CN111965091A - Rock seepage characteristic testing device and method under thermal shock and dynamic shock coupling - Google Patents

Abstract

The invention discloses a test device and method for rock seepage characteristics under the coupling of thermal shock and dynamic shock. The test device includes a true triaxial stress loading system and a thermal shock generating mechanism, an upper loading head and a rear end of the true triaxial stress loading system. The loading end faces of the loading head and the right loading head are all cut with criss-cross infiltration guide grooves, and the liquid inlet channels connected to the infiltration guide grooves are set inside; the loading end faces of the lower loading head, the front loading head and the left loading head There are criss-crossing liquid collecting guide grooves cut on the upper part, and a liquid return flow channel connected with the liquid collecting guide groove is set inside. The perturbation incident rod. The application can simulate the in-situ high stress, high ground temperature, high seepage pressure, high temperature difference and dynamic load action environment of rocks, and can analyze and study the rock seepage characteristics in a multi-field coupling environment.

Description

Device and method for testing rock seepage characteristics under the coupling of thermal shock and dynamic shock

technical field

The invention belongs to the technical field of deep rock testing, and in particular relates to a device and method for testing rock seepage characteristics under the coupling of thermal shock and dynamic shock.

Background technique

In recent years, with the rapid development of geotechnical engineering construction in my country, the problems of geotechnical engineering have become increasingly complex. However, bridges and tunnels on the entire Sichuan-Tibet Railway account for more than 80% of the 1,200km area. The construction of the project faces unprecedented engineering geological challenges and faces special geological conditions such as high cold, high ground stress, high water pressure, and high ground temperature. Under the multi-field coupling action of high ground stress, high ground temperature, high seepage pressure, high temperature difference and dynamic load, the catastrophic process and mechanism of rock and soil show particularity and complexity.

Taking tunnel construction as an example, the dynamic disturbance of the excavation and unloading process is coupled with the problem of high rock temperature drop. The stress field and temperature field are destroyed, and even lead to changes in the structural characteristics of the rock mass, as well as changes in its permeability characteristics, and then lead to disaster consequences; the changes in the dynamic and static characteristics of the rock under the action of this dynamic load disturbance and thermal shock of high temperature difference are the cause of seepage flow. The direct cause of disaster consequences such as mutation. Therefore, in the face of new problems and challenges, it is urgent to carry out analysis and research on the characteristics of rock seepage under the coupling of dynamic disturbance and thermal shock.

However, the existing test equipment cannot meet the above requirements of multi-field coupling and dynamic disturbance direction coupling. Part of the test equipment, for example, the method for determining the thermal shock factor in the process of rock thermal shock fracture disclosed in the patent CN109709135A, can only achieve the thermal shock effect of the rock under the condition of water bath heating, but cannot be close to the in-situ geological conditions and working conditions of the rock. conditions, and further test the process changes of rock properties. In reality, various physical and mechanical properties of rock and soil will show complex and differentiated results due to changes in the actual geological conditions and working conditions.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a device and method for testing rock seepage characteristics under the coupling of thermal shock and dynamic shock. This application can simulate the in-situ high stress, high temperature, high seepage pressure, high temperature difference and dynamic load action environment of rocks, and can analyze and study the rock seepage characteristics in a multi-field coupling environment.

To achieve the above object, the application adopts the following technical solutions:

A test device for rock seepage characteristics under the coupling of thermal shock and dynamic shock, including a true triaxial stress loading system for applying a true triaxial load to the rock specimen and a thermal shock generating mechanism for applying the thermal shock load to the rock specimen, so The true triaxial stress loading system includes an upper loading head, a lower loading head, a front loading head, a rear loading head, a left loading head and a right loading head;

The loading end faces of the upper loading head, the rear loading head and the right loading head are all cut with crisscross infiltration guide grooves, and the interior is provided with a liquid inlet flow channel that communicates with the infiltration guide groove;

The loading end faces of the lower loading head, the front loading head and the left loading head are all cut with criss-crossing liquid collecting guide grooves, and a liquid return channel communicated with the liquid collecting guide groove is arranged inside, and the liquid inlet flow Both the channel and the return flow channel are connected with the high-pressure seepage loading mechanism;

A through hole is opened in the center of the left loading head, and a disturbance incident rod for applying impact load to the rock specimen is slidably arranged in the through hole, and the disturbance incident rod is connected with the dynamic impact loading system.

Specifically, a chute is provided on the side of the through hole away from the rock specimen, the disturbance incident rod is provided with a boss matching the chute, and the extension direction of the chute is the same as that of the The sliding direction of the disturbance incident rod is parallel;

When the left loading head loads the rock specimen, the boss abuts the left end of the chute, and the disturbance incident rod is flush with the loading end face of the left loading head.

Specifically, the rock specimen is wrapped by a flexible sleeve body, and the flexible sleeve body is provided with avoidance holes corresponding to the positions of the disturbance incident rods, and seepage holes are evenly distributed on each end surface.

Specifically, each corner of the rock specimen is wrapped by a rubber sleeve frame, and the rubber sleeve frame and the upper loading head, the lower loading head, the front loading head, the rear loading head, the left loading head and the right loading head are jointly enclosed with the upper loading head, the lower loading head, and the right loading head. The rock specimen is fitted and enclosed in an osmotic loading chamber.

Specifically, the rubber sleeve frame, the upper loading head, the lower loading head, the front loading head, the rear loading head, the left loading head and the right loading head are arranged in a hollow rigid frame, and the hollow rigid frame is provided with a pressing The top-tightening mechanism of the rubber sleeve frame is described.

