Indoor drilling water pressure test equipment and test method for permeability characteristics of fractured rock mass

Abstract

The application provides a fissure rock mass permeability characteristic indoor borehole water pressure test device and test method, and relates to the technical field of fissure rock mass permeability characteristic test. In the test process, the fissure rock mass sample is placed in the environment simulation tank, the bottom water stop plug and the top water stop plug block the two ends of the test hole, the servo axial compression pump drives the hydraulic cylinder to give the fissure rock mass sample a specified axial compression, the oil pump and the servo confining pressure pump give the fissure rock mass sample a specified confining pressure, the natural water pump performs specified water pressure on the environment simulation tank to simulate the natural water flow environment of the fissure rock mass sample; after accurately simulating the stress environment and the water flow environment around the fissure rock mass, the test water pump pressurizes the water in the test hole, and the obtained data such as the water pressure of the fissure rock mass borehole test section and the water pressure can accurately obtain the permeability characteristic and the water permeability of the fissure rock mass; the device not only inherits the advantages of convenient and fast field borehole water pressure test, but also inherits the advantages of high precision and high accuracy in indoor test.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fissure rock mass permeability test, in particular to a fissure rock mass permeability indoor borehole water pressure test device and test method. BACKGROUND

[0002] There are a large number of fissures in natural rock mass, and groundwater mainly flows in rock mass through fissures. The permeability of rock mass is closely related to the occurrence, density, opening, continuity and filling conditions of fissures, and the permeability is an important basis for rock mass stability evaluation and design of seepage control measures, and is an important research topic and technical problem of rock mass engineering.

[0003] At present, the permeability of fissure rock mass is mainly obtained by field test and indoor test in rock mass engineering. The borehole water pressure test is widely used to test the permeability in the field test, the borehole water pressure test adopts single plug or double plug to block the borehole wall, a certain length of borehole is isolated, then the clean water is pressed into the borehole test section by a fixed water head, and the rock mass permeability and water permeability are determined according to the relationship between the water quantity pressed in a certain time and the water pressure.

[0004] However, the field borehole water pressure test is high in cost, time-consuming and labor-intensive, and it is difficult to find out the initial geological conditions such as deep rock mass fissure occurrence and fissure opening, and it is very difficult to further reveal the evolution law of the permeability of fissure rock mass. The indoor test equipment of fissure rock mass can set the initial conditions of the sample, has the advantages of repeatability and refinement, and has an irreplaceable role in revealing the seepage characteristics of fissure rock mass and mastering the influencing factors of fissure rock mass seepage.

[0005] However, the current indoor test method is mainly divided into steady state method and transient method, both of which test the permeability and water permeability of rock mass sample by applying water pressure to both ends of the sample, and cannot meet the requirements of simulating the complex geological environment of field test, so there is a gap between the measured water permeability and the actual permeability of engineering rock mass. SUMMARY

[0006] (I) Technical problems to be solved

[0007] In view of the shortcomings of the prior art, the present application provides a fissure rock mass permeability indoor borehole water pressure test device and test method, which solves the problem of poor accuracy of indoor test of fissure rock mass permeability under stress-seepage coupling condition.

[0008] (II) Technical scheme

[0009] In order to achieve the above purpose, the present application is realized by the following technical scheme:

[0010] The test equipment comprises a test table, a hydraulic cylinder, a support, a test cabin, an environment simulation tank, a lifting machine and a conducting rod.

[0011] The hydraulic cylinder and the support are installed on the test table.

[0012] The test cabin is placed on the hydraulic cylinder, and the environment simulation tank is installed in the test cabin.

[0013] The conducting rod is connected with the lifting machine below the support.

[0014] The conducting rod penetrates into the test cabin and the environment simulation tank in sequence and is connected with a pressure head in the environment simulation tank.

[0015] The hydraulic cylinder is connected with a servo shaft pressure pump.

[0016] The test cabin is connected with an oil pump and a servo confining pressure pump through a conversion valve.

