CN110146389A - True triaxial direct shear test box and method for simulating force-heat-liquid coupling environment - Google Patents

Abstract

The invention discloses a true three-axis direct shear test box and a method for simulating a force-heat-liquid coupling environment, comprising a direct shear box and a test piece chamber located in the direct shear box, and the direct shear box includes a sealing gland device, loading indenter device, sliding platen device, hydraulic device and heating device. The loading indenter device includes vertical loading indenter, horizontal loading indenter and shearing indenter. The sliding platen device includes upper sliding platen and side sliding platen. The sliding pressure plate is located below the vertical loading pressure head, and the upper sliding pressure plate can slide relatively along the vertical loading pressure head; there are six side sliding pressure plates, which can slide relatively along the horizontal loading pressure head and the shear pressure head; the The hydraulic device includes hydraulic oil inlet and hydraulic oil outlet; the heating device includes heating tank and heating wire. The invention effectively simulates the rock mass environment below a kilometer, and truly reflects the shear failure characteristics of the rock mass under the force-thermal-liquid coupling environment.

Description

True triaxial direct shear test box and method for simulating force-heat-liquid coupling environment

technical field

The invention relates to a large-scale true triaxial direct shear test box and a method for simulating a force-heat-liquid coupling environment, in particular to a test box and a method that can simulate the high temperature, high ground pressure and high water in the development process of hot dry rock. Large-scale true triaxial direct shear test box and test method for pressure environment.

Background technique

China is a country with large reserves of geothermal resources in the world. Geothermal resources have become a new type of clean energy that is being researched and developed by countries around the world because of their extremely high cleanliness, operational stability and extensive spatial distribution. The hot dry rock resources in the depths of 3-10 km in mainland China are about 260,000 times the current total annual energy consumption in China. The national geothermal energy development plan specifically points out that various technologies of hot dry rock should be actively explored and developed. Therefore, the shear failure and cracks of hot dry rock reservoir fractures in the force-thermal-liquid coupling environment and water injection pressure should be further systematically studied. Propagation characteristics, in-depth study of the formation mechanism of shear cracks in hot dry rock mass, is to break through the technical bottleneck of hot dry rock development, and it is urgent to solve key technical problems, and it is necessary for my country's future energy conservation, emission reduction and environmental pollution control as well as a new round of energy structure adjustment. It has important theoretical value and practical guiding significance.

However, the traditional direct shear test device still has the following shortcomings:

(1) The three-dimensional stress cannot be applied to the specimen while the shear test is performed, or the sliding displacement of the specimen cannot be solved; (2) It is difficult to carry out the shear test under the coupled environment of high pressure ground pressure, high water pressure and high temperature, The sealing performance of the device is often not guaranteed; (3) the size of the traditional direct shear test sample is often less than 7mm, and the shear test results are difficult to reflect the real dry hot rock mass; (4) the traditional direct shear test box cannot realize the test. Acoustic emission monitoring of the process.

CN204807547U discloses a stress-seepage coupled true triaxial shear box, which is mainly a small-size true triaxial direct shear-seepage test. The device cannot meet the conditions of a large-size rock mass shear test, and does not consider high temperature and high hydraulic pressure. The problem.

CN103743633B discloses a fluid-solid coupling coal-rock shear-seepage test device, which is mainly used for coal-rock shear-seepage test, and the device cannot satisfy true triaxial loading and force-heat-liquid coupling conditions.

To sum up, the test devices in the prior art have not yet solved the technical problems of true triaxial compression, active shearing, force-heat-liquid coupling simulation, and large-size samples. Therefore, researchers in this field are devoted to developing a large-scale true triaxial direct shear test box for simulating the force-thermal-liquid coupling environment.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a true triaxial direct shear test box and a test method for simulating a force-heat-liquid coupling environment. , It can also carry out direct shear test of large-size samples, ensure that the surrounding of rock samples is subject to constant three-dimensional stress, constant high stress, high temperature and high water pressure environment, and at the same time, it can realize the acoustic emission monitoring of the whole process of shear test. , which can better reflect the dynamic evolution characteristics of shear cracks and the characteristics of slip failure when the rock is fractured by complex external forces.

