Anti-seepage wall dam foundation soil stress-seepage coupling anti-seepage characteristic testing device

Abstract

The invention discloses a device for testing the stress-seepage coupling anti-permeability characteristic of a dam foundation soil body of an anti-seepage wall. The device comprises a test box, a loading system, a seepage system and a monitoring system, a groove is formed in the wall of the test box and used for embedding the rigid diaphragm wall model, and the space between the groove and the diaphragm wall model is filled with a flexible water stop material to ensure sealing. The loading system is of a double-flexible-water-bag structure, and uniform vertical stress is applied to soil bodies on the two sides of the diaphragm wall. The seepage system applies hydraulic gradient from the water inlet end through the water supply device, so that water flow horizontally passes through the soil body and the diaphragm wall model. The monitoring system comprises pore pressure sensors arranged in an array mode and a water outlet surface vertical strip-shaped through hole observation window, and the pore water pressure distribution and the seepage damage phenomenon are monitored in real time. Through series innovative design, the limitation that only seepage model test can be carried out on the suspension type diaphragm wall dam foundation in the prior art is overcome, and a brand-new test platform is provided for researching a diaphragm wall dam foundation stress-seepage coupling anti-seepage mechanism.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical testing equipment, in particular to a stress-seepage coupling anti-seepage characteristic testing device for an anti-seepage wall dam foundation soil. Background Art

[0002] A dam's cutoff wall, made of concrete, serves as a vertical seepage barrier, connecting to the dam's anti-seepage system, including the slab and core walls. Installed vertically within the dam foundation soil, it is a critical component of the dam's anti-seepage system, effectively ensuring the seepage stability and structural safety of the dam body and foundation. Therefore, the quality of the cutoff wall is directly related to the long-term operational safety of water conservancy projects. However, due to quality control during construction, long-term fluctuations in temperature, environmental water levels, and uneven dam foundation settlement, cutoff walls are prone to various defects, such as cracks, internal holes, surface spalling, and chemical corrosion. Cracks in the cutoff wall are the most serious of these defects. They can cause seepage deformation of the dam foundation, increase leakage in the anti-seepage system, structural instability, and reduced durability. In severe cases, they can even lead to dam failure. Numerous dam accidents caused by defects in the cutoff wall have occurred both domestically and internationally, resulting in significant casualties and property losses. Therefore, in addition to strengthening quality control during the construction of cut-off walls, in-depth research is needed on the seepage erosion patterns and deformation mechanisms of the cut-off wall foundation to scientifically guide its construction and ensure the long-term safety of the dam. However, current research on the seepage and deformation patterns of cut-off wall foundations has primarily relied on numerical calculations, often simplifying model parameters and boundary conditions. This has led to significant limitations in the research results. Due to the limitations of experimental equipment, few studies have used physical model testing, which more closely resembles the actual dam conditions and provides more reliable results.

[0003] Chinese invention patent publication number CN107192811B discloses a large-deformation, fully enclosed, visual measurement device for horizontal erosion. This device can perform horizontal permeability tests on graded soils with controlled vertical stress under confined conditions. However, this device cannot accommodate materials other than soil within the specimen, making it incapable of conducting physical model tests of seepage within soil containing an impervious wall dam foundation. Conventional seepage testing devices under stress conditions, such as this device, are unable to achieve watertightness for composite specimens of materials with different deformation moduli (impervious wall concrete, sand), nor do they offer effective monitoring or observation methods for capturing seepage erosion and seepage deformation within the specimens. Consequently, these technical limitations have prevented existing devices from conducting stress-seepage coupled permeability tests on soil containing an impervious wall dam foundation, preventing them from accurately revealing the seepage erosion patterns and seepage deformation mechanisms within the impervious wall dam foundation.

