Indoor loading test device for simulating seepage cracking of high-water-pressure tunnel in karst area

Abstract

The invention discloses an indoor loading device for simulating seepage cracking of a high-water-pressure tunnel in a karst area, and the device comprises a bottom plate, the top surface of the bottom plate is provided with a model box, the model box is filled with a surrounding rock model, and the surrounding rock model is internally provided with a karst cavity; through cavities are formed in the middle positions of the front surfaces of the tunnel lining model and the surrounding rock model; the loading system is mounted at the top of the model box; the pressurizing system penetrates through the front side of the model box and is connected with the front end of the tunnel lining model; the pressure relief system is connected with the rear end of the tunnel lining model; a plurality of groups of deformation monitoring modules are arranged in the tunnel lining model; the front end and the rear end of the tunnel lining model are respectively provided with a sealing assembly. By constructing a controllable surrounding rock-karst cavity-tunnel lining multi-field coupling test environment, a reliable test means is provided for structural safety assessment and prevention and control measure research of the high-water-pressure tunnel in the karst area.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering testing equipment, and in particular to an indoor loading device for simulating seepage cracking in high-water-pressure tunnels in karst regions. Background Technology

[0002] In major engineering projects such as water conservancy and hydropower, transportation and municipal works, tunnels, as key water conveyance, navigation or transportation channels, often need to traverse karst areas. Karst areas have complex geological conditions, with special geological structures such as dissolution fissures and karst cavities commonly found in the surrounding rock. Furthermore, hydraulic tunnels face high water pressure during operation. When the water pressure on the tunnel lining exceeds its impermeability threshold, it is highly susceptible to the coupling effect of the seepage field and stress field, leading to cracking and leakage in the lining and surrounding rock structure. This reduces the load-bearing capacity and durability of the tunnel structure, and can cause major safety accidents such as structural instability, seriously threatening the safety of project construction and operation.

[0003] To ensure the safe implementation of high-water-pressure tunnel projects in karst areas, it is necessary to understand the seepage and cracking mechanisms of tunnels under high water pressure and complex geological conditions in advance. Indoor physical simulation experiments are one of the core methods for revealing this mechanism. Currently, some indoor devices related to tunnel seepage or stress loading exist in the industry, but these devices still have many key technical shortcomings when simulating the actual working conditions of high-water-pressure tunnels in karst areas: First, existing devices often neglect the influence of karst cavities on the seepage field, conducting tests only on homogeneous surrounding rock or simple fracture models. This fails to accurately reproduce the seepage path and pressure transmission patterns among the surrounding rock, karst cavity, and tunnel in karst areas, leading to significant discrepancies between simulation results and actual engineering conditions. Second, the loading system designs are often simplistic, mostly capable of only vertical or unidirectional stress loading. This makes it difficult to simulate the actual three-dimensional high ground stress environment experienced by tunnels, and thus fails to accurately reflect the inducing effect of the coupling effect of high ground stress and high water pressure on tunnel cracking. Third, the coordination between water pressure control and pressure relief systems is insufficient, with some devices only capable of constant water pressure loading. First, there is a lack of simulation capabilities for dynamic water pressure changes (such as periodic water level changes in hydraulic tunnels of pumped storage power stations). Second, the sealing structure design at both ends of the tunnel lining model is unreasonable, which easily leads to water pressure leakage and affects the accuracy of the test data. Third, the monitoring and observation methods are inadequate. The deformation monitoring module only sets up a small number of monitoring points on the outer wall of the tunnel, which makes it difficult to fully capture the deformation and cracking process at different locations on the inner wall of the tunnel. In addition, the video acquisition unit has a fixed perspective and limited coverage, which cannot clearly record the external deformation and internal cracking evolution characteristics of the surrounding rock and the tunnel lining model, resulting in insufficient support for the correlation analysis between the test phenomena and the data.