One of the tasks of the present invention is to provide a true triaxial direct shear test box for simulating a force-heat-liquid coupling environment, the technical solutions of which include:

A true triaxial direct shear test box for simulating a force-heat-liquid coupling environment, comprising a direct shear box and a specimen chamber located in the direct shear box, wherein the specimen chamber is used for placing concrete shears A block and a shear sample, the concrete shear block includes an upper shear block and a lower shear block, and the shear sample is between the upper shear block and the lower shear block;

The straight shear box includes a sealing and pressing device, a loading head device, a sliding pressing plate device, a hydraulic device and a heating device. The heating gland and the bottom gland are composed, and the adjacent glands are closely connected;

The loading indenter device includes a vertical loading indenter, a horizontal loading indenter and a shearing indenter, the vertical loading indenter is located on the upper gland, and the horizontal loading indenter is located in the On the side gland, the shearing indenter is located on the heating gland;

The sliding pressure plate device includes an upper sliding pressure plate and a side sliding pressure plate, the upper sliding pressure plate is located below the vertical loading pressure head, and the upper sliding pressure plate can slide relatively along the vertical loading pressure head; The side sliding pressure plate is provided with six, of which four are located on one side of the horizontal loading pressure head, and the other two are located on one side of the shearing pressure head, which can be located along the horizontal loading pressure head. The head and the shearing indenter slide relative to each other;

The hydraulic device includes a hydraulic oil inlet and a hydraulic oil outlet, the hydraulic oil inlet and the hydraulic oil outlet are located above the heating gland, and the hydraulic oil inlet is connected with a hydraulic pump and an oil tank;

The heating device includes a heating tank and a heating wire, the heating tank is located under the heating press cover, the heating wire is arranged in the heating tank, and the heating wire is used for heating the test piece after electrification. The hydraulic oil in the tank warms up.

As a preferred solution of the present invention, the size of the above-mentioned upper shearing block and the lower shearing block are both 200mm×200mm×150mm, and the distance between the upper shearing block and the lower shearing block is 10mm; The sample is a cube original rock sample, and its side length is greater than 70mm and less than 150mm.

As another preferred solution of the present invention, the upper end surface of the above-mentioned upper sliding platen is provided with several ball grooves 1, and each ball groove 1 is provided with a ball 1, through which the upper sliding platen and the above-mentioned vertical loading head are realized relative sliding.

Further, a plurality of ball grooves 2 are arranged on the opposite surfaces of the above-mentioned side sliding pressure plate and the above-mentioned horizontal loading indenter and shearing indenter, and each ball groove 2 is provided with a ball 2, through which the side sliding pressure plate and the horizontal Relative sliding of the loading indenter and the shear indenter.

Further, the adjacent glands are connected together by high temperature resistant gaskets and fastening bolts.

Further, the above-mentioned heating groove is a rectangular groove.

Further, an acoustic emission probe hole is provided on the upper end face of the above-mentioned side sliding platen, and the above-mentioned acoustic emission probe hole is used for fixing the acoustic emission sensor.

Another task of the present invention is to provide a true triaxial direct shear test method for simulating a force-heat-liquid coupling environment, which adopts the above-mentioned test box, and the method includes:

a. Prepare the test pieces, respectively prepare the upper shear block and the lower shear block with the size of 200mm×200mm×150mm, and prepare the cube original rock sample as the shear sample;

b. Installation, insert the horizontal loading pressure head into the side gland, insert the shear pressure head into the heating gland, fix and seal the two side glands, the two heating glands and the bottom gland to each other; Embed the acoustic emission sensor In the acoustic emission detection hole, the side sliding pressure plate is placed on the opposite side of the horizontal loading indenter and the shearing indenter; the upper shear block and the lower shear block are placed in the test chamber, and the sliding pressure plate is covered in turn, and the vertical loading is performed. Pressure head and upper gland, and fixed seal;

