Karst grouting simulation test device and method

Abstract

The invention discloses a karst grouting simulation test device and method, and relates to the technical field of karst grouting simulation, and the karst grouting simulation test device comprises a karst cavity simulation system, a rock-soil layer simulation system, a water environment simulation system, a grouting simulation system and a control system; the rock-soil layer simulation system comprises a shell with an inner cavity, the inner cavity is filled with a layered rock-soil body used for simulating rock stratum characteristics of a selected research area, and two open holes are formed in the shell; and the like. The device can simulate karst morphology, rock stratum characteristics and karst underground water of a selected research area, simulates a prepared karst grouting treatment scheme through the grouting system, collects stress-strain data through the control system, and researches a stress-strain evolution rule of a rock-soil layer before and after grouting based on field survey data so as to evaluate the grouting effect. And test data support is provided for application of grouting in karst treatment.

Description

Technical Field

[0001] The invention relates to the technical field of karst grouting simulation, and in particular to a karst grouting simulation test device and method. Background Art

[0002] Karst refers to the grooves, cracks and cavities produced by soluble rock layers under physical and chemical effects. In karst geological areas, due to the influence of natural and human factors, various karst collapse disasters often occur, such as vacuum erosion collapse and groundwater erosion, which directly or potentially endanger the safety of above-ground structures. Karst is widely distributed. As the construction of infrastructure projects advances to different geomorphic areas, some new projects will inevitably be built in karst areas due to various factors.

[0003] Karst grouting refers to the process of injecting grouting medium into a cavity or crack area under pressure, and achieving the purpose of filling and reinforcing after curing and solidification. It is one of the most commonly used technologies for karst disease treatment. Due to the many deficiencies of existing scaled test equipment, there are currently two main methods for the research on karst grouting treatment technology: theoretical analysis and field tests. The main problems are: 1. Considering the differences in the morphology of karst cavities and rock formation characteristics in different karst areas, various theoretical analysis effect evaluations are not universally applicable; 2. Although field tests can directly determine the various grouting parameters through water injection tests, the cost is too high and it is impossible to quantitatively evaluate the karst grouting treatment effect. At present, there are also some simulation test devices for karst grouting. However, most of these simulation test devices are too simplified and idealized, and cannot simulate the morphology of karst caves and rock formation characteristics. Summary of the invention

[0004] In order to overcome the above-mentioned defects of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide a karst grouting simulation test device and method, which can simulate the karst morphology, rock layer characteristics and karst groundwater in the selected study area, simulate the proposed karst grouting treatment plan through the grouting system, collect stress and strain data through the control system, and study the stress and strain evolution law of the rock and soil layer before and after grouting based on the field survey data to evaluate the grouting effect, so as to provide experimental data support for the application of grouting in karst treatment.

[0005] The specific technical solution of the embodiment of the present invention is:

[0006] A karst grouting simulation test device, comprising: a karst cavity simulation system, a rock and soil layer simulation system, a water environment simulation system, a grouting simulation system, and a control system; wherein:

[0007] The rock layer simulation system comprises: a shell having an inner cavity, the inner cavity is filled with a layered rock body for simulating the rock layer characteristics of the selected study area, and the shell has two openings;

[0008] The karst cavity simulation system comprises: a karst cavity body arranged in the rock and soil body, the karst cavity body having a cavity inside, the karst cavity body having a grouting port connected with the cavity, part of the karst cavity body passing through one of the openings and forming a first flow channel connected with the cavity, and part of the karst cavity body passing through another of the openings and forming a second flow channel connected with the cavity;

[0009] The water environment simulation system comprises: a water pump and a water pipe, wherein the outlet of the water pump can be communicated with the first flow channel through the water pipe;

[0010] The grouting simulation system comprises: a grouting pipe inserted in the rock and soil body and connected to the grouting port of the karst cavity body; a grouting unit for outputting slurry, which is connected to the grouting pipe;

[0011] The control system includes: a plurality of strain gauges arranged in the rock and soil body near the karst cavity, an image acquisition device for photographing the rock and soil layer simulation system and the karst cavity simulation system, and a controller. The plurality of strain gauges are electrically connected to the controller, and the controller is used to record the stress and strain data of the strain gauges.

[0012] Preferably, the karst cavity is a double-layer cavity wall structure, comprising an inner cavity wall and an outer cavity wall, wherein the inner cavity wall is a plastic metal wire mesh, and the outer cavity wall is made of a thin layer of flexible material with extensibility; the slurry injected into the cavity can squeeze the outer cavity wall through the inner cavity wall to act on the rock and soil body in the rock and soil layer simulation system.

[0013] Preferably, the plastic wire mesh in the inner wall of the cavity can be folded into a shape corresponding to the karst of the selected research area, and the outer wall of the cavity can be adapted to form a shape identical to the folded shape of the plastic wire mesh.