Specifically, the thermal shock generating mechanism includes a heating container, a hot liquid circulation pump, a condensation container and a cold liquid circulation pump;

At least one loading head of the true triaxial stress loading system is provided with a cold flow channel and a hot flow channel. The heating container, the hot liquid circulation pump and the hot flow channel are connected in sequence to form a heating circulation loop. The circulation pump and the cold flow channel are connected in sequence to form a cooling circulation loop, the heating container is filled with a heat medium, and the condensation container is filled with a cooling medium.

Specifically, the cold flow channel and the hot flow channel are all provided on the upper loading head, the lower loading head, the front loading head and the rear loading head.

Specifically, the high-pressure seepage loading mechanism includes a liquid-measuring pressure mechanism and a gas-measuring pressure mechanism;

The liquid measuring and pressurizing mechanism includes a water tank, a high-pressure advection pump and an intermediate container. The intermediate container is divided into a front cavity and a rear cavity by a piston. The water tank, the high-pressure advection pump and the front cavity are sequentially connected by pipes, so The back cavity is provided with a seepage liquid injection port and a seepage output main pipe, and the seepage output main pipe is divided into a plurality of seepage output pipes connected with the liquid inlet flow channels in each loading head of the true triaxial stress loading system, Each of the seepage output pipes is provided with a stop valve;

The return flow channel in each loading head of the true triaxial stress loading system is connected with the seepage return pipe, and both the seepage output pipe and the seepage return pipe are provided with a pressure sensor and a flow sensor;

The gas measurement and pressurization mechanism comprises a high-pressure nitrogen source, a pressure reducing valve and a gas shut-off valve connected in sequence, and the output end of the gas shut-off valve is connected to the seepage output main pipe.

Specifically, the true triaxial stress loading system further includes a static stress actuator connected to each loading head, and the disturbance incident rod is connected to the dynamic impact loading system through the corresponding static stress actuator.

The test method for rock seepage characteristics under the coupling of thermal shock and dynamic shock, using the above-mentioned test device for rock seepage characteristics under the coupling of thermal shock and dynamic shock, includes the following steps:

S1: The true triaxial load is applied to the rock specimen using the true triaxial stress loading system;

S2: While applying the true triaxial load, start the dynamic shock loading system and the thermal shock generating mechanism, and apply the shock disturbance load and thermal shock load to the rock specimen respectively;

S3: Activate the high-pressure seepage loading mechanism, and at the same time apply the true triaxial load, perform in-situ measurement of the three-dimensional permeability parameters of the rock specimen after the shock disturbance load and the thermal shock load are applied.

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

The application can simultaneously apply true triaxial static stress load, dynamic disturbance load and thermal shock load to the rock specimen, and can monitor the three-dimensional permeability change of the rock in real time in real time, effectively overcoming the deviation of the existing rock thermal shock experimental system from the original Due to the defects of the coupled environment of high static stress, dynamic disturbance and high osmotic pressure, the analysis and research of rock permeability under the multi-field coupled environment of high in-situ stress, high geothermal temperature, high osmotic pressure, high temperature difference and dynamic load are realized, which can satisfy complex engineering requirements. Research needs of the catastrophic process characteristics of rock mass under geological conditions.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

Fig. 1 is a schematic diagram of a device for testing rock seepage characteristics under the coupling of thermal shock and dynamic shock provided by the embodiment;

Fig. 2 is the X-Y plane sectional view of the rock seepage characteristic testing device under the coupling of thermal shock and dynamic shock provided by the embodiment;

Fig. 3 is the Y-Z plane sectional view of the rock seepage characteristic testing device under the coupling of thermal shock and dynamic shock provided by the embodiment;

Fig. 4 is the axonometric view of the loading head involved in the embodiment;

5 is an exploded view of the loading head involved in the embodiment;

FIG. 6 is an axonometric view of the cold-heat convection circulation tube involved in the embodiment

7 is an axonometric view of the left loading head involved in the embodiment;

8 is a cross-sectional view of the left loading head involved in the embodiment;

Fig. 9 is the axonometric view of the right loading head involved in the embodiment;

FIG. 10 is an exploded view of the heat shield according to the embodiment;

11 is an axonometric view of the reaction force frame involved in the embodiment;

12 is a cross-sectional view of the reaction force frame involved in the embodiment;

13 is an exploded view of the boundary seepage seal loading device involved in the embodiment;

Fig. 14 is an axonometric view of a square rock specimen carrying a flexible sleeve body involved in the embodiment.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

Referring to Fig. 1, a test device for rock seepage characteristics under the coupling of thermal shock and dynamic shock includes a true triaxial stress loading system 2 for applying true triaxial load to rock specimen 1, and applying thermal shock load to rock specimen 1. The thermal shock generating mechanism 3 , the true triaxial boundary seepage sealing mechanism 6 and the control and monitoring mechanism 7 sealed at the junction of each surface of the rock specimen 1 .

Referring to Fig. 2 and Fig. 3, the true triaxial stress loading system 2 includes six loading heads arranged on the six faces of the rock specimen 1. Here, for the convenience of description, the six loading heads are named as fronts according to different orientations. Loading head 201 , rear loading head 202 , upper loading head 203 , lower loading head 204 , left loading head 205 and right loading head 206 .

Wherein, the loading end faces of the rear loading head 202, the upper loading head 203 and the right loading head 206 are all cut with crisscross infiltration guide grooves 221, and the liquid inlet channels 222 communicated with the infiltration guide grooves 221 are arranged inside; The front loading head 201, the lower loading head 204 and the left loading head 205 are all cut with crisscross liquid collecting guide grooves 223 on the loading end surfaces, and a liquid return flow channel 224 communicating with the liquid collecting guide groove 223 is arranged inside, and the liquid inlet flow Both the channel 222 and the return flow channel 224 are connected to the high-pressure seepage loading mechanism 4 .