The large-size true triaxial direct shear test box is placed in the true triaxial pressure testing machine for testing, and the hydraulic oil inlet and hydraulic oil outlet are connected to the hydraulic pump and the oil tank by high-pressure hoses, and the acoustic emission sensor and heating are connected. Silk;

c. Inject hydraulic oil, raise the temperature and pressurize, use the hydraulic pump to inject hydraulic oil into the test chamber through the hydraulic oil inlet, turn on the power supply and use the heating wire to heat the hydraulic oil, and monitor the hydraulic oil temperature through the external temperature sensor to meet the test conditions. ;Increase oil pressure until hydraulic conditions are met;

d. Test, turn on the true triaxial pressure testing machine, apply vertical stress and horizontal stress, monitor the sample through the acoustic emission monitoring device, apply shear stress until the sample is damaged; after the test, release the confining pressure and extract the hydraulic pressure. Oil, observe the failure mode of the sample, and reveal the dynamic evolution characteristics of shear cracks and the slip failure mechanism by combining the test data and the crack propagation mode.

Compared with the prior art, the present invention brings the following beneficial technical effects:

First, the main body of the shear box is made of high-density steel with high compressive strength and good water corrosion resistance, which can simulate the high in-situ stress environment of deep hot dry rock reservoirs; The maximum temperature is 300℃, and the test box is kept warm by means of an external sensor; the interior of the test box is filled with hydraulic oil to simulate underground high-pressure water, and the external oil pump is used to load the oil pressure in the test box to 5MPa, and the pressure can be maintained at the same time. And then it satisfies the simulation of force-heat-liquid coupling environment.

Second, the use of split rigid sliding platens, balls and indenters can achieve shear displacement within 5mm, and can fully study the failure modes of different rock samples under different temperature, hydraulic and stress conditions, and the spatial distribution of shear cracks feature.

Third, the upper end face of the side sliding platen is provided with acoustic emission probe holes, which are used to fix the acoustic emission sensor and realize the monitoring of the acoustic emission events, energy and amplitude of the rock shear failure process.

Fourth, the overall size of the shear block in the test chamber is 200mm × 200mm × 300mm, and the maximum size of the internal effective rock mass can reach 150mm × 150mm × 150mm. mechanical properties.

Fifth, the test box of the present invention can simulate the coupled environment of high ground stress, high water pressure and high ground temperature where the deep rock mass is located, and use the sliding pressure plate to realize the direct shear test of large-scale original rock in the true triaxial environment, and the channel acoustic emission probe hole It realizes the monitoring of acoustic emission information in the whole process of the test, effectively simulates the rock mass environment below a kilometer, and truly reflects the shear failure characteristics of the rock mass under the force-thermal-liquid coupling environment.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings:

1 is a front sectional view of a large-size true triaxial direct shear test box for simulating a force-heat-liquid coupling environment according to the present invention;

Fig. 2 is the side sectional view of the test box of the present invention;

Fig. 3 is the assembly drawing of the upper sliding platen of the test box of the present invention;

Fig. 4 is the side sliding pressure plate assembly drawing of the test box of the present invention;

FIG. 5 is an assembly view of the heating and pressing lid of the test box of the present invention.

The reference numbers are as follows:

1-upper gland; 2-side gland; 3-heating gland; 31-heating tank; 32-heating wire; 4-bottom gland; 5-vertical loading indenter; 6-horizontal loading indenter; 7- Shearing head; 8- sliding pressure plate at the upper end; 9- sliding pressure plate at the side end; 91- acoustic emission probe hole; 10- ball; 11- hydraulic oil inlet; 12- hydraulic oil outlet; 13- large size concrete shear block; 14-shear specimen; 15-fastening bolt; 16-high temperature sealing gasket.

Detailed ways

The present invention proposes a true triaxial direct shear test box and method for simulating a force-heat-liquid coupling environment. In order to make the advantages and technical solutions of the present invention clearer and clearer, the present invention is described in detail below with reference to specific embodiments. illustrate.

