'Slurry-rock' combination permeability evolution research test device

Abstract

The utility model belongs to the technical field of geotechnical engineering, and particularly relates to a slurry-rock combination permeability evolution research test device, which is characterized in that a confining pressure controller loads confining pressure to a rock sample in a main pressure chamber to control the pressure on the outer side of the rock sample, and one end of the confining pressure controller is connected with a monitoring system for controlling the pressure application; the other end is connected with the main pressure chamber; the axial pressure controller applies axial pressure through an upper bearing platform of the main pressure chamber, the axial pressure controller is respectively connected with the main pressure chamber and the monitoring system, the water supply pressurization control system and the high-pressure grouting system are connected with the main pressure chamber through pipelines, and the rock fracture prefabricating device adopts a three-section mold to provide a required standard rock sample for a test. The crack filling bodies with different shapes, roughness and widths are manufactured in advance by using the solid paraffin, and the built-in cracks meeting different requirements can be manufactured in the process of manufacturing the standard rock sample according to the characteristic that the crack filling bodies are melted when being heated, so that the method is simpler and more practical, and the actual requirements are better met.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of geotechnical engineering, and particularly relates to a "slurry-rock" combination permeability evolution research test device, which is based on the slurry-rock coupling effect to study the permeability evolution of the "slurry-rock" combination. BACKGROUND

[0002] The existence of soft structural planes including faults, joints and fissures has an important influence on the safe construction of underground projects such as tunnel engineering, foundation pit excavation and mine exploitation, and often leads to geological disasters such as rock mass instability and damage and sudden gushing of water, such as water inrush in coal mines, water gushing in tunnels and foundation pits, and instability and collapse of surrounding rock. The existence of fissures in rock mass reduces the strength and stability of rock on the one hand, and is also a good water channel on the other hand. Due to the complexity, concealment and unpredictability of underground engineering geological problems, problems such as water inrush and sand inrush have been plaguing us. At present, grouting reinforcement is widely used in water hazard prevention, and by plugging the main water-conducting fissures, the purpose of water control and water isolation and reinforcement of surrounding rock is achieved, and practice shows that grouting plays a great role in promoting the safety production of underground engineering.

[0003] Fissured rock mass grouting, grouting theory, grouting material, temperature, rock mass fissure characteristics and underground water flow characteristics are important factors in analyzing the grouting diffusion law, and the physical and mechanical property test of fissured rock mass before and after grouting is the basis for analyzing the grouting effect. In actual engineering, the fissures in rock mass are unevenly distributed and have different characteristics, and the slurry flow has obvious "flowing effect" during grouting, and the newly generated and original small fissures cannot be effectively plugged, causing the instability of rock mass permeability after grouting. In addition, the influence of strong ground stress and temperature at a certain depth below the ground surface also needs to be considered. Indoor fissured rock mass grouting research can microscopically study the cracking, expansion and plugging of fissures, and better serve the research of grouting mechanism. At present, there are problems in the research of water-rich fissured rock mass grouting and the properties of slurry-rock combination:

[0004] (1) Pre-fabricated fissured rock mass grouting is the main means of laboratory research at present, but the pre-fabricated fissures in the current research are mainly flat or through fissures on the surface of rock mass, which can only consider the length and opening of the fissures without considering the influence of roughness, and the through fissure grouting cannot explore the influence of the grouting process on the change of the opening of the fissures, such as the rock standard sample fissure high-pressure grouting filling device, system and method disclosed in CN114993787A. If the broken rock mass is all through fissures, the grouting reinforcement mechanism is obviously different from that of fissured grouting, so the research method is also different, such as the disclosed model test device and test method for water-rich broken rock layer dynamic water grouting reinforcement.