A through hole is opened in the center of the left loading head 205, and a disturbance incident rod 225 for applying an impact load to the rock specimen 1 is slid in the through hole. The disturbance incident rod 225 is connected with the dynamic impact loading system 208, and the dynamic impact loading system 208 can use SHPB impact mechanism or dynamic impact cylinder.

This embodiment can simultaneously apply true triaxial static stress load, dynamic disturbance load and thermal shock load to the rock specimen, and can monitor the rock permeability change in three directions in real time in real time, which effectively overcomes the deviation of the existing rock thermal shock experimental system. Due to the defects of in-situ high static stress, dynamic disturbance and high osmotic pressure coupled environment, the analysis and research of rock permeability under the multi-field coupled environment of high in-situ stress, high geothermal temperature, high osmotic pressure, high temperature difference and dynamic load are realized. Research needs of the catastrophic process characteristics of rock mass under engineering geological conditions.

Referring to Fig. 14, in practical application, the rock specimen 1 is wrapped by a flexible sleeve body 801. The flexible sleeve body 801 is provided with avoidance holes corresponding to the positions of the disturbance incident rods 225, and seepage holes 802 are evenly distributed on each end face. The thickness of the flexible sleeve body 801 is generally controlled at about 1% of the side length of the rock sample 1. After the flexible sleeve body 801 wraps the rock sample 1, the axial sealing effect is strengthened, and the flexible boundary can also serve as a viscous boundary. It has better energy absorption effect, absorbs the stress wave that reaches the impact load at the boundary of the specimen, so as to truly simulate the infinite boundary condition of the actual rock layer, and greatly reduces the reflection effect of the stress wave on the boundary of the rock specimen 1, among which , the material of the flexible sleeve body 801 can be rubber, copper or polytetrafluoroethylene.

4-6, the front loading head 201, the rear loading head 202, the upper loading head 203, and the lower loading head 204 are mainly composed of the front loading plate 209, the cold and heat convection circulation pipe 210, the special-shaped transition plate 211 and the rear cover The plate 212 is formed by bolting from the front to the rear; wherein, the front loading plate 209 is a square high-temperature alloy plate, and the rear end surface is provided with a return-shaped pipe groove 213; the rear end of the special-shaped transition plate 211 is cylindrical, and the front end is a cube. A high temperature alloy can also be used, the front end surface of the special-shaped transition plate 211 is provided with a return-shaped pipe groove 213, and the pipe hole 214 is provided laterally from the front end surface to the rear end;

The cold and heat convection circulation pipe 210 is composed of a cold liquid inlet pipe 215, a hot liquid inlet pipe 216, a loop-shaped heat exchange pipe 217, a loop-shaped cold exchange pipe 218, a cold return pipe 219 and a heat return pipe 220; the loop-shaped heat exchange pipe 217 Consistent with the structure of the loop-shaped cold exchange tube 218, it is installed in parallel in the hole formed by the loop-shaped pipe groove 213 of the special-shaped transition plate 211 and the loop-shaped pipe groove 213 of the front loading plate 209. The loop-shaped heat exchange pipe 217 It is opposite to the liquid flow direction in the return-shaped cold exchange pipe 218; the cold liquid inlet pipe 215, the hot liquid inlet pipe 216, the cold return pipe 219 and the hot return pipe 220 pass through the pipe hole 214 in the special-shaped transition plate 211 to the back The end side surface is connected to the thermal shock generating mechanism 3; the cold liquid inlet pipe 215, the loop-shaped cold exchange pipe 218 and the cold return pipe 219 are connected in sequence to form a cold flow channel, the hot liquid inlet pipe 216, the loop-shaped heat exchange pipe 217 and The heat return pipes 220 are connected in sequence to form a heat flow channel;

The rear cover plate 212 has a cylindrical structure, and the front end is connected to the special-shaped transition plate 211 and is slotted at the cold liquid inlet pipe 215, the hot liquid inlet pipe 216, the cold return pipe 219 and the hot return pipe 220. A thermal barrier coating is applied all around.

1, the thermal shock generating mechanism 3 is mainly composed of a heating mechanism 301 and a cooling mechanism 302; wherein: the heating mechanism 301 consists of a heating machine 303, a heating container 304, a hydrothermal circulation pump 305, a hydrothermal output pipe 306 and a hydrothermal return pipe The heating machine 303 is connected to the heating container 304, and the heating container 304 is filled with high-temperature heat-conducting oil; the hydrothermal circulation pump 305 pumps the high-temperature heat-conducting oil through the hydrothermal output pipe 306 into the front loading head 201, the rear loading head 202, and the upper loading head. 203. The hot liquid inlet pipe 216 of the cold and hot convection circulation pipe 210 in the lower loading head 204 is recycled to the heating container 304 through the hot liquid return pipe 307 connected to the heat return pipe 220 after backflow;

The refrigeration mechanism 302 is composed of a refrigerator 308, a condensing container 309, a cold liquid circulation pump 310, a cold liquid output pipe 311 and a cold liquid return pipe 312; the refrigerator 308 is connected to the condensing container 309, and the condensing container 309 is filled with ethylene glycol refrigeration liquid; The cold liquid circulation pump 310 pumps the ethylene glycol refrigerant through the cold liquid output pipe 311 into the cold liquid inlet pipe of the cold and hot convection circulation pipe 210 in the front loading head 201, the rear loading head 202, the upper loading head 203, and the lower loading head 204. 215. After reflux, it is recovered to the condensing container 309 through the cold liquid return pipe 312 connected to the cold return pipe 219.