[0004] Chinese patent application number CN108035301B discloses a test device and method for simulating the anti-seepage effect of a suspended cut-off wall under seepage-stress coupling. This device, primarily targeting suspended cut-off walls, employs transparent soil, a CCD camera, a laser, and other tools for visual observation. The cut-off wall model consists of an organic tempered glass plate, the depth of which is controlled by a lifting device. Stress is applied to the engineering piles via a loading plate and weights. This device is suitable for studying the seepage characteristics and soil displacement of suspended cut-off walls in transparent ideal media. However, it is difficult to realistically simulate the more common rigid concrete cut-off walls found in engineering projects that are fully embedded in the foundation, particularly the complex mechanical and hydraulic coupling behavior between defective cut-off walls and the original soil. Furthermore, its loading method and sealing structure are not suitable for simulating the combination of such rigid walls and actual soil. Summary of the Invention

[0005] In order to overcome the deficiency that the existing test device cannot carry out the seepage test of the embedded anti-seepage wall dam foundation, the present invention provides a stress-seepage coupling anti-seepage characteristic test device of the anti-seepage wall dam foundation soil.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: A stress-seepage coupling anti-seepage characteristic test device for soil in an anti-seepage wall dam foundation, comprising: a test box, a top cover provided on the top surface of the test box, the top cover being provided with two independent first water inlet holes and two corresponding first exhaust holes, a left side of the test box serving as a water inlet surface being provided with a second exhaust hole and a second water inlet hole, a right side of the test box serving as a water outlet surface having a water outlet porous plate provided on its inner side, a water collecting trough fixedly mounted on the right side of the test box, a water outlet hole provided at the lower portion of the water collecting trough, grooves being provided along predetermined paths on the inner walls of the front, rear, and bottom sides of the test box or on two of the sides thereof, the grooves being used to embed a prefabricated rigid anti-seepage wall model, a flexible water-stopping material being filled between the inner surface of the groove and the outer surface of the rigid anti-seepage wall model; A loading system is provided on the top of the test box and includes a first flexible water bag and a second flexible water bag. The first flexible water bag and the second flexible water bag are symmetrically or partitionedly arranged above the rigid cut-off wall model and the soil on both sides. The first flexible water bag and the second flexible water bag are both connected to a pressure-volume controller; A seepage system comprising a water inlet structure provided on one side of the test box, a water outlet structure provided on the opposite side, and a water supply device connected to the water inlet structure, the water supply device being connected to the second water inlet hole and configured to allow water to flow horizontally through the soil in the test box and the rigid anti-seepage wall model; The monitoring system includes a plurality of pore pressure sensors installed in an array on the inner side of the test box wall or pre-buried in the soil and the rigid anti-seepage wall model, and an observation device arranged at the water outlet structure for observing the seepage channel.

[0007] Preferably, the depth of the groove is less than the thickness of the test box wall, and the width and shape of the groove match the cross section of the rigid anti-seepage wall model.

[0008] Preferably, the left, right and bottom sides of the rigid anti-seepage wall model are completely embedded in the grooves of the test box wall, the top surface is not in fixed contact with the top cover, and the rigid anti-seepage wall model contains common engineering defects such as through cracks.

[0009] Preferably, the flexible water-stopping material is a high molecular polymer sealant or a modified asphalt-based sealing material, and the pressure-volume controller is a servo-controlled hydraulic or pneumatic system that can accurately control the pressure or volume in the flexible water bag.

[0010] Preferably, a porous plate at the water inlet end is provided inside the water inlet structure and the water outlet structure to ensure that water flows into and out of the sample evenly.

[0011] Preferably, the observation device is a vertical through-hole observation window arranged outside the water outlet structure.

[0012] Preferably, the pore pressure sensor is a micro sensor, and its arrangement can reflect the pore water pressure distribution in the upstream, downstream and nearby key areas of the rigid anti-seepage wall model.

[0013] Preferably, the test box is made of stainless steel or a metal material with similar strength and rigidity.