[0005] (2) The existing fissure rock mass grouting rarely considers the influence of surrounding rock stress and seepage water pressure, and no axial pressure or confining pressure is applied before grouting. The influence of deep high ground stress on rock mass damage is immeasurable, and direct grouting of pre-fabricated fissures is too idealistic. It is more realistic to consider the influence of ground stress on the expansion law of fissures before pre-fabricated fissure rock mass grouting, and then to study the grouting effect. How to realize safe high-pressure grouting under the consideration of seepage is one of the problems to be solved.

[0006] (3) Grouting reinforcement is widely used in engineering, but cases of seepage instability of rock mass after grouting also occur, and the stability of the grout-rock combination is one of the problems to be solved in grouting engineering. Some scholars have studied the permeability of the grout-rock combination, such as the literature "Yuan Shichong. Research on grout diffusion mechanism and mining effect of "grout-rock" combination in deep mine fissure rock mass curtain grouting[D]. China University of Mining and Technology, 2023" and "Zhang Peisen, Xu Daqiang, LiTenghui, et al. Experimental study on seepage characteristics before and after fissure sandstone grouting and mechanical characteristics after grouting[J]. Rock and Soil Mechanics, 2023, 44(S1): 12-26", but the evolution of the mechanical properties of the grout-rock combination after grouting based on the fissure network needs further study.

[0007] Therefore, it is necessary to design a "grout-rock" combination permeability evolution research test device, a pre-fabricated fissure three-dimensional high-pressure grouting device that comprehensively considers confining pressure, axial pressure, seepage water pressure and grouting pressure, and based on this, to study the stability of the grout-rock combination. Content of the utility model

[0008] The utility model aims at providing a "grout-rock" combination permeability evolution research test device, solving the problem of pre-fabrication of built-in fissures in standard rock samples in indoor tests, and considering the influence of ground stress and seepage pressure on the damage and fracture mechanism of fissure rock mass permeability and grouting effect, realizing grouting of fissure network rock mass and stability research of the grout-rock combination.

[0009] To achieve the above-mentioned purpose, the utility model realizes the following technical solutions:

[0010] The utility model provides a kind of " pulp-rock " combination body permeability evolution research test device, including main pressure chamber, axial pressure controller, confining pressure controller, water supply pressurizing control system, high pressure grouting system and monitoring system composition;Confining pressure controller controls the outside pressure of rock sample by loading confining pressure in main pressure chamber to rock sample, one end of confining pressure controller is connected with monitoring system for controlling pressure exertion size, other end is connected with main pressure chamber;Axial pressure controller applies axial pressure through the upper bearing platform of main pressure chamber, axial pressure controller is connected with main pressure chamber and monitoring system respectively, water supply pressurizing control system is connected with main pressure chamber by pipeline with high pressure grouting system, rock fracture prefabrication device adopts three labiums mould, provides required standard rock sample for test.

[0011] As a further technical solution of the utility model, the main pressure chamber is a core device for grouting reinforcement of fractured rock mass, comprising a grout pipe flowmeter, a grout pipe, a sample placing table, an annular sensor, a rock sample, an internal fracture, a rubber sleeve, a pressure relief valve, an upper bearing platform, a lower bearing platform, a fixing bracket, a fixing bolt, a confining pressure gauge, and a grouting flowmeter. The upper bearing platform and the lower bearing platform in cylindrical structure are fixed by the fixing bolt through two vertical fixing brackets. The height between the upper bearing platform and the lower bearing platform is adjustable. The sample placing table is arranged between the upper bearing platform and the lower bearing platform. The rock sample with the internal fracture is placed on the sample placing table and the height can be adjusted to facilitate the placement of the rock sample. The prepared rock sample is placed on the sample placing table and contacts with the lower bearing platform. The rubber sleeve is sleeved outside the rock sample to fix the rock sample on the sample placing table. The annular sensor is arranged outside the rubber sleeve. The pressure relief valve, the confining pressure gauge, and the grouting flowmeter are arranged on the upper part of the main pressure chamber. The grout pipe flowmeter is arranged at the bottom of the main pressure chamber. The water inlet hole is connected with the water inlet pipe and the water storage tank to ensure the permeation water pressure of the fractured rock mass. The grout inlet is connected with the grout storage tank through the grouting pipe. The main pressure chamber is arranged on the support table. The waste liquid collection tank is arranged in the support table. The grout pipe at the bottom of the main pressure chamber is connected with the waste liquid collection tank. The waste liquid collection tank is used for collecting the waste liquid from the grout pipe.