Referring to FIGS. 3-9 , the loading end surfaces of the front loading plates 209 of the rear loading head 202 and the upper loading head 203 are further provided with criss-cross infiltration guide grooves 221 , and the special-shaped transition plates 211 of the rear loading head 202 and the upper loading head 203 A liquid inlet channel 222 connected to the infiltration guide groove 221 is provided from the center of the front end to the side surface of the rear end, and the loading end surfaces of the front loading plates 209 of the front loading head 201 and the lower loading head 204 are also provided with criss-crossing liquid collecting guide grooves 223. A liquid return flow channel 224 connected to the liquid collecting channel 223 is provided on the front-end center to the rear-end side surface of the special-shaped transition plates 211 of the front loading head 201 and the lower loading head 204 .

Referring to FIGS. 7 and 8 , the loading surface of the loading plate 226 of the left loading head 205 is provided with criss-crossing liquid collecting guide grooves 223 , and the front side of the loading plate 226 to the rear side is provided with a liquid return flow that communicates with the liquid collecting guide groove 223 There is also a circular through hole 228 in the center of the loading plate 226, and an annular groove 229 is opened around the through hole 228 near the front end of the loading surface. The disturbance incident rod 225 is a round rod-shaped alloy rod, which is coaxially installed in the through hole 228 through the sealing ring 227. The boss 231 matched with the chute 230, the extension direction of the chute 230 is parallel to the sliding direction of the disturbance incident rod 225; the length of the chute 230 is greater than the width of the boss 231, during assembly, the disturbance incident rod 225 and the loading plate 226 The loading end face of the shovel is flush, and the boss 231 is in contact with the left end of the chute 230, so that the disturbance incident rod 225 can be affected by the static stress actuator 207 to apply static stress to eliminate the front-end stress blank, and can also be affected by the dynamic impact loading system. Apply strong dynamic disturbances.

Referring to FIG. 9 , the loading end face of the right loading head 206 is cut with criss-cross infiltration guide grooves 221 , and the inside of the right loading head 206 is provided with a liquid inlet channel 222 connected to the infiltration channel 221 . One end protrudes from the side of the right loading head 206 .

2 and 3, six sets of static stress actuators 207 of the true triaxial stress loading system 2 are provided, which are respectively connected to the front loading head 201, the rear loading head 202, the upper loading head 203, the lower loading head 204, and the left loading head The rear end surface of the head 205 and the right loading head 206; the static stress actuator 207 connected with the left loading head 205 has an opening in the middle for connecting the disturbance incident rod 225 to the dynamic impact loading system.

Referring to FIG. 1 , the high-pressure seepage loading mechanism 4 is mainly composed of a liquid measuring pressure mechanism 401 , a gas measuring pressure mechanism 402 , a seepage flow output main pipe 403 , a first seepage flow output pipe 404 , a second seepage flow output pipe 405 , and a third seepage flow output pipe 406 , the first seepage flow return pipe 407, the second seepage flow return pipe 408 and the third seepage flow return pipe 409 are composed;

The liquid measuring and pressurizing mechanism 401 is composed of a water tank 410, a high-pressure advection pump 411, an intermediate container 412 and a liquid stop valve 413. The water tank 410, the high-pressure advection pump 411, the intermediate container 412 and the liquid stop valve 413 are sequentially connected by a high-pressure pipeline The intermediate container 412 is slidably provided with a piston 414, which divides the intermediate container 412 into a front chamber 415 and a rear chamber 416, the front chamber 415 is hydraulically connected with the high-pressure advection pump 411, and the rear chamber 416 is connected with the liquid stop valve 413 by the liquid. The seepage output main pipe 403 is hydraulically connected, and the back chamber 416 is also provided with a seepage liquid injection port 417;

The gas measurement pressurizing mechanism 402 is made up of the high pressure nitrogen cylinder 418, the pressure reducing valve 419 and the gas stop valve 420 connected in sequence; the gas stop valve 420 output end is connected to the seepage output main pipe 403;

The seepage output main pipe 403 is connected to the first seepage output pipe 404, the second seepage output pipe 405 and the third seepage output pipe 406 through the first stop valve 421, the second stop valve 422 and the third stop valve 423 respectively; the first seepage output The pipe 404, the second seepage output pipe 405, and the third seepage output pipe 406 are further connected to the liquid inlet channels 222 of the upper loading head 203, the rear loading head 202 and the right loading head 206; The seepage output pipe 405 and the third seepage output pipe 406 are connected with a pressure sensor 424 and a flow sensor 425;

The first seepage return pipe 407, the second seepage return pipe 408 and the third seepage return pipe 409 are respectively connected with the return flow channels 224 of the lower loading head 204, the front loading head 201 and the left loading head 205; the first seepage return pipe 407 , the second seepage return pipe 408 and the third seepage return pipe 409 are connected with a pressure sensor 424 and a flow sensor 425 .

1 , 2 , 3 and 10 , a thermal insulation mechanism 5 is provided between the static stress actuator 207 and the corresponding loading head, and the thermal insulation mechanism 5 consists of a thermal insulation plate connected to the front end of the static stress actuator 207 501. The cooling channel 502 and the cooling tower 503 are composed; the heat insulating plate 501 is composed of the front clapboard 504, the central stress connecting column 505, the boundary stress connecting cylinder 506, the spiral cooling pipe 507 and the rear clapboard 508; the central stress connecting column 505 It is concentrically assembled with the boundary stress connecting cylinder 506, and a spiral cooling pipe 507 is installed in the annular gap formed therebetween, and the two ends cover the front baffle plate 504 and the rear baffle plate 508 respectively; The space between the outer boundary stress connecting cylinders 506 is filled with thermally conductive material; the two ends of the spiral cooling pipe 507 are respectively pierced through the incisions at both ends of the boundary stress connecting cylinder 506, and are connected to the cooling tower 503 through the cooling flow channel 502; the inside of the spiral cooling pipe 507 The cooling liquid flows in from the end of the rear partition plate 508 close to the static stress actuator 207, and flows out from the front partition plate 504 after passing through the spiral flow. to connect the disturbance incident rod 225.