[0014] Preferably, the rigid anti-seepage wall model is a scaled-down concrete anti-seepage wall segment or a model made of other rigid anti-seepage materials commonly used in engineering projects.

[0015] The present invention also provides an experimental method for an anti-seepage wall dam foundation soil stress and seepage coupling anti-seepage characteristics test device, comprising the following steps: S1. Carefully embed the rigid anti-seepage wall model prefabricated according to the test requirements into the groove of the test box wall, and evenly apply the flexible water-stopping material on the contact surface between the groove and the rigid anti-seepage wall model to ensure a tight seal. Then, on both sides of the rigid anti-seepage wall model, fill the test soil material according to the predetermined soil gradation, dry density or porosity ratio by layered compaction or underwater deposition to form a soil sample area until a predetermined height is reached. The production of the first soil sample and the second soil sample is completed, the top cover is installed, and the first flexible water bag and the second flexible water bag are placed in place; S2. Connect the pressure-volume controller to the first and second flexible water bags, inject liquid into the two water bags through the two first water inlet holes, and simultaneously exhaust gas from the two water bags through the first exhaust holes corresponding to the two first water inlet holes. Apply vertical stress to the soil sample area according to the stress path and magnitude set in the test plan. Gradual loading can be performed. After the deformation of the sample stabilizes under each level of load, the next level of load is applied until the target stress state is reached. Simultaneously, both water bags apply lateral stress to the portion of the cut-off wall that is higher than the soil sample to achieve water stopping on the upper part of the sample. S3. After the sample reaches a predetermined stress state and consolidates stably, a hydraulic gradient is applied to the sample from the second water inlet through the water supply device, so that water flows horizontally through the soil sample area and the rigid anti-seepage wall model and flows out from the water outlet structure. A constant head difference test or a step-by-step head difference test method can be used. During the entire seepage process, the pore water pressure changes at various points inside the soil sample are monitored in real time by the pore pressure sensor. The seepage outflow is closely observed through the vertical through-hole observation window on the water outlet surface, the flow rate is recorded, and attention is paid to whether soil particles are carried out and whether there are any seepage damage phenomena such as concentrated seepage channels. All data are recorded by the data acquisition system; S4. After the test, the collected pore pressure, flow rate and other data are analyzed, and combined with the observed seepage damage phenomenon, the anti-seepage characteristics and stability of the rigid anti-seepage wall model under specific stress-seepage coupling conditions are evaluated.

[0016] In summary, the present invention mainly has the following beneficial effects: 1. By providing grooves in the test chamber wall to embed a rigid cutoff wall model and using flexible water-stopping materials to address the contact sealing problem between rigid materials, this device can more realistically simulate the working conditions of embedded cutoff walls (especially concrete cutoff walls) in soil in actual projects and their complex hydraulic connections with the surrounding soil. This overcomes the limitation of existing technologies that can only conduct model tests on dam foundations with suspended cutoff walls. This device can be used to conduct physical model tests of dam foundation seepage for embedded cutoff walls, which are more common in engineering projects. This is of great significance for comprehensively revealing the seepage characteristics of dam foundations and improving the safety of water conservancy projects.

[0017] 2. For combined specimens with huge differences in deformation modulus such as rigid anti-seepage wall and soil, the present invention adopts double flexible water bags as stress loading system, which can not only ensure the water-stopping effect of the specimen, but also realize uniform loading and control of the vertical stress of the dam foundation soil, avoiding the water-stopping hidden dangers caused by the uneven deformation of the combined specimens with large differences in modulus between the anti-seepage wall and the dam foundation. It is significantly better than the traditional rigid plate loading or single water bag loading method, and solves the problem that existing devices and technologies in the engineering and academic circles cannot accurately grasp the stress-deformation characteristics under seepage conditions, making the stress-seepage coupling anti-seepage test of the anti-seepage wall dam foundation possible.