[0014] Preferably, the plastic metal wire mesh in the inner wall of the cavity is folded into a fold shape at the first flow channel passing through the outside of the opening.

[0015] Preferably, the shell is made of transparent tempered glass; and the upper end of the shell is open.

[0016] Preferably, the inlet of the water pump can be communicated with the second flow channel through the water pipe.

[0017] Preferably, the inner diameter and outer diameter of the water delivery pipe at the connection with the first flow channel and the second flow channel are gradually expanded so as to be consistent with the inner wall and outer wall of the cavity forming the first flow channel and the second flow channel respectively.

[0018] Preferably, an on-off valve is provided on the water pipe connected to the first flow channel; and an on-off valve is provided on the water pipe connected to the second flow channel.

[0019] Preferably, the grouting unit comprises: a grouting vehicle, comprising a slurry filling funnel, a grouting pump, a slurry storage tank and a pressure gauge; the grouting pump is connected to the grouting pipe through a grouting pipe;

[0020] The slurry can enter the slurry storage tank through the slurry filling funnel and be transported to the slurry delivery pipe through the grouting pump; the pressure gauge is used to detect the pressure of the slurry in the slurry delivery pipe.

[0021] Preferably, the geotechnical layer simulation system also includes: a flange, a circular groove is provided in the middle of one side of the flange, a through hole is opened in the axial direction of the flange, an annular sealing plate is arranged between the flange and the shell, and a plurality of bolts are passed through the flange, the sealing plate and the shell in the circumferential direction to connect the flange with the shell, the through hole corresponds to the opening, a sealing block is arranged in the sealing plate and the circular groove, the sealing block has a through hole, a part of the karst cavity body passes through one of the openings, the through hole of the sealing block and the through hole of the flange and forms the first flow channel connected with the cavity; the side wall of the through hole of the sealing block is tightly pressed against the outer wall of the karst cavity body forming the first flow channel; the sealing block is made of elastic material.

[0022] A karst grouting simulation test method using any of the above-mentioned karst grouting simulation test devices, the karst grouting simulation test method comprising:

[0023] Select a research area, and analyze the karst cavity morphology, rock layer characteristics and karst groundwater in the research area in combination with geological survey data;

[0024] The shape of the karst cavity is adjusted to correspond to the morphology of the karst cavity, and then the karst cavity is placed in the inner cavity of the shell in the rock and soil layer simulation system, part of the karst cavity passes through one of the openings and forms a first flow channel connected to the cavity, and part of the karst cavity passes through another opening and forms a second flow channel connected to the cavity, and the layered rock and soil body simulating the characteristics of the rock layer is filled in the inner cavity;

[0025] In the process of filling the inner cavity with a layered rock mass simulating the characteristics of the rock layer, a plurality of strain gauges are arranged near the outside of the karst cavity, and a grouting pipe is connected to a grouting port of the karst cavity;

[0026] Connecting the water environment simulation system to the first flow channel, and controlling the water flow input to the first flow channel according to the conditions of the karst groundwater;

[0027] The image acquisition device is turned on, and the grouting unit is started to grout into the karst cavity. During the grouting process, the stress-strain data collected by the strain gauge is recorded by the controller, and the changes of the karst cavity and the rock and soil body are collected by the image acquisition device.

[0028] Preferably, the karst grouting simulation test method further comprises:

[0029] By changing the shape of the karst cavity to simulate different karst cavity forms, or by changing the type and layer thickness of the rock and soil body to simulate different rock layer characteristics, or by changing the water environment simulation system to simulate different karst groundwater in the karst cavity, or by changing the grouting medium and grouting pressure of the grouting simulation system, the stress and strain variation law of the rock and soil body before and after grouting can be studied through the experimental data recorded in real time by the control system to evaluate the grouting effect.

[0030] The technical solution of the present invention has the following significant beneficial effects:

[0031] The karst grouting simulation test device and method in the present application can be used to simulate the karst morphology, rock layer characteristics and karst groundwater in the selected study area, and simulate the proposed karst grouting treatment plan through the grouting system. For example, the medium and pressure of the karst grouting can be controlled, and stress-strain data can be collected through the control system. The stress-strain evolution law of the rock and soil layers before and after grouting can be studied based on the field survey data to evaluate the grouting effect, thereby providing experimental data support for the application of grouting in karst treatment.

[0032] With reference to the following description and drawings, specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope. Features described and / or shown for one embodiment can be used in one or more other embodiments in the same or similar manner, combined with features in other embodiments, or replace features in other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the figures are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to the teachings of the present invention.

