A device and method for testing the anti-seepage effect of a slope capillary resistance cover layer

Abstract

The application discloses a device and method for testing the anti-seepage effect of a slope capillary resistance cover layer, the device comprising an inclination-adjustable model box, the model box being filled with a test soil sample, the upper part of the model box being in communication with a slope runoff collector, the side of the model box being in communication with a lateral seepage collector, the bottom of the model box being in communication with a bottom seepage collector, a rainfall simulation system being arranged on a support frame above the model box, a data acquisition unit being arranged in the test soil sample, and the data acquisition unit being connected with a data processing system; the method is to use the device to test the anti-seepage effect of a slope capillary resistance cover layer. The application solves the problems of the existing test device, such as inconvenient slope angle adjustment and incomplete monitoring of the multi-path conversion amount of rainwater, and provides reliable test support for the research on the hydrological characteristics of a slope and the early warning of instability. The application is suitable for the technical field of slope hydrological monitoring tests.

Description

Technical Field

[0001] This invention belongs to the field of slope hydrological monitoring and testing technology, specifically, it relates to a device and method for testing the seepage prevention effect of capillary blocking cover layer on slopes. Background Technology

[0002] Slope engineering, as a crucial component of civil and hydraulic engineering, directly impacts the normal operation of infrastructure and the protection of the ecological environment. Under complex climatic conditions, changes in soil moisture content and increased pore water pressure caused by rainwater infiltration are major contributing factors to slope instability, landslides, and geological disasters. Therefore, research on the transport patterns of rainwater in slope soil under different working conditions is of significant practical engineering importance for accurately assessing slope hydrogeological effects and developing scientific protection measures.

[0003] Currently, research methods for studying the characteristics of rainwater transport on slopes mainly include in-situ monitoring and indoor physical model tests. While in-situ monitoring can reflect real-world conditions, it is limited by geographical environment, climate conditions, and construction costs, resulting in drawbacks such as long monitoring cycles, poor controllability of operating conditions, and susceptibility to external interference. Indoor simulation tests, on the other hand, offer advantages such as controllable operating conditions, good repeatability, and high data accuracy, and have become an important tool for studying the hydrological response mechanisms of slopes. Existing slope hydrological monitoring and testing devices often suffer from the following technical deficiencies:

[0004] I. Insufficient flexibility in slope condition adjustment: Most traditional devices have fixed slope inclination angles, or have complex adjustment structures and cumbersome operations, making it difficult to quickly simulate soil stability changes under different slopes and failing to meet diverse test requirements.

[0005] II. Incomplete monitoring of rainwater transformation pathways: Existing devices often focus on monitoring a single indicator of surface runoff, or can only roughly measure the overall infiltration volume, lacking synchronous and accurate quantitative monitoring of multiple pathways of rainwater transformation, such as surface runoff, soil storage, and deep infiltration. This makes it impossible to establish a complete water balance equation and difficult to reveal the transport mechanism of rainwater within the slope.

[0006] 3. Low data acquisition accuracy and integration: Some devices use manual reading or single sensor acquisition methods, resulting in low sampling frequency and data lag. This makes it impossible to achieve real-time, high-frequency acquisition of key parameters such as soil moisture content and pore water pressure, and it is difficult to meet the demand for high-precision data. Summary of the Invention

[0007] This invention provides a device and method for testing the seepage prevention effect of capillary blocking cover layer on slopes, which solves the problems of inconvenient slope angle adjustment and incomplete monitoring of rainwater multipath conversion in existing test devices, and provides reliable test support for slope hydrological characteristic research and instability early warning.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A device for testing the seepage prevention effect of capillary barrier capillary cover layer on slopes includes an adjustable tilt model box set in a support frame. The adjustable tilt model box is filled with a test soil sample. The upper part of the adjustable tilt model box, located on the upper surface of the test soil sample, is connected to a slope runoff collector. The side of the adjustable tilt model box, corresponding to the test soil sample, is connected to a lateral seepage collector. The bottom surface of the adjustable tilt model box is connected to a bottom seepage collector. A rainfall simulation system is set on the support frame above the adjustable tilt model box. A data acquisition unit is set inside the test soil sample. The data acquisition unit is connected to a data processing system.

[0010] A further technical solution is that the tilt-adjustable model box includes a rectangular box body with the upper end in an open state, one side of the lower end of the rectangular box body is hinged to a hinge seat, the other side of the lower end of the rectangular box body is hinged to the upper end of a lifting member, and the lower end of the hinge seat and the lower end of the lifting member are connected to a support frame.

[0011] A further technical solution is that multiple assembly hole groups are vertically spaced on the side of the rectangular box along its length, and the multiple assembly holes in each assembly hole group extend along the length of the rectangular box; the data acquisition unit includes multiple moisture sensors and multiple pore water pressure sensors installed at each assembly hole group, and each moisture sensor and pore water pressure sensor extends into the test soil sample through the corresponding assembly hole, and each moisture sensor and pore water pressure sensor is connected to the data processing system.

[0012] A further technical solution is that multiple lateral collection hole groups are respectively arranged vertically at intervals on two sides of the rectangular box in the width direction. Multiple lateral collection holes in each lateral collection hole group extend along the width direction of the rectangular box. The uppermost lateral collection hole group is connected to the slope runoff collector, and the lateral collection hole groups located at the next uppermost and lower are connected to the lateral seepage collector.

