mass during the similar rock mass is prefabricated; loading the testing specimen, and moving one of the pressure bearing plates in the X-axis direction to an initial position thereof after the lateral limitation frame is lifted to an initial height thereof, so as to ensure that the pre-embedded grouting-fracturing pipe passes through the grouting-fracturing orifice, and is connected to the first switch, maintaining the first switch in an open state; loading each of the pressure bearing plates on the six surface of the triaxial pressure bearing cavity into an initial position thereof;

[0025] S3, after filling a pressure-bearing water storage tank with water configured for fracturing, keeping the pressure-bearing water storage tank sealed, loading the pressure applied on each of the pressure bearing plates, opening the high-pressure air storage pump, so that the air storage pressure of the high-pressure air storage pump is greater than a pre-set fracturing pressure, setting a flow rate of the water configured for fracturing, turning the third switch to left, so that a high-pressure gas passes through the pressure-bearing water storage tank, turning the second switch to left to start fracturing, and at the same time, activating the data acquisition and analysis module to acquire data during the fracturing;

[0026] S4, completing the fracturing once there is a sudden drop in a fracturing pressure, finishing a hydraulic fracturing test, closing the first switch, turning off the data acquisition and analysis module, sequentially closing the high-pressure air storage pump, the third switch and the second switch;

[0027] S5, saving the data acquired during the hydraulic fracturing test, unloading the pressure applied on each of the pressure bearing plates, retracting one of the pressure bearing plates in the X-axis direction, dismounting the pre-embedded grouting-fracturing pipe from the grouting-fracturing orifice, moving the lateral limitation frame into the groove of the base by means of the lifting support, and taking out the fractured integral rock mass or the fractured similar rock mass;

[0028] S6, taking out the fractured integral rock mass or the fractured similar rock mass, cleaning the triaxial pressure bearing cavity, and resetting the testing device to an original state thereof for a next test.

[0029] The present disclosure realizes the following technical effects with respect to the prior art:

[0030] The present disclosure provides a true triaxial testing device for rock and soil mass having the functions of grouting and hydraulic fracturing, and provides a testing method more fitting to engineering practice for fracturing and grouting of the integral rock mass and clastic rock mass. On the basis of the true triaxial testing device, the grouting module and the hydraulic fracturing module are integrated to form a multifunctional true triaxial testing device for rock masses, which has advantages such as full function, wide use and strong operability. The feed inlet is provided at the top of the testing device to feed the clastic rock mass into the sealed triaxial pressure bearing cavity, so that a triaxial hydraulic fracturing test and a grouting test can be performed on the clastic rock mass, and therefore the testing device is more applicable and functions are completed. A detachable grouting-fracturing pipe is provided, so that pressures of the grouted rock mass can be maintained after the grouting are completed, so as to avoid the reduced cogency caused by different between the tests and the engineering field as change of the stress environment subjected by rock masses, and therefore the testing device has the advantages of being stable and reliable, and strong practicability, etc. By means of monitoring, a monitoring device using an ultrasonic wave has the advantages of being lossless, accurate and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] To describe the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present disclosure, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

[0032] FIG. 1 is an overall structural arrangement diagram of the present disclosure;

[0033] FIG. 2 is a top view of a triaxial bearing cavity;

[0034] FIG. 3 is a left view of the triaxial bearing cavity;

[0035] FIG. 4 is a front view of the triaxial bearing cavity;

[0036] FIG. 5 is an enlarged view of a hexagonal tension wrench and a sealing plug;

[0037] FIG. 6 is an enlarged view of a vicinity of a grouting-fracturing orifice;

[0038] FIG. 7 is an enlarged view of a second switch; and

[0039] FIG. 8 is an enlarged view of a third switch;