[0004] In summary, existing indoor simulation devices cannot accurately reproduce the coupled working conditions of "high ground stress-high water pressure-karst cavity" in high-water-pressure tunnels in karst areas, making it difficult to effectively reveal the intrinsic mechanism of tunnel seepage and cracking, and failing to provide reliable experimental basis for engineering design and disease prevention. Therefore, developing an indoor loading device that can realistically simulate karst geological conditions, achieve multi-field coupled loading, and provide precise monitoring and visualization has become an urgent need to solve the safety problems of high-water-pressure tunnel engineering in karst areas, and is of great significance to promoting the advancement of related engineering technologies. Summary of the Invention

[0005] The purpose of this invention is to provide an indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas, in order to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides an indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas, comprising: A base plate, on the top surface of which a model box is installed, the model box is filled with a surrounding rock model, and a karst cavity is opened in the surrounding rock model, the karst cavity is connected to a water supply pipe; A tunnel lining model, wherein the tunnel lining model has a cylindrical structure, and a cavity is opened in the middle of the front of the surrounding rock model, and the tunnel lining model is placed horizontally in the cavity; A loading system is installed on top of the model box and perpendicularly contacts the top of the surrounding rock model. The loading system is used to simulate high ground stress in the surrounding rock. A pressurization system, which passes through the front side of the model box and is connected to the front end of the tunnel lining model, is used to apply water pressure to the tunnel lining model; A pressure relief system is connected to the rear end of the tunnel lining model; A deformation monitoring module, wherein several sets of the deformation monitoring module are arranged inside the tunnel lining model, and the deformation monitoring module is connected to the terminal system; A video acquisition unit is mounted on the base plate and located outside the model box, with the video acquisition unit arranged corresponding to the model box. The tunnel lining model is equipped with sealing components at its front and rear ends.

[0007] According to the present invention, an indoor loading device for simulating seepage and cracking in a high-pressure tunnel in a karst region is provided. The loading system includes jacks, and several sets of jacks are provided. A pressure plate is fixed on the top of the model box. Several sets of jacks are arranged at equal intervals on the bottom surface of the pressure plate. The output end of the jacks abuts against the top surface of the surrounding rock model.

[0008] According to the indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas provided by the present invention, the pressurization system includes: A first water tank, with a first water pipe installed at the output end of the first water tank; A booster pump is connected to the first water pipe, and the output end of the booster pump is connected to a water delivery pipe, which is connected to the tunnel lining model. A water inlet valve is installed on the first water pipe.

[0009] According to the indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas provided by the present invention, the pressure relief system includes: The second water tank has a second water pipe installed at the second vertical output end, and one end of the second water pipe is connected to the rear end of the tunnel lining model. A water outlet valve is installed on the second water pipe.

[0010] According to the indoor loading device for simulating seepage cracking in high-water-pressure tunnels in karst areas provided by the present invention, the deformation monitoring module includes deformation plates, and the deformation plates are arranged in several groups, with the groups of deformation plates staggered on the inner wall of the tunnel lining model.

[0011] According to the indoor loading device for simulating seepage and cracking in high-pressure tunnels in karst areas provided by the present invention, the sealing assembly includes a flange and a rubber gasket. The front and rear sides of the model box are respectively provided with installation ports, and the flanges are respectively installed in the installation ports. The rubber gaskets are respectively disposed between the flanges and the front and rear ends of the tunnel lining model. The two sets of flanges are fixed together by horizontally arranged tie rod bolts. The water supply pipe and the second water pipe respectively pass through the two sets of flanges and extend into the tunnel lining model.

[0012] According to the indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas provided by the present invention, the video acquisition unit includes a camera, which is mounted on the base plate and corresponds to the model box.

[0013] According to the indoor loading device for simulating seepage cracking in high-water-pressure tunnels in karst areas provided by the present invention, a pressure sensor is installed inside the tunnel lining model.

[0014] The present invention discloses the following technical effects: This invention establishes a controllable karst cavity within a surrounding rock model, applies high ground stress to the surrounding rock and high water pressure to the tunnel lining, and introduces karst water pressure loading conditions. This enables the construction of a multi-field coupled environment of "surrounding rock - karst cavity - tunnel lining" under indoor conditions, realistically simulating the complex hydraulic and mechanical conditions of tunnels in karst areas, and improving the similarity between experimental results and actual engineering.