1 to 5, the present invention is a true triaxial direct shear test box for simulating a force-heat-liquid coupling environment, including a test piece bin and a direct shear box. A large-size concrete shear block 13 and a shear sample 14 are arranged inside the specimen chamber. The shear sample 14 is embedded in the middle of the two concrete shear blocks 13, and the distance between the two concrete shear blocks 13 is 10 mm.

The direct shear box includes a sealing gland device, a loading head device, a sliding platen device, a hydraulic device and a heating device. The sealing gland device includes an upper gland 1, a side gland 2, a heating gland 3, and a bottom gland 4. Each gland is provided with fastening bolts 15 and a high temperature resistant gasket 16, and a high temperature resistant gasket is used between each gland. 16. The fastening bolts 15 are tightly connected to ensure the high temperature resistance and high sealing performance of the direct shear box;

The upper gland 1 is provided with a vertical loading indenter 5, the side gland 2 is provided with a horizontal loading indenter 6, and the heating gland 3 is provided with a shearing indenter 7, a heating groove 31, a heating wire 32, a hydraulic oil inlet 11 and a hydraulic pressure Oil outlet 12.

The loading head device includes a vertical loading head 5 , a horizontal loading head 6 and a shearing head 7 .

The sliding pressure plate device includes an upper end sliding pressure plate 8 and a side end sliding pressure plate 9; the upper end sliding pressure plate 8 is located under the vertical loading pressure head 5, the upper end surface of the upper end sliding pressure plate 8 is provided with a ball groove, and the ball groove is arranged with balls 10 to ensure the upper end head. The sliding pressure plate 8 and the vertical loading pressure head 5 can slide; there are a total of six side end sliding pressure plates 9, four of which are located on one side of the horizontal loading pressure head 6, and a side end sliding pressure plate 9 is arranged up and down, two of which are located on the side of the horizontal loading pressure head 6. On one side of the shear indenter 7, the upper end face of the side end sliding pressure plate 9 is provided with a ball groove, the ball groove is arranged with the ball 10, and the upper end surface of the side end sliding pressure plate 9 is provided with an acoustic emission detection hole 91, which is used to fix the acoustic emission sensor and realize the Monitoring of acoustic emission parameters during the test.

The hydraulic device includes a hydraulic oil inlet 11 and a hydraulic oil outlet 13. The hydraulic oil inlet 11 and the hydraulic oil outlet 13 are located above the heating gland 3, and the high-pressure rubber tube is fixed by a high-pressure sealing ring.

The heating device includes a heating tank 31 and a heating wire 32. The heating tank 31 is located under the heating gland 3 and is processed into a rectangular groove. A heating wire 32 is arranged in the heating tank 31. After the heating wire 32 is energized, the hydraulic oil in the specimen chamber is heated up. , set a tungsten wire in the heating tank to heat the hydraulic oil to 300 ℃ at most, and realize the thermal insulation of the test box by means of an external sensor; the interior of the test box is filled with hydraulic oil to simulate underground high-pressure water, and the external oil pump is used to make the test box inside the test box. The oil pressure is loaded to 5MPa, and the pressure can be maintained at the same time.

Using the above test box, the test can be carried out according to the following steps:

(1) Specimen preparation

Raw rock: The raw rock samples taken from the site are sealed with plastic wrap and placed in a coring machine for coring. Finally, the raw rock taken out is carefully ground into raw coal cube rock samples with a grinder. The minimum size of the cube rock samples is 70mm x 70mm x 70mm, the maximum size is 150mm x 150mm x 150mm, and the finished original rock is placed in a constant temperature and humidity curing box for curing.

Concrete shearing block: prepare C30 concrete, in which the mass ratio of water, cement, sand and stone is 0.38:1:1.11:2.72, place the prepared concrete in a double-opening mold of 200mm×200mm×150mm and tamp it. The completed original rock sample is placed in the middle of the concrete, and at the same time, it is ensured that half of the cube rock sample is embedded in the concrete; a 10mm backing plate is placed above the double-opening mold, and a double-opening mold of 200mm×200mm×150mm is placed above the backing plate, and poured into the concrete. Tamping; when the concrete shearing block is formed, the prepared concrete shearing block is placed in a constant temperature and constant humidity curing box for curing.