[0017] The servo shaft pressure pump, the oil pump and the servo confining pressure pump are connected with an oil tank.

[0018] The environment simulation tank comprises a tank base, a tank cover and a flexible shell.

[0019] The two ends of the flexible shell are sealingly connected with the tank base and the tank cover respectively.

[0020] The inner wall of the flexible shell is provided with a plurality of confining pressure conducting media.

[0021] The bottom wall of the flexible shell is provided with a natural water inlet, and the top wall is provided with a water outlet; the natural water inlet is connected with a natural water pump, the water outlet is connected with a water tank, and the natural water pump is connected with the water tank.

[0022] A bottom water stop plug is arranged at the center of the tank base; a top water stop plug is arranged at the center of the pressure head, and the top water stop plug is provided with a test water inlet; the test water inlet is connected with a test water pump, and the test water pump is connected with the water tank.

[0023] Preferably, a support seat and a loading plate are arranged between the hydraulic cylinder and the test cabin.

[0024] An axial displacement sensor is arranged in the loading plate.

[0025] Preferably, the test cabin comprises a cabin base, a cabin shell and a cabin cover.

[0026] The cabin base and the cabin shell are connected through a sealing steel bar.

[0027] The cabin shell and the cabin cover are sealingly connected.

[0028] Preferably, the conductive rod is connected with the hatch cover in a dynamic sealing manner;

[0029] The outer wall of the conductive rod is provided with a limiting ring below the hatch cover.

[0030] Preferably, the bottom surface of the pressure head is provided with an axial pressure sensor.

[0031] The free end of the confining pressure conducting medium is provided with a confining pressure sensor.

[0032] Preferably, the natural water inlet is communicated with the natural water pump through a natural water inlet pipe, the water outlet is communicated with the water tank through a water outlet pipe, and the test water inlet is communicated with the test water pump through a test water inlet pipe.

[0033] The natural water inlet pipe is provided with a natural water inlet water pressure sensor and a natural water inlet valve, and the water outlet pipe is provided with a water outlet water pressure sensor, a water outlet flow sensor and a water outlet valve.

[0034] The test water inlet pipe is provided with a test water inlet water pressure sensor, a test water inlet flow sensor and a test water inlet valve.

[0035] Preferably, the test device further comprises a computer control system.

[0036] The computer control system is connected with the servo axial pressure pump, the servo confining pressure pump, the natural water pump, the test water pump, the axial displacement sensor, the axial pressure sensor, the confining pressure sensor, the natural water inlet water pressure sensor, the water outlet water pressure sensor, the water outlet flow sensor, the test water inlet water pressure sensor, the test water outlet water pressure sensor and the test water flow sensor.

[0037] A method for indoor borehole water pressure test of permeability characteristics of fractured rock mass, the test method comprising the following steps:

[0038] S1, rock sample installation

[0039] A fractured rock sample with a through cylindrical test hole in the middle is made, the treated fractured rock sample is placed in an environment simulation tank, the test hole is placed against the bottom water stop plug, and the test chamber is sealed;

[0040] S2, applying axial pressure

[0041] The servo axial pressure pump is started, the test chamber is lifted by the hydraulic cylinder, and the axial pressure reaches the preset value;

[0042] S3, applying confining pressure

[0043] The cavity between the test chamber and the environment simulation tank is filled with hydraulic oil, the servo confining pressure pump is started to pressurize the hydraulic oil in the cavity, and the confining pressure reaches the preset value;

[0044] S4, applying natural water flow environment

[0045] Start the natural water pump, inject water from the water tank into the environmental simulation tank, and when the water pressure reaches the preset natural water pressure value and remains stable, the water flow environment simulation is completed.