[0040] In the drawings: 1-base; 2-lateral limitation frame; 3-pressure bearing plate; 4-square shaping frame; 5-longitudinal limitation frame; 6-hexagonal tension wrench; 7-sealing plug; 8-feed inlet; 9-loading oil cylinder; 10-lifting support; 11-pre-embeded grouting-fracturing pipe; 12-first switch; 13-gronting-fracturing pipe; 14-base groove; 15-second switch; 16-slurry mixing-stirring tank; 17-pressure-bearing water storage tank;18-third switch; 19-high pressure air storage pump; 20-main oil pump; 21-X-axis servo loading pump; 22-Y-axis servo loading pump; 23-Z-axis servo loading pump; 24-data storage center; 25-integrated operation control center; 26-rotating handle; 27-rigid body; 28-hexagonal protrusion; 29-hexagonal groove; 30-rigid sealing plug; 31-screw thread; 32-sealing ring; 33-X-axis pressure bearing plate with grouting-fracturing orifice; 34-sealing connector; 35-second switch outlet; 36-electronic flowmeter; 37-second switch knob; 38-slurry inlet; 39-high-pressure water inlet; 40-slurry mixing-stirring tank interface; 41-pressure-bearing water storage tank interface; 42-third switch knob; 43-high pressure gas inlet; 44-pressure stabilizing valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] The following clearly and completely describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skilled in the art based on the embodiments of the present disclosure without creative efforts shall belong to the scope of the present disclosure.

[0042] The objective of the present disclosure is to provide a true triaxial testing device for rock and soil masses and a testing method therefor, so as to solve the problems described above existing in the prior art, and to be able to perform a triaxial grouting test and a triaxial hydraulic fracturing test, so that not only a true triaxial hydraulic fracturing test and a true triaxial grouting test can be performed on an integral rock mass, but also a true triaxial grouting test can be performed on a clastic material.

[0043] To make the objective, features, and advantages of the present disclosure clearer and more comprehensible, the following further describes the present disclosure in detail with reference to the accompanying drawings and specific embodiments.

[0044] Currently, the rock mass testing equipment is generally single triaxial grouting equipment or triaxial hydraulic fracturing equipment, and the testing equipment has a single functionality. Many rock masses are integral standard testing specimens, and there are few testing equipment capable of performing triaxial hydraulic fracturing and grouting tests on the integral rock mass and triaxial grouting tests on the clastic material, and the testing equipment has poor adaptability to the rock mass. With regard to the grouting equipment for the clastic material, most of the grouting equipment adopts the testing methods such as open and non-pressurized and false triaxial, resulting in a relatively large different between the tests and the engineering field, and the testing results with the reduced cogency. With regard to the triaxial grouting equipment, currently, the triaxial test, due to its sealing property, results in that the grouting pipe and the fracturing pipe are not detachable, so that pressure-maintaining grouting cannot be performed, and when it is needed to perform the pressure-maintaining grouting, the rock mass needs to be taken out after the grouting-fracturing pipe is dismounted, the rock mass then is put into a triaxial stress environment for pressure-maintaining, however, when the grouting test is performed on the fractured rock mass, the grouted rock mass cannot be taken out before the slurry is not yet consolidated, and the grouting pipe is blocked by the slurry after the slurry is consolidated, so that the current triaxial grouting equipment has disadvantages of difficult cleaning and unsustainable test.

[0045] Based on the described disadvantages of the prior art, the present disclosure provides a true triaxial testing device for rock and soil masses, as shown in FIGS. 1-8, including a triaxial loading module, a grouting module, a hydraulic fracturing module and a data acquisition and analysis module, where the triaxial loading module includes a triaxial servo loading system and a triaxial bearing system, the triaxial servo loading system is configured for applying pressures in an X direction, a Y direction and a Z direction to pressure bearing plates of the triaxial bearing system, respectively; the grouting module and the hydraulic fracturing module are communicated with the grouting-fracturing pipe 13 in the triaxial bearing system via pipelines, respectively; the data acquisition and analysis module is communicated with an ultrasonic transmission sensor and an ultrasonic receiving sensor provided in the triaxial bearing system via a pipeline.