[0018] 3. The monitoring system of the present invention is designed specifically for non-transparent, actual engineering materials (such as concrete cut-off walls and real soil). By arranging pore pressure sensors in an array at key locations, the pore water pressure field distribution and its dynamic changes within the specimen can be directly acquired. By providing vertical through-hole observation windows at the water outlet, the macroscopic phenomena and development processes of seepage damage can be directly observed and recorded without relying on overall transparency. The data obtained by these monitoring methods has more direct guiding significance for engineering design and safety evaluation, expanding the scope of application of the test device.

[0019] 4. The present invention comprehensively solves the key technical difficulties in the simulation of embedded rigid anti-seepage walls, including rigid interface sealing, uniform loading of the assembly, and effective monitoring of non-transparent media. It provides a new test platform that is closer to actual engineering conditions for in-depth research on the anti-seepage mechanism, seepage characteristics, and failure mode of embedded anti-seepage wall dam foundations under complex stress-seepage coupling, as well as for evaluating their long-term service performance, filling the technical gap in dedicated test equipment in this field. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a test device provided in an embodiment of the present invention; Figure 2 A schematic diagram of the three-dimensional structure of a test box provided in an embodiment of the present invention.

[0021] In the figure: 1. Test chamber; 2. Water supply device; 3. Pressure-volume controller; 4. First flexible water bag; 5. Second flexible water bag; 6. Top cover; 7. First water inlet; 8. First exhaust hole; 9. Second exhaust hole; 10. Second water inlet; 11. Porous plate at water inlet end; 12. Rigid anti-seepage wall model; 13. Porous plate at water outlet end; 14. Vertical through-hole observation window; 15. Water collecting trough; 16. Water outlet; 17. Pore pressure sensor; 18. Groove; 19. Flexible water-stopping material; 20. First soil sample; 21. Second soil sample. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The following examples are intended to illustrate the present invention but are not intended to limit the scope of protection of the present invention. The conditions in the examples may be further adjusted according to specific conditions. Simple improvements to the method of the present invention within the scope of the present invention are also within the scope of protection claimed in the present invention.