[0012] As a further technical solution of the utility model, the water supply pressurizing control system is used for simulating the grouting fracture expansion of rock mass below the actual underground water level. When the indoor test is for mudstone or sandstone, the water supply pressurizing control system is arranged. Otherwise, the water supply pressurizing control system is not arranged. The water supply pressurizing control system comprises a water pump, a water inlet pipe, a water pressure gauge, and a water storage tank. The water pressure gauge is arranged between the water pump and the water storage tank. The water supply pressurizing control system is connected with the main pressure chamber through the water inlet pipe. The water inlet pipe penetrates through the upper bearing platform and enters the inside of the main pressure chamber. The water supply pressurizing control system is connected with the control box. The control box is used for controlling the water supply pressure.

[0013] As a further technical solution of the utility model, the grouting system comprises a grout storage tank and a grouting pump. The grout storage tank is connected with the main pressure chamber through the pipeline. The grout storage tank is used for preparing and storing grout. The grouting pump is connected with the grout storage tank and the control box respectively. The control box is used for controlling the grouting pressure.

[0014] As a further technical scheme of the utility model, the monitoring system is composed of a computer, an axial pressure controller, a confining pressure controller and an annular sensor in the device, is used for obtaining relevant data in a test process, including confining pressure, axial pressure and water pressure; the computer, the axial pressure controller and the confining pressure controller are used for controlling to give a pressure design value and collecting and summarizing data through the sensor, and finally presenting data monitoring results on the computer.

[0015] Compared with the prior art, the utility model has the beneficial effects that:

[0016] (1) The high-pressure grouting utility model device considers the influence of osmotic pressure and surrounding rock pressure. In actual grouting engineering, the diffusion of slurry generally occurs in an aquifer with relatively broken rock mass and suitable rock thickness, and the influence of osmotic water pressure cannot be ignored when the buried depth is large, while the existing indoor grouting test generally does not consider the influence of osmotic water pressure. The utility model sets osmotic water pressure in the grouting device, which is more functional and practical.

[0017] (2) The stability research of slurry-rock combination can obtain grouting reinforcement effect under different fracture conditions, analyze the main control factors of stability, obtain the evolution characteristics of the permeability and compressive and shear strength of the combination, and provide reference for researching the permeability stability of slurry-rock combination, further improving the grouting reinforcement effect and revealing the grouting mechanism of fracture network.

[0018] (3) The solid paraffin is used to pre-manufacture fracture filling bodies with different shapes, roughnesses and widths, and the built-in fractures meeting different requirements can be manufactured in the process of manufacturing standard rock samples according to the melting characteristics of the solid paraffin. Considering the complexity of the damage of rock mass fractures in the actual process, the existing methods are dedicated to simple fractures such as single fractures, and cannot realize the preparation of complex fracture networks. The device and method in the utility model are simple, practical and more practical. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a structure diagram of the "slurry-rock" combination permeability evolution research test device.

[0020] Figure 2 It is a transverse sectional structure diagram of the sample placing table.

[0021] Figure 3 It is a built-in through and non-through fracture network rock sample diagram.

[0022] Figure 4 It is a "slurry-rock" combination permeability evolution research test method flow chart.