[0046] Specifically, the triaxial bearing system in the present disclosure includes a cubic structure enclosed by multiple pressure bearing plates 3, in which a triaxial pressure bearing cavity is formed, the pressure bearing plates 3 are fixed to positioning grooves inside a square shaping frame 4, and a rubber sealing strip is provided on sides of the pressure bearing plate 3; a grouting-fracturing orifice is provided at the centre of a pressure bearing plate 3 in the X-axis direction, forming a X-axis pressure bearing plate 33 with the grouting-fracturing orifice, a sealing connector 34 is provided at an opening of the X-axis pressure bearing plate 33 with the grouting-fracturing orifice, so as to ensure the sealing performance at the opening, and a grouting-fracturing pipe 13 penetrates through the grouting-fracturing orifice; a feed inlet 8 is provided on a pressure bearing plate in the Z-axis direction, a sealing plug 7 is fixedly and hermetically provided at the feed inlet 8, and the sealing plug 7 includes a thread 31, a hexagonal groove 29, sealing rings 32 and a rigid sealing plug 30, in which the hexagonal groove 29 is provided at the top of the rigid sealing plug 30, the thread 31 is formed on the upper part of the outer wall of the rigid sealing plug 30, two circles of grooves are formed on the lower part of the outer wall of the rigid sealing plug 30, the sealing rings 32 is sheathed and filled in the two circles of grooves, the hexagonal groove 29 is provided at the top of the rigid sealing plug 30, and a hexagonal tension wrench 6 may be clamped inside the hexagonal groove 29. The hexagonal tension wrench 6 includes a rigid main body 27, a rotating handle 26 is fixedly connected on the upper part of the rigid main body 27, a hexagonal protrusion 28 is fixedly provided at the bottom of the rigid main body 27, and the hexagonal protrusion 28 can be clamped into the hexagonal groove 29; the triaxial servo loading system includes a loading oil cylinder 9, the loading oil cylinder 9 including an X-axis oil cylinder, a Y-axis oil cylinder and a Z-axis oil cylinder, in which the X-axis oil cylinder, the Y-axis oil cylinder and the Z-axis oil cylinder are respectively externally communicated with an X-axis servo loading pump 21, a Y-axis servo loading pump 22 and a Z-axis servo loading pump 23 via pipelines, and the X-axis servo loading pump 21, the Y-axis servo loading pump 22 and the Z-axis servo loading pump 23 are externally communicated with a main oil pump 20 via pipelines; a base 1 is provided at the bottom of the triaxial bearing system, a longitudinal limitation frame 5 sleeves the triaxial bearing system, and the longitudinal limitation frame 5 includes a top plate horizontally arranged at the top of the triaxial bearing system, vertical plates are fixedly provided at two ends of the top plate, the bottom of the vertical plate is fixedly provided on the base 1, and a lateral limitation frame 2 with a rectangular cross section sleeves the triaxial bearing system, the bottom of the lateral limitation frame 2 is connected to the base 1 via lifting supports 10, and the lower part of the lifting support 10 is connected to the base 1, the top of the lifting support 10 is connected to the lateral limitation frame 2, and the lifting support 10 is distributed at each of the four comers of the lateral limitation frame 2. These lifting supports 10 can be lifted and lowered simultaneously, and the lifting and lowering amplitude thereof is consistent; the X-axis oil cylinder is fixed on the lateral limitation frame 2, the Y-axis oil cylinder and the Z-axis oil cylinder are respectively fixed on the longitudinal limitation frame 5, and the upper surface of the base 1 is provided with a base groove 14 which can be clamped with the bottom of the lateral limitation frame 2.