[0046] S5, carry out drilling water pressure test

[0047] It is carried out according to three levels of pressure and five stages (i.e. P1-P2-P3-P2-P1, P1

[0048] Start the test water pump, open the test water inlet valve, and send water to the test hole until the water pressure monitored by the test water inlet water pressure sensor reaches the predetermined water pressure value of the drilling water pressure test. At the same time, adjust the outlet valve so that the outlet water pressure monitored by the outlet water pressure sensor is basically the same as the natural water pressure value. When the outlet water flow monitored by the outlet water flow sensor has no continuous increasing trend, and the fluctuation of the maximum value and the minimum value in the flow reading is within an acceptable range, the test of this stage is completed, and the final value is taken as the calculation value. Then adjust the test water pressure to a new predetermined value and repeat the above test process until the test of the test section is completed.

[0049] Based on the test data, the relationship curves of drilling test section water pressure and water injection amount are drawn, the test data is analyzed, and the permeability characteristics and water permeability of the fractured rock mass are obtained.

[0050] S6, disassemble the device

[0051] After the drilling water pressure test is completed, stop the water flow loading, confining pressure loading and axial pressure loading, unload the water pressure and stress until the initial state, open the test chamber, and disassemble the fractured rock mass sample.

[0052] (Three) beneficial effects

[0053] The present application provides a kind of fractured rock mass permeability characteristics indoor drilling water pressure test equipment and test method. Compared with prior art, it has the following beneficial effects:

[0054] In the application, during the use of the test device, the fractured rock mass sample of the test hole is placed in the environment simulation tank, the bottom water stop plug and the top water stop plug block the two ends of the test hole, the servo axial pressure pump drives the hydraulic cylinder to give the fractured rock mass sample a specified axial pressure, the oil pump and the servo confining pressure pump press oil into the test chamber to give the fractured rock mass sample a specified confining pressure, and the natural water pump pressurizes the water in the environment simulation tank to simulate the natural water flow environment for the fractured rock mass sample; after accurately simulating the stress environment and the water flow environment around the fractured rock mass, the test water pump pressurizes the water in the test hole, and the obtained data of the water pressure and the water volume of the fractured rock mass drilling test section can accurately obtain the permeability and the water permeability of the fractured rock mass; the device not only inherits the advantages of convenient and fast field drilling water pressure test, but also inherits the advantages of high precision and high accuracy in the indoor test, and provides a device basis for the test of the permeability of the fractured rock mass under the stress-seepage coupling effect. BRIEF DESCRIPTION OF DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0056] Figure 1 It is a structural schematic diagram of the test device in the embodiments of the present application;

[0057] Figure 2 It is Figure 1 the enlarged view of A in FIG. 4;

[0058] Figure 3 It is a structural schematic diagram of the test chamber and the environment simulation tank in the opened state;

[0059] In the drawings, the reference signs are as follows: test table 1, hydraulic cylinder 2, support 3, elevator 4, transmission rod 5, pressure head 6, servo axial pressure pump 7, conversion valve 8, oil pump 9, servo confining pressure pump 10, oil tank 11, tank base 12, tank cover 13, flexible shell 14, confining pressure transmission medium 15, natural water inlet 16, water outlet 17, natural water pump 18, water tank 19, bottom water stop plug 20, top water stop plug 21, test water inlet 22, test water pump 23, test hole 24, fractured rock mass sample 25, rock mass sample fracture 26, computer control system 27, support base 28, loading plate 29, chamber base 30, chamber shell 31, chamber cover 32, sealing steel bar 33, natural water inlet water pressure sensor 34, natural water inlet valve 35, water outlet water pressure sensor 36, water outlet flow sensor 37, water outlet valve 38, test water inlet water pressure sensor 39, test water inlet valve 40, test water inlet flow sensor 41. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] This application provides an indoor borehole water pressure test device and method for permeability characteristics of fractured rock masses, which solves the problem of poor accuracy in indoor tests of permeability characteristics of fractured rock masses under stress-seepage coupling conditions.