[0023] In the diagram: 1- Grout outlet flow meter, 2- Grout outlet pipe, 3- Sample placement platform, 4- Ring sensor, 5- Rock sample, 5-1- Built-in fracture, 6- Rubber sleeve, 7- Main pressure chamber, 7-1 Pressure relief valve, 7-2 Upper support platform, 7-3 Lower support platform, 8- Fixed bracket, 9- Fixed bolt, 10- Confining pressure gauge, 11- Grouting flow meter, 12- Grouting pressure gauge, 13- Inlet pipe, 14- Water pressure gauge, 15- Water supply and pressurization system, 16- Water storage tank, 17- Grout storage tank, 18- Grouting system, 19- Grouting pump, 20- Control box, 21- Axial pressure controller, 22- Confining pressure controller, 23- Monitoring system, 24- Support platform. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific implementation examples.

[0025] Example:

[0026] like Figure 1 As shown, this embodiment provides an experimental device for studying the permeability evolution of a "grout-rock" composite, comprising a main pressure chamber 7, an axial pressure controller 21, a confining pressure controller 22, a water supply and pressurization control system 15, a high-pressure grouting system 18, and a monitoring system 23. The confining pressure controller 22 controls the pressure on the outside of the rock sample 5 by applying confining pressure to the rock sample 5 inside the main pressure chamber 7, which can more realistically simulate the influence of the magnitude of in-situ stress on the grouting of the sample. One end of the confining pressure controller 22 is connected to the monitoring system 23 to control the magnitude of the applied pressure, and the other end is connected to the main pressure chamber 7. The axial pressure controller 21 applies axial pressure through the upper support platform 7-2 of the main pressure chamber 7 to apply pressure to the grouted rock sample 5 in order to analyze the compressive strength of the rock sample 5 after grouting reinforcement. The axial pressure controller 21 is connected to the main pressure chamber 7 and the monitoring system 23 respectively. The water supply and pressurization control system 15 and the high-pressure grouting system 18 are connected to the main pressure chamber 7 through pipelines. The prefabricated standard sample of fractured rock is made by a three-lobed mold.

[0027] Specifically, the main pressure chamber 7 is a fissure rock mass grouting reinforcement core device, which comprises a grout outlet pipe flow meter 1, a grout outlet pipe 2, a sample placing table 3, a ring-shaped sensor 4, a rock sample 5, an internal fissure 5-1, a rubber sleeve 6, a pressure relief valve 7-1, an upper bearing platform 7-2, a lower bearing platform 7-3, a fixed support 8, a fixed bolt 9, a confining pressure gauge 10 and a grouting flow meter 11. The upper bearing platform 7-2 and the lower bearing platform 7-3 in a cylindrical structure are fixed by the fixed bolt 9 through two vertical fixed supports 8. The height between the upper bearing platform 7-2 and the lower bearing platform 7-3 is adjustable. The sample placing table 3 is arranged between the upper bearing platform 7-2 and the lower bearing platform 7-3. The rock sample 5 with the internal fissure 5-1 is placed on the sample placing table 3 and the height is appropriately adjustable to facilitate the placement of the rock sample 5. The prepared rock sample 5 is placed on the sample placing table and is in contact with the lower bearing platform 7-3. The rubber sleeve 6 is sleeved outside the rock sample 5 to fix the rock sample 5 on the sample placing table 3. The ring-shaped sensor 4 is arranged outside the rubber sleeve 6. The main pressure chamber is provided with the pressure relief valve 7-1, the confining pressure gauge 10 and the grouting flow meter 11 at the upper portion and is provided with the grout outlet pipe flow meter 1 at the bottom. The water inlet hole is connected with the water inlet pipe 13 and the water storage tank 16 to ensure the fissure rock mass permeation water pressure. The grout inlet is connected with the grout storage tank 17 through the grouting pipe. The main pressure chamber 7 is arranged on the support table 24. The waste liquid collecting tank is arranged in the support table 24. The grout outlet pipe 2 at the bottom of the main pressure chamber 7 is connected with the waste liquid collecting tank. The waste liquid collecting tank is used for collecting the waste liquid flowed through the grout outlet pipe 2.

