Rock penetration testing device and testing method for simulating field environment

Abstract

The invention provides a rock penetration testing device and a rock penetration testing method for simulating a field environment. The device comprises a test rack; the crack grouting assembly is arranged on the test rack and comprises a reaction cavity, an axial pressure loading unit and a grouting pressure loading unit, a sample is placed in the reaction cavity, the axial pressure loading unit is used for applying axial pressure to the sample, and the grouting pressure loading unit is used for injecting grout into the reaction cavity; and the visual detection assembly is used for determining the grouting effect of the sample.

Description

Technical Field

[0001] The present invention belongs to the field of rock fracture grouting, and particularly relates to a rock permeability test device and a test method for simulating on-site environment. Background Art

[0002] Rock fracture grouting is an important method to solve the problem of water permeability in rock formations. In many engineering constructions such as tunnels, dams, mines, etc., the rock formations often have geological defects such as fractures, faults, and broken zones, resulting in low rock mass strength and high permeability, which are prone to engineering problems such as leakage and collapse. Rock fracture grouting has become an indispensable technical means in modern geotechnical engineering. Determining the development process of rock fracture grouting is of great significance to the production practice in the geotechnical field.

[0003] At present, the main rock fracture grouting visualization devices at home and abroad use transparent materials to make fracture models, and record the slurry flow process through high-speed cameras. However, the transparent fracture model can only apply grouting pressure with a single function, and the permeating liquid is all water, with a single application scenario, and cannot simulate the slurry flow process in the on-site environment.

[0004] Due to the transparent characteristics of the transparent fracture model, researchers can directly observe the flow, diffusion, and filling behaviors of the slurry in the fracture, and it is now widely used in rock permeability testing technology. However, the existing rock fracture grouting visualization devices have the following deficiencies: (1) The transparent fracture model is usually in a stress-free or low-stress state and cannot simulate the in-situ stress in the actual rock mass. However, the actual rock mass is in a complex in-situ stress environment, and the aperture and deformation of the fracture are affected by the stress field. The influence of stress on the slurry flow cannot be simulated in the laboratory, resulting in a large difference between the slurry flow path and filling effect in the actual grouting process and the laboratory results; (2) The geometric shape of the transparent fracture model is usually a regular fracture, and the fracture width is uniform. However, the geometric shape of the actual rock fracture is complex, including irregular fractures, cross fractures, branch fractures, etc. It is difficult for the laboratory model to fully simulate the complex geometric shape of the actual fracture, resulting in the slurry flow path in the laboratory model may not conform to the actual conditions; (3) The transparent fracture model usually uses materials such as plexiglass and resin. The surfaces of these materials are smooth and the mechanical properties are uniform. However, the surface of the actual rock fracture is rough and irregular, and there may be mineral deposits, oxide layers, etc. The laboratory results may underestimate the flow resistance of the slurry in the actual fracture, resulting in the diffusion range of the slurry in the laboratory model may be larger than the actual conditions. Summary of the Invention

[0005] The present invention provides a rock permeability test device and a test method for simulating on-site environment, which can improve the test accuracy of rock permeability test.

[0006] On the one hand, a rock permeability test device for simulating a field environment is provided, including: A test stand; A crack grouting assembly, arranged on the test stand, including a reaction chamber, an axial compression loading unit, and a grouting pressure loading unit. The reaction chamber is used to place a specimen, the axial compression loading unit is used to apply axial compression to the specimen, and the grouting pressure loading unit is used to inject grout into the reaction chamber; A visualization detection assembly, used to determine the grouting effect of the specimen.

[0007] Optionally, the test stand includes a loading frame, a cross beam arranged on the top of the loading frame, and a base arranged on the bottom of the loading frame.