[0034] Figure 1 It is a structural schematic diagram of a karst grouting simulation test device in an embodiment of the present invention;

[0035] Figure 2 It is a structural schematic diagram of the karst grouting simulation test device at the opening in an embodiment of the present invention;

[0036] Figure 3 It is a side view of the karst grouting simulation test device at the opening in the embodiment of the present invention;

[0037] Figure 4 Schematic diagram of the structure of the cavity wall of the karst cavity body in an embodiment of the present invention;

[0038] Figure 5 It is a structural schematic diagram of a grouting vehicle in an embodiment of the present invention;

[0039] Figure 6 It is a flow chart of the karst grouting simulation test method in an embodiment of the present invention.

[0040] Reference numerals of the above drawings:

[0041] 1. Geotechnical layer simulation system; 2. Shell; 3. Strain gauge; 4. Cavity; 5. Slurry pipe; 6. On-off valve; 7. Water pipe; 8. Inner wall of cavity; 9. Outer wall of cavity; 10. Geotechnical body; 11. Base; 12. Grouting unit; 13. Image acquisition device; 14. Bracket; 16. Sealing piece; 17. Sealing block; 18. Filter; 19. Bolt; 20. Flange; 21. Nut; 22. Water pump; 23. Controller; 24. Connecting line; 25. Opening; 26. Grouting port; 27. Grouting pipe; 28. Slurry filling funnel; 29. ​​Pressure gauge; 30. Grouting pump; 31. Slurry storage tank; 32. First flow channel; 33. Second flow channel. DETAILED DESCRIPTION

[0042] The details of the present invention can be more clearly understood by combining the accompanying drawings and the description of the specific embodiments of the present invention. However, the specific embodiments of the present invention described herein are only used for the purpose of explaining the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should be regarded as belonging to the scope of the present invention. It should be noted that when an element is referred to as "arranged on" another element, it can be directly on another element or there can also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to another element or there may be a central element at the same time. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the communication between the two elements, it can be directly connected, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation method.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0044] In order to simulate the karst morphology, rock formation characteristics and karst groundwater in the selected study area, a karst grouting treatment scheme is proposed through the grouting system, stress-strain data are collected through the control system, and the stress-strain evolution law of the rock and soil layer before and after grouting is studied based on the field survey data to evaluate the grouting effect and provide experimental data support for the application of grouting in karst treatment. In this application, a karst grouting simulation test device is proposed. Figure 1 This is a structural schematic diagram of a karst grouting simulation test device in an embodiment of the present invention. As shown in 1, the karst grouting simulation test device may include: a karst cavity simulation system, a rock and soil layer simulation system 1, a water environment simulation system, a grouting simulation system, and a control system.

[0045] Among them, the rock layer simulation system 1 is used to simulate the rock layer characteristics of the selected study area. As shown in Figure 1, the rock layer simulation system 1 may include: a shell 2 with an inner cavity, the inner cavity is filled with a layered rock body 10 for simulating the rock layer characteristics of the selected study area, and the shell 2 has two openings 25. Through the openings 25, fluid can be input and discharged into the karst cavity simulation system to simulate karst groundwater. The layered rock body 10 is used to make the rock body 10 filled in the shell 2 similar to the rock layer characteristics of the selected study area. The karst cavity simulation system is used to simulate the karst cavity morphology of the selected study area. The karst cavity simulation system may include: a karst cavity 4 body arranged in the rock body 10. The karst cavity 4 body has a cavity 4 inside, and the karst cavity 4 body has a grouting port connected to the cavity 4, and the grouting port can enable the grouting simulation system to inject slurry into the cavity 4 in the karst cavity 4 body. Part of the karst cavity 4 passes through an opening 25 and forms a first flow channel 32 connected to the cavity 4, and part of the karst cavity 4 passes through another opening 25 and forms a second flow channel 33 connected to the cavity 4. The first flow channel 32 and the second flow channel 33 formed by the part of the karst cavity 4 passing through the opening 25 can input and discharge fluid to the karst cavity simulation system to simulate karst groundwater. The water environment simulation system is used to simulate the karst groundwater in the selected study area. The water environment simulation system may include: a water pump 22 and a water pipe 7, and the outlet of the water pump 22 can be connected to the first flow channel 32 through the water pipe 7. The fluid is injected into the first flow channel 32 through the water pump 22 and the water pipe 7, thereby entering the cavity 4 in the karst cavity 4 to simulate the karst groundwater flowing through the karst cavity, and then the injected fluid can be discharged from the second flow channel 33. The type and properties of the fluid can be adjusted according to the karst groundwater to be simulated. The grouting simulation system is used to simulate the injection of slurry into the karst cavity in the study area. The grouting simulation system may include: a grouting pipe 27 inserted in the rock and soil body 10 and connected to the grouting port of the karst cavity 4; a grouting unit 12 for outputting slurry, which is connected to the grouting pipe 27. When the grouting unit 12 continuously inputs slurry, the output slurry is injected into the cavity 4 of the karst cavity 4 in the rock and soil body 10 in the shell 2 by using the grouting pipe 27. The control system may include: a plurality of strain gauges 3 arranged near the karst cavity 4 in the rock and soil body 10, an image acquisition device 13 for shooting the rock and soil layer simulation system 1 and the karst cavity simulation system, and a controller 23. The strain gauge 3 is used to collect the stress and strain of the rock and soil body 10 near the karst cavity 4 during the process of injecting grout into the cavity 4 of the karst cavity 4 in the rock and soil body 10 in the shell 2 or before and after grouting. The plurality of strain gauges 3 are electrically connected to the controller 23, and the controller 23 is used to record the stress and strain data of the strain gauge 3.