[0062] The technical solution in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0063] In this embodiment of the invention, during the use of the experimental equipment, a fractured rock mass sample from the central drilled test hole is placed in an environmental simulation tank. Bottom and top water-stop plugs seal both ends of the test hole. A servo axial pressure pump drives a hydraulic cylinder in conjunction with a pressure head to apply a specified axial pressure to the fractured rock mass sample. An oil pump and a servo confining pressure pump pressurize oil into the test chamber to apply a specified confining pressure to the fractured rock mass sample. A natural water pump pressurizes water into the environmental simulation tank to simulate a natural water flow environment for the fractured rock mass sample. After accurately simulating the stress and water flow environment around the fractured rock mass, the test water pump pressurizes water into the test hole. Based on the obtained data such as water pressure and water injection volume in the drilled section of the fractured rock mass, the permeability characteristics and permeability of the fractured rock mass can be accurately determined. This equipment inherits both the advantages of convenient and rapid on-site drilling water pressure testing and the advantages of high precision and accuracy in indoor testing, providing an equipment foundation for in-depth research on the testing of permeability characteristics of fractured rock masses under stress-seepage coupling.

[0064] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0065] Example:

[0066] like Figures 1-3 As shown, the present invention provides an indoor borehole water pressure test device for the permeability characteristics of fractured rock mass. The test device includes: a test bench 1, a hydraulic cylinder 2, a support 3, a test chamber, an environmental simulation tank, a lift 4, and a transmission rod 5.

[0067] The test bench 1 is equipped with a hydraulic cylinder 2 and a support 3;

[0068] The hydraulic cylinder 2 is equipped with a test chamber, and an environmental simulation tank is installed inside the test chamber;

[0069] The support 3 is connected with a conducting rod 5 through an elevator 4 below the support 3;

[0070] The conducting rod 5 penetrates into the test cabin and the environment simulation tank in sequence and is connected with a pressure head 6 in the environment simulation tank;

[0071] The hydraulic cylinder 2 is connected with a servo shaft pressure pump 7;

[0072] The test cabin is connected with an oil pump 9 and a servo confining pressure pump 10 through a conversion valve 8 respectively;

[0073] The servo shaft pressure pump 7, the oil pump 9 and the servo confining pressure pump 10 are connected with an oil tank 11;

[0074] The environment simulation tank comprises a tank base 12, a tank cover 13 and a flexible shell 14;

[0075] Two ends of the flexible shell 14 are sealingly connected with the tank base 12 and the tank cover 13 respectively;

[0076] The inner wall of the flexible shell 14 is provided with a plurality of confining pressure conducting media 15;

[0077] A natural water inlet 16 is formed in the bottom wall of the flexible shell 14 and a water outlet 17 is formed in the top wall; the natural water inlet 16 is connected with a natural water pump 18, the water outlet 17 is connected with a water tank 19, and the natural water pump 18 is connected with the water tank 19;

[0078] A bottom water stop plug 20 is arranged in the center of the tank base 12; a top water stop plug 21 is arranged in the center of the pressure head 6 and is provided with a test water inlet 22; the test water inlet 22 is connected with a test water pump 23, and the test water pump 23 is connected with the water tank 19;

[0079] During use of the test equipment, a fractured rock sample 25 with a central drill test hole 24 is placed in the environment simulation tank, the bottom water stop plug 20 and the top water stop plug 21 block two ends of the test hole 24, the servo shaft pressure pump 7 drives the hydraulic cylinder 2 to give the fractured rock sample 25 a specified axial pressure in cooperation with the pressure head 6, the oil pump 9 and the servo confining pressure pump 10 press oil into the test cabin to give the fractured rock sample 25 a specified confining pressure, and the natural water pump 18 pressurizes water in the environment simulation tank to simulate a natural water flow environment for the fractured rock sample 25; after accurately simulating the stress environment and the water flow environment around the fractured rock, the test water pump 23 pressurizes water in the test hole 24, and the permeability and the water permeability of the fractured rock can be accurately obtained according to obtained data such as water pressure and water volume of the fractured rock drill test section, the equipment not only inherits the advantages of convenient and fast field drill water pressure test, but also inherits the advantages of high precision and high accuracy in indoor test, and provides equipment basis for in-depth study on the test of the permeability of the fractured rock under the stress-seepage coupling effect.