[0028] Specifically, the water supply and pressure control system 15 is used for simulating the fissure expansion of the rock mass below the actual underground water level. When the indoor test is aimed at the mudstone or sandstone, the test sample made of similar materials has good water impermeability (mudstone) or high water permeability (sandstone) and does not have the ability to disintegrate when meeting water. The water supply and pressure control system 15 is arranged in this case. Otherwise, the water supply and pressure control system 15 is not arranged. The water supply and pressure control system 15 comprises a water inlet pipe 13, a water pressure gauge 14 and a water storage tank 16. The water supply and pressure control system 15 is connected with the main pressure chamber 7 through the water inlet pipe 13. The water inlet pipe 13 penetrates through the upper bearing platform 7-2 and enters the inside of the main pressure chamber 7. The water supply and pressure control system 15 is connected with the control box 20. The control box 20 is used for controlling the water supply pressure.

[0029] Specifically, the grouting system 18 comprises a grout storage tank 17 and a grouting pump 19. The grout storage tank 17 is connected with the pipeline of the main pressure chamber 7. The grout storage tank 17 is used for preparing and storing grout. The grouting pump 19 is connected with the grout storage tank 17 and the control box 20 respectively. The control box 20 is used for controlling the grouting pressure.

[0030] The embodiment adopts the "grout-rock" combination permeability evolution research test device to perform the test. As shown in FIG. 1, the specific steps are as follows: Figure 4

[0031] S1, rock sample preparation: as shown in FIG. 2, the specific steps are as follows: Figure 3 ​The pre-cracked rock sample schematic diagram is shown, including the through crack rock sample and the non-through crack rock sample, the three-petal mold is used when the rock sample 5 is made, the similar material is laid at the designed position at the bottom, the paraffin wax crack network model is placed, the similar material is laid to the model top level at the periphery, vibration and slow hammering are used to make the sample form and reach the design standard, after the sample is formed, it is placed in a 65℃ constant temperature box, after the solid paraffin is melted, the liquid paraffin is pumped out through a small water pump, and then the rock sample 5 is obtained under standard curing conditions;

[0032] S2, device installation and inspection: first, connect each system and perform inspection, then arrange the pressure sensor and the water pressure sensor, connect the sensors with the data acquisition instrument and the computer, set the related parameters in the control software on the computer, including the application of confining pressure, axial pressure and water pressure and the pressure grade, finally adjust the readings of the water pressure gauge 14 and the grouting pressure gauge 12 in the device to 0;

[0033] S3, slurry preparation: according to the test design scheme, the slurry is configured, the prepared slurry is placed in the slurry storage tank 17, before starting grouting, it is necessary to note that the slurry is stirred uniformly before grouting is implemented to prevent slurry sedimentation, if the grouting time is too long, a retarder needs to be configured to delay the slurry setting time;

[0034] S4, rock sample placement: the prepared rock sample 5 is placed on the sample placing table 3 of the main pressure chamber 7, the lower part is fixed, and the upper part is connected with the grouting pipe. Open the water supply and pressure control system 15, check the water pipe connection, slowly apply pressure to the designed value to simulate confining pressure;

[0035] S5, grouting test: during the test process, the changes of each stress, the grouting pressure and the grouting amount during grouting are recorded to facilitate subsequent data analysis, and the grouting reinforcement body is obtained after the test is completed;

[0036] S6, standard curing of rock sample after grouting: the grouting reinforcement body is respectively cured for 3d, 7d and 28d to ensure that the grouting reinforcement body is not damaged, and the rock sample 5 is ground by a rock grinding machine to obtain a φ50×H100 mm double-end flat rock sample 5.

[0037] S7, control rock sample preparation: repeat the above steps to obtain the control rock sample;

[0038] S8, data analysis: the GDS triaxial test system, the electro-hydraulic servo universal testing machine and the scanning electron microscope are used to realize the data acquisition and data analysis of the uniaxial compressive strength, the shear strength, the permeability and the slurry-rock interface effect of the combination body, and the mechanical property evolution law of the slurry-rock combination body is researched.