[0013] A further technical solution is to evenly distribute bottom collection holes on the bottom surface of the rectangular box, and each bottom collection hole is connected to a bottom seepage collector.

[0014] A further technical solution is that the rainfall simulation system includes a water storage tank set above the tilt-adjustable model box, simulated rain shower heads are evenly distributed on the lower end surface of the water storage tank, and the water storage tank is connected to the lower part of the water replenishment tank through a water supply pipe equipped with a control valve, and the water replenishment tank is set at the upper end of the lifting mechanism.

[0015] A further technical solution involves injecting a brilliant blue FCF tracer aqueous solution into the water replenishment tank, installing a supplementary light on the outside of the tilt-adjustable model box, and making the part of the tilt-adjustable model box filled with the test soil sample a structure made of transparent plexiglass.

[0016] This invention also discloses a method for testing the seepage prevention effect of capillary retardant cover layers on slopes, using the aforementioned testing device, comprising the following steps:

[0017] Step 1. Obtain the optimum moisture content and maximum dry density of the soil under a specific gradation through compaction tests, calculate the amount of soil required for the test, and prepare the soil sample;

[0018] Step 2. Adjust the tilt angle of the adjustable tilt model box, the rainfall amount of the rainfall simulation system, and the accuracy of the data acquisition unit respectively;

[0019] Step 3. The prepared soil sample is laid in layers in an adjustable tilt model box to form a test soil sample. The soil sample is laid in layers from top to bottom according to the particle size, and each layer is compacted and roughened between layers. Simultaneously, the data acquisition unit is assembled between the layers during the layer laying process.

[0020] Step 4. Calculation and arrangement of rainfall parameters, including the effective rainfall area and water supply per unit time of the test soil sample slope;

[0021] Step 5. Continuous simulated rainfall test: The rainfall simulation system is supplied with water at constant pressure to make the rainfall simulation system uniform and stable, and the movement path of water in the tilt-adjustable model box is observed at the same time.

[0022] Step 6. Multi-path synchronous data acquisition: The dynamic data of water content and pore water pressure of the test soil sample are collected through the data acquisition unit, and the slope runoff, lateral seepage and bottom seepage are collected in three ways through the slope runoff collector, lateral seepage collector and bottom seepage collector.

[0023] Step 7. Weigh the water volume of the slope runoff collector, lateral seepage collector, and bottom seepage collector respectively using an electronic balance, and record the time points of soil breakdown and saturation.

[0024] Step 8. Test completion and result analysis: disassemble the device, clean the test soil sample, organize all time-series monitoring data, compare the working conditions under multiple slopes, and evaluate the seepage prevention effect of the capillary barrier cover layer.

[0025] A further technical solution involves calculating the required dry soil mass, water addition, wet soil mass, and soil volume for each layer when the compaction degree is a%, as follows:

[0026] Based on the effective internal dimensions of the tilt-adjustable model box, the single-layer filling volume is calculated as follows:

[0027] V i =L×B×h i (1)

[0028] In the formula, L is the effective length of the tilt-adjustable model box, B is the effective width, and h is the effective length of the model box. i The design fill thickness of the i-th soil layer;

[0029] The required dry soil mass for the i-th layer for:

[0030] (2)

[0031] Considering the optimal moisture content requirement, the required water addition for this layer is... for:

[0032] (3)

[0033] The mass m of the wet soil in each layer is:

[0034] (4)

[0035] Under the condition of compaction degree a%, the required soil volume ma for each layer is:

[0036] (5)

[0037] Based on formulas (1) to (5), calculate the amount of soil required for each layer under a certain compaction condition. After weighing and mixing the soil in each layer, fill the soil according to the design thickness to ensure that the compaction and moisture content of each layer of soil are controlled within the test requirements.

[0038] A further technical solution involves the following calculation method and formula for rainfall condition parameters:

[0039] The rainfall area A is:

[0040] (6)

[0041] In the formula, b is the top area of ​​the adjustable tilt model box (m²), h is the top width of the adjustable tilt model box (m), and α is the slope angle of the adjustable tilt model box.

[0042] The water supply rate Q per unit time is:

[0043] (7)

[0044] In the formula, Q is the water supply per unit time (mL / h), I is the design rainfall intensity (mm / h), and A is the rainfall area (m²). 2 ).

[0045] The present invention, by employing the above-described structure, achieves the following technological advancements compared to existing technologies:

[0046] The device of this invention adopts an adjustable-angle model box structure, enabling flexible simulation of multi-slope conditions. This allows for continuous adjustment of the slope angle, breaking the limitations of traditional model boxes with fixed slopes and cumbersome disassembly and assembly for slope modifications. It can quickly simulate various common engineering slopes such as 35°, 40°, and 45°. One device can complete multi-slope comparative tests, significantly expanding the scope of application and reducing the manufacturing cost of devices for multiple tests. It also allows for direct observation of the entire process of rainwater seepage channels, preferential flow, and soil penetration evolution within capillary-impregnated layered soil, visually revealing the failure mechanism of the capillary-impregnated seepage barrier layer. The device features independent water collection structures at the top, side, and bottom, enabling complete quantification of the entire rainwater transformation path. Traditional devices can only monitor surface runoff or total seepage individually, failing to establish a complete water balance. This device, equipped with separate slope runoff collectors, lateral seepage collectors, and bottom seepage collectors, enables independent collection of these three water transport paths. It comprehensively captures all forms of post-rainfall water transformation: slope surface runoff, stratified lateral seepage between soil layers, and deep bottom penetration seepage. This allows for precise construction of the soil water balance equation, quantitative calculation of the slope runoff proportion, soil water storage, and penetration seepage volume, directly quantifying the capillary action of the cover layer in intercepting rainwater and preventing deep seepage. The three seepage streams can be individually weighed using an electronic balance. By analyzing the start time and volume changes of each path, the device accurately pinpoints the location where the slope first experiences seepage (slope top / middle / bottom), clearly reconstructing the seepage damage propagation path and providing quantitative experimental data for differentiated slope protection and reinforcement schemes. An independently arranged rainfall simulation system above the support frame enables stable and controllable simulation of natural rainfall. The rainfall system is positioned directly above the tilt-adjustable model box. Combined with the constant pressure water supply structure, the rainfall intensity is stable and adjustable, simulating different rainfall conditions such as light rain and heavy rain. The rainfall is uniform without localized concentrated scouring, and the test conditions have good repeatability, eliminating test errors caused by unstable water supply and uneven rainfall.