[0047] The grouting module includes a slurry mixing-stirring tank 16; a pre-embedded grouting-fracturing pipe 11 is provided inside the triaxial pressure bearing cavity, the pre-embedded grouting-fracturing pipe 11 is connected to an interface of a first switch 12 on one side via a thread on a port thereof, an interface of the first switch 12 on the other side is connected to the grouting-fracturing pipe 13 via a thread, and one end of the grouting-fracturing pipe 13 away from the first switch 12 is communicated with the slurry mixing-stirring tank 16 via a pipeline and a second switch 15; the slurry mixing-stirring tank 16 is communicated with a high-pressure air storage pump 19 via a pipeline and a third switch 18; the hydraulic fracturing module includes a pressure-bearing water storage tank 17; the end of the grouting-fracturing pipe away from the first switch is communicated with the pressure-bearing water storage tank 17 via the pipeline and the second switch; the pressure-bearing water storage tank 17 is communicated with the high-pressure air storage pump 19 via a pipeline and the third switch. The second switch 15 and the third switch 18 are both three-way switches, the second switch 15 is communicated with the slurry mixing-stirring tank 16 and the pressure-bearing water storage tank 17 via the slurry inlet 38 and the high-pressure water inlet 39, respectively; the third switch 18 is communicated with the slurry mixing-stirring tank 16 and the pressure-bearing water storage tank 17 via the slurry mixing-stirring tank interface 40 and the pressure-bearing water storage tank interface 41, respectively; a second switch knob 37 of the second switch 15 and a third switch knob 42 of the third switch 18 are three-state knobs, in which the middle state is a closed state, a fracturing line communicated with the pressure-bearing water storage tank is opened as the second switch and the third switch are turned simultaneously to left, and a grouting line communicated with the slurry mixing-stirring tank is opened as the second switch and the third switch are turned simultaneously to right; an electronic flowmeter 36 is provided at a second switch outlet 35 for measuring the flow rate of the slurry or water flowing therethrough, and a pressure stabilizing valve 44 is provided at a high pressure gas inlet 43 of the third switch 18 for stabilizing the pressure of the gas flowing therethrough.

[0048] The data acquisition and analysis module includes an ultrasonic probe, an ultrasonic transceiver, a flow meter, an operating system and a data storage centre 24 which are respectively communicated with the triaxial loading module, in which the operating system includes an integrated operation control centre 25; an array of the ultrasonic probe is embedded into the pressure bearing plate in the Y-axial direction in the triaxial pressure bearing cavity, data of the ultrasonic transmission sensor and the ultrasonic receiving sensor are transmitted to a data processing centre via a line, and processed data is transmitted to the data storage centre 24 via a line; the operating system may control pressures of the X-axis servo loading pump, the Y-axis servo loading pump and the Z-axis servo loading pump, acquire ultrasonic data and form an image, set an injection pressure, and acquire data of accumulated injection flow.

[0049] The present disclosure also provides a testing method for a true triaxial testing device for rock and soil masses, including a grouting testing method for clastic materials. The grouting testing method for clastic materials includes the following steps 1 to 8:

[0050] In Step 1, clastic materials are obtained from a field or clastic materials fitting a practical field is prepared according to a certain particle grade, an operation condition of a device is detected to ensure that the device can operate stably and safely;

[0051] In Step 2, the sealing plug 7 sealing the feed inlet is unscrewed and taken out by means of the hexagonal tension wrench 6, so that the feed inlet 8 at the top remains open; at the same time, the pre-embedded grouting-fracturing pipe 11 is fixed on the grouting-fracturing orifice by a screw first and externally connected to the first switch 12 and the grouting-fracturing pipe 13, and the first switch 12 is kept in an open state; each of the pressure bearing plates on the six sides of the triaxial pressure bearing cavity is loaded into an initial position thereof, and the triaxial pressure bearing cavity is kept relatively sealed, thereby ensuring that the clastic materials are not be squeezed out during a process of being pressurized;

[0052] In Step 3, the prepared clastic materials are fed into the triaxial pressure bearing cavity through the feed inlet; when the clastic materials are stacked and then block the feed inlet 8, the stacked clastic materials can be flattened by a roller bar and then the clastic materials are fed continually until the clastic materials fill the whole triaxial pressure bearing cavity, and then the sealing plug 7 is tightened by the hexagonal tension wrench 6 to block the feed inlet 8, so as to seal the interior of the triaxial pressure bearing cavity;

[0053] In Step 4, the required slurry is prepared in the slurry mixing-stirring tank 16 in a pre-set slurry ratio, the slurry mixing-stirring tank 16 is sealed after the preparation is completed, and the slurry mixing-stirring tank 16 keeps running during the preparation to prevent the slurry from solidifying and then blocking the slurry mixing-stirring tank;