[0015] This invention sets up a pressurization system and a depressurization system to work together, which can not only achieve constant loading of water pressure inside the tunnel lining, but also simulate the process of gradual increase and change of water pressure, effectively reproduce the response characteristics of the tunnel under the working conditions of periodic water level changes in pumped storage power stations, and make up for the shortcomings of the single water pressure loading method of existing devices.

[0016] This invention deploys multiple deformation monitoring modules within a tunnel lining model, and combines them with pressure sensors and video acquisition units to simultaneously acquire visualized information on the deformation, water pressure changes, and crack initiation and propagation of the tunnel lining during loading. This provides complete and reliable data support for revealing the tunnel seepage cracking mechanism and critical failure conditions. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a front view of the indoor loading device for simulating seepage cracking in high-water-pressure tunnels in karst areas according to the present invention; Figure 2 This is a cross-sectional view of the left side of the indoor loading device for simulating seepage and cracking in a high-water-pressure tunnel in a karst region, according to the present invention.

[0019] The components include: 1. Surrounding rock model; 2. Flange; 3. Rubber gasket; 4. Tie rod bolt; 5. Jack; 6. Karst cavity; 7. First water tank; 8. Inlet valve; 9. Pressurized water pump; 10. Tunnel lining model; 11. Pressure sensor; 12. Deformation plate; 13. Outlet valve. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Reference Figures 1-2This invention provides an indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas, comprising: The base plate has a model box installed on its top surface. The model box is filled with a surrounding rock model 1. A karst cavity 6 is opened in the surrounding rock model 1. The karst cavity 6 is connected to a water supply pipe. The tunnel lining model 10 has a cylindrical structure. A cavity is opened in the middle of the front of the surrounding rock model 1. The tunnel lining model 10 is placed horizontally in the cavity. The loading system is installed on top of the model box and perpendicularly contacts the top of the surrounding rock model 1. The loading system is used to simulate the high ground stress of the surrounding rock. A pressurization system, which passes through the front side of the model box and connects to the front end of the tunnel lining model 10, is used to apply water pressure to the tunnel lining model 10; A pressure relief system is connected to the rear end of the tunnel lining model 10; Deformation monitoring module: Several sets of deformation monitoring modules are arranged inside the tunnel lining model 10, and the deformation monitoring modules are connected to the terminal system. The video acquisition unit is mounted on the base plate and located outside the model box. The video acquisition unit is arranged correspondingly to the model box. Sealing components are installed at the front and rear ends of the tunnel lining model 10.

[0023] In operation, the present invention fills the surrounding rock model 1 into the model box of the base plate, and karst cavity 6 and through cavity are opened in the surrounding rock model 1 according to the design; the cylindrical tunnel lining model 10 is horizontally placed into the through cavity, and the sealing components at its front and rear ends are sealed; the water supply pipe is connected to the karst cavity 6, the pressurization system is connected to the front end of the tunnel lining model 10, the pressure relief system is connected to the rear end, the deformation monitoring module is deployed in the tunnel lining model 10 and connected to the terminal system, and the video acquisition unit is adjusted to the monitoring position corresponding to the model box. The loading system is started to apply vertical pressure to the top of the surrounding rock model 1 to simulate high ground stress; after the stress stabilizes, water pressure is applied to the tunnel lining model 10 through the pressurization system. If it is necessary to simulate pressure changes, the pressure in the tunnel lining model 10 can be adjusted through the pressure relief system; at the same time, the water supply pipe is opened to put the karst cavity 6 into a preset hydrological state, thus constructing a multi-field coupling environment. The deformation monitoring module collects deformation data at various points on the inner wall of the tunnel lining model 10 in real time and transmits it to the terminal system; the video acquisition unit simultaneously captures the surrounding rock inside the model box and the external state of the tunnel lining model 10, recording the evolution process of seepage, cracking, etc., until the end of the test.