[0008] Optionally, the reaction chamber includes: A first wall body, a second wall body, a spacer, and a cover plate; a cavity is formed between the first wall body and the second wall body; the spacer is arranged on the contact surface between the first wall body and the second wall body to improve the sealing effect between the first wall body and the second wall body; the cover plate is arranged on the top of the cavity, and the bottom of the cavity is hermetically connected to the base.

[0009] Optionally, tempered glass plates and steel fences are arranged inside the first wall body and the second wall body.

[0010] Optionally, the axial compression loading unit includes: A hydraulic unit and a transmission member. The hydraulic unit is fixed on the cross beam, the transmission member is fixedly connected to the cover plate, and the hydraulic unit applies axial compression to the specimen in the reaction chamber through the transmission member and the cover plate.

[0011] Optionally, the grouting pressure loading unit includes: A grout delivery pipeline and a grouting unit; A base groove is formed in the base, the grout delivery pipeline is communicated with the reaction chamber through the base groove, and the grouting unit is used to deliver grout into the reaction chamber through the grout delivery pipeline.

[0012] Optionally, the visualization detection assembly includes a sliding track, a driving unit, and an image sensor; The sliding track is arranged on both sides of the loading frame, the image sensor is slidably fixed on the sliding track, and can slide on the sliding track under the drive of the driving unit.

[0013] Optionally, the image sensor is a CMOS image sensor.

[0014] On the other hand, a test method for a rock penetration test device simulating a field environment is provided. The test method for the rock penetration test device simulating a field environment is applied to the rock penetration test device simulating a field environment as described in any one of the above, and includes: Place the specimen in the reaction chamber; Set the target grouting pressure and the target axial pressure; Apply the axial pressure and the grouting pressure through the axial pressure loading unit and the grouting pressure loading unit; After the axial pressure and the grouting pressure reach the target axial pressure and the target grouting pressure and remain stable, set the target test time and start the test; After the test time meets the target test time, determine the grouting effect through the visual inspection component.

[0015] Optionally, determining the grouting effect through the visual inspection component includes: Determine the grouting effect according to the image of the specimen in the reaction chamber detected by the visual inspection component. The grouting effect is determined by the flow characteristics of the slurry, the formation state of the grouting curtain body, and the filling condition of the original fissures.

[0016] The beneficial effects brought by the technical solution provided by the present invention are: The present invention provides a rock penetration test device simulating a field environment. The axial pressure loading unit and the grouting pressure loading unit in the fissure grouting component apply pressure to the specimen in the reaction chamber, and the visual inspection component is used to obtain the grouting effect of the specimen in real time, which is more in line with the stress environment of the rock mass, thereby improving the accuracy of the rock penetration performance test. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figures 1 to 3 It is a schematic structural diagram of a rock penetration test device simulating a field environment provided by the present invention; Figure 4 It is a schematic structural diagram of a reaction chamber provided by the present invention; Figure 5 It is a schematic diagram of a tempered glass plate provided by the present invention; Figure 6 It is a schematic diagram of a steel fence provided by the present invention; Figure 7Flow chart of the test method for a rock permeability test device simulating the on-site environment provided by the present invention.

[0019] The reference signs are as follows: 1: Test stand; 11: Loading frame; 12: Cross beam; 13: Base; 2: Fracture grouting assembly; 21: Reaction chamber; 211: First wall body; 212: Second wall body; 213: Spacer; 214: Cover plate; 215: Cavity; 216: Bolt; 217: Stainless steel handle; 218: Tempered glass plate; 219: Steel fence; 22: Axial compression loading unit; 221: Hydraulic unit; 222: Oil pipeline; 223: Oil cylinder; 224: Transmission member; 23: Grouting pressure loading unit; 231: Grouting unit; 232: Slurry pipeline; 3: Visual inspection assembly; 31: Sliding track; 32: Image sensor; 4: Signal cable. Detailed implementation manners

[0020] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0021] Figures 1 to 3 Structural schematic diagram of a rock permeability test device simulating the on-site environment provided by the present invention. Among them, Figure 1 is the front view, Figure 2 is the side view, Figure 3 is the top view.