[0054] In Step 5, the pressure applied on each of the pressure bearing plates is loaded to a pre-set pressure, the high-pressure gas storage pump 19 then is activated, wherein the pressure of the high-pressure gas storage pump 19 is greater than a pre-set grouting pressure, the third switch 18 then is turned to right, so that high-pressure gas passes through the slurry mixing-stirring tank, and the second switch 15 then is turned to right to start the grouting, and at the same time, the data acquisition and analysis module is activated to acquire data during the grouting;

[0055] In Step 6, after the flow rate of the slurry drops to a set range, the grouting is finished, then the first switch 12 is closed, the data acquisition and analysis module is turned off, the high-pressure gas storage pump 19, the third switch 18, the slurry mixing-stirring tank 16 and the second switch 15 are sequentially closed, the grouting-fracturing pipe 13 is dismounted, and the slurry mixing-stirring tank 16 is cleaned;

[0056] In Step 7, after the grouted clastic materials in the triaxial pressure bearing cavity are maintained for a required period of time, the pressure applied on each of the pressure bearing plates is unloaded, the pressure bearing plates in the X-axis and Y-axis directions are retracted, the lateral limitation frame is moved into the base groove by means of the lifting supports, and the reinforced clastic materials are taken out;

[0057] In Step 8, after the reinforced clastic materials are taken out, the triaxial pressure bearing cavity is cleaned, and the device is reset to the original state thereof for the next test.

[0058] The testing method of the present disclosure also includes a hydraulic fracturing testing method for integral rock masses. The hydraulic fracturing testing method for integral rock masses includes the following steps 1-6:

[0059] In Step 1, an integral rock mass or a similar rock mass fitting the practical field is obtained from a field or made in a certain ratio, an operation condition of a device is detected to ensure that the device can operate stably and safely, the lateral limitation frame is lowered to facilitate the loading of a testing specimen;

[0060] In Step 2, a drilling hole needs to be drilled in the centre of the field rock mass to be tested, the pre-embedded grouting-fracturing pipe 11 is fixed in the drilling hole via epoxy resin glue; alternatively, the pre-embedded grouting-fracturing pipe 11 is directly embedded in the similar rock mass during it is prefabricated. The testing specimen is loaded, and the X-axis pressure bearing plate is moved to an initial position thereof after the lateral limitation frame is lifted to an initial height thereof, so as to ensure that the pre-embedded grouting-fracturing pipe 11 passes through the grouting-fracturing orifice and is connected to the first switch 12, and the first switch 12 is kept in an open state; each of the pressure bearing plates on the six surface of the triaxial pressure bearing cavity is loaded into an initial position thereof;

[0061] In Step 3, after the pressure-bearing water storage tank is filled with the water configured for fracturing, the pressure-bearing water storage tank is kept sealed, and the pressure applied on each of the pressure bearing plates is loaded to a pre-set pressure, the high-pressure gas storage pump 19 is opened, so that the air storage pressure of high-pressure gas storage pump is greater than a preset fracturing pressure, and the flow rate of the fracturing water is set, the third switch 18 then is turned to left, so that the high-pressure gas passes through the pressure-bearing water storage tank 17 and the second switch 15 is turned to left to start the fracturing, and at the same time, the data acquisition and analysis module is activated to acquire data during the grouting, so as to facilitate analysis;

[0062] In Step 4, once there is a sudden drop in the fracturing pressure, the fracturing is completed, and the test is finished, the first switch 12 is closed, the data acquisition and analysis module is turned off, the high-pressure air storage pump 19, the third switch 18 and the second switch 15 are sequentially closed;

[0063] In Step 5, the data acquired during the test is saved, the pressure applied on each of the pressure bearing plates is unloaded, the pressure bearing plate in the X-axis direction is retracted, the pre-embedded grouting-fracturing pipe is dismounted from the grouting-fracturing orifice, the lateral limitation frame is moved into the base groove by means of the lifting supports, and the fractured rock mass is taken out;

[0064] In Step 6, the fractured rock mass is taken out, the triaxial pressure bearing cavity is cleaned, and the device is reset to the original state for the next test.