1 , 11 , 12 and 13 , the true triaxial boundary seepage seal mechanism 6 consists of a cubic hollow rigid frame 601 and six sets of boundary seepage seal loading devices 602 (top It is composed of an oil supply mechanism 603 that provides oil pressure for the boundary seepage seal loading device 602;

The hollow rigid frame 601 is a hollow cube structure, which is mainly composed of an outer hollow cubic frame 604 and an inner hollow cubic frame 605 (plastic sleeve frame). The outer hollow cubic frame 604 is made of alloy material, and each outer side is provided with stepped square nesting windows 606 for fixing the boundary seepage sealing loading device 602; the inner hollow cubic frame 605 is arranged inside the outer hollow cubic frame 604 and is made of high temperature rubber material ; The outer side of each edge of the inner hollow cubic frame 605 is closely fitted with the corresponding edges of the outer hollow cubic frame 604, and semicircular steps 607 protrude on both sides of the joint for fitting with the boundary seepage sealing loading device 602; A right-angled groove 608 is cut inside each edge of the hollow cubic frame 605, and the right-angled groove 608 is attached to the junction of each surface of the specimen not covered by the loading head (that is, the corner of the rock specimen 1).

The rock specimen 1 is installed on the inner hollow cubic frame 605. After wrapping the corners of the rock specimen 1, the inner hollow cubic frame 605 and the rock specimen 1 are put into the outer hollow cubic frame 604 as a whole. The front loading head 201, the rear The loading head 202 , the upper loading head 203 , the lower loading head 204 , the left loading head 205 and the right loading head 206 are respectively inserted into the inner hollow cubic frame 605 from the square nesting windows 606 on the corresponding faces of the outer hollow cubic frame 604 , and It is in close contact with the end face of the rock specimen 1, and the boundary seepage sealing loading device 602 arranged in the outer hollow cubic frame 604 tightly presses the rubber sleeve frame against the rock sample 1, so that the rubber sleeve frame and the front loading head 201, The rear loading head 202 , the upper loading head 203 , the lower loading head 204 , the left loading head 205 and the right loading head 206 together enclose a permeable loading chamber adapted to the rock specimen 1 and closed.

The boundary seepage sealing loading device 602 is composed of a looped hydraulic base 609, a looped hydraulic oil chamber cover 610 and a looped loading pad 611; the looped hydraulic base 609 has a stepped square outer contour, and a loading head is opened in the center of the upper and lower end faces Through hole 612; the upper end of the return-shaped hydraulic base 609 is provided with a return-shaped hydraulic oil cavity 613 around the loading head through-hole 612, and the lower end of the hydraulic oil cavity 613 is provided with four groups of cylindrical piston cavities 614 that pass through to the return-shaped hydraulic base 609 The lower end face; each of the four groups of piston chambers 614 is provided with a hydraulic jacking piston 615, the upper ends of the four hydraulic jacking pistons 615 are connected to the hydraulic oil chamber 613, and the lower ends protrude from the lower end face of the loop hydraulic base 609, and are connected to the loop loading Pad 611; the cover plate 610 of the return-shaped hydraulic oil chamber is used to cover the upper end of the hydraulic oil chamber 613, and is fastened to the upper end of the return-shaped hydraulic base 609 through the sealing bolt 616; the cover plate 610 of the return-shaped hydraulic oil chamber is provided with an oil injection Port 617, one end of the oil filling port 617 is connected to the hydraulic oil chamber 613, and the other end is connected to the oil supply mechanism 603; the upper end face of the hydraulic base 609 is also provided with a reaction force bolt hole 618, and the boundary seepage is sealed by the tightening bolt 619. Loading device 602 It is fixed on each surface of the outer hollow cubic frame 604 .

The oil supply mechanism 603 is composed of an oil tank 620, a first oil supply advective pump 621, a second oil supply advective pump 622, a third oil supply advective pump 623, and three sets of heat-insulating oil filling intermediate containers 624 connected to each oil supply advective pump. The output port of the first oil supply advection pump 621 is connected with the oil injection port 617 of the front and rear boundary seepage seal loading device 602 through the heat insulation oil filling intermediate container 624 by a high pressure pipeline, and a first oil pressure sensor 625 is arranged on the high pressure pipeline; The output port of the oil advection pump 622 is connected with the oil filling port 617 of the boundary seepage sealing loading device 602 at the upper and lower ends through the heat insulating oil filling intermediate container 624 by a high pressure pipeline, and a second oil pressure sensor 626 is arranged on the high pressure pipeline; the third oil supply The output port of the advective pump 623 is connected with the oil filling port 617 of the left and right boundary seepage seal loading device 602 through the heat insulating oil filling intermediate container 624 by a high pressure pipeline, and a third oil pressure sensor 627 is arranged on the high pressure pipeline.