[0024] refer to Figure 1 、 Figure 2 The present invention provides a stress-seepage coupling anti-seepage characteristic test device for anti-seepage wall dam foundation soil, comprising: a test box 1, wherein the test box 1 is preferably welded or assembled with high-strength stainless steel plates and has sufficient rigidity and stability. In this embodiment, the test box 1 is in the shape of a rectangular parallelepiped, and its internal dimensions can be set according to test requirements, such as 1100mm×500mm×600mm (length×width×height), and the box wall thickness is 50mm. The top surface of the test box 1 is provided with a top cover 6, and the top surface of the top cover 6 is provided with at least two independent first water inlet holes 7 and corresponding first exhaust holes 8. The left side of the test box 1 is provided with a second exhaust hole 9 and a second water inlet hole 10 as the water inlet surface. The right side of the test box 1 is provided with a water outlet porous plate 13 on its inner side as the water outlet surface. A water collecting tank 15 is fixedly installed on the right side of the test box 1. A water outlet hole 16 is provided at the lower part of the water collecting tank 15, which can be connected to a water measuring device or a drainage system. A continuous groove 18 is provided in the middle position of the inner wall of the front wall, rear wall and bottom plate of the test box 1. The groove 18 is used to embed the prefabricated rigid anti-seepage wall model 12 The width of the groove 18 is slightly larger than the thickness of the rigid anti-seepage wall model 12, such as 100 mm, and the depth is smaller than the thickness of the box wall, such as 25 mm. The inner surface of the groove 18 and the outer surface of the rigid anti-seepage wall model 12 are filled with a flexible water-stopping material 19. This design effectively solves the contact water-stopping problem between the rigid anti-seepage wall model 12 and the wall of the rigid test box 1 through the limiting effect of the groove 18, the extension of the seepage path, and the sealing effect of the flexible water-stopping material 19, ensuring that water can only penetrate through the soil sample area and the defects of the rigid anti-seepage wall model 12 (such as through cracks) itself, and will not leak from the contact gaps. The loading system is arranged on the top of the test box 1, and includes a first flexible water bag 4 and a second flexible water bag 5. The first flexible water bag 4 and the second flexible water bag 5 are symmetrically or partitionedly arranged above the rigid anti-seepage wall model 12 and the soil on both sides. The first flexible water bag 4 and the second flexible water bag 5 are both connected to the pressure volume controller 3. By controlling the pressure and volume of the liquid (usually water or oil) transported to the first flexible water bag 4 and the second flexible water bag 5, a precisely controllable and uniformly distributed vertical stress can be applied to the soil below. The deformation modulus of the rigid cutoff wall model 12 and the soil sample areas on both sides may be significantly different. The independent control of the two water bags can ensure that stress is only applied to the non-rigid soil, avoiding direct loading of the combined sample composed of the rigid cutoff wall model 12 and the soil, which would cause a large soil settlement and no or very small settlement of the cutoff wall model 12, thereby affecting the water-stopping effect on the upper surface of the sample. In addition, both water bags apply lateral stress to the part of the cutoff wall that is higher than the soil sample, preventing water from leaking upward along the cutoff wall, thereby achieving water-stopping on the upper part of the sample. The seepage system is used to simulate horizontal seepage and includes a water inlet structure provided on one side of the test box 1, a water outlet structure provided on the opposite side, and a water supply device 2 connected to the water inlet structure. The water supply device 2 is connected to the second water inlet hole 10 and is used to allow water to flow horizontally through the soil and rigid anti-seepage wall model 12 in the test box 1; The monitoring system is used to obtain key data during the test, including several pore pressure sensors 17 installed on the wall of the test box 1 in contact with the soil or pre-buried in the soil or inside the rigid anti-seepage wall model 12, and an observation device set at the water outlet structure for observing the seepage channel. The observation device is a vertical through-hole observation window 14 set outside the water outlet structure, which is used to directly observe the seepage outflow from the soil sample area and possible seepage damage.

[0025] The width and shape of the groove 18 match the cross-section of the rigid anti-seepage wall model 12. The flexible water-stopping material 19 is a high-molecular polymer sealant or a modified asphalt-based sealing material. The pressure-volume controller 3 is a servo-controlled hydraulic or pneumatic system that can accurately control the pressure or volume in the flexible water bag. A water inlet porous plate 11 is provided inside the water inlet structure and the water outlet structure to ensure that water flows into and out of the sample evenly. The pore pressure sensor 17 is a miniature sensor, and its arrangement can reflect the pore water pressure distribution in the upstream, downstream and nearby key areas of the rigid anti-seepage wall model 12. The rigid anti-seepage wall model 12 is a scaled-down concrete anti-seepage wall section or a model made of rigid anti-seepage materials commonly used in other projects.