[0065] The present disclosure integrates a grouting module and a hydraulic fracturing module to form a multifunctional testing device and method having both the functions of grouting and hydraulic fracturing. At the same time, in the present disclosure, the feed inlet for feeding a clastic rock mass is provided at the top of the testing device, so that a test can be performed on an integral rock testing specimen and a clastic rock mass. In the present disclosure, the grouting-fracturing pipe is improved to be a detachable grouting-fracturing pipe, so that pressures of the rock mass stress environment and the slurry can be maintained after the grouting are completed, which facilitates the cleaning of the grouting-fracturing pipe, enables the test to better comply with an engineering field, and makes data more convincing.

[0066] In the description of the present disclosure, it should be noted that the orientations or position relations indicated by the terms such as “center”, “’top”, “bottom”, “left”, “right”, “vertical”, “horizontal”, “inner” and “outer” are based on the orientations or position relations shown in the drawings, which are only for convenience in describing the present disclosure and simplifying the description, rather than indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, Therefore, they cannot be construed to be the limitation on the present disclosure. In addition, the terms “first” and “second” are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

[0067] The principle and embodiments of the present disclosure are illustrated by using specific examples in the present disclosure, and the description of the above embodiments is only used to help understand the method and core idea of the present disclosure; in addition, a person of ordinary skilled in the art may make modifications to the specific implementations and application scopes according to the ideas of the present disclosure. In conclusion, the content of the description shall not be construed as a limitation on the present disclosure.

Claims

1. A true triaxial testing device for rock and soil masses, comprising:a triaxial loading module comprising a triaxial servo loading system and a triaxial bearing system, wherein the triaxial servo loading system is configured for applying pressures in an X direction, a Y direction and a Z direction to the triaxial bearing system;a grouting module communicated with a grouting-fracturing pipe in the triaxial bearing system via a pipeline;a hydraulic fracturing module communicated with the grouting-fracturing pipe in the triaxial bearing system via a pipeline; anda data acquisition and analysis module communicated with an ultrasonic transmission sensor and an ultrasonic receiving sensor provided in the triaxial bearing system via a line.

2. The true triaxial testing device for rock and soil masses according to claim 1, wherein the triaxial bearing system comprises a cubic structure enclosed by a plurality of pressure bearing plates, a triaxial pressure bearing cavity is formed in the triaxial bearing system, and the pressure bearing plates are fixed to positioning grooves inside a square shaping frame; a grouting-fracturing orifice is provided at a center of a pressure bearing plate of the pressure bearing plates in a X-axis direction, and a grouting-fracturing pipe penetrates through the grouting-fracturing orifice; a feed inlet is provided on a pressure bearing plate of the pressure bearing plates in a Z-axis direction, and a sealing plug is fixedly and hermetically provided at the feed inlet; the triaxial servo loading system comprises an X-axis oil cylinder, a Y-axis oil cylinder and a Z-axis oil cylinder, wherein the X-axis oil cylinder, the Y-axis oil cylinder and the Z-axis oil cylinder are respectively externally communicated with an X-axis servo loading pump, a Y-axis servo loading pump and a Z-axis servo loading pump via pipelines, and the X-axis servo loading pump, the Y-axis servo loading pump and the Z-axis servo loading pump are externally communicated with a main oil pump via a pipeline; a base is provided at a bottom of the triaxial bearing system, and a longitudinal limitation frame sleeves the triaxial bearing system, the longitudinal limitation frame comprises a top plate horizontally arranged at a top of the triaxial bearing system, and vertical plates are fixedly provided at two ends of the top plate, a bottom of each of the vertical plates is fixedly arranged on the base, and a lateral limitation frame with a rectangular cross section sleeves the triaxial bearing system, a bottom of the lateral limitation frame is connected to the base via a lifting support; the X-axis oil cylinder is fixed on the lateral limitation frame, the Y-axis oil cylinder and the Z-axis oil cylinder are fixed on the longitudinal limitation frame, and an upper surface of the base is provided with a groove.