1, the control and monitoring mechanism 7 is composed of an industrial computer 701, a pressure flow collector 702 and a servo controller 703; the pressure flow collector 702 is connected to the first seepage output pipe 404, the second seepage output pipe 405, and the third seepage output The six groups of pressure sensors 424 and flow sensors 425 on the pipe 406 , the first seepage return pipe 407 , the second seepage return pipe 408 and the third seepage return pipe 409 are electrically connected; The first oil pressure sensor 625, the second oil pressure sensor 626 and the third oil pressure sensor 627 are electrically connected; the servo controller 703 is connected to the high pressure advection pump 411, the first oil supply advection pump 621, the second oil supply advection pump 622, The third oil supply advective pump 623 , the heater 303 , the refrigerator 308 and the cooling tower 503 are electrically connected.

Referring to Figure 1 to Figure 14, the test method of rock seepage characteristics under the coupling of thermal shock and dynamic shock The test method of rock seepage characteristics under the coupling of thermal shock and dynamic shock of the device includes the following steps:

S1: The true triaxial load is applied to the rock specimen using the true triaxial stress loading system;

S2: While applying the true triaxial load, start the dynamic shock loading system and the thermal shock generating mechanism, and apply the shock disturbance load and thermal shock load to the rock specimen respectively;

S3: Activate the high-pressure seepage loading mechanism, and at the same time apply the true triaxial load, perform in-situ measurement of the three-dimensional permeability parameters of the rock specimen after the shock disturbance load and the thermal shock load are applied.

Specifically, it includes the following steps:

The first step is to assemble the rock specimen 1 and the loading device:

First, a square rock specimen 1 is prepared, and the flexible sleeve body 801 is wrapped outside the rock specimen 1; then the specimen is put into the inner hollow cubic frame 605 of the hollow rigid frame 601, so that the right-angled groove 608 inside each edge is connected to the inner hollow cubic frame 605 of the hollow rigid frame 601. The junctions of each surface of the corresponding specimen should be close to each other at right angles;

Further, the front loading head 201 , the rear loading head 202 , the upper loading head 203 , the lower loading head 204 , the left loading head 205 and the right loading head 206 are nested in a square shape corresponding to the surface of the outer hollow cubic frame 604 of the hollow rigid frame 601 . The window 606 is inserted into the inner hollow cubic frame 605, and the front end is in close contact with the end face of the square rock specimen 1;

Further, six groups of boundary seepage seal loading devices 602 are installed into the square nesting windows 606 on the corresponding surfaces of the outer hollow cubic frame 604, and the boundary seepage seal loading devices 602 are fixed on each surface of the outer hollow cubic frame 604 by tightening bolts 619. ; Make the lower end surface of the back-shaped loading pad 611 fit with the semicircular step 607 protruding from the inner hollow cubic frame 605 .

The second step is to connect the true three-axis loading platform:

The six groups of heat shields 501 are respectively connected to the rear surfaces of the front loading head 201, the rear loading head 202, the upper loading head 203, the lower loading head 204, the left loading head 205 and the right loading head 206; The static stress actuator 207 is then connected, the disturbance incident rod 225 is connected to the dynamic impact loading system; in addition, other pipelines and circuits are connected.

The third step is to apply static stress load and boundary seal pressure:

According to the measurement results of in-situ stress, the required true triaxial triaxial stress is calculated, and six groups of static stress actuators 207 are used to load the square rock specimen 1 in stages to the set load;

Further, according to the applied true triaxial triaxial stress and the contact area of the right-angled groove 608 of the inner hollow cubic frame 605, the oil pressure required by the boundary seepage seal loading device 602 is calculated; the first oil supply advective pump 621 and the second oil supply are activated. The advection pump 622 and the third oil supply advection pump 623 are respectively set with their rated injection pressures, and then respectively inject hydraulic oil into the corresponding heat insulation oil filling intermediate containers 624, and then inject the hydraulic oil into the heat insulation oil filling intermediate containers 624 respectively. The oil filling port 617 of the sealing loading device 602 is seeped to the corresponding front and rear, upper and lower, and left and right boundaries; after the hydraulic oil flows into the hydraulic oil chamber 613, the four hydraulic jacking pistons 615 are extended under the action of oil pressure, and push the back-shaped loading pad 611 pressurizes the semicircular step 607 protruding from the inner hollow cubic frame 605, and then applies sealing pressure to the boundary right angle at the right angle groove 608; through the corresponding first oil pressure sensor 625, second oil pressure sensor 626 and third oil pressure The pressure sensor 627 monitors the pressurization process until the sealing pressure at the right-angle groove 608 reaches the corresponding static load stress value of the loading surface of the square rock specimen 1;

The fourth step, initial temperature load application

First, start the cooling tower 503, so that the cooling liquid in the cooling tower 503 circulates stably in the spiral cooling pipes 507 of each cooling and heat insulation plate 501 through the cooling flow channel 502;

Start the heating machine 303 and set it to the initial target temperature of the temperature field, and then start the hydrothermal circulation pump 305 to pump the high-temperature heat-conducting oil into the front loading head 201, the rear loading head 202, the upper loading head 203, and the lower loading head 204. The convection cycle of cold and heat The hot liquid inlet pipe 216 of the pipe 210 is returned to the heating container 304 through the hydrothermal liquid return pipe 307 to form a thermal circulation path, and the square rock specimen 1 is heated on all sides until it reaches the initial temperature field environment.