[0026] The present invention also provides an experimental method for an anti-seepage wall dam foundation soil stress and seepage coupling anti-seepage characteristics test device, comprising the following steps: S1. Embed the rigid anti-seepage wall model 12 prefabricated according to the test requirements into the groove 18 of the wall of the test box 1, and evenly apply the flexible water-stopping material 19 on the contact surface between the groove 18 and the rigid anti-seepage wall model 12 to ensure a tight seal. Then, on both sides of the rigid anti-seepage wall model 12, fill the test soil material according to the predetermined soil material gradation, dry density or porosity ratio by layered compaction or underwater deposition to form a soil sample area until the predetermined height is reached. The production of the first soil sample 20 and the second soil sample 21 is completed, the top cover 6 is installed, and the first flexible water bag 4 and the second flexible water bag 5 are placed in place; S2. Connect the pressure-volume controller 3 with the first flexible water bag 4 and the second flexible water bag 5. Liquid is injected into the water bags respectively through independent controllers. Vertical stress is applied to the soil sample area according to the stress path and magnitude set in the test plan. Gradual loading can be performed. After the deformation of the sample stabilizes under each level of load, the next level of load is applied until the target stress state is reached. At the same time, both water bags apply lateral stress to the part of the cut-off wall that is higher than the soil sample to achieve water stopping on the upper part of the sample. S3. After the sample reaches a predetermined stress state and consolidates stably, a hydraulic gradient is applied to the sample from the second water inlet 10 through the water supply device 2, so that the water flows horizontally through the soil sample area and the rigid anti-seepage wall model 12 and flows out from the water outlet structure. A constant head difference test or a step-by-step head difference test method can be used. During the entire seepage process, the pore water pressure changes at various points inside the soil sample are monitored in real time by the pore pressure sensor 17. The seepage outflow is closely observed through the vertical through-hole observation window 14 on the water outlet surface, the flow rate is recorded, and attention is paid to whether soil particles are carried out or whether there are seepage damage phenomena such as concentrated seepage channels. All data are recorded by the data acquisition system; S4. After the test, the collected pore pressure, flow rate and other data are analyzed, and combined with the observed seepage damage phenomenon, the anti-seepage characteristics and stability of the rigid anti-seepage wall model 12 under specific stress-seepage coupling conditions are evaluated.

[0027] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that, unless otherwise defined, the technical or scientific terms used in the present invention shall have the ordinary meanings understood by persons having ordinary skills in the field to which the present invention belongs. The words "include" or "comprise" and the like used in the present invention mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The words "connect" or "connected" and the like are not limited to physical or mechanical connections, but may also include electrical connections, whether direct or indirect. The words "upper", "lower", "left", "right", etc. are only used to indicate relative position relationships. When the absolute position of the described object changes, the relative position relationship may also change accordingly.

[0028] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A stress-seepage coupling anti-seepage characteristic test device for anti-seepage wall dam foundation soil, characterized in that: include: A test box (1), wherein the top surface of the test box (1) is provided with a top cover (6), the top cover (6) is provided with two independent first water inlet holes (7) and corresponding two first exhaust holes (8), the left side of the test box (1) is provided with a second exhaust hole (9) and a second water inlet hole (10) as a water inlet surface, the right side of the test box (1) is provided with a water outlet porous plate (13) on its inner side as a water outlet surface, a water collecting trough (15) is fixedly installed on the right side of the test box (1), the lower part of the water collecting trough (15) is provided with a water outlet hole (16), the inner wall of the front, rear and bottom three sides or two of the box walls of the test box (1) is provided with a groove (18) along a predetermined path, the groove (18) is used to embed a prefabricated rigid anti-seepage wall model (12), and the space between the inner surface of the groove (18) and the outer surface of the rigid anti-seepage wall model (12) is filled with a flexible water-stopping material (19); A loading system is provided on the top of the test box (1), comprising a first flexible water bag (4) and a second flexible water bag (5), wherein the first flexible water bag (4) and the second flexible water bag (5) are symmetrically or partitionedly arranged above the rigid anti-seepage wall model (12) and the soil on both sides, and the first flexible water bag (4) and the second flexible water bag (5) are both connected to a pressure volume controller (3); A seepage system, the seepage system comprising a water inlet structure provided on one side of the test box (1), a water outlet structure provided on the opposite side, and a water supply device (2) connected to the water inlet structure, the water supply device (2) being connected to the second water inlet hole (10) and being used to allow water to flow horizontally through the soil in the test box (1) and the rigid anti-seepage wall model (12); A monitoring system includes a plurality of pore pressure sensors (17) installed in an array on the inner side of the test box (1) wall or pre-buried in the soil and the rigid anti-seepage wall model (12), and an observation device arranged at the water outlet structure for observing the seepage channel.

2. The test device according to claim 1, characterized in that The depth of the groove (18) is less than the thickness of the wall of the test box (1), and the width and shape of the groove (18) match the cross section of the rigid anti-seepage wall model (12).