[0046] In some embodiments, as shown in Figure 1, the shell 2 is made of transparent tempered glass, so that the image acquisition device 13 can clearly record and photograph the changes of the rock and soil body 10 before, during and after grouting during the entire test process. The upper end of the shell 2 can be open, so that it is convenient to fill the rock and soil body 10 in layers after the karst cavity 4 is placed in the shell 2, so that the rock and soil body 10 is consistent with the rock formation characteristics of the selected research area. The upper surface of the filled rock and soil body 10 can be used as a free surface to simulate the natural ground.

[0047] As feasible, as shown in Figure 1, the shell 2 can be generally in the shape of a cuboid, and the two openings 25 on the shell 2 can be opened on two opposite side walls of the shell 2. A base 11 can be installed at the bottom of the shell 2, and the base 11 can be made of rubber material, so as to protect the entire shell 2 and prevent it from breaking.

[0048] In some embodiments, Figure 4 FIG. 1 is a schematic diagram of the structure of the cavity wall of the karst cavity body in an embodiment of the present invention. Figure 4 As shown, the karst cavity 4 can be a double-layer cavity wall structure. The karst cavity 4 includes a cavity inner wall 8 and a cavity outer wall 9. The cavity inner wall 8 is a plastic metal wire mesh, for example, it can be a plastic steel wire mesh. The cavity outer wall 9 is made of a thin layer of a flexible material with extensibility. In some feasible embodiments, the flexible material can be selected from silicone, silicone rubber, latex, thermoplastic resin material, thermoplastic polyurethane elastic material or photosensitive resin material, etc. The slurry injected into the cavity 4 can squeeze the cavity outer wall 9 through the cavity inner wall 8 to act on the rock and soil body 10 in the rock and soil layer simulation system 1. Through the above structure, after the karst cavity 4 is placed in the layered rock and soil body 10 in the shell 2, before the slurry and fluid are input, the karst cavity 4 can be made to have sufficient strength to support the load of the rock and soil body 10 covered above the karst cavity 4 by using the plastic metal wire mesh, so as to ensure that the later fluid and slurry can be input into the cavity 4 in the karst cavity 4. Since the outer wall 9 of the cavity is a thin layer made of flexible material with extensibility, it can expand and contract. When the slurry is injected into the cavity 4 inside the karst cavity 4, the slurry can squeeze the outer wall 9 of the cavity so that the slurry and the outer wall 9 of the cavity can extend into the gaps of the surrounding rock and soil 10 together. The working conditions simulated by the above operation are more consistent with the actual service environment of karst.

[0049] Secondly, the plastic metal wire mesh in the inner wall 8 of the cavity can be folded into a shape corresponding to the karst in the selected research area, and the outer wall 9 of the cavity can adapt to form a shape that is the same as the shape of the plastic metal wire mesh after folding. In the above manner, the entire karst grouting simulation test device can simulate the karst in the selected research area of ​​any shape. At the same time, the karst cavity 4 can be reused. After a karst grouting simulation test is completed, the karst cavity 4 can be taken out from the rock and soil body 10 and folded into the shape required for the next test, thereby greatly reducing the cost of the test in the process of continuously performing the karst grouting simulation test.

[0050] In some embodiments, Figure 2 FIG. 1 is a schematic diagram of the structure of the karst grouting simulation test device at the opening in an embodiment of the present invention. Figure 2 As shown, the plastic metal wire mesh in the inner wall 8 of the cavity is folded into a fold at the first flow channel 32 passing through the outside of the opening 25, so that the karst cavity 4 passing through the outside of the opening 25 has a higher strength to form a tubular structure, which is convenient for connection with the water pipe 7 in the water environment simulation system.

[0051] In some embodiments, Figure 1 As shown, in order to recycle the fluid input into the karst cavity 4 and reduce the overall usage of the fluid, the inlet of the water pump 22 can be connected to the second flow channel 33 through the water pipe 7, so that the fluid discharged from the second flow channel 33 in the karst cavity 4 can be circulated from the first flow channel 32 into the karst cavity 4.