[0047] The data acquisition units, integrated with a data processing system, are installed inside the test soil samples, enabling high-precision, synchronous, real-time monitoring. By directly embedding the data acquisition units within the soil samples, high-frequency, synchronous acquisition of dynamic changes in moisture content and pore water pressure at different depths and layers is achieved. This overcomes the shortcomings of traditional devices, such as manual readings, low sampling frequency, and data lag, comprehensively capturing the evolution of hydrological parameters throughout the entire process of rainwater infiltration, soil saturation, and seepage breakdown. The data acquisition units are layered at the interfaces of each layer of the capillary barrier capillary layer, allowing for comparison of the response time differences in moisture content and pore water pressure between coarse and fine-grained soil layers. This quantitatively characterizes the core seepage prevention function of the capillary barrier layer in delaying pore water pressure rise and inhibiting deep seepage. The data acquisition units directly interface with the data processing system, automatically storing and exporting time-series monitoring data, reducing human error from manual recording. Batch comparative analysis of data under multiple slopes and rainfall conditions can be performed to quantitatively evaluate the long-term seepage prevention stability of the capillary barrier capillary layer.

[0048] In summary, this invention modularly integrates rainfall simulation, slope modeling, multi-path water collection, and sensor monitoring functions. The overall structure is simple, easy to assemble and disassemble, allows for rapid replacement of test soil samples, has a low operational threshold, and facilitates numerous parallel comparative experiments. The device can simultaneously couple and monitor macroscopic water distribution (three-path seepage volume) with microscopic soil hydrological parameters (moisture content, pore water pressure), fully revealing the intrinsic mechanism by which rainwater infiltration induces an increase in pore water pressure and soil instability in slopes. The entire device is a controllable indoor testing equipment, unaffected by site climate, location, or construction costs. Test conditions are controllable, and data repeatability is high, providing standardized and reliable indoor testing support for slope capillary barrier protection design and rainfall-induced slope instability early warning. Attached Figure Description

[0049] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0050] In the attached diagram:

[0051] Figure 1 This is a front view of the structure according to an embodiment of the present invention;

[0052] Figure 2 This is a structural side view of an embodiment of the present invention.

[0053] Components marked: 1-Support frame, 2-Rectangular box, 3-Hinge seat, 4-Jack, 5-Assembly hole, 6-Data processing system, 7-Lateral collection hole, 8-Slope runoff collector, 9-Lateral seepage collector, 10-Bottom seepage collector, 11-Water supply tank, 12-Water supply pipe, 13-Control valve, 14-Water storage tank, 15-Simulated rain shower head, 16-Lifting mechanism, 17-Supplemental light. Detailed Implementation

[0054] The preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0055] This invention discloses a device for testing the seepage prevention effect of capillary-impeded cover layers on slopes, such as... Figure 1 , Figure 2 As shown, the system includes an adjustable tilt model box housed within a support frame 1, which is filled with a test soil sample. The upper part of the adjustable tilt model box, located at the upper end of the test soil sample, is connected to a slope runoff collector 8. The side of the adjustable tilt model box, corresponding to the test soil sample, is connected to a lateral seepage collector 9. The bottom surface of the adjustable tilt model box is connected to a bottom seepage collector 10. A rainfall simulation system is installed on the support frame 1 above the adjustable tilt model box. A data acquisition unit is installed inside the test soil sample, and the data acquisition unit is connected to a data processing system 6.