3. The test device according to claim 1, characterized in that The left, right and bottom sides of the rigid anti-seepage wall model (12) are completely embedded in the grooves (18) of the test box (1) wall, and the top surface is in non-fixed contact with the top cover (6). The rigid anti-seepage wall model (12) contains common engineering defects such as through cracks.

4. The test device according to claim 1, characterized in that The flexible water-stopping material (19) is a high molecular polymer sealant or a modified asphalt-based sealing material, and the pressure-volume controller (3) is a servo-controlled hydraulic or pneumatic system capable of accurately controlling the pressure or volume in the flexible water bag.

5. The test device according to claim 1, characterized in that A water inlet porous plate (11) is provided inside the water inlet structure and the water outlet structure to ensure that water flows into and out of the sample evenly.

6. The test device according to claim 1, characterized in that The observation device is a vertical strip-shaped through-hole observation window (14) arranged outside the water outlet structure.

7. The test device according to claim 1, characterized in that The pore pressure sensor (17) is a micro sensor, and its arrangement can reflect the pore water pressure distribution in the upstream, downstream and nearby key areas of the rigid anti-seepage wall model (12).

8. The test device according to claim 1, characterized in that The test box (1) is made of stainless steel or a metal material with similar strength and rigidity.

9. The test device according to claim 1, characterized in that The rigid anti-seepage wall model (12) is a scaled-down concrete anti-seepage wall segment or a model made of other rigid anti-seepage materials commonly used in engineering projects.

10. A method for conducting a stress-seepage coupling anti-seepage characteristic test of an anti-seepage wall dam foundation soil according to the test device according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Carefully embed the rigid anti-seepage wall model (12) prefabricated according to the test requirements into the groove (18) of the wall of the test box (1), and evenly apply the flexible water-stopping material (19) on the contact surface between the groove (18) and the rigid anti-seepage wall model (12) to ensure a tight seal. Then, on both sides of the rigid anti-seepage wall model (12), fill the test soil material by layered compaction or underwater deposition according to the predetermined soil material gradation, dry density or porosity ratio to form a soil sample area until a predetermined height is reached. The production of the first soil sample (20) and the second soil sample (21) is completed, the top cover (6) is installed, and the first flexible water bag (4) and the second flexible water bag (5) are placed in place; S2, connecting the pressure volume controller (3) with the first flexible water bag (4) and the second flexible water bag (5), injecting liquid into the two water bags through the two first water inlet holes (7), and at the same time, the first exhaust holes (8) corresponding to the two first water inlet holes (7) will exhaust the gas in the two water bags, and applying vertical stress to the soil sample area according to the stress path and magnitude set in the test plan, and can be loaded in stages. After the deformation of the sample stabilizes under each level of load, the next level of load is applied until the target stress state is reached. At the same time, the two water bags apply lateral stress to the part of the anti-seepage wall that is higher than the soil sample, so as to achieve water stopping on the upper part of the sample; S3. After the sample reaches a predetermined stress state and consolidates stably, a hydraulic gradient is applied to the sample from the second water inlet (10) through the water supply device (2), so that the water flows horizontally through the soil sample area and the rigid anti-seepage wall model (12) and flows out from the water outlet structure. A constant head difference test or a step-by-step head difference test method can be used. During the entire seepage process, the pore water pressure changes at various points inside the soil sample are monitored in real time through the pore pressure sensor (17). The seepage outflow is closely observed through the vertical strip-shaped through-hole observation window (14) on the water outlet surface, the flow rate is recorded, and attention is paid to whether soil particles are carried out, whether concentrated seepage channels and other seepage damage phenomena occur, and all data are recorded by the data acquisition system; S4. After the test, the collected data such as pore pressure and flow rate are analyzed, and combined with the observed seepage damage phenomenon, the anti-seepage characteristics and stability of the rigid anti-seepage wall model (12) under specific stress-seepage coupling conditions are evaluated.

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