[0052] In some embodiments, the inner diameter and outer diameter of the water pipe 7 at the connection with the first flow channel 32 and the second flow channel 33 gradually expand, so as to be consistent with the inner wall 8 and the outer wall 9 of the cavity forming the first flow channel 32 and the second flow channel 33, respectively, so as to facilitate the water pipe 7 to be fixedly connected with the partial karst cavity 4 forming the first flow channel 32 and the second flow channel 33, respectively.

[0053] In some embodiments, Figure 2 As shown, a filter screen 18 can be installed at the end of the karst cavity 4 body forming the first flow channel 32, and a filter screen 18 can be installed at the end of the karst cavity 4 body forming the second flow channel 33. In this way, solids in the slurry injected into the karst cavity 4 body during the test can be prevented from flowing out of the first flow channel 32 or the second flow channel 33.

[0054] In some embodiments, Figure 1As shown, the water pipe 7 connected to the first flow channel 32 is provided with an on-off valve 6; the water pipe 7 connected to the second flow channel 33 is provided with an on-off valve 6. The above structure can adjust the on-off and flow rate of the fluid input into the cavity 4 of the karst cavity 4 on the one hand, and on the other hand, when both on-off valves 6 are closed, the cavity 4 of the karst cavity 4 can be in a sealed state, so that the grouting of the karst cavity without groundwater flow can be simulated, so as to evaluate and study the grouting effect in this state and the stress-strain evolution law of the rock-soil body 10 before and after grouting.

[0055] In some embodiments, Figure 3 FIG. 1 is a side view of the karst grouting simulation test device at the opening in an embodiment of the present invention. Figure 2 and Figure 3 As shown, the geotechnical layer simulation system 1 may include: a flange 20, a circular groove is provided in the middle of one side of the flange 20, a through hole is provided in the axial direction of the flange 20, an annular sealing sheet 16 is provided between the flange 20 and the housing 2, and a plurality of bolts 19 are passed through the flange 20, the sealing sheet 16 and the housing 2 in the circumferential direction so as to connect the flange 20 with the housing 2, the through hole corresponds to the opening 25, a sealing block 17 is provided in the sealing sheet 16 and the circular groove, the sealing block 17 has a through hole, a part of the karst cavity 4 passes through an opening 25, the through hole of the sealing block 17 and the through hole of the flange 20 and forms a first flow channel 32 communicating with the cavity 4; the side wall of the through hole of the sealing block 17 is tightly pressed against the outer side wall of the karst cavity 4 forming the first flow channel 32; the sealing block 17 is made of elastic material. The bolts 19 cooperate with the nuts 21 to fix the flange 20, the sealing sheet 16 and the housing 2. The sealing block 17 can be divided into two parts in the axial direction, one part has a diameter equal to the circular groove of the flange 20 , and the other part has a diameter equal to the diameter of the inner side wall of the annular sealing sheet 16 .

[0056] Through the above method, on the one hand, the opening 25 on the shell 2 can be sealed when part of the karst cavity 4 can pass through the shell 2, so as to prevent the rock and soil body 10 in the shell 2 and the water input by the water environment simulation system from leaking out; on the other hand, the entire above-mentioned sealing structure is detachable and can be reused. When the part of the karst cavity 4 that passes through the shell 2 is sealed, the part of the karst cavity 4 can be passed through the opening 25 on the shell 2, and then through the through hole of the sealing block 17 and the through hole of the flange 20, and then the flange 20, the sealing block 17 and the sealing sheet 16 are installed on the shell 2 by bolts 19.

[0057] In some embodiments, Figure 5 Schematic diagram of the structure of the grouting vehicle in the embodiment of the present invention. Figure 5As shown, the grouting unit 12 may include: a grouting vehicle, including a slurry filling funnel 28, a grouting pump 30, a slurry storage tank 31 and a pressure gauge 29. The grouting pump 30 is connected to the grouting port 26 at the upper end of the grouting pipe 27 through the grouting pipe 5. The slurry can enter the slurry storage tank 31 through the slurry filling funnel 28, and the slurry in the slurry storage tank 31 can be transported to the grouting pipe 5 through the grouting pump 30. The pressure gauge 29 is used to detect the pressure of the slurry in the grouting pipe 5, so as to control the pressure of the slurry injected into the karst cavity 4, and then the grouting effect under different grouting pressures and the stress-strain evolution law of the rock and soil body 10 before and after grouting can be tested.

[0058] In some embodiments, the grouting port on the karst cavity 4 is located on the upper end surface of the karst cavity 4, and the shape of the grouting port can be wide at the bottom and narrow at the top, and the cross-sectional size can be a circular ring, and the inner circle size of the circular ring is consistent with the outer diameter size of the slurry delivery pipe 5, so as to facilitate connection with the slurry delivery pipe 5. The pipe wall of the slurry delivery pipe 5 can be made of hard rubber material.