[0056] The working principle and advantages of this invention are as follows: The device adopts an adjustable-angle model box structure, enabling flexible simulation of multiple slope conditions. This allows for continuous adjustment of the slope angle, breaking the limitations of traditional model boxes with fixed slopes and cumbersome disassembly and assembly for slope modifications. It can quickly simulate various common engineering slopes such as 35°, 40°, and 45°. One device can complete multi-slope comparative tests, significantly expanding the scope of application and reducing the manufacturing cost of devices for multiple tests. It also allows for direct observation of the entire process of rainwater seepage channels, preferential flow, and soil penetration evolution within capillary-impregnated layered soil, visually revealing the failure mechanism of the capillary-impregnated seepage barrier layer. The device features independent water collection structures at the top, side, and bottom, enabling complete quantification of the entire rainwater transformation path. Traditional devices can only monitor surface runoff or total seepage individually, failing to establish a complete water balance. This device, equipped with a slope runoff collector 8, a lateral seepage collector 9, and a bottom seepage collector 10, achieves independent and separate collection of three types of water transport paths, comprehensively capturing all transformations of water after rainfall: slope surface runoff, stratified lateral seepage between soil layers, and deep bottom penetration seepage. It can accurately construct the soil water balance equation, quantitatively calculate the proportion of slope runoff, soil water storage, and penetration seepage, directly quantifying the capillary-impeded capillary layer's ability to intercept rainwater and block deep seepage. The three seepage streams can be weighed individually using an electronic balance. By analyzing the start time and volume changes of each path, the device accurately locates the initial location of slope penetration (slope top / middle / bottom), clearly reconstructing the seepage damage propagation path and providing quantitative experimental basis for differentiated slope seepage prevention and reinforcement schemes. An independently arranged rainfall simulation system above the support frame 1 enables stable and controllable simulation of natural rainfall. The rainfall system is positioned directly above the tilt-adjustable model box. Combined with the constant pressure water supply structure, the rainfall intensity is stable and adjustable, simulating different rainfall conditions such as light rain and heavy rain. The rainfall is uniform without localized concentrated scouring, and the test conditions have good repeatability, eliminating test errors caused by unstable water supply and uneven rainfall.

[0057] The data acquisition units, integrated with the data processing system 6, are installed inside the test soil samples, enabling high-precision, synchronous, real-time monitoring. By directly embedding the data acquisition units within the soil samples, high-frequency synchronous acquisition of dynamic changes in moisture content and pore water pressure at different depths and layers is achieved. This overcomes the shortcomings of traditional devices, such as manual readings, low sampling frequency, and data lag, comprehensively capturing the evolution of hydrological parameters throughout the entire process of rainwater infiltration, soil saturation, and seepage breakdown. The data acquisition units are layered at the interfaces of each layer of the capillary barrier capillary layer, allowing for comparison of the response time differences in moisture content and pore water pressure between coarse and fine-grained soil layers. This quantitatively characterizes the core seepage prevention function of the capillary barrier layer in delaying pore water pressure rise and inhibiting deep seepage. The data acquisition units directly interface with the data processing system 6, automatically storing and exporting time-series monitoring data, reducing human error caused by manual recording. Batch comparative analysis of data under multiple slopes and rainfall conditions can be performed to quantitatively evaluate the long-term seepage prevention stability of the capillary barrier capillary layer.

[0058] In summary, this invention modularly integrates rainfall simulation, slope modeling, multi-path water collection, and sensor monitoring functions. The overall structure is simple, easy to assemble and disassemble, allows for rapid replacement of test soil samples, has a low operational threshold, and facilitates numerous parallel comparative experiments. The device can simultaneously couple and monitor macroscopic water distribution (three-path seepage volume) with microscopic soil hydrological parameters (moisture content, pore water pressure), fully revealing the intrinsic mechanism by which rainwater infiltration induces an increase in pore water pressure and soil instability in slopes. The entire device is a controllable indoor testing equipment, unaffected by site climate, location, or construction costs. Test conditions are controllable, and data repeatability is high, providing standardized and reliable indoor testing support for slope capillary barrier protection design and rainfall-induced slope instability early warning.

[0059] As a preferred embodiment of the present invention, such as Figure 1 , Figure 2 As shown, the tilt-adjustable model box includes a rectangular box 2 with the upper end in an open state. One side of the lower end of the rectangular box 2 is hinged to the hinge seat 3, and the other side of the lower end of the rectangular box 2 is hinged to the upper end of the lifting component. The lower end of the hinge seat 3 and the lower end of the lifting component are connected to the support frame 1. The lifting component is generally a jack 4.

[0060] In this embodiment, the combination structure of the hinged seat 3 as a fixed rotation fulcrum and the jack 4 as a lifting drive component enables continuous stepless adjustment of the slope inclination angle. The rectangular box 2, with the hinged point of the hinged seat 3 as its sole axis of rotation, can smoothly change its tilt angle by extending or retracting the piston rod of the jack 4 to raise or lower the bottom end of the box on the other side. This eliminates the need for disassembly, replacement of pads, or reconstruction of the model support structure. It allows for rapid switching between various test slope angles such as 35°, 40°, and 45°. One device can complete multi-slope control tests, saving the processing cost of multiple fixed-slope model boxes, significantly expanding the range of test conditions, and making the test operation convenient and efficient. Because the hinged fulcrum limits rotation, it constrains the model box to only rotate circumferentially, preventing horizontal slippage and lateral displacement of the box during slope adjustment. With only the hinge seat 3 providing rotational constraint, the jack 4 only bears the vertical lifting load. The force path of the rectangular box 2 is clear and the force distribution is uniform. Long-term repeated adjustment of the tilt angle will not cause problems such as deformation of the rectangular box 2, loosening of the supporting components, or tilting and deviation of the rectangular box 2. The overall structure of the device is more durable. When the same slope is maintained for a long time to carry out continuous rainfall test, the rectangular box 2 is stable in posture and will not shift in angle due to its own weight or soil load, ensuring that the test slope condition is constant and improving the stability and repeatability of test data.