3. The true triaxial testing device for rock and soil masses according to claim 2, wherein the grouting module comprises a slurry mixing-stirring tank; a pre-embedded grouting-fracturing pipe is provided inside the triaxial pressure bearing cavity, the pre-embedded grouting-fracturing pipe is connected to one end of the grouting-fracturing pipe via a first switch, and one end of the grouting-fracturing pipe away from the first switch is communicated with the slurry mixing-stirring tank via a pipeline and a second switch; the slurry mixing-stirring tank is communicated with a high-pressure air storage pump via a pipeline and a third switch.

4. The true triaxial testing device for rock and soil masses according to claim 3, wherein the hydraulic fracturing module comprises a pressure-bearing water storage tank; the end of the grouting-fracturing pipe away from the first switch is communicated with the pressure-bearing water storage tank via a pipeline and the second switch; the pressure-bearing water storage tank is communicated with the high-pressure air storage pump via a pipeline and the third switch; the second switch and the third switch are both three-way switches; each of the second switch and the third switch has a three-speed knob, wherein a middle state of the three-speed knob is a closed state; a fracturing line communicated with the pressure-bearing water storage tank is opened as the three-speed knob is turned to left, and a grouting line communicated with the slurry mixing-stirring tank is opened as the three-speed knob is turned to right; an electronic flowmeter is provided at an outlet of the second switch, and a pressure stabilizing valve is provided at an outlet of the third switch.

5. The true triaxial testing device for rock and soil masses according to claim 2, wherein the data acquisition and analysis module comprises an ultrasonic probe, an ultrasonic transceiver, a flow meter, an operating system and a data storage centre; wherein an array of the ultrasonic probe is embedded into a pressure bearing plate of the pressure bearing plates in a Y-axial direction in the triaxial pressure bearing cavity, data of the ultrasonic transmission sensor and the ultrasonic receiving sensor are transmitted to a data processing centre via a line, and the processed data is transmitted to the data storage centre via a line; the operating system is able to control pressures of the X-axis servo loading pump, the Y-axis servo loading pump and the Z-axis servo loading pump, acquire ultrasonic data to form an image, set an injection pressure, and acquire data of accumulated injection flow.

6. The true triaxial testing device for rock and soil masses according to claim 2, wherein the sealing plug comprises a thread, a hexagonal groove, a sealing ring, and a rigid sealing plug; the hexagonal groove is provided at a top of the rigid sealing plug, the thread is formed on an upper part of an outer wall of the rigid sealing plug, two circles of grooves are formed on a lower part of the outer wall of the rigid sealing plug, the sealing ring is arranged in each of the two circlesof grooves, and a hexagonal tension wrench is able to be clamped inside the hexagonal groove.

7. The true triaxial testing device for rock and soil masses according to claim 6, wherein the hexagonal tension wrench comprises a rigid main body, a rotating handle is fixedly connected to an upper part of the rigid main body, a hexagonal protrusion is fixedly provided at a bottom of the rigid main body, and the hexagonal protrusion is able to be clamped into the hexagonal groove.