[0024] To further optimize the design, the surrounding rock model 1 can be prepared by mixing materials such as sand, gypsum, cement, fly ash, or stone powder in a certain mass ratio. By adjusting the content of the cementing material and the moisture content, the compressive strength, elastic modulus, and permeability of the surrounding rock model can be matched with the target rock mass under similarity conditions. The surrounding rock model is formed by layered filling and layer-by-layer compaction to reduce the impact of internal heterogeneity on the test results and improve overall stability.

[0025] The tunnel lining model 10 can be cast using gypsum mortar, low-strength concrete, or resin-based composite materials. Its material mix is ​​designed to scale down based on the strength, stiffness, and impermeability of the prototype lining. By controlling the aggregate particle size, cementitious material ratio, and curing conditions, the tunnel lining model can produce deformation and cracking patterns similar to the prototype during loading.

[0026] After the models are fabricated, basic mechanical parameters of the surrounding rock model 1 and the tunnel lining model 10 can be tested. The material ratios can be fine-tuned according to experimental requirements to ensure the consistency and repeatability of the model material properties under different experimental conditions. Through the optimization of the above material ratios and fabrication methods, the experimental device can not only simulate high ground stress and high water pressure conditions, but also realistically reflect the mechanical and seepage characteristics of the surrounding rock and tunnel lining in karst areas at the material level.

[0027] Further optimization of the scheme: the loading system includes jacks 5, and several sets of jacks 5 are set up. A pressure plate is fixed on the top of the model box. Several sets of jacks 5 are arranged at equal intervals on the bottom surface of the pressure plate. The output end of the jacks 5 abuts against the top surface of the surrounding rock model 1.

[0028] The loading system transmits the load through the pressure plate on the top of the model box: several sets of jacks 5 are evenly spaced on the bottom surface of the pressure plate. After starting, the output end of the jacks 5 pushes the pressure plate synchronously. The pressure plate converts the dispersed hydraulic force into a uniform surface load, which acts vertically on the top surface of the surrounding rock model 1. This accurately simulates the high ground stress environment where the tunnel is actually located, avoids local stress concentration in the surrounding rock caused by single-point loading, and ensures that the stress field distribution is more in line with the actual engineering situation.

[0029] A small pressure sensor 11 is installed between the output end of each set of jacks 5 and the pressure plate to monitor the output value of each jack 5 in real time. By independently or in conjunction with the control of the loading force and loading rate of each jack 5, the surrounding rock model can be subjected to constant stress, graded increasing stress, or a specific stress path loading state at different stages, thereby simulating the stress environment of the tunnel under different burial depths and different initial ground stress conditions. This loading method effectively avoids local damage to the surrounding rock caused by single-point or non-uniform loading, making the stress field of the surrounding rock more stable, controllable, and repeatable during the test. A 1-2cm thick rubber buffer layer is laid on the contact surface between the pressure plate and the surrounding rock model 1 to reduce the damage to the surface of the surrounding rock model 1 caused by the rigid contact of the pressure plate, and at the same time improve the uniformity of load transfer.

[0030] Further optimization of the solution, the pressurization system includes: First water tank 7, the output end of first water tank 7 is equipped with first water pipe; A booster pump is connected to the first water pipe. The output end of the booster pump is connected to a water delivery pipe, which is connected to the tunnel lining model 10. Water inlet valve 8 is installed on the first water pipe.

[0031] The pressurization system provides stable water pressure for the tunnel model: the first water tank 7 stores the test water. After the inlet valve 8 is opened, the pressurization pump draws water from the water tank through the first water pipe, and after pressurization, it is delivered to the inside of the tunnel model through the water supply pipe. The target water pressure can be set by adjusting the power of the pressurization pump. The inlet valve 8 is used to control the water flow, realizing the closed-loop control of "water supply-pressurization-water delivery", and providing a power source for simulating the high water pressure environment of the tunnel.

[0032] A precision pressure regulating valve is installed near the tunnel model on the water supply pipe, and a booster pump is used to achieve micro-adjustment of water pressure (such as 0.01MPa level) to meet the requirements of dynamic water pressure simulation. An electromagnetic flow meter is added to the first water pipe to monitor the inlet water flow in real time. At the same time, a level gauge is installed in the first water tank 7 to facilitate the correlation of water pressure and water volume data, and to prevent the booster pump from running dry due to water shortage in the water tank.