[0061] In this embodiment, the tilt-adjustable model box is set as a rectangular box 2 with an open top. On the one hand, it is convenient to fill the test soil sample with fine-grained soil and coarse-grained soil to form a capillary retardant cover layer. There is no top obstruction for operations such as filling, layer compaction, interlayer roughening, and sensor installation, and there is sufficient space for construction operations. On the other hand, the open top can completely simulate the natural slope surface, and rainwater can fall evenly to the soil surface without the top of the box obstructing the rainfall blind zone. It can truly restore the distribution of natural rainfall on the slope surface, and at the same time, it is convenient for personnel to observe the entire process of slope runoff formation, soil surface infiltration, and surface soil saturation penetration in real time.

[0062] As a preferred embodiment of the present invention, such as Figure 1 As shown, multiple assembly hole groups are vertically spaced along the side of the rectangular box 2 along its length, and multiple assembly holes 5 in each assembly hole group extend along the length of the rectangular box 2. The data acquisition unit includes multiple moisture sensors and multiple pore water pressure sensors installed at each assembly hole group. Each moisture sensor and each pore water pressure sensor extends into the test soil sample through the corresponding assembly hole 5, and each moisture sensor and each pore water pressure sensor is connected to the data processing system 6.

[0063] In this embodiment, the assembly holes are arranged vertically and layered along the side wall of the box, allowing for the setting of monitoring points at different depths and interlayer interfaces of the capillary-impregnated cover layer of fine-grained soil and coarse-grained soil, achieving longitudinal depth layered fixed-point monitoring of the soil. Multiple vertically arranged assembly holes 5 can be matched to key locations such as the slope surface, the interface between coarse and fine-grained soil, and the deep slope layer, accurately capturing the temporal changes in soil moisture content and pore water pressure at different depths during rainwater infiltration. This clearly distinguishes the hydrological response time difference between the capillary-impregnated layer of the surface fine-grained soil and the underlying coarse-grained soil layer, intuitively quantifying the core seepage prevention function of the capillary-impregnated layer in delaying the rise of pore water pressure and blocking deep seepage, thus overcoming the deficiency of traditional single-point sensors in distinguishing the layered seepage characteristics of soil. The assembly holes 5 within each assembly hole group extend along the length of the rectangular box 2, allowing multiple sensors to be deployed longitudinally along the slope at the same vertical height, achieving multi-point synchronous monitoring at the same soil depth. Deploying sensors at multiple points along the length of the slope can capture differences in moisture distribution in the longitudinal space, identify preferential flow channels and concentrated seepage areas within the slope, and avoid the problem that data from a single measuring point can only reflect the local soil condition and cannot represent the hydrological characteristics of the entire slope profile. This improves the spatial representativeness of the monitoring data and fully restores the evolutionary spatial distribution patterns of rainwater infiltration, saturation, and breakdown seepage along the entire longitudinal section of the slope. The sensors extend into the soil through external mounting holes 5 on the side walls of the rectangular housing, eliminating the need to pre-embed all sensing elements during the layered backfilling process, significantly reducing the difficulty of experimental operation. After completing the processes of layered filling, compaction, and roughening of the soil, the test personnel can insert the moisture sensor and pore water pressure sensor from the outside of the rectangular box 2 through the assembly hole 5. The sensor installation process will not disturb the compacted test soil sample, and can completely preserve the preset compaction degree and interlayer bonding state of the soil. It avoids changes in pore structure caused by secondary disturbance of the soil when pre-embedding the sensor, ensuring that the physical state of the test soil sample is consistent with the design conditions, and improving the authenticity and reliability of the test data. At the same time, the assembly hole 5 can be equipped with a sealing rubber ring to achieve water-stop sealing of the hole, which can prevent water seepage and leakage from the side wall of the rectangular box 2 from interfering with the internal seepage monitoring results, and ensure that the internal seepage path of the rectangular box 2 is not affected by external water leakage.

[0064] In this embodiment, moisture sensors and pore water pressure sensors are deployed synchronously. These two types of monitoring elements simultaneously collect two core parameters—volume water content and pore water pressure—at the same location, achieving coupled monitoring of soil hydrological indicators. By synchronously acquiring dynamic change data on moisture content and pore water pressure at the same monitoring point, a linkage relationship between the two can be established. This allows for precise analysis of the intrinsic correlation mechanism between capillary-impeded overburden layer moisture saturation, pore water pressure rise, and seepage breakdown. It quantitatively reveals the evolution process of rainwater infiltration inducing slope soil softening, a sudden increase in pore water pressure, and ultimately slope instability, providing complete coupled monitoring data support for slope instability mechanism analysis. All moisture sensors and pore water pressure sensors are uniformly connected to the data processing system 6 via signal lines, achieving multi-channel, high-frequency automated synchronous data acquisition. Unlike traditional monitoring methods that rely on manual, segmented readings and independent recording by a single sensor, this structure can simultaneously collect real-time monitoring data from all sensor locations. The data acquisition frequency is not limited by manual operation, and it can fully capture the instantaneous characteristics of rapid changes in soil moisture content and pore water pressure during short periods of rainwater infiltration. It eliminates issues such as data lag, omissions, and reading errors inherent in manual recording. The data processing system 6 can automatically store and export full-time monitoring data, facilitating subsequent batch comparative analysis under multiple slope and rainfall conditions, significantly reducing data processing workload and improving experimental data analysis efficiency. Multiple assembly holes 5 in each assembly hole group are independently arranged in zones. If a single sensor fails or is damaged, it can be disassembled and replaced individually without disturbing the entire test soil sample. If a sensor at a certain depth or longitudinal point experiences abnormal data, only the corresponding assembly hole 5 needs to be removed for repair or replacement. The structure of other soil layers and points remains intact, eliminating the need for refilling and repeating the test, significantly saving on test soil and time costs, and facilitating long-term continuous rainfall monitoring experiments. The assembly holes are located on the side wall along the length of the rectangular box 2, without occupying the top slope space of the rectangular box 2. They will not obstruct or interfere with the flow of slope runoff or the uniformity of rainfall. They can simultaneously carry out two tasks: slope runoff collection and soil internal layer hydrological monitoring, without interfering with each other.