[0022] Combined with Figures 1 to 3 , the rock permeability test device simulating the on-site environment includes: Test stand 1; Fracture grouting assembly 2, arranged on the test stand 1, including a reaction chamber 21, an axial compression loading unit 22 and a grouting pressure loading unit 23. The reaction chamber 21 is used to place the specimen. The axial compression loading unit 22 is used to apply axial compression to the specimen, and the grouting pressure loading unit 23 is used to inject slurry into the reaction chamber 21; Visual inspection assembly 3, used to determine the grouting effect of the specimen.

[0023] The present invention provides a rock permeability test device for simulating the on-site environment, which applies pressure to the specimen in the reaction chamber through the axial pressure loading unit and the grouting pressure loading unit in the crack grouting assembly, and obtains the grouting effect of the specimen in real time through the visual detection assembly, which is more in line with the stress environment of the rock mass, so as to improve the accuracy of the rock permeability performance test.

[0024] In this embodiment, the test stand 1 includes a loading frame 11, a cross beam 12 arranged at the top of the loading frame 11, and a base 13 arranged at the bottom of the loading frame 11.

[0025] In this embodiment, the loading frame 11 is a stainless steel frame.

[0026] See Figure 4 , in this embodiment, the reaction chamber 21 includes: A first wall body 211, a second wall body 212, a separator 213 and a cover plate 214; a cavity 215 is formed between the first wall body 211 and the second wall body 212; the separator 213 is arranged on the contact surface of the first wall body 211 and the second wall body 212 for improving the sealing effect between the first wall body 211 and the second wall body 212; the cover plate 214 is arranged on the top of the cavity 215, and the bottom of the cavity 215 is hermetically connected to the base 13.

[0027] In this embodiment, the reaction chamber 21 further includes: bolts 216 and a stainless steel handle 217.

[0028] In this embodiment, tempered glass plates 218 (see Figure 5 ) and steel fences 219 (see Figure 6 ) are arranged inside the first wall body 211 and the second wall body 212.

[0029] In this embodiment, the first wall body 211 and the second wall body 212 are stainless steel wall bodies.

[0030] In this embodiment, the axial pressure loading unit 22 includes: A hydraulic unit 221, an oil delivery pipeline 222, an oil cylinder 223 and a transmission member 224. The hydraulic unit 221 is fixed to the cross beam 12, the transmission member 224 is fixedly connected to the cover plate 214, and the hydraulic unit 221 applies axial pressure to the specimen in the reaction chamber 21 through the transmission member 224 and the cover plate 214.

[0031] In this embodiment, the hydraulic unit 221 delivers liquid to the oil cylinder 223 through the oil delivery pipeline 222 and applies power to the transmission member 224 through the liquid.

[0032] In this embodiment, the grouting pressure loading unit 23 includes: The grouting unit 231 and the slurry delivery pipeline 232; The base 13 is provided with a base groove 131, and the slurry delivery pipeline 232 communicates with the reaction chamber 21 through the base groove 131. The grouting unit 231 is used to deliver slurry into the reaction chamber 21 through the slurry delivery pipeline 232.

[0033] In this embodiment, the visual inspection component 3 includes a sliding track 31, a driving unit (a driving motor, not shown in the figure), and an image sensor 32; The sliding track 31 is arranged on both sides of the loading frame 11. The image sensor 32 is slidably fixed on the sliding track 31 and can slide on the sliding track 31 under the drive of the driving unit.

[0034] In this embodiment, the image sensor 33 is a CMOS image sensor.

[0035] In this embodiment, the test device further includes: A signal cable 4 for connecting to an external computer to transmit control signals and data.

