Plate-shaped fracture body model hydraulic coupling test process visualization device

Abstract

The application provides a plate-shaped fracture body model hydraulic coupling test process visualization device, which is characterized in that: an image acquisition system for acquiring the whole process of fracture generation and expansion on the fracture body model is connected to the side wall of a test cavity, a water pressure sealing device is arranged on the through fracture of the fracture body model, and the fracture water pressure inside the fracture body model is ensured to be less than the lateral water pressure outside the fracture body model during the test process, so as to utilize the pressure difference between the lateral water pressure and the fracture water pressure, the mutual relationship between the mica sheet, the vaseline and the rubber sleeve in the water pressure sealing device and the fracture body model, realize the pressure maintaining problem of the high-pressure fracture water in the fracture body model during the test process, and ensure the reliability of the collected data. Through the above-mentioned mode, the purpose of directly tracking and observing the crack shape and the dynamic expansion process under the high-stress and high-water-pressure coupling effect is realized, the test process is closer to the environment in which the fractures are generated in the actual rock mass, and an effective implementation method for studying the rock mass performance is provided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rock performance testing, and particularly relates to a device for visualizing the process of a hydraulic coupling test of a plate-shaped fracture body model. BACKGROUND

[0002] Rock mass hydraulic coupling refers to a physical process in which a mechanical process and a seepage process interact with each other. Under the coupling action of high ground stress and high fracture water pressure, the original fracture of an engineering rock mass is prone to expansion and mutual penetration, which leads to weakening of the rock mass strength and instability and destruction of an engineering structure. Since the destruction process of the engineering rock mass is directly related to the dynamic expansion of the fracture in the rock mass, in order to scientifically analyze the deformation and destruction process of the engineering rock mass and clarify the rock mass fracture mechanics mechanism, it is necessary to directly observe or detect the morphological parameters such as the fracture development and expansion in the engineering rock mass, and to master the evolution law of the fracture expansion and penetration under the hydraulic coupling action of the engineering rock mass.

[0003] In order to directly observe the rock mass destruction and crack expansion process in the hydraulic coupling process, researchers have made many technical innovations. In the prior art, a patent document with the application number 201711120001.X and the publication date of June 2, 2020 and the name of "a visualized coal rock mechanical behavior monitoring test device" discloses a test device with a built-in steel pressure-resistant cavity endoscope. The test device simulates the stress condition of the coal rock mass under long-term high ground stress environment in the mining process by continuously and stably applying confining pressure and axial pressure to the fracture body model. The test device collects various strain signals, acoustic emission signals, electrical signals and appearance image signals of the sample generated during the entire loading process of the sample. According to the signals, the axial and radial strain in the long-term evolution and destruction process of the sample, the time and space evolution law of the acoustic emission signal and charge signal in the destruction process of the sample, and the destruction process of the sample can be obtained, which is more conducive to establishing the action mechanism of the high ground stress field on the mechanical behavior evolution and instability catastrophe of the coal rock mass. However, the built-in endoscope of the above-mentioned device cannot work normally in the high-pressure liquid for a long time, in addition, the built-in endoscope is filled with hydraulic oil medium between the fracture body model, and the light transmission performance of the hydraulic oil is not ideal, so that the built-in endoscope is difficult to clearly track the micro-crack development process.

[0004] Secondly, in the prior art, a patent document with application number 201821829006.X and publication date of August 6, 2019, entitled "Rock closed fracture water pressure transient change testing device under impact load" seals the first pressure head and the second pressure head at both ends of the rock test piece with glass glue, and then uses an impact device to provide impact load to the rock test piece. Under the sealing action of the first pressure head and the second pressure head on the water pressure in the rock test piece, the rock test piece produces a fracture under the action of the load. However, in the above technical solution, the glass glue is used to seal the first pressure head and the second pressure head with the rock test piece. After the fracture appears in the rock test piece under high water pressure, a gap will also appear on the glass glue, causing the high-pressure water sealed in the rock test piece to overflow, resulting in unstable pressure in the rock test piece and inaccurate water pressure analysis data.