[0065] As a preferred embodiment of the present invention, such as Figure 2As shown, multiple lateral collection hole groups are vertically spaced on two sides of the rectangular box 2 along its width. Multiple lateral collection holes 7 in each lateral collection hole group extend along the width direction of the rectangular box 2. The uppermost lateral collection hole group is connected to the slope runoff collector 8, and the next uppermost and lower lateral collection hole groups are connected to the lateral seepage collector 9. Bottom collection holes (not shown in the figure) are evenly distributed on the bottom surface of the rectangular box 2, and each bottom collection hole is connected to the bottom seepage collector 10. The slope runoff collector 8, the lateral seepage collector 9, and the bottom seepage collector 10 can all be beakers, and nylon filter mesh is laid on the inner side of the lateral collection holes 7 and the bottom collection holes. There are two specific connection methods. The first method involves the uppermost lateral collection hole group connecting to a first conduit, which in turn connects to the slope runoff collector 8. The next uppermost and lower lateral collection hole groups are each connected to a second conduit, and all second conduits connect to the lateral seepage collector 9. All bottom collection holes are connected to a third conduit, which connects to the bottom seepage collector 10. The second method involves a first collection trough constructed on the side wall of the rectangular box 2, below the uppermost lateral collection hole group. This first collection trough connects to the slope runoff collector 8 via a first guide pipe. A second collection trough is constructed on the side wall of the rectangular box 2, covering the next uppermost and lower lateral collection hole groups to collect water from these groups. This second collection trough connects to the lateral seepage collector 9 via a second guide pipe. A third collection trough is constructed at the lower end of the rectangular box 2, and this third collection trough connects to the bottom seepage collector 10 via a third guide pipe. In this embodiment, there can be multiple bottom seepage collectors 10, which collect seepage water from different areas at the bottom of the rectangular box 2, thus achieving the purpose of zoned water collection and obtaining the water collection volume of different areas within a certain period of time.

[0066] In this embodiment, the lateral collection hole groups are arranged vertically in layers along the sidewall of the rectangular box 2, achieving physical separation and collection of slope runoff and lateral seepage in the soil layers, accurately distinguishing the two different water transport paths. Slope runoff formed by rainwater that has not infiltrated the slope surface is separately guided and collected by the uppermost lateral collection hole group, while interlayer lateral seepage generated at the interface between coarse and fine soil particles is uniformly collected by the lower lateral collection hole groups. The two types of water flows are independent and do not mix with each other, allowing for separate calculation of the total slope runoff and soil lateral seepage, clearly distinguishing the two transformation forms of rainwater "surface runoff" and "soil internal seepage", avoiding data distortion caused by the mixing of runoff and lateral seepage, and providing basic data support for quantitatively calculating the water storage capacity of the slope soil and the interception effect of the capillary retardation layer. Each set of lateral collection holes 7 extends along the width of the box, with multiple collection points at the same vertical height along the cross-section of the slope. This ensures complete collection of lateral outflow from the entire width of the slope, preventing issues such as incomplete collection or uncollected seepage in localized areas. This guarantees that the lateral seepage flow monitoring data represents the seepage characteristics of the entire slope profile, eliminating the bias caused by single-point collection. The bottom surface of the rectangular box 2 is evenly covered with bottom collection holes, which can completely capture deep seepage water penetrating the capillary-resistant capping layer. The bottom collection holes, distributed throughout the bottom area, can collect seepage water penetrating downwards from any location within the rectangular box 2, eliminating bottom collection blind spots. All deep seepage penetrating the soil can be uniformly collected into the bottom seepage collection beaker through the third conduit or third collection trough, accurately quantifying the seepage volume of the capillary-resistant capping layer. This allows for a direct comparison of the differences in bottom seepage volume under different slopes and rainfall conditions, directly evaluating the core seepage prevention performance of the capillary-resistant structure in blocking deep seepage.