(2) Test piece installation and installation

Insert the horizontal loading indenter 6 into the side gland 2, insert the shear indenter 7 into the heating gland 3, and attach the two side glands 2, the two heating glands 3 and the bottom gland 4 with the fastening bolts 15 and the resistance. The high temperature gaskets 16 are fixed and sealed with each other; the acoustic emission sensor is embedded in the acoustic emission probe hole 91, and the side end sliding pressure plate 9 equipped with the ball 10 is placed on the horizontal loading pressure head 6; the side of the shear pressure head 7; The concrete shear block 13 is placed in the test chamber to cover the upper end sliding pressure plate 8, the vertical loading pressure head 5 and the upper pressure cover 1 in sequence, and is fixed and sealed with the fastening bolts 15 and the high temperature resistant gasket 16.

The true triaxial direct shear test box is placed in the true triaxial pressure testing machine for testing, and the hydraulic oil inlet 11 and the hydraulic oil outlet 12 are connected to the hydraulic pump and the oil tank by the high-pressure hose, and the acoustic emission sensor and the heating wire 32 are connected.

(3) Inject hydraulic oil, heat up and pressurize

Use the hydraulic pump to inject hydraulic oil into the test chamber through the hydraulic oil inlet 11, turn on the power supply and use the heating wire 32 to heat the hydraulic oil, and monitor the hydraulic oil temperature through the external temperature sensor to achieve the test conditions; increase the oil pressure until the hydraulic pressure is satisfied. condition.

(4) Carry out the test

Turn on the true triaxial pressure testing machine, apply vertical stress and horizontal force, turn on the acoustic emission monitoring device to monitor the sample, and apply shear stress until the sample fails; after the test, the confining pressure is relieved, the hydraulic oil is drawn out, and the concrete is taken out The shear block is used to observe the failure mode of the specimen, and the dynamic evolution characteristics of the shear crack and the slip failure mechanism are revealed by combining the test data and the crack propagation mode.

The parts not mentioned in the present invention can be realized by referring to the prior art.

It should be noted that any equivalent manner or obvious modification manner made by those skilled in the art under the teaching of this specification shall fall within the protection scope of the present invention.

Claims (8)

1. a kind of true triaxial direct shear test box for analog force-heat-liquid coupling environment, including direct shear box and it is located at the staight scissors Test specimen storehouse in box, for placing concrete shearing block and shearing sample in the test specimen storehouse, it is characterised in that:

The concrete shearing block includes top cutout and lower part cutout, the top cutout and lower part cutout Between be the shearing sample；

The direct shear box includes sealing gland device, load indenter device, sliding clamp device, hydraulic device and heating dress It sets, the sealing gland device is a frame-shaped construction, by upper gland, side gland, heating gland and bottom gland group At wherein closely being connected between adjacent gland；

The load indenter device includes Vertical loading pressure head, horizontal addload pressure head and shearing pressure head, the Vertical loading Pressure head is located on the upper gland, and the horizontal addload pressure head is located on the side gland, the shearing pressure Head is located on the heating gland；

The sliding clamp device includes upper sliding clamp and sideslip dynamic pressure plate, and the upper sliding clamp is located at described hang down The lower section of straight load pressure head, the upper sliding clamp can be along the opposite slidings of the Vertical loading pressure head；The sideslip dynamic pressure There are six plate settings, wherein four are located at the side of the horizontal addload pressure head, other two is located at the shearing pressure head Side, can along the horizontal addload pressure head, shearing pressure head is opposite slides；

The hydraulic device includes hydraulic oil inlet and hydraulic oil outlet, and the hydraulic oil inlet and hydraulic oil outlet are located at The top of the heating gland, the hydraulic oil inlet are connected with hydraulic pump and fuel tank；

The heating device includes heating tank and heater strip, and the heating tank is located at the lower section of the heating gland, in institute The arrangement heater strip in the heating tank stated, the heater strip heat up the hydraulic oil in test specimen storehouse after being used to be powered.