The fifth step, the three-way initial penetration parameter measurement of the specimen

According to the test requirements, choose the liquid permeability test or the gas test permeability plan;

When the liquid measuring permeability scheme is adopted, firstly close the gas stop valve 420 of the gas measuring pressurizing mechanism 402, disconnect the passage with the seepage output main pipe 403, and open the liquid stop valve 413 to make the liquid measuring pressurizing mechanism 401 and seepage output Mains 403 is turned on. Then, open the first shut-off valve 421 or the second shut-off valve 422 or the third shut-off valve 423, so that the corresponding first seepage output pipe 404 or the second seepage output pipe 405 or the third seepage output pipe 406 is communicated with the seepage output main pipe 403 . Further, the seepage fluid is injected into the back chamber 416 of the intermediate container 412 from the seepage fluid injection port 417, and the rated fluid injection pressure of the high pressure advection pump 411 is set according to the required seepage pressure; after starting the high pressure advection pump 411, the high pressure advection pump 411 411 injects distilled water into the front volume chamber 415 of the intermediate container 412, and pushes the seepage liquid in the rear volume chamber 416 into the first seepage output pipe 404 or the second seepage output pipe 405 or the third seepage output pipe 406 through the seepage output header 403, and then Through the corresponding upper loading head 203 or the rear loading head 202 or the right loading head 206, the liquid inlet channel 222, the seepage channel and the seepage plate 801 infiltrate into one end of the rock specimen 1, and from the corresponding seepage plate 801, collector at the other end. The liquid channel 223 and the liquid return channel 224 flow out of the first seepage return pipe 407 or the second seepage return pipe 408 or the third seepage return pipe 409 . According to the indications of the pressure sensor 424 and the flow sensor 425, calculate the initial liquid permeability coefficient of the simulated rock specimen 1 in three directions;

When the gas measurement permeability scheme is adopted, first, the liquid stop valve 413 of the liquid measurement pressurizing mechanism 401 is disconnected from the passage with the seepage output main pipe 403, and the gas stop valve 420 is opened to connect the gas measurement pressurization mechanism 402 to the seepage output main pipe. 403 is on. Then, open the first stop valve 421 or the second stop valve 422 or the third stop valve 423, so that the corresponding first seepage output pipe 404 or the second seepage output pipe 405 or the third seepage output pipe 406 is communicated with the seepage output main pipe 403 . Further, adjust the pressure reducing valve 419 to the test pressure, so that the high-pressure nitrogen gas is input into the first seepage output pipe 404 or the second seepage output pipe 405 or the third seepage output pipe 406 through the seepage output main pipe 403, and then passes through the corresponding loading head. 203 or the back loading head 202 or the right loading head 206, the inlet flow channel 222, the seepage guide groove and the seepage plate 801 seep into one end of the rock specimen 1, and the corresponding seepage plate 801, the collecting guide groove 223 and the return flow plate 801 from the other end. The liquid flow channel 224 flows out of the first seepage return pipe 407 or the second seepage return pipe 408 or the third seepage return pipe 409 . According to the indications of the pressure sensor 424 and the flow sensor 425, calculate the initial gas permeability coefficient of the simulated rock specimen 1 in three directions;

The sixth step is to apply the perturbation load

According to the dynamic disturbance loads such as blasting or impact applied under the actual working conditions, parameters such as waveform, delay time and impact cycle times of the simulated disturbance load are calculated, so as to select the loading form such as SHPB impact mechanism or dynamic impact oil cylinder for the dynamic impact loading system 208 ; Then, start the dynamic impact loading system, apply impact load to the disturbance incident rod 225 of the left loading head 205, and act on one side of the square rock specimen 1;

Step 7, Apply Thermal Shock Load

First, the heating mechanism 301 is turned off, and the application of the initial temperature load to the rock specimen 1 is terminated; then, the cooling temperature of the condensing container 309 of the refrigeration mechanism 302 is set, and the ethylene glycol refrigerant in the condensing container 309 is cooled by the refrigerant to the set temperature. Then start the cold liquid circulation pump 310, and set the pumping rate of the cold night circulation pump according to the cooling rate, and output the ethylene glycol refrigeration liquid from the cold liquid output pipe 311 to the front loading head 201, the rear loading head 202, the upper The cold liquid inlet pipe 215 of the cold and hot convection circulation pipe 210 in the loading head 203 and the lower loading head 204 is recovered to the condensation container 309 through the cold liquid return pipe 312 after reflux to form a cold circulation path, and the setting is applied to the four sides of the square rock specimen 1. The low temperature load of the speed is completed, and the thermal shock process from the initial high temperature to the rapid low temperature cooling is completed;

In addition, steps 4, 6 and 7 can be repeated according to the actual working conditions;

The eighth step, the three-way penetration parameter measurement of the specimen after the coupling of thermal shock and dynamic shock

Repeat step 5 to measure the three-dimensional permeability parameters of the specimen after the coupling of thermal shock and dynamic shock, and evaluate the change parameters of the permeability characteristics of rock specimen 1.

The application effectively overcomes the defects of the existing rock thermal shock experiment system deviating from the in-situ high static stress, dynamic disturbance and high osmotic pressure coupled environment, and can simulate the in-situ high stress, high temperature, high osmotic pressure, high temperature difference and dynamic load of rocks. It can realize the whole-process analysis of rock seepage characteristics and other physical and mechanical performance parameters under the coupling of thermal shock and dynamic shock, and meet the research needs of the catastrophic process characteristics of rock mass under complex engineering geological conditions.