[0080] The pressure head 6 is a device with a diameter of 200 mm and a height of 60 mm, used for axial compression loading.

[0081] Both the bottom water stop plug 20 and the top water stop plug 21 are cylindrical devices with a diameter of 30 mm and a height of 20 mm, and are made of high-performance rubber.

[0082] The environmental simulation tank is a tank-shaped device with an inner diameter of 200mm, an outer diameter of 215mm, and a height of 210mm. The environmental simulation tank is fixed to the center of the cabin 30 by bolts.

[0083] like Figure 1 , Figure 2 As shown, a support base 28 and a loading plate 29 are provided between the hydraulic cylinder 2 and the test chamber;

[0084] The support base 28 is used to maintain the stability of the device, and the loading plate 29 is provided with an axial displacement sensor to sense the axial advance distance of the hydraulic cylinder 2.

[0085] like Figures 1-3 As shown, the test chamber includes: a chamber base 30, a chamber shell 31, and a chamber cover 32;

[0086] The cabin 30 is connected to the outer shell 31 by a sealing steel strip 33;

[0087] The outer shell 31 and the hatch cover 32 are sealed together.

[0088] The outer shell 31 is a cylindrical steel structure with a diameter of 400 mm and a height of 800 mm.

[0089] The cabin 30 is equipped with oil inlet / outlet and water pipe passage.

[0090] like Figure 1 , Figure 2 As shown, the transmission rod 5 is dynamically sealed to the hatch cover 32;

[0091] The outer wall of the transmission rod 5 is provided with a limiting ring, which is located below the hatch cover 32;

[0092] With the sealing steel bar 33 released, when the elevator 4 drives the transmission rod 5 to rise, under the action of the limit ring, the hatch cover 32 and the outer shell 31 will rise together with the transmission rod 5 to open the test chamber, making it easier to place the fractured rock mass sample 25.

[0093] An axial pressure sensor is provided on the bottom surface of the pressure head 6;

[0094] A confining pressure sensor is provided at the free end of the confining pressure conducting medium 15.

[0095] The natural water inlet 16 is communicated with the natural water pump 18 through a natural water inlet pipe, the water outlet 17 is communicated with the water tank 19 through a water outlet pipe, and the test water inlet 22 is communicated with the test water pump 23 through a test water inlet pipe;

[0096] The natural water inlet pipe is provided with a natural water inlet water pressure sensor 34 and a natural water inlet valve 35, and the water outlet pipe is provided with a water outlet water pressure sensor 36, a water outlet flow sensor 37 and a water outlet valve 38.

[0097] The test water inlet pipe is provided with a test water inlet water pressure sensor 39, a test water inlet flow sensor 41 and a test water inlet valve 40.

[0098] As shown in Figure 1 the test device further comprises a computer control system 27.

[0099] The computer control system 27 is connected with the servo shaft pressure pump 7, the servo confining pressure pump 10, the natural water pump 18, the test water pump 23, the axial displacement sensor, the shaft pressure sensor, the confining pressure sensor, the natural water inlet water pressure sensor 34, the water outlet water pressure sensor 36, the water outlet flow sensor 37, the test water inlet water pressure sensor 39 and the test water inlet flow sensor 41.

[0100] The computer control system 27 comprises a servo control system, a data acquisition and output system and various sensors; the servo control system is an independent control system, and each test device can be controlled in real time through a computer, wherein the shaft pressure sensor is used for collecting the pressure after the pressure head 6 contacts the fractured rock sample 25, and the axial displacement sensor is used for collecting the axial displacement distance; the confining pressure sensor and the water pressure sensor arranged in the environment simulation tank are used for monitoring the change of the confining pressure and the water pressure of the fractured rock sample 25; the natural water inlet water pressure sensor 34, the water outlet water pressure sensor 36, the water outlet flow sensor 37, the test water inlet water pressure sensor 39 and the test water inlet flow sensor 41 are used for collecting real-time data during the drilling water pressure test; the sensors are pasted through a coupling agent and a heat shrink tube and are connected with a data collector through wires, and the wires pass through the bottom of the support seat 28. The data acquisition and output system is connected with the natural stress loading device, the natural water flow loading device, the drilling water pressure test water flow loading device and the computer control system, and is used for collecting, displaying and outputting the test data measured in the above systems.