[0033] Further optimization of the solution includes the following pressure relief system: The second water tank has a second water pipe installed at the second vertical output end, and one end of the second water pipe is connected to the rear end of the tunnel lining model 10. Water outlet valve 13 is installed on the second water pipe.

[0034] The pressure relief system is used to regulate the pressure inside the tunnel model: when it is necessary to simulate the pressure relief condition, the outlet valve 13 on the second water pipe is opened, and the high-pressure water inside the tunnel model flows naturally into the second water tank through the second water pipe to achieve pressure attenuation; the pressure relief system is not only used for conventional pressure release, but also for simulating the rapid pressure relief condition of the tunnel under the condition of local structural damage. By precisely controlling the opening sequence, opening speed and opening amplitude of the outlet valve 13, the water pressure inside the tunnel lining model 10 can be significantly reduced in a short time, thereby simulating the sudden drop in water pressure in the project.

[0035] Pressure sensor 11 and liquid level sensor are installed in the second water tank to record the changes in pressure and liquid level in the water tank in real time during the depressurization process, which is convenient for reverse deduction of the relationship between the tunnel depressurization rate and the water inflow.

[0036] Further optimization of the scheme: the deformation monitoring module includes deformation plates 12, and several groups of deformation plates 12 are set up and staggered on the inner wall of the tunnel lining model 10.

[0037] The deformation plate 12 monitors the tunnel status through the principle of "deformation-resistance change": several sets of deformation plates 12 are staggered and arranged on the inner wall of the tunnel model. When the tunnel deforms due to seepage pressure or stress, the deformation plate 12 is stretched / compressed along with the tunnel wall, and its resistance value changes accordingly. This change is converted into quantitative deformation data by the data acquisition device and transmitted to the terminal system to realize synchronous monitoring of deformation at multiple points.

[0038] The deformation monitoring module forms a multi-point monitoring network along the circumferential and axial directions on the inner wall of the tunnel lining model 10. Deformation plates 12 are arranged in a staggered and zoned manner in key stress areas such as the arch crown, arch waist, and arch bottom. By synchronously collecting and comparing deformation data from different monitoring points, strain concentration areas of the tunnel lining model under seepage-stress coupling can be identified.

[0039] Temperature compensation plates are arranged in parallel next to the deformation plate 12 to counteract the interference of temperature changes in the test environment on the resistance of the deformation plate 12 and improve the accuracy of the data. Deformation plates 12 are densified (5cm apart) in the easily cracked parts of the tunnel model (such as the arch and the waist of the arch), and high-sensitivity deformation plates 12 (such as K value 2.0) are selected to capture small deformations (0.001mm level) and provide early warning of cracking trends.

[0040] The design is further optimized. The sealing assembly includes a flange 2 and a rubber gasket 3. The front and rear sides of the model box are respectively provided with installation ports. The flange 2 is installed in the installation ports respectively. The rubber gasket 3 is respectively set between the flange 2 and the front and rear ends of the tunnel lining model 10. The two sets of flanges 2 are fixed together by horizontally set tie rod bolts 4. The water supply pipe and the second water pipe pass through the two sets of flanges 2 and extend into the tunnel lining model 10.

[0041] The sealing assembly achieves waterproofing through "mechanical compression + elastic sealing": the flange 2 inside the mounting ports on the front and rear sides of the model box is tightened and fixed by the horizontal tie rod bolts 4, so that the flange 2 fits tightly with the front and rear ends of the tunnel model; the rubber gasket 3 between the flange 2 and the tunnel is squeezed and undergoes elastic deformation, filling the gaps on the contact surface. At the same time, when the water supply pipe and the second water pipe pass through the flange 2, they seal with the plate body, completely blocking the leakage path of high-pressure water inside the tunnel.

[0042] The solution has been further optimized so that the video acquisition unit includes a camera, which is mounted on the base plate.