[0059] In some embodiments, in order to facilitate the arrangement of the strain gauge 3 in the rock mass 10 near the karst cavity 4, the strain gauge 3 can be glued to the outside of the cavity outer wall 9 of the karst cavity 4. For example, the strain gauge 3 can be evenly and equidistantly arranged along the cavity outer wall 9. During the test, the strain gauge 3 is buried in the rock mass 10 and connected to the controller 23 via a connecting line 24. As feasible, the image acquisition device 13 may include a high-speed camera and a connecting line 24, and the connecting line 24 may connect the high-speed camera and the controller 23, so that the controller 23 collects and stores high-speed images collected by the high-speed camera, and may control the opening and closing of the high-speed camera. A high-speed camera bracket 14 with adjustable speed and angle may be installed at the bottom of the high-speed camera, and the number of high-speed cameras may be increased in combination with the test requirements, so as to collect high-speed images in all directions of the shell 2. If necessary, a DIC test system may also be arranged.

[0060] The karst grouting simulation test device proposed in the present application can be used to simulate the karst morphology, rock formation characteristics and karst groundwater in the selected study area, and simulate the proposed karst grouting treatment plan through the grouting system. For example, the medium and pressure of the karst grouting can be controlled, and stress-strain data can be collected through the control system. The stress-strain evolution law of the rock and soil layers before and after grouting can be studied based on the field survey data to evaluate the grouting effect and provide experimental data support for the application of grouting in karst treatment.

[0061] Figure 6 FIG. 4 is a flow chart of the karst grouting simulation test method in an embodiment of the present invention, as shown in FIG. Figure 6 As shown, a karst grouting simulation test method using any one of the above karst grouting simulation test devices may include the following steps:

[0062] S1: Select the study area and analyze the karst cavity morphology, rock characteristics and karst groundwater in the study area based on geological survey data.

[0063] In the above steps, the study area is selected, and the karst cavity morphology, rock layer characteristics and karst groundwater in the study area are analyzed in combination with geological survey data. For example, when the karst geological type of the study area is selected as a karst funnel, the cross-sectional shape of the karst cavity is elliptical, and the stratigraphic profile is from bottom to top: 4-1-2 silty clay, layer thickness 1.6-2.1m; 7-1-2 mudstone, layer thickness 0.5-0.7m; 7-1-3 mudstone, layer thickness 9.0m. There is groundwater in the karst cavity.

[0064] S2: The shape of the karst cavity 4 is adjusted to correspond to the karst cave morphology, and then the karst cavity 4 is placed in the inner cavity of the shell 2 in the rock and soil layer simulation system 1, part of the karst cavity 4 passes through an opening 25 and forms a first flow channel 32 connected to the cavity 4, and part of the karst cavity 4 passes through another opening 25 and forms a second flow channel 33 connected to the cavity 4, and the layered rock and soil body 10 simulating the rock layer characteristics is filled in the inner cavity.

[0065] In the above steps, the shape of the karst cavity 4 is adjusted to an ellipse corresponding to the karst cavity morphology, and the cross-sectional size is 1 / 20 of the size of the karst cavity. Part of the karst cavity 4 passes through an opening 25 and forms a first flow channel 32 connected to the cavity 4, and part of the karst cavity 4 passes through another opening 25 and forms a second flow channel 33 connected to the cavity 4, and then the flange 20, the sealing sheet 16, the sealing block 17, and the bolt 19 are installed. Finally, the layered rock and soil body 10 simulating the characteristics of the rock formation is filled in the inner cavity, and the layered rock and soil body 10 is the same as the stratum profile. For example, the type and thickness of the rock and soil body 10 are 7-1-3 mud limestone 45cm, 7-1-2 mud limestone 4cm and 4-1-2 silty clay 10cm from bottom to top.

[0066] S3: During the process of filling the inner cavity with the layered rock and soil body 10 simulating the rock layer characteristics, a plurality of strain gauges 3 are arranged near the outside of the karst cavity 4 , and the grouting pipe 27 is connected to the grouting port of the karst cavity 4 .

[0067] In the above steps, multiple strain gauges 3 can be glued to the outside of the cavity wall 9 of the karst cavity 4 body with glue, and then the karst cavity 4 body is placed in the inner cavity of the shell 2 in the rock and soil layer simulation system 1, and then the layered rock and soil body 10 simulating the rock layer characteristics is filled in the inner cavity. It is more convenient to set the strain gauge 3 through the above process, and the strain gauge 3 is better set outside the cavity wall 9 of the karst cavity 4 body, so as to accurately collect the stress and strain of the rock and soil body 10 near the karst cavity 4 body during the process of grouting into the rock and soil body 10 in the shell 2 or before and after grouting.

[0068] S4: Connect the water environment simulation system to the first flow channel 32, and control the water flow input to the first flow channel 32 according to the conditions of the karst groundwater.