[0101] The present application provides a kind of fractured rock mass permeability characteristic indoor drilling water pressure test method, the test method includes the following steps:

[0102] S1, rock sample installation

[0103] The production specification is about 200mm in diameter and 200mm in height, with a through cylindrical test hole 24 of 30mm in diameter in the middle. The elevator 4 is lifted to a certain height, and the treated fractured rock sample 25 is placed in the environmental simulation tank. The test hole 24 is placed against the bottom water stop plug 20, and after being fixed, the elevator 2 is controlled to return to the original position. The sealing steel bar 33 is wrapped around the joint between the cabin seat 30 and the cabin shell 31 to seal and close the cabin seat 30 and the cabin shell 31;

[0104] S2, apply axial pressure

[0105] After the test cabin is sealed, the servo axial pressure pump 7 is started, the axial pressure preloading value and the preset value are set through the computer control system 27, the hydraulic cylinder 2 is slowly lifted to make the fractured rock sample 25 touch the pressure head 6 and bear the force until the axial pressure value transmitted by the axial pressure sensor to the computer control system 27 reaches the preset value. At this time, the top water stop plug 21 completely enters the test hole 24, and the real-time change of the axial pressure is transmitted to the computer control system 27 through the axial pressure sensor. When the axial pressure reaches the preloading value, the loading rate is switched, and when the axial pressure reaches the preset value, the axial pressure application is completed.

[0106] S3, apply confining pressure

[0107] The conversion valve 8 is adjusted, the oil pump 9 is started, and the hydraulic oil is filled in the cavity between the test cabin and the environmental simulation tank from the oil tank 11. When the cavity is filled with hydraulic oil, the conversion valve 8 is switched, the oil pump 9 is closed, the servo confining pressure pump 10 is started, the confining pressure preset value is set through the computer control system 27, the loading rate is controlled, and the hydraulic oil in the cavity is slowly pressurized to make the confining pressure transmission medium 15 generate corresponding confining pressure on the fractured rock sample 25. The confining pressure sensor displays the confining pressure change on the computer in real time until the confining pressure preset value is reached, and the confining pressure loading is completed.

[0108] S4, apply natural water flow environment

[0109] The natural water pump 18 is started, the natural water inlet valve 35 is opened, and water is injected from the water tank 19 into the environmental simulation tank to gradually apply water pressure to the fractured rock sample 25. When the natural water inlet water pressure sensor 34 displays that the natural water pressure value reaches the preset value and remains stable, the natural water flow environment simulation is completed.

[0110] S5, carry out borehole water pressure test

[0111] The borehole water pressure test should generally be carried out in three stages and five stages (i.e. P1-P2-P3-P2-P1, P1

[0112] Start the test water pump 23, open the test water inlet valve 40, send water to the test hole 24 until the water pressure monitored by the test water inlet pressure sensor 39 reaches the predetermined water pressure value of the borehole water pressure test; At the same time, adjust the water outlet valve 38 so that the water outlet pressure monitored by the water outlet pressure sensor 36 is basically the same as the natural water pressure value; When the water outlet flow sensor 37 monitors that the water outlet flow has no continuous increasing trend, and the fluctuation of the maximum value and the minimum value in the flow reading is within an acceptable range, the test of this stage can be ended, and the final value is taken as the calculation value; Then adjust the test water pressure to a new predetermined value and repeat the above test process until the test of the test section is completed.

[0113] Before the end of the borehole water pressure test, check whether the original record is complete and correct, and correct the problem in time if found; Based on the test data, the relationship curve of the water pressure of the borehole test section and the water pressure can be drawn, the test data can be analyzed, and the permeability of the fractured rock mass and the water permeability can be obtained.