[0005] Therefore, it is necessary to design an improved plate-shaped fracture body model hydraulic coupling test process visualization device to solve the above problems. SUMMARY

[0006] The purpose of the present application is to provide a plate-shaped fracture body model hydraulic coupling test process visualization device.

[0007] To achieve the above-mentioned purpose of the application, the present application provides a plate-shaped fracture body model hydraulic coupling test process visualization device, which comprises a steel test cavity, a top cover arranged at the upper end of the steel test cavity and a base arranged at the bottom end of the steel test cavity, the side wall of the test cavity is connected with an image acquisition system, and a pressure transmission shaft is arranged in the middle of the top cover.

[0008] The surface of the fracture body model in the interior of the test cavity is provided with a water pressure sealing device, and the base is provided with a water flow channel for injecting fracture water into the fracture body model and a water inlet channel for applying lateral pressure to the fracture body model.

[0009] Preferably, the water pressure sealing device comprises a mica sheet matched with a prefabricated fracture on the fracture body model and a rubber sleeve for fixing the mica sheet to the outer wall of the fracture body model.

[0010] Preferably, vaseline is coated between the mica sheet and the fracture body model.

[0011] Preferably, the mica sheet and the rubber sleeve are made of high-transmittance material.

[0012] Preferably, the upper surface of the base is provided with an underplate, the lower surface of the pressure transmission shaft is provided with an upper pressure disc, and the fracture body model is arranged between the upper pressure disc and the underplate.

[0013] Preferably, the image acquisition system comprises a miniature scope penetrating through the side wall of the test cavity and an image acquisition device connected with one end of the miniature scope.

[0014] Preferably, the micro endoscope is provided with a toughened glass near one end of the fissure body model, and built-in light sources are arranged above and below the toughened glass, which are used to provide light sources for the image acquisition process.

[0015] Preferably, the water flow channel is provided with a pressure detection device for monitoring the pressure data change of the fissure water; the water flow channel is arranged at a position of the base in contact with the fissure body model, and the bottom end of the fissure body model is provided with a water inlet, and the size of the water inlet is equal to the size of the end of the water flow channel.

[0016] Preferably, the water inlet channel is arranged inside the base between the side wall of the fissure body model and the inner wall of the test cavity.

[0017] Preferably, the top cover and the test cavity are detachably connected through a first clamp, and the base and the test cavity are detachably connected through a second clamp.

[0018] The beneficial effects of the present application are:

[0019] 1. The plate-shaped fissure body model hydraulic coupling test process visualization device provided by the present application realizes the purpose of directly tracking and observing the crack morphology and dynamic expansion process under the coupling action of high stress and high water pressure, and makes the test process more close to the actual environment of the generation of fissures in rock mass, thereby providing an effective implementation method for studying the performance of rock mass.

[0020] 2、The plate-shaped fracture body model hydraulic coupling test process visualization device provided by the application can effectively isolate the fracture water and lateral pressure water inside and outside the fracture body model by setting the water pressure sealing device including the mica sheet and the rubber sleeve for fixing the mica sheet on the outer wall of the fracture body model, so that the mixing of the fracture water and the lateral pressure water is avoided to affect the test, on the other hand, the good fluidity and viscosity of the vaseline ensure that the mica sheet can maintain good sealing effect during the micro-crack propagation of the fracture body, because when the fracture body model has displacement in the plane after cracking, the fracture body model will not be subjected to the surface constraint effect from the mica sheet under the lubrication of the vaseline; by ensuring that the fracture water pressure inside the fracture body model is less than the lateral pressure outside the fracture body model, the pressure difference between the fracture water pressure and the lateral pressure and the lubrication of the vaseline between the mica sheet and the fracture body model can make the mica sheet not separate from the fracture body model, ensure that the sealing effect is good during the whole process of applying pressure to the fracture body model, and ensure the accuracy of data collection; by setting the image acquisition system for collecting the growth and extension direction of the fracture inside the fracture body model on the side wall of the test cavity, combined with the high light transmittance of the mica sheet and the rubber sleeve, the process of the generation and extension of the fracture in the fracture body model is visualized, and the difficulty of observing the fracture distribution inside the fracture body model is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a structural schematic view of the plate-shaped fracture body model hydraulic coupling test process visualization device of the application.

[0022] Figure 2 It is a structural schematic view of the plate-shaped fracture body model hydraulic coupling test process visualization device of the application. Figure 1 It is a structural schematic view of the plate-shaped fracture body model hydraulic coupling test process visualization device of the application.

[0023] Figure 3 It is a structural schematic view of the plate-shaped fracture body model hydraulic coupling test process visualization device of the application. Figure 2 It is a structural schematic view of the plate-shaped fracture body model hydraulic coupling test process visualization device of the application.

[0024] Figure 4 It is a structural schematic view of the plate-shaped fracture body model hydraulic coupling test process visualization device of the application. Figure 2 It is a structural schematic view of the plate-shaped fracture body model hydraulic coupling test process visualization device of the application.

[0025] The following signs are used in the drawings:

[0026] 10, base; 101, second clamp; 11, lateral pressure water; 12, fracture water; 20, test cavity; 201, built-in light source; 21, upper pressure disc; 22, fracture body model; 221, water pressure sealing device; 2211, mica sheet; 2212, through fracture; 2213, rubber sleeve; 23, lower pad; 30, cavity top cover; 301, first clamp; 31, pressure transmission shaft; 40, image acquisition system; 41, miniature scope; 411, tempered glass; 42, image acquisition device. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described in detail below with reference to the drawings and specific embodiments.

[0028] Here, it also needs to be explained that, in order to avoid obscuring the present application due to unnecessary details, only structures and / or processing steps closely related to the solutions of the present application are shown in the drawings, and other details not closely related to the present application are omitted.

[0029] In addition, it also needs to be explained that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0030] Please refer to Figures 1 to 4 As shown in the figure, the plate-shaped fracture body model hydraulic coupling test process visualization device provided by the present application comprises a steel test cavity 20, a top cover 30 arranged at the upper end of the steel test cavity 20 and a base 10 arranged at the bottom end of the steel test cavity 20, an image acquisition system 40 for acquiring the whole process of the generation and expansion of the fractures on the fracture body model 22 is connected to the side wall of the test cavity 20, the contact part between the test cavity 20 and the top cover 30 is detachably connected through a first clamp 301, the contact part between the base 10 and the test cavity 20 is detachably connected through a second clamp 101, and a pressure transmission shaft 31 is arranged through the middle part of the top cover 30.

[0031] Further, please refer to Figure 2 and combine Figure 3 and Figure 4 As shown in the figure, the upper surface of the base 10 is provided with a lower pad 23, the lower surface of the pressure transmission shaft 31 is provided with an upper pressure disc 21, the fracture body model 22 is fixed between the upper pressure disc 21 and the lower pad 23, the outer surface of the fracture body model 22 is provided with a water pressure sealing device 221, and the base 10 and the test cavity 20 are fixed through the second clamp 101. Specifically, the water pressure sealing device 221 comprises a mica sheet 2211 fitted with the prefabricated fractures on the fracture body model 22 and a rubber sleeve 2213 for fixing the mica sheet 2211 to the outer wall of the fracture body model 22, and vaseline is coated between the fracture body model 22 and the mica sheet 2211. In particular, the rubber sleeve 2213 is a high-transparency and high-elasticity rubber sleeve 2213, and the mica sheet 2211 is a high-transparency mica sheet, so as to facilitate the observation of the fractures on the fracture body model 22.

[0032] Still further, please refer to Figure 2 and combine Figure 1As shown, the inside of the base 10 at the position in contact with the fracture body model 22 is formed with a water flow channel by drilling, the bottom end of the fracture body model 22 is provided with a water inlet, the size of the water inlet is equal to the size of the end of the water flow channel, when the two are matched, the fracture water 12 can be injected into the inside of the fracture body model 22 through the water flow channel and the water inlet; the inside of the base 10 between the side wall of the fracture body model 22 and the inner wall of the test cavity 20 is provided with a water inlet channel for injecting the lateral pressure water 11 into the area between the inner wall of the test cavity 20 and the fracture body model 22; the water flow channel is provided with a pressure detection device (not shown in the figure) for monitoring the pressure data change of the fracture water 12, the monitoring process is realized by using the basic principle of fluid mechanics, when the fracture body model does not produce micro cracks, the fracture water 12 is in a static state, at this time, the mechanical energy of the fracture water 12 is all collected by the pressure detection device in the form of potential energy, when the fracture body model produces micro cracks, at this time, the inner fracture volume of the fracture body model 22 expands, the fracture water 12 flows again, and part of the potential energy of the fracture water 12 is converted into kinetic energy, the pressure data collected by the pressure detection device will become smaller, according to the change of the pressure data, the cracking time of the micro cracks of the fracture body model can be obtained; the image acquisition system 40 is arranged on the side wall of the test cavity 20 at the position corresponding to the fracture body model 22, the image acquisition system 40 includes a miniature scope 41 penetrating through the side wall of the test cavity 20 and an image acquisition device 42 connected with one end of the miniature scope 41, specifically, the end of the miniature scope 41 close to the fracture body model 22 is provided with a tempered glass 411, the built-in light source 201 is arranged above and below the tempered glass 411, the built-in light source 201 is used to provide light source for collecting the fracture distribution process.

[0033] The working principle of the plate-shaped fracture body model hydraulic coupling test process visualization device of the present application is as follows: when the plate-shaped fracture body model hydraulic coupling test process visualization device of the present application is applied, first, the water pressure sealing device 221 is arranged on the fracture body model 22, and the mica sheet 2211 is pressed tightly and closely on the surface of the fracture body model 22 by the rubber sleeve 2213 to avoid the side pressure water 11 entering the fracture body model 22 through the gap between the mica sheet 2211 and the fracture body model 22 to mix with the fracture water 12 and affect the test; then, the fracture body model 22 is placed between the upper pressure plate 21 and the lower base plate 23, and the transmission pressure shaft 31 is used to press the upper pressure plate 21 to fix the fracture body model 22 between the upper pressure plate 21 and the lower base plate 23; then, the side pressure water 11 is injected into the area between the fracture body model 22 and the test cavity 20 to provide side pressure for the fracture body model 22, and the fracture water is injected into the fracture body model 22 to apply fracture water pressure to the inside of the fracture body model 22; the above process should ensure that the water pressure of the side pressure water 11 is always greater than the water pressure of the fracture water 12, so that in the process of generating the fracture on the fracture body model 22, the pressure difference between the side pressure and the fracture water pressure makes the mica sheet 2211 remain attached to the surface of the fracture body model 22, and at the same time, the lubricating effect of the vaseline makes the fracture body model 22 have displacement in the plane when the fracture body model 22 generates a crack along the tip of the through fracture 2212, and the fracture body model 22 is not constrained by the surface of the attached mica sheet 2211, ensuring that the micro-crack of the fracture body is not constrained by the surface force during the micro-crack propagation process; on the other hand, the good fluidity and viscosity of the vaseline can ensure the sealing effect of the mica sheet 2211 during the micro-crack propagation process of the fracture body; in addition, the high-transmittance mica sheet 2211 and the rubber sleeve 2213 can clearly present the whole process of the micro-crack initiation and propagation of the fracture body model, and the built-in light source 201 and the miniature scope 41 can collect image data of the whole process of the micro-crack initiation and propagation in the model.

[0034] In summary, the plate-shaped fracture body model hydraulic coupling test process visualization device of the present application can ensure that the mica sheet 2211 does not separate from the fracture body model 22 by setting the water pressure sealing device 221 including the mica sheet 2211 and the rubber sleeve 2213 on the through fracture 2212 of the fracture body model 22, and ensuring that the fracture water pressure inside the fracture body model 22 is less than the side pressure water pressure outside the fracture body model 22, the pressure difference between the fracture water pressure and the side pressure water pressure, and the lubricating effect of the vaseline between the mica sheet 2211 and the fracture body model 22, so as to ensure the accuracy of the collected data by effectively sealing the water pressure in the fracture body model 22 during the collection of the fracture propagation process in the fracture body model 22; by setting the image acquisition system 40 for collecting the growth and expansion direction of the fracture in the fracture body model 22 on the side wall of the test cavity 20, the generation and expansion of the fracture in the fracture body model 22 can be visualized.

[0035] The above examples are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalent replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A device for visualizing the process of a hydraulic coupling test of a plate-like fracture model, characterized in that, The application relates to a steel test cavity, a top cover arranged at the upper end of the steel test cavity and a base arranged at the bottom end of the steel test cavity, a side wall of the test cavity is connected with an image acquisition system, a pressure transmission shaft is arranged in the middle of the top cover; The surface of the fracture body model in the test cavity is provided with a water pressure sealing device, the base is internally provided with a water flow channel for injecting fracture water into the fracture body model and a water inlet channel for applying lateral pressure to the fracture body model; the water inlet channel is used for injecting lateral pressure water into the area between the inner wall of the test cavity and the fracture body model, and the water pressure of the lateral pressure water is always greater than that of the fracture water; The water pressure sealing device comprises a mica sheet matched with a prefabricated fracture on the fracture body model and a rubber sleeve for fixing the mica sheet to the outer wall of the fracture body model; vaseline is coated between the mica sheet and the fracture body model.

2. The process visualizing apparatus for the hydraulic coupling test of the plate-like crack model according to claim 1, wherein The mica sheet and the rubber sleeve are both made of high-transmittance materials.

3. The plate-like fracture model hydraulic coupling test process visualization device according to claim 1, characterized in that, The upper surface of the base is provided with a lower pad, the lower surface of the pressure transmission shaft is provided with an upper pressure disc, and the fracture body model is arranged between the upper pressure disc and the lower pad.

4. The process visualizing apparatus for hydraulic coupling test of plate-like fracture model according to claim 1, wherein The image acquisition system comprises a microscope penetrating the side wall of the test cavity and an image acquisition device connected with one end of the microscope.

5. The process visualizing apparatus for the hydraulic coupling test of plate-like fracture body model according to claim 4, characterized in that, One end of the microscope close to the fracture body model is provided with tempered glass, and built-in light sources are arranged above and below the tempered glass, which are used for providing light sources for the image acquisition process.

6. The process visualizing apparatus for hydraulic coupling test of plate-like fracture model according to claim 1, wherein The water flow channel is provided with a pressure detection device for monitoring the pressure data change of the fracture water; the water flow channel is arranged at the position of the base in contact with the fracture body model, the bottom end of the fracture body model is provided with a water inlet, and the size of the water inlet is equal to that of the terminal end of the water flow channel.

7. The process visualizing apparatus for the hydraulic coupling test of plate-like fracture body model according to claim 1, wherein The water inlet channel is arranged in the inside of the base between the side wall of the fracture body model and the inner wall of the test cavity.

8. The process visualizing apparatus for hydraulic coupling test of plate-like fracture model according to claim 1, wherein The top cover and the test cavity are detachably connected through a first clamp, and the base and the test cavity are detachably connected through a second clamp.

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