[0069] In the above steps, the outlet of the water pump 22 is connected to the first flow channel 32 through the water pipe 7, and the water pipe 7 connected to the first flow channel 32 is provided with an on-off valve 6. The water flow rate input to the first flow channel 32 is controlled according to the conditions of the karst groundwater, for example, by controlling the power of the pump and the opening degree of the on-off valve 6. When the flow rate and total amount of the fluid in the karst cavity 4 are consistent with the conditions of the karst groundwater, the inlet of the water pump 22 can be connected to the second flow channel 33 through the water pipe 7, so that the fluid is discharged from the karst cavity 4 and then input again when the flow rate and total amount of the fluid in the karst cavity 4 are consistent with the conditions of the karst groundwater, and in particular, the fluid in the karst cavity 4 can simulate the condition that the karst groundwater does not fill the lower karst.

[0070] S5: Turn on the image acquisition device 13 and start the grouting unit 12 to grout into the karst cavity 4. During the grouting process, the controller 23 records the stress-strain data collected by the strain gauge 3 and the changes of the karst cavity 4 and the rock and soil body 10 collected by the image acquisition device 13.

[0071] In the above steps, the height and angle of the bracket 14 of the image acquisition device 13 are adjusted, the image acquisition device 13 is placed on the bracket 14 of the image acquisition device 13, the image acquisition device 13 is turned on, and the shooting frequency and parameters of the image acquisition device 13 are set. Combined with the on-site grouting test parameters, the grouting pressure is preliminarily determined, the grouting unit 12 is started to start grouting, and during the grouting process, the stress and strain data collected by the strain gauge 3 and the changes of the karst cavity 4 and the rock and soil body 10 are recorded by the controller 23. After the grouting is completed, the grouting unit 12 is closed, the water pump 22 is closed, the on-off valve 6 is closed, the image acquisition device 13 is closed, the rock and soil body 10 is dug out, the karst cavity simulation system is disassembled, the scaled test is compared with the on-site grouting test results, and the test data is analyzed and sorted. In addition, the above experiment can also be used as a reference for actual on-site grouting.

[0072] S6: By changing the shape of the karst cavity 4 to simulate different karst cavity forms, or by changing the type and layer thickness of the rock and soil body 10 to simulate different rock layer characteristics, or by changing the water environment simulation system to simulate the karst groundwater in different karst cavities, or by changing the grouting medium and grouting pressure of the grouting simulation system, the experimental data recorded in real time by the control system can be used to study the stress and strain variation law of the rock and soil body 10 before and after grouting, so as to evaluate the grouting effect.

[0073] Through the above process, the grouting of karst cavities under different conditions can be repeatedly simulated to study the grouting conditions of karst cavities under different conditions, thereby studying the stress-strain variation law of the rock-soil body 10 during and before and after grouting of karst cavities under different conditions.

[0074] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for various purposes. The term "consisting essentially of ... " describing a combination should include determined elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel features of the combination. The use of the terms "comprising" or "including" to describe the combination of elements, ingredients, parts or steps here also contemplates the implementation method consisting essentially of these elements, ingredients, parts or steps. Here, by using the term "may", it is intended to illustrate that any attribute described that "may" includes is optional. Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "one" used to describe an element, ingredient, part or step is not said to exclude other elements, ingredients, parts or steps.

[0075] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. The above embodiments are only for illustrating the technical concept and features of the present invention. The purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A karst grouting simulation test device, It is characterized in that The karst grouting simulation test device comprises: a karst cavity simulation system, a rock and soil layer simulation system, a water environment simulation system, a grouting simulation system, and a control system; wherein, The rock layer simulation system comprises: a shell having an inner cavity, the inner cavity is filled with a layered rock body for simulating the rock layer characteristics of the selected study area, and the shell has two openings; The karst cavity simulation system comprises: a karst cavity body arranged in the rock and soil body, the karst cavity body having a cavity inside, the karst cavity body having a grouting port connected with the cavity, part of the karst cavity body passing through one of the openings and forming a first flow channel connected with the cavity, and part of the karst cavity body passing through another of the openings and forming a second flow channel connected with the cavity; The water environment simulation system comprises: a water pump and a water pipe, wherein the outlet of the water pump can be communicated with the first flow channel through the water pipe; The grouting simulation system comprises: a grouting pipe inserted in the rock and soil body and connected to the grouting port of the karst cavity body; a grouting unit for outputting slurry, which is connected to the grouting pipe; The control system includes: a plurality of strain gauges arranged in the rock and soil body near the karst cavity, an image acquisition device for photographing the rock and soil layer simulation system and the karst cavity simulation system, and a controller. The plurality of strain gauges are electrically connected to the controller, and the controller is used to record the stress and strain data of the strain gauges.