2. it is according to claim 1 a kind of for analog force-heat-liquid coupling environment true triaxial direct shear test box, it is special Sign is: the size of the top cutout and lower part cutout is 200mm × 200mm × 150mm, top cutout with Spacing between the cutout of lower part is 10mm；The shearing sample is cube protolith sample, and size dimension is greater than 70mm And it is less than 150mm.

3. it is according to claim 2 a kind of for analog force-heat-liquid coupling environment true triaxial direct shear test box, it is special Sign is: being provided with several ball grooves one on the upper surface of the upper sliding clamp, is provided with rolling on each ball grooves one Pearl one realizes the opposite sliding of upper sliding clamp and the Vertical loading pressure head by ball one.

4. it is according to claim 3 a kind of for analog force-heat-liquid coupling environment true triaxial direct shear test box, it is special Sign is: the sideslip dynamic pressure plate and the horizontal addload pressure head are sheared and are provided with several ball grooves on the opposite face of pressure head Two, ball two is provided on each ball grooves two, is passed through ball two and is realized sideslip dynamic pressure plate and horizontal addload pressure head, shearing pressure head Opposite sliding.

5. it is according to claim 4 a kind of for analog force-heat-liquid coupling environment true triaxial direct shear test box, it is special Sign is: being linked together between adjacent gland by refractory seals pad, fastening bolt.

6. it is according to claim 5 a kind of for analog force-heat-liquid coupling environment true triaxial direct shear test box, it is special Sign is: the heating tank is rectangular recess.

7. it is according to claim 6 a kind of for analog force-heat-liquid coupling environment true triaxial direct shear test box, it is special Sign is: acoustic emission inspecting hole is arranged in the sideslip dynamic pressure plate upper end, and the sound emission inspecting hole is sent out for fixed sound Penetrate sensor.

8. a kind of analog force-heat-liquid coupling environment true triaxial direct shear test method, which is characterized in that use claim 1-7 It is described in any item a kind of for analog force-heat-liquid coupling environment large scale true triaxial direct shear test box, the test method Successively the following steps are included:

A, test specimen is prepared, is prepared respectively having a size of 200mm × 200mm × 150mm top cutout and lower part cutout, preparation Cube protolith sample is as shearing sample；

B, install, by horizontal addload pressure head be embedded in side gland, will shearing pressure head insertion heating gland, by two side glands, Two heating glands and bottom gland are fixed to each other and seal；Acoustic emission sensor is embedded in sound emission inspecting hole, by Slideslip The opposite side that pressing plate is placed in horizontal addload pressure head, shears pressure head；Top cutout, lower part cutout are placed in test cabin In, successively cover upper sliding clamp, Vertical loading pressure head and upper gland, and fixing seal；

The large scale true triaxial direct shear test box is placed in be tested in true triaxial pressure testing machine, utilizes high pressure resistant hose By hydraulic oil inlet, hydraulic oil outlet connection hydraulic pump and fuel tank, connecting acoustic emission sensor and heater strip；

C, hydraulic oil, pressure build up are injected, hydraulic oil is injected to test cabin by hydraulic oil inlet using hydraulic pump, is powered on Hydraulic oil is heated using heater strip, hydraulic oil oil temperature is monitored by external temp sensor, to reach experimental condition；Increase oil Straightening is to meeting hydraulics；

D, it tests, opens true triaxial pressure testing machine, apply vertical stress and horizontal stress, by acoustic emission monitor(ing) device to examination Sample is monitored, and applies shear stress until sample destroys；Release confining pressure, extraction hydraulic oil after the test, observation examination Sample failure mode discloses shear fissure Dynamic Evolution Characteristics and sliding rupture mechanism in conjunction with test data and crack propagation form.