8. A testing method for a true triaxial testing device for rock and soil masses, comprising a grouting testing method for clastic materials, wherein the grouting testing method for clastic materials comprises following steps:SI, preparing clastic materials fitting a practical field, detecting operating conditions of a testing device to ensure that the testing device is able to operate stably and safely;S2, unscrewing and taking out a sealing plug sealing a feed inlet at a top by means of a hexagonal tension wrench; at the same time, fixing a pre-embedded grouting-fracturing pipe onto a grouting-fracturing orifice via a screw, and externally connecting the pre-embedded grouting-fracturing pipe to a first switch and a grouting-fracturing pipe; loading each of pressure bearing plates on six sides of a triaxial pressure bearing cavity into an initial position thereof, keeping the triaxial pressure bearing cavity sealed, thereby ensuring that the clastic materials are not be squeezed out during a process of being pressurized;S3, feeding the prepared clastic materials into the triaxial pressure bearing cavity through the feed inlet until the clastic materials fill the whole triaxial pressure bearing cavity, and then tightening the sealing plug by means of the hexagonal tension wrench to block the feed inlet, so as to seal an interior of the triaxial pressure bearing cavity;S4, preparing a required slurry in a slurry mixing-stirring tank in a pre-set slurry ratio, sealing the slurry mixing-stirring tank after the preparing step is completed, and the slurry mixing-stirring tank keeps running during the preparing step;S5, loading a pressure applied on each of the pressure bearing plates to a pre-set pressure, activating a high-pressure gas storage pump, wherein a gas storage pressure of the high-pressure gas storage pump is greater than a pre-set grouting pressure, turning a third switch to right to pass a high-pressure gas through the slurry mixing-stirring tank, turning a second switch to right, starting a grouting test, and at the same time, activating a data acquisition and analysis module to acquire data during the grouting test;S6, finishing the grouting test after a flow rate of slurry drops to a set range, closing the first switch, turning off the data acquisition and analysis module, sequentially closing the high-pressure gas storage pump, the third switch, the slurry mixing-stirring tank and the secondswitch, dismounting the grouting-fracturing pipe, cleaning pipelines and the grouting-stirring tank;S7, after maintaining the grouted clastic materials in the triaxial pressure bearing cavity for a required period of time, unloading the pressure applied on each of the pressure bearing plates, retracting pressure bearing plates in an X-axis direction and a Y-axis direction, moving a lateral limitation frame into a groove of a base by means of a lifting support, and taking out the reinforced clastic materials;S8, after taking out the reinforced clastic materials, cleaning the triaxial pressure bearing cavity, and resetting the testing device to an original state thereof for a next test.

9. The testing method for a true triaxial testing device for rock and soil masses according to claim 8, further comprising a hydraulic fracturing testing method for integral rock masses, wherein the hydraulic fracturing testing method for integral rock masses comprises the following steps:SI, preparing an integral rock mass or a similar rock mass fitting the practical field, detecting operating conditions of the testing device to ensure that the testing device is able to operate stably and safely, lowering a lateral limitation frame to facilitate loading of a testing specimen;S2, drilling a drilling hole in a centre of the integral rock mass, fixing a pre-embedded grouting-fracturing pipe in the drilling hole via epoxy resin glue; alternatively, directly embedding the pre-embedded grouting-fracturing pipe in the similar rock mass during the similar rock mass is prefabricated; loading the testing specimen, and moving one of the pressure bearing plates in the X-axis direction to an initial position thereof after the lateral limitation frame is lifted to an initial height thereof, so as to ensure that the pre-embedded grouting-fracturing pipe passes through the grouting-fracturing orifice, and is connected to the first switch, maintaining the first switch in an open state; loading each of the pressure bearing plates on the six surface of the triaxial pressure bearing cavity into an initial position thereof;S3, after filling a pressure-bearing water storage tank with water configured for fracturing, keeping the pressure-bearing water storage tank sealed, loading the pressure applied on each of the pressure bearing plates to a pre-set pressure, opening the high-pressure air storage pump, so that the air storage pressure of the high-pressure air storage pump is greater than a pre-set fracturing pressure, setting a flow rate of the water configured for fracturing, turning the third switch to left, so that a high-pressure gas passes through the pressure-bearing water storage tank, turning the second switch to left to start fracturing, and at the same time, activating the data acquisition and analysis module to acquire data during the fracturing;S4, completing the fracturing once there is a sudden drop in a fracturing pressure, finishing a hydraulic fracturing test, closing the first switch, turning off the data acquisition and analysis module, sequentially closing the high-pressure air storage pump, the third switch and the second switch;S5, saving the data acquired during the hydraulic fracturing test, unloading the pressure applied on each of the pressure bearing plates, retracting one of the pressure bearing plates in the X-axis direction, dismounting the pre-embedded grouting-fracturing pipe from the grouting-fracturing orifice, moving the lateral limitation frame into the groove of the base by means of the lifting support, and taking out the fractured integral rock mass or the fractured similar rock mass;S6, taking out the fractured integral rock mass or the fractured similar rock mass, cleaning the triaxial pressure bearing cavity, and resetting the testing device to an original state thereof for a next test.

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