2. The karst grouting simulation test device according to claim 1, It is characterized in that The karst cavity body is a double-layer cavity wall structure, comprising an inner cavity wall and an outer cavity wall, wherein the inner cavity wall is a plastic metal wire mesh, and the outer cavity wall is a thin layer made of a flexible material with extensibility; the slurry injected into the cavity can squeeze the outer cavity wall through the inner cavity wall to act on the rock and soil body in the rock and soil layer simulation system.

3. The karst grouting simulation test device according to claim 2, It is characterized in that The plastic wire mesh in the inner wall of the cavity can be folded into a shape corresponding to the karst in the selected research area, and the outer wall of the cavity can adapt to form a shape that is the same as the shape of the plastic wire mesh after folding.

4. The karst grouting simulation test device according to claim 2, It is characterized in that The plastic metal wire mesh in the inner wall of the cavity is folded into a fold shape at the first flow channel passing through the outside of the opening.

5. The karst grouting simulation test device according to claim 1, It is characterized in that The shell is made of transparent tempered glass; the upper end of the shell is open.

6. The karst grouting simulation test device according to claim 1, It is characterized in that The inlet of the water pump can be communicated with the second flow channel through the water delivery pipe.

7. The karst grouting simulation test device according to claim 6, It is characterized in that The inner diameter and outer diameter of the water delivery pipe at the connection with the first flow channel and the second flow channel are gradually expanded, so as to be consistent with the inner wall and outer wall of the cavity forming the first flow channel and the second flow channel respectively.

8. The karst grouting simulation test device according to claim 6, It is characterized in that An on-off valve is provided on the water delivery pipe connected to the first flow channel; an on-off valve is provided on the water delivery pipe connected to the second flow channel.

9. The karst grouting simulation test device according to claim 1, It is characterized in that The grouting unit comprises: a grouting vehicle, comprising a slurry filling funnel, a grouting pump, a slurry storage tank and a pressure gauge; the grouting pump is connected to the grouting pipe through a grouting pipe; The slurry can enter the slurry storage tank through the slurry filling funnel and be transported to the slurry delivery pipe through the grouting pump; the pressure gauge is used to detect the pressure of the slurry in the slurry delivery pipe.

10. The karst grouting simulation test device according to claim 2, It is characterized in that The geotechnical layer simulation system also includes: a flange, a circular groove is provided in the middle of one side of the flange, a through hole is opened in the axial direction of the flange, an annular sealing sheet is arranged between the flange and the shell, and a plurality of bolts are passed through the flange, the sealing sheet and the shell in the circumferential direction to connect the flange with the shell, the through hole corresponds to the opening, a sealing block is arranged in the sealing sheet and the circular groove, the sealing block has a through hole, a part of the karst cavity body passes through one of the openings, the through hole of the sealing block and the through hole of the flange and forms the first flow channel connected with the cavity; the side wall of the through hole of the sealing block is tightly pressed against the outer side wall of the karst cavity body forming the first flow channel; the sealing block is made of elastic material.

11. A karst grouting simulation test method using the karst grouting simulation test device as claimed in any one of claims 1 to 10, It is characterized in that The karst grouting simulation test method comprises: Select a research area, and analyze the karst cavity morphology, rock layer characteristics and karst groundwater in the research area in combination with geological survey data; The shape of the karst cavity is adjusted to correspond to the morphology of the karst cavity, and then the karst cavity is placed in the inner cavity of the shell in the rock and soil layer simulation system, part of the karst cavity passes through one of the openings and forms a first flow channel connected to the cavity, and part of the karst cavity passes through another opening and forms a second flow channel connected to the cavity, and the layered rock and soil body simulating the characteristics of the rock layer is filled in the inner cavity; In the process of filling the inner cavity with a layered rock mass simulating the characteristics of the rock layer, a plurality of strain gauges are arranged near the outside of the karst cavity, and a grouting pipe is connected to a grouting port of the karst cavity; Connecting the water environment simulation system to the first flow channel, and controlling the water flow input to the first flow channel according to the conditions of the karst groundwater; The image acquisition device is turned on, and the grouting unit is started to grout into the karst cavity. During the grouting process, the stress-strain data collected by the strain gauge is recorded by the controller, and the changes of the karst cavity and the rock and soil body are collected by the image acquisition device.

12. According to the karst grouting simulation test method described in claim 11, It is characterized in that The karst grouting simulation test method also includes: By changing the shape of the karst cavity to simulate different karst cavity forms, or by changing the type and layer thickness of the rock and soil body to simulate different rock layer characteristics, or by changing the water environment simulation system to simulate different karst groundwater in the karst cavity, or by changing the grouting medium and grouting pressure of the grouting simulation system, the stress and strain variation law of the rock and soil body before and after grouting can be studied through the experimental data recorded in real time by the control system to evaluate the grouting effect.

Images