[0114] S6, disassembly device

[0115] After the borehole water pressure test is completed, wait for the water backflow to be completed, close the test water flow control system, close the natural water flow control system, adjust the conversion valve 8, start the oil pump 9 to make the hydraulic oil backflow to the oil tank 11, close the confining pressure loading control system, control the test chamber to return to the initial position, close the axial pressure control system, and finally open the test chamber to disassemble the fractured rock mass sample 25.

[0116] Compared with the prior art, the present application has the following beneficial effects:

[0117] In the embodiment of the present application, the fractured rock mass sample of the central drilling test hole is placed in the environment simulation tank during the use of the test equipment, the bottom water stop plug and the top water stop plug block the two ends of the test hole, the servo axial pressure pump drives the hydraulic cylinder to give the fractured rock mass sample a specified axial pressure, the oil pump and the servo confining pressure pump press oil into the test chamber to give the fractured rock mass sample a specified confining pressure, and the natural water pump performs specified water pressure in the environment simulation tank to simulate the natural water flow environment for the fractured rock mass sample; After accurately simulating the stress environment and the water flow environment around the fractured rock mass, the test water pump pressurizes the test hole, and the permeability of the fractured rock mass can be accurately obtained according to the obtained data such as the water pressure of the fractured rock mass drilling test section and the water pressure; The equipment not only inherits the advantages of convenient and fast field borehole water pressure test, but also inherits the advantages of high precision and high accuracy in indoor test, and provides equipment foundation for in-depth research on the test of the permeability of the fractured rock mass under the stress-seepage coupling effect.

[0118] It is to be noted that, in the present text, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0119] The above examples are merely used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A laboratory borehole water pressure test apparatus for determining the permeability characteristics of fractured rock masses, characterised in that, The test device comprises a test table (1), a hydraulic cylinder (2), a support (3), a test cabin, an environment simulation tank, an elevator (4) and a conducting rod (5); The test table (1) is provided with the hydraulic cylinder (2) and the support (3); The test cabin is placed on the hydraulic cylinder (2), and the environment simulation tank is installed in the test cabin; The conducting rod (5) is connected with the pressure head (6) in the environment simulation tank through the elevator (4) below the support (3); The conducting rod (5) penetrates into the test cabin and the environment simulation tank in sequence and is connected with the pressure head (6) in the environment simulation tank; The hydraulic cylinder (2) is connected with a servo shaft pressure pump (7); The test cabin is connected with an oil pump (9) and a servo surrounding pressure pump (10) through a conversion valve (8); The servo shaft pressure pump (7), the oil pump (9) and the servo surrounding pressure pump (10) are connected with an oil tank (11); The environment simulation tank comprises a tank base (12), a tank cover (13) and a flexible shell (14); Two ends of the flexible shell (14) are respectively sealed and connected with the tank base (12) and the tank cover (13); The inner wall of the flexible shell (14) is provided with a plurality of surrounding pressure conducting media (15); A natural water inlet (16) is formed in the bottom wall of the flexible shell (14), and a water outlet (17) is formed in the top wall; the natural water inlet (16) is connected with a natural water pump (18), the water outlet (17) is connected with a water tank (19), and the natural water pump (18) is connected with the water tank (19); A bottom water stop plug (20) is arranged at the center of the tank base (12); a top water stop plug (21) is arranged at the center of the pressure head (6), and the top water stop plug (21) is provided with a test water inlet (22); the test water inlet (22) is connected with a test water pump (23), and the test water pump (23) is connected with the water tank (19).

2. The fracture rock mass permeability characteristics laboratory borehole water pressure test apparatus according to claim 1, wherein A support seat (28) and a loading plate (29) are arranged between the hydraulic cylinder (2) and the test cabin; An axial displacement sensor is arranged in the loading plate (29).