[0036] Figure 7 It is a flowchart of the test method for a rock penetration test device that simulates the on-site environment provided by the present invention. Refer to Figure 7 , including: S101. Place the specimen in the reaction chamber; S102. Set the target grouting pressure and the target axial pressure; S103. Apply the axial pressure and the grouting pressure through the axial pressure loading unit and the grouting pressure loading unit; S104. After the axial pressure and the grouting pressure reach the target axial pressure and the target grouting pressure and remain stable, set the target test time and start the test; S105. After the test time meets the target test time, determine the grouting effect through the visual inspection component.

[0037] In one example, determining the grouting effect through the visual inspection component includes: Determine the grouting effect according to the image of the specimen in the reaction chamber detected by the visual inspection component. The grouting effect is determined by the flow characteristics of the slurry, the formation state of the grouting curtain body, and the filling condition of the original fissures.

[0038] In an embodiment provided by the present invention, the test steps are as follows: Step 1. Specimen installation: Install the crack grouting assembly and fix it with bolts to make it a tight whole. Place the specimen into the square cavity and then put it into the test stand. Observe the installation situation to ensure a tight fit with the test stand. Press the grouting pressure head into the slurry delivery pipe to ensure that the lower head of the grouting pressure head fits tightly with the specimen, and then cover the cover plate.

[0039] Step 2. Connect the pressure application pipes: Connect the top of the grouting pressure head of the crack grouting device to the grouting pressure application pipe and connect it to the square cavity; connect the axial pressure valve of the crack grouting assembly to the axial pressure application pipe and connect it to the oil cylinder.

[0040] Step 3. Loading settings: First, set the target grouting pressure and axial pressure to be achieved. Then, set the loading mode through a computer. You can choose pressure control in kPa / s or penetration control in mm / s. After setting, start the loading. Generally, load the axial pressure first and then the grouting pressure.

[0041] Step 4. Loading process: The grouting pressure (N / m) and axial pressure (N / m) can be monitored in real time through the computer control system. After the grouting pressure and axial pressure are stable, confirm and input the continuous operation time. Stop the grouting experiment after maintaining the set grouting pressure and axial pressure for a sufficient time.

[0042] Step 5. After the experiment is completed, set the axial pressure to negative pressure again, re-pump the liquid in the crack grouting assembly into the hydraulic chamber, close the loading after the pressure of the rock crack grouting device drops to 0, then close the axial pressure valve, open the pressure relief valve, disconnect the connection of the grouting pressure and axial pressure, take out the crack grouting assembly, remove the cover plate, tempered glass plate, and steel fence, unscrew the steel bolts, and take out the specimen.

[0043] Step 6. Data processing: Export the data analysis of the CMOS image sensor with respect to time change from the computer to analyze the real-time changes of the grouting pressure and axial pressure during the grouting experiment.

[0044] The present invention optimizes the visual detection device to achieve random detection or fixed-point detection of the grouting situation of rock fractures by adding a slide rail and a CMOS image sensor. Its essence is that the motor on the slide rail drives the CMOS image sensor to move on the slide rail. The core of the CMOS image sensor is an optoelectronic conversion device based on semiconductor technology, and its fast reading characteristic enables it to efficiently capture the real-time state of rock fractures. At the same time, through the optimized design of the structure of the test stand, the convenient installation of the fracture grouting device is realized. This device can not only directly carry out experiments using in-situ rocks, but also be used in cooperation with fracture molds, significantly expanding its application range. The optimized design facilitates the removal of the grouting block, realizes the efficient reuse of the mold, greatly improves the reuse rate of the mold, and reduces the test cost. In addition, this device supports multiple repeated experiments, providing convenience for data extraction and analysis. The tank body of the fracture grouting device is made of stainless steel rolling process, has excellent corrosion resistance, can store various liquids, meets the requirements of rock fracture grouting experiments in different acid-base environments, and thus realizes the simulation of various grouting environments.