[0043] The camera records the test process through visual monitoring: the camera is fixed on the base plate, and the lens is facing the model box. It can capture the deformation, cracking and seepage traces on the surface of the surrounding rock model 1 and the outside of the tunnel model in real time. By taking pictures at timed intervals or recording continuously, the image data of the whole test process is preserved, which provides an intuitive basis for subsequent analysis of the coupled evolution law of "stress-seepage-deformation".

[0044] To further optimize the design, a pressure sensor 11 was installed inside the tunnel lining model 10.

[0045] Pressure sensor 11 directly monitors the dynamic water pressure inside the tunnel: Pressure sensor 11 is installed on the inner wall of the tunnel model and can collect water pressure data at different locations inside the tunnel in real time. The data is transmitted to the terminal system via wired / wireless transmission. It can not only verify the water pressure control accuracy of the pressurization system, but also capture the instantaneous changes in water pressure during the depressurization process, providing data support for the judgment of critical water pressure for seepage cracking.

[0046] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0047] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas, characterized in that, include: A base plate, on the top surface of which a model box is installed, the model box is filled with a surrounding rock model (1), and a karst cavity (6) is opened in the surrounding rock model (1), the karst cavity (6) is connected to a water supply pipe; The tunnel lining model (10) has a cylindrical structure. A cavity is provided in the middle of the front of the surrounding rock model (1). The tunnel lining model (10) is placed horizontally in the cavity. A loading system is installed on top of the model box and perpendicularly contacts the top of the surrounding rock model (1). The loading system is used to simulate high ground stress in the surrounding rock. A pressurization system, which passes through the front side of the model box and is connected to the front end of the tunnel lining model (10), is used to apply water pressure to the tunnel lining model (10); A pressure relief system is connected to the rear end of the tunnel lining model (10); Deformation monitoring module, wherein several sets of deformation monitoring modules are arranged in the tunnel lining model (10), and the deformation monitoring module is connected to the terminal system; A video acquisition unit is mounted on the base plate and located outside the model box, with the video acquisition unit arranged corresponding to the model box. The tunnel lining model (10) is equipped with sealing components at its front and rear ends.

2. The indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas according to claim 1, characterized in that, The loading system includes jacks (5), and several sets of jacks (5) are provided. A pressure plate is fixed on the top of the model box. Several sets of jacks (5) are arranged at equal intervals on the bottom surface of the pressure plate. The output end of the jacks (5) abuts against the top surface of the surrounding rock model (1).

3. The indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas according to claim 1, characterized in that, The pressurization system includes: The first water tank (7) has a first water pipe installed at its output end; A booster pump is connected to the first water pipe, and the output end of the booster pump is connected to a water delivery pipe, which is connected to the tunnel lining model (10). Water inlet valve (8) is installed on the first water pipe.

4. The indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas according to claim 3, characterized in that, The pressure relief system includes: The second water tank has a second water pipe installed at the second vertical output end, and one end of the second water pipe is connected to the rear end of the tunnel lining model (10). Water outlet valve (13) is installed on the second water pipe.

5. The indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas according to claim 1, characterized in that, The deformation monitoring module includes a deformation plate (12), and the deformation plate (12) is arranged in several groups, and the several groups of deformation plates (12) are staggered on the inner wall of the tunnel lining model (10).

6. The indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas according to claim 4, characterized in that, The sealing assembly includes a flange (2) and a rubber gasket (3). The front and rear sides of the model box are respectively provided with installation ports. The flange (2) is installed in the installation ports respectively. The rubber gasket (3) is respectively set between the flange (2) and the front and rear ends of the tunnel lining model (10). The two sets of flanges (2) are fixed together by horizontally arranged tie rod bolts (4). The water supply pipe and the second water pipe respectively pass through the two sets of flanges (2) and extend into the tunnel lining model (10).

7. The indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas according to claim 1, characterized in that, The video acquisition unit includes a camera, which is mounted on the base plate and corresponds to the model box.

8. The indoor loading device for simulating seepage and cracking in high-water-pressure tunnels in karst areas according to claim 1, characterized in that, A pressure sensor (11) is installed inside the tunnel lining model (10).

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