[0067] In this embodiment, nylon filter mesh is laid on the inner side of the side collection hole 7 and the bottom collection hole. This effectively blocks fine soil particles from flowing out with the seepage water, preventing the loss of fine soil particles from altering the soil pore structure and disrupting the soil gradation. This ensures that the capillary resistance structure of the test soil sample remains in its designed state throughout the entire process. At the same time, the nylon filter mesh can intercept soil particles from entering the guide pipe and collection trough, preventing small soil particles from clogging the pipes and guide trough. This eliminates the need for frequent disassembly and cleaning of the pipes, ensuring the smooth and stable water collection channel during long-term continuous rainfall tests, reducing the frequency of maintenance during the test, extending the duration of a single continuous monitoring test, and improving the continuity of the test and the integrity of the data. The slope runoff collector 8, lateral seepage collector 9, and bottom seepage collector 10 all use beakers as water collection containers. Their structure is universal and cost-effective. The beakers can be directly placed on a high-precision electronic balance for weighing, eliminating the need for additional metering equipment modifications. The volume of seepage water in each path can be calculated by weighing the water in the beaker, enabling simultaneous and accurate quantitative measurement of multiple water sources. It can record the start time, rate, and total volume of water discharge for each path, accurately capturing the time points of local soil penetration and overall seepage continuity, pinpointing the location of the first seepage failure on the slope, and providing quantitative experimental basis for targeted slope anti-seepage reinforcement schemes. The slope runoff, interlayer lateral seepage, and deep bottom seepage are collected completely independently, allowing for the complete construction of the slope soil moisture balance equation. By separately calculating the total surface runoff, total lateral seepage, and total bottom leakage, and combining this with the total rainfall replenishment, the amount of water stored inside the soil can be calculated. This allows for a complete quantification of the distribution ratio of all rainwater transformation paths after rainfall. It also provides an intuitive analysis of the impact of slope gradient and rainfall intensity on the interception, infiltration, and leakage patterns of rainwater in the capillary-resistant cover layer. From the perspective of water distribution, this fully reveals the seepage prevention and control mechanism of the capillary-resistant cover layer, making up for the shortcomings of traditional single water collection devices that cannot conduct water balance analysis.

[0068] As a preferred embodiment of the present invention, such as Figure 1 As shown, the rainfall simulation system includes a water storage tank 14 positioned above an adjustable-angle model box. Simulated rain shower heads 15 are evenly distributed on the lower surface of the water storage tank 14. The water storage tank 14 is connected to the lower part of a water replenishment tank 11 via a water supply pipe 12 equipped with a control valve 13. The water replenishment tank 11 is positioned above a lifting mechanism 16, which is a scissor lift platform. A Maslow water replenishment bottle is used for the water replenishment tank 11. A brilliant blue FCF tracer aqueous solution is injected into the water replenishment tank 11. A supplemental light 17 is installed on the outside of the adjustable-angle model box, and the portion of the adjustable-angle model box that fills with the test soil sample is made of transparent plexiglass.

[0069] In this embodiment, a Marshall water replenishment bottle is selected as the water replenishment tank 11 of the entire rainfall system. This enables a constant head and pressure water supply during long-term experiments, ensuring stable rainfall intensity from the source. Based on the inherent constant pressure water supply principle of the Marshall bottle, the system's water head can remain constant regardless of how the liquid level of the tracer solution in the bottle decreases. This avoids the problem of continuous decrease in water flow as the water volume decreases, as is common in water tanks. At the same time, the water supply pipe 12 draws water from the bottom of the Marshall water replenishment bottle. The water intake process does not disturb the stagnant brilliant blue FCF tracer solution in the bottle, effectively preventing the tracer pigment from settling and stratifying. This ensures that the tracer concentration in the water delivered to the storage tank 14 and dripping onto the soil slope is uniform throughout the entire process, and there is no significant difference in the visual effect of seepage observation at different experimental stages. The system is equipped with two control valves 13 installed on the water supply pipeline 12. Through the coordinated regulation of these dual control valves 13, the water flow rate within the pipeline 12 can be precisely controlled. This allows for continuous, stepless fine-tuning of the pipeline flow rate based on a constant water supply head, enabling precise control of rainfall intensity. It can stably simulate various rainfall conditions, including light rain, moderate rain, and heavy rain. During continuous rainfall tests lasting hundreds of minutes, there is no rainfall intensity drift, significantly improving the consistency and repeatability of data from multiple parallel control experiments. The lifting mechanism 16 supporting the Marshall water replenishment bottle uses a scissor-type lifting platform, allowing for continuous, stepless adjustment of the overall height of the Marshall water replenishment bottle. This forms a dual rainfall intensity control system: coarse adjustment of the head pressure difference and fine-tuning of the flow control valves 13, greatly expanding the range of rainfall conditions that the device can simulate. The scissor lift platform can be manually and smoothly raised and lowered. After adjusting to the target height, it can be self-locked. During long-term testing, the water tank height will not fall back on its own or the water supply head will deviate. By changing the vertical height difference between the Mass water replenishment bottle and the upper water storage tank 14 through the scissor lift platform, the overall water supply pressure of the system can be actively adjusted to match the real rainfall environment of the field slope.

[0070] In this embodiment, a water storage tank 14 is independently arranged directly above the tilt-adjustable model box. The lower surface of the water storage tank 14 is evenly covered with simulated rain shower heads 15, which can achieve uniform and blind-spot-free simulated rainfall across the entire area, while completely protecting the original structure of the surface soil of the capillary-resistant capillary cover layer. The water storage tank 14 itself has a water buffer and pressure stabilization chamber function, which can further buffer the instantaneous water flow fluctuations generated during the water delivery process of the Mach3 water supply bottle, ensuring that the water flow rate of each simulated rain shower head 15 is completely uniform. The matrix-style uniformly arranged simulated rain shower heads 15 completely cover the entire slope area, eliminating the phenomenon of blind spots without rainfall coverage or local concentrated water flow eroding the soil. The water droplets fall slowly at a gentle speed, without forming high-speed water flow impacting the surface fine-grained soil, effectively avoiding problems such as the loss of surface soil particles, changes in surface compaction, and damage to the internal pore structure of the soil layer. It completely preserves the preset filling gradation and compaction state of the capillary-resistant capillary cover layer, restores the real working conditions of natural uniform rainfall, and ensures the authenticity and reliability of the test data.