[0045] The present invention adds a hydraulic device to achieve multi-physical field coupling experiments. Its essence lies in using the incompressibility of the liquid, compressing the liquid through an external power system, so as to form a high-pressure environment in a closed chamber. This high-pressure liquid further acts on the piston assembly, pushing the piston rod to move axially downward, and then applying axial pressure to the experimental sample. This design can not only accurately control the magnitude and loading rate of the axial pressure, but also realize the dynamic loading and unloading of the axial pressure by adjusting the pressure parameters of the hydraulic system, so as to meet the simulation requirements of complex mechanical boundary conditions in multi-physical field coupling experiments.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rock permeability test device for simulating on-site environment, characterized in that Comprising: Test stand; Fracture grouting assembly, arranged on the test stand, including a reaction chamber, an axial compression loading unit and a grouting pressure loading unit. The reaction chamber is used to place the specimen. The axial compression loading unit is used to apply axial compression to the specimen, and the grouting pressure loading unit is used to inject grout into the reaction chamber; Visual inspection assembly, used to determine the grouting effect of the specimen.

2. The rock permeability testing device for simulating a field environment according to claim 1, characterized in that, The test stand includes a loading frame, a cross beam arranged on the top of the loading frame, and a base arranged on the bottom of the loading frame.

3. The rock permeability testing device for simulating a field environment according to claim 2, wherein, The reaction chamber includes: A first wall body, a second wall body, a spacer and a cover plate; a cavity is formed between the first wall body and the second wall body; the spacer is arranged on the contact surface of the first wall body and the second wall body to improve the sealing effect between the first wall body and the second wall body; the cover plate is arranged on the top of the cavity, and the bottom of the cavity is hermetically connected to the base.

4. The rock permeability testing device for simulating a field environment according to claim 3, wherein, Tempered glass plates and steel fences are arranged inside the first wall body and the second wall body.

5. The rock permeability test device for simulating a field environment according to any one of claims 2 to 4, characterized in that, The axial compression loading unit includes: A hydraulic unit and a transmission member. The hydraulic unit is fixed to the cross beam, the transmission member is fixedly connected to the cover plate, and the hydraulic unit applies axial compression to the specimen in the reaction chamber through the transmission member and the cover plate.

6. The rock permeability testing device for simulating a field environment according to any one of claims 2 to 4, characterized in that The grouting pressure loading unit includes: A grout delivery pipeline and a grouting unit; A base groove is formed in the base, the grout delivery pipeline is communicated with the reaction chamber through the base groove, and the grouting unit is used to convey grout into the reaction chamber through the grout delivery pipeline.

7. The rock permeability testing device for simulating a field environment according to any one of claims 2 to 4, characterized in that The visual inspection assembly includes a sliding track, a driving unit and an image sensor; The sliding track is arranged on both sides of the loading frame, and the image sensor is slidably fixed on the sliding track and can slide on the sliding track under the drive of the driving unit.

8. The rock permeability testing device for simulating the on-site environment according to claim 7, wherein The image sensor is a CMOS image sensor.

9. A test method for a rock permeability test device simulating a field environment, characterized in that, The test method of the rock permeability test device for simulating the in-situ environment is applied to the rock permeability test device for simulating the in-situ environment as described in any one of claims 1 to 8, and includes: Placing the specimen in the reaction chamber; Setting the target grouting pressure and the target axial compression; Applying axial compression and grouting pressure through the axial compression loading unit and the grouting pressure loading unit; After the axial compression and the grouting pressure reach the target axial compression and the target grouting pressure and remain stable, setting the target test time and starting the test; After the test time meets the target test time, determining the grouting effect through the visual inspection assembly.

10. The testing method of a rock permeability testing device for simulating on-site environment according to claim 9, characterized in that, Determining the grouting effect through the visual inspection assembly includes: Determining the grouting effect according to the image of the specimen in the reaction chamber detected by the visual inspection assembly. The grouting effect is determined by the flow characteristics of the grout, the formation state of the grouting curtain body, and the filling condition of the original fractures.

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