3. The fracture rock mass permeability characteristics laboratory borehole water pressure test apparatus according to claim 1, wherein The test cabin comprises a cabin base (30), a cabin shell (31) and a cabin cover (32); The cabin base (30) is connected with the cabin shell (31) through a sealing steel bar (33); The cabin shell (31) is sealingly connected with the cabin cover (32); The conducting rod (5) is dynamically sealingly connected with the cabin cover (32); A limiting ring is arranged on the outer wall of the conducting rod (5), and the limiting ring is below the cabin cover (32).

4. The fracture-mass permeability laboratory borehole water-pressurization test apparatus of claim 1, wherein An axial pressure sensor is arranged on the bottom surface of the pressure head (6); A surrounding pressure sensor is arranged at the free end of the surrounding pressure conducting medium (15); The natural water inlet (16) is communicated with the natural water pump (18) through a natural water inlet pipe, the water outlet (17) is communicated with the water tank (19) through a water outlet pipe, and the test water inlet (22) is communicated with the test water pump (23) through a test water inlet pipe; The natural water inlet pipe is provided with a natural water inlet water pressure sensor (34) and a natural water inlet valve (35), and the water outlet pipe is provided with a water outlet water pressure sensor (36), a water outlet flow sensor (37) and a water outlet valve (38); The test water inlet pipe is provided with a test water inlet water pressure sensor (39), a test water inlet flow sensor (41) and a test water inlet valve (40).

5. The apparatus of claim 4, wherein the fracture-matrix permeability test apparatus is characterized by, The test device further comprises a computer control system (27); The computer control system (27) is connected with the servo axial pressure pump (7), the servo confining pressure pump (10), the natural water pump (18), the test water pump (23), the axial displacement sensor, the axial pressure sensor, the confining pressure sensor, the natural water inflow pressure sensor (34), the outflow pressure sensor (36), the outflow flow sensor (37), the test water inflow pressure sensor (39) and the test water inflow flow sensor (41) respectively.

6. A method of a laboratory borehole water pressure test for permeability characteristics of a fractured rock mass, characterized by, The test method is implemented by the fissured rock mass permeability characteristic indoor borehole water pressure test device as claimed in claim 5, and comprises the following steps: S1, rock sample installation A fissured rock sample (25) with a through cylindrical test hole (24) in the middle is prepared, the treated fissured rock sample (25) is placed in the environment simulation tank, the test hole (24) is placed against the bottom water stop plug (20), and the test chamber is sealed; S2, axial pressure application The servo axial pressure pump (7) is started, the test chamber is lifted by the hydraulic cylinder (2), and the axial pressure reaches a preset value; S3, confining pressure application The cavity between the test chamber and the environment simulation tank is filled with hydraulic oil, the servo confining pressure pump (10) is started to pressurize the hydraulic oil in the cavity, and the confining pressure reaches a preset value; S4, natural water flow environment application The natural water pump (18) is started, water is injected from the water tank (19) into the environment simulation tank, the water pressure reaches a preset natural water pressure value and remains stable, and the water flow environment simulation is completed; S5, borehole water pressure test Three-stage pressure and five-stage (P1-P2-P3-P2-P1, P1 The test water pump (23) is started, the test water inflow valve (40) is opened, water is sent into the test hole (24), the water pressure monitored by the test water inflow pressure sensor (39) reaches a predetermined water pressure value of the borehole water pressure test, the outflow valve (38) is adjusted, the outflow pressure monitored by the outflow pressure sensor (36) is basically the same as the natural water pressure value, when the outflow flow monitored by the outflow flow sensor (37) has no continuous increasing trend, and the fluctuation of the maximum value and the minimum value in the flow reading is within an acceptable range, the test in this stage is completed, and the final value is taken as a calculation value, the test water pressure is adjusted to a new predetermined value, and the above test process is repeated until the test of the test section is completed, the borehole test section water pressure and the water injection amount are plotted based on the test data, the test data is analyzed, and the fissured rock mass permeability characteristic and the water permeability are obtained; S6, device disassembly After the borehole water pressure test is completed, the water flow loading, the confining pressure loading and the axial pressure loading are stopped, the water pressure and the stress are unloaded until the initial state, the test chamber is opened, and the fissured rock sample (25) is disassembled.

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