The above-mentioned embodiments are only examples to clearly illustrate the present invention, and are not intended to limit the embodiments. For those of ordinary skill in the art, on the basis of the above description, other different forms of changes or modifications can also be made. Neither need nor can all embodiments be exhaustive here. And the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (10)

1. The rock seepage characteristic testing device under the coupling of thermal shock and dynamic shock comprises a true triaxial stress loading system for applying true triaxial load to a rock test piece and a thermal shock generating mechanism for applying thermal shock load to the rock test piece, wherein the true triaxial stress loading system comprises an upper loading head, a lower loading head, a front loading head, a rear loading head, a left loading head and a right loading head, and is characterized in that:

the loading end surfaces of the upper loading head, the rear loading head and the right loading head are all cut with criss-cross infiltration guide grooves, and liquid inlet flow channels communicated with the infiltration guide grooves are arranged inside the loading end surfaces;

the loading end surfaces of the lower loading head, the front loading head and the left loading head are all cut with criss-cross liquid collecting guide grooves, liquid return channels communicated with the liquid collecting guide grooves are arranged in the lower loading head, the front loading head and the left loading head, and the liquid inlet channels and the liquid return channels are both connected with a high-pressure seepage loading mechanism;

the center of the left loading head is provided with a through hole, a disturbance incident rod for applying impact load to a rock test piece is arranged in the through hole in a sliding mode, and the disturbance incident rod is connected with a dynamic impact loading system.

2. The device for testing the seepage characteristics of the rock under the coupling of the thermal shock and the dynamic shock according to claim 1, is characterized in that: a chute is arranged on one side of the through hole, which is far away from the rock test piece, a boss matched with the chute is arranged on the disturbance incident rod, and the extending direction of the chute is parallel to the sliding direction of the disturbance incident rod;

when the left loading head loads the rock test piece, the boss is abutted to the left end of the sliding groove, and the disturbance incident rod is flush with the loading end face of the left loading head.

3. The device for testing the seepage characteristics of the rock under the coupling of the thermal shock and the dynamic shock according to claim 1, is characterized in that: the rock test piece is wrapped up by the flexible sleeve body, be equipped with on the flexible sleeve body with the hole of dodging that disturbance incident rod position corresponds, and the equipartition has the seepage hole on each terminal surface.

4. The device for testing the seepage characteristics of the rock under the coupling of the thermal shock and the dynamic shock according to claim 1, is characterized in that: and each corner of the rock test piece is wrapped by a rubber sleeve frame, and the rubber sleeve frame, the upper loading head, the lower loading head, the front loading head, the rear loading head, the left loading head and the right loading head jointly enclose a penetration loading chamber which is matched with the rock test piece and is closed.

5. The device for testing the seepage characteristics of the rock under the coupling of the thermal shock and the dynamic shock according to claim 4, is characterized in that: the rubber sleeve frame, the upper loading head, the lower loading head, the front loading head, the rear loading head, the left loading head and the right loading head are arranged in a hollow rigid frame, and a jacking mechanism for tightly pressing the rubber sleeve frame is arranged in the hollow rigid frame.

6. The device for testing the seepage characteristics of rocks under the coupling of thermal shock and dynamic shock according to any one of claims 1 to 5, characterized in that: the thermal shock generating mechanism comprises a heating container, a hot liquid circulating pump, a condensing container and a cold liquid circulating pump;

the device comprises a true triaxial stress loading system and is characterized in that a cold flow channel and a hot flow channel are arranged in at least one loading head of the true triaxial stress loading system, a heating container, a hot liquid circulating pump and the hot flow channel are sequentially connected to form a heating circulation loop, a condensing container, the cold liquid circulating pump and the cold flow channel are sequentially connected to form a cooling circulation loop, a heat medium is injected into the heating container, and a cold medium is injected into the condensing container.

7. The device for testing the seepage characteristics of the rock under the coupling of the thermal shock and the dynamic shock according to claim 6, is characterized in that: the upper loading head, the lower loading head, the front loading head and the rear loading head are respectively provided with the cold flow channel and the hot flow channel.

8. The device for testing the seepage characteristics of rocks under the coupling of thermal shock and dynamic shock according to any one of claims 1 to 5, characterized in that: the high-pressure seepage loading mechanism comprises a liquid measurement pressurizing mechanism and a gas measurement pressurizing mechanism;

the liquid measurement pressurizing mechanism comprises a water tank, a high-pressure advection pump and an intermediate container, the intermediate container is divided into a front containing cavity and a rear containing cavity through a piston, the water tank, the high-pressure advection pump and the front containing cavity are sequentially connected through a pipeline, a seepage liquid injection port and a seepage output main pipe are arranged on the rear containing cavity, the seepage output main pipe is divided into a plurality of seepage output pipes communicated with liquid inlet flow channels in the loading heads of the true triaxial stress loading system, and each seepage output pipe is provided with a stop valve;

a liquid return flow channel in each loading head of the true triaxial stress loading system is connected with a seepage return pipe, and a pressure sensor and a flow sensor are arranged on the seepage output pipe and the seepage return pipe;

the gas survey pressurization mechanism includes high-pressure nitrogen gas source, relief pressure valve and the gas stop valve of connecting in order, the output of the gas stop valve is connected seepage flow output house steward.

9. The device for testing the seepage characteristics of rocks under the coupling of thermal shock and dynamic shock according to any one of claims 1 to 5, characterized in that: the true triaxial stress loading system further comprises static stress actuators connected with the loading heads, and the disturbance incident rod penetrates through the corresponding static stress actuators to be connected with the dynamic impact loading system.

10. The method for testing the seepage characteristics of the rock under the coupling of thermal shock and dynamic shock is characterized by comprising the following steps of: the device for testing the seepage characteristics of rocks under the coupling of thermal shock and dynamic shock according to any one of claims 1 to 9, comprising the following steps:

s1: applying true triaxial load to the rock test piece by using a true triaxial stress loading system;

s2: when true triaxial load is applied, a dynamic impact loading system and a thermal impact generating mechanism are started, and impact disturbance load and thermal impact load are applied to the rock test piece respectively;

s3: and starting the high-pressure seepage loading mechanism, and carrying out in-situ measurement on three-way seepage parameters of the rock test piece after the impact disturbance load and the thermal shock load are applied while the true triaxial load is applied.

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