[0071] In this embodiment, a brilliant blue FCF tracer solution is added to the Marshall water replenishment bottle, enabling visual marking of externally infiltrated rainwater and clearly distinguishing between rainwater infiltration and native pore water in the soil. After the rainwater with the blue tracer pigment infiltrates the stratified soil sample, it forms a highly recognizable blue water flow channel. Researchers can directly identify preferential flow and localized concentrated seepage areas within the slope, accurately pinpointing the location where capillary-impeded coarse-grained soil interface first breaks down and leaks. This allows for a complete observation of the entire evolution of seepage from localized micro-penetration to overall seepage barrier failure. It overcomes the technical shortcomings of not being able to distinguish between inherent soil moisture and rainwater infiltration under tracer-free conditions, and is difficult to determine the seepage development path. This provides intuitive qualitative observational evidence for revealing the intrinsic mechanism of capillary-impeded cover layer seepage failure. The portion of the rectangular box 2 filled with the test soil sample is made of transparent plexiglass, and supplementary lighting 17 is arranged on the outside of the rectangular box 2 to completely eliminate visual blind spots within the soil, achieving clear and visual observation in all weather conditions. The transparent plexiglass has excellent light transmission properties, allowing direct and intuitive observation of the blue tracer water flow distribution at different depths and the interface between coarse and fine soil layers from the outside of the rectangular box 2. The accompanying supplementary light 17 can compensate for insufficient natural light in the indoor environment, eliminate shadows on the side walls of the rectangular box 2, enhance the visual contrast of the blue tracer water flow, and clearly observe the differences in water transport between the surface fine soil and the lower coarse soil. This allows for intuitive verification of the core role of the capillary barrier layer in blocking deep seepage, transforming the abstract process of seepage evolution within the soil into a visually observable phenomenon, thus enhancing the intuitiveness and persuasiveness of the mechanism analysis.

[0072] This invention also discloses a method for testing the seepage prevention effect of capillary retardant cover layers on slopes, using the aforementioned testing device, comprising the following steps:

[0073] Step 1. Obtain the optimum moisture content and maximum dry density of the soil under a specific gradation through compaction tests, calculate the amount of soil required for the test, and prepare the soil sample;

[0074] Step 2. Adjust the tilt angle of the adjustable tilt model box, the rainfall amount of the rainfall simulation system, and the accuracy of the data acquisition unit respectively;

[0075] Step 3. The prepared soil sample is laid in layers in an adjustable tilt model box to form a test soil sample. The soil sample is laid in layers from top to bottom according to the particle size, and each layer is compacted and roughened between layers. Simultaneously, the data acquisition unit is assembled between the layers during the layer laying process.

[0076] Step 4. Calculation and arrangement of rainfall parameters, including the effective rainfall area and water supply per unit time of the test soil sample slope;

[0077] Step 5. Continuous simulated rainfall test: The rainfall simulation system is supplied with water at constant pressure to make the rainfall simulation system uniform and stable, and the movement path of water in the tilt-adjustable model box is observed at the same time.

[0078] Step 6. Multi-path synchronous data acquisition: The dynamic data of water content and pore water pressure of the test soil sample are collected through the data acquisition unit, and the slope runoff, lateral seepage and bottom leakage are collected in three paths through the slope runoff collector 8, the lateral seepage collector 9 and the bottom seepage collector 10.

[0079] Step 7. Weigh the water volume of the slope runoff collector 8, the lateral seepage collector 9, and the bottom seepage collector 10 using an electronic balance, and record the time points of soil breakdown and saturation.

[0080] Step 8. Test completion and result analysis: disassemble the device, clean the test soil sample, organize all time-series monitoring data, compare the working conditions under multiple slopes, and evaluate the seepage prevention effect of the capillary barrier cover layer.

[0081] The bottom of the rectangle is filled with fine-grained soil and coarse-grained soil in layers from top to bottom, as shown in Table 1. Each soil layer is compacted and roughened, and the interface between the layers is flat. The thickness of the soil layer is controlled according to the test requirements.

[0082] Table 1 shows the soil gradation for each layer.

[0083] Particle size 0-0.075mm 0.075-0.25mm 0.25-0.5mm 0.5-2mm 2-5mm 5-10mm 10-20mm 20-40mm Fine-grained soil 55% 10% 5% 5% 15% 10% coarse soil 5% 7% 9% 33% 11% 17% 17% 1%

[0084] The calculation methods for the required dry soil mass, water addition, wet soil mass, and soil volume when the compaction degree is a% for each layer are as follows:

[0085] Based on the effective internal dimensions of the tilt-adjustable model box, the single-layer filling volume is calculated as follows:

[0086] V i =L×B×h i (1)

[0087] In the formula, L is the effective length of the tilt-adjustable model box, B is the effective width, and h is the effective length of the model box. i The design fill thickness of the i-th soil layer;

[0088] The required dry soil mass for the i-th layer for:

[0089] (2)

[0090] Considering the optimal moisture content requirement, the required water addition for this layer is... for:

[0091] (3)

[0092] The mass m of the wet soil in each layer is:

[0093] (4)

[0094] The required soil volume (m³) for each layer under a compaction degree of a%. a for:

[0095] (5)

[0096] Based on formulas (1) to (5), calculate the amount of soil required for each layer under a certain compaction condition. After weighing and mixing the soil in each layer, fill the soil according to the design thickness to ensure that the compaction and moisture content of each layer of soil are controlled within the test requirements.

[0097] The calculation methods and formulas for rainfall