[0039] The above are only preferred embodiments of the present application, and are not used to limit the present application, and for those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0040] Although the specific embodiments of the present application are described above in combination with the drawings, it is not a limitation on the protection scope of the present application, and those skilled in the art should understand that various modifications or changes made on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. A device for studying the evolution of the permeability of a "pulp-rock" assembly, characterized in that it comprises: The device comprises a main pressure chamber, an axial pressure controller, a confining pressure controller, a water supply and pressure control system, a high-pressure grouting system and a monitoring system; the confining pressure controller controls the external pressure of the rock sample by loading the confining pressure in the main pressure chamber; one end of the confining pressure controller is connected with the monitoring system, and the other end is connected with the main pressure chamber; the axial pressure controller applies axial pressure through the upper bearing platform of the main pressure chamber; the axial pressure controller is connected with the main pressure chamber and the monitoring system respectively; the water supply and pressure control system is connected with the main pressure chamber through pipelines; and the rock fracture precasting device adopts a three-piece mold.

2. The device for studying the evolution of the permeability of a "pore-fluid - rock" assembly according to claim 1, characterized in that, The main pressure chamber is a core device for grouting reinforcement of fractured rock mass, comprising a grout outlet pipe flowmeter, a grout outlet pipe, a sample placing platform, an annular sensor, a rock sample, an internal fracture, a rubber sleeve, a pressure relief valve, an upper bearing platform, a lower bearing platform, a fixing support, a fixing bolt, a confining pressure gauge and a grouting flowmeter; the upper bearing platform and the lower bearing platform in a cylindrical structure are fixed by the fixing bolt through two vertical fixing supports; the height between the upper bearing platform and the lower bearing platform is adjustable; the sample placing platform is arranged between the upper bearing platform and the lower bearing platform; the rock sample with the internal fracture is placed on the sample placing platform; the prepared rock sample is placed on the sample placing platform and contacts with the lower bearing platform; the rubber sleeve is sleeved on the outside of the rock sample to fix the rock sample on the sample placing platform; the annular sensor is arranged outside the rubber sleeve; the pressure relief valve, the confining pressure gauge and the grouting flowmeter are arranged on the upper part of the main pressure chamber; the grout outlet pipe flowmeter is arranged on the bottom; the water inlet hole is connected with the water inlet pipe and the water storage tank to ensure the permeation water pressure of the fractured rock mass; the grout inlet is connected with the slurry storage tank through the grouting pipe; the main pressure chamber is arranged on the support platform; the waste liquid collection tank is arranged in the support platform; and the grout outlet pipe at the bottom of the main pressure chamber is connected with the waste liquid collection tank.

3. The device for studying the evolution of the permeability of a "pore-fluid - rock" assembly according to claim 2, characterized in that, The water supply and pressure control system comprises a water pump, a water inlet pipe, a water pressure gauge and a water storage tank; the water pressure gauge is arranged between the water pump and the water storage tank; the water supply and pressure control system is connected with the main pressure chamber through the water inlet pipe; the water inlet pipe penetrates through the upper bearing platform and enters the inside of the main pressure chamber; and the water supply and pressure control system is connected with the control box.

4. The device for studying the evolution of the permeability of a "pore-fluid - rock" assembly according to claim 3, characterized in that, The grouting system comprises a slurry storage tank and a grouting pump; the slurry storage tank is connected with the pipeline of the main pressure chamber; the slurry storage tank is used for preparing and storing the slurry; and the grouting pump is connected with the slurry storage tank and the control box respectively.

5. The device for studying the evolution of the permeability of a "pore-fluid - rock" assembly according to claim 4, characterized in that, The monitoring system is composed of a computer, an axial pressure controller, a confining pressure controller and an annular sensor in the device; the monitoring system is used for obtaining the related data in the test process, including the confining pressure, the axial pressure and the water pressure; the computer, the axial pressure controller and the confining pressure controller are used for controlling the given pressure design value and collecting and summarizing the data through the sensor; and finally the data monitoring result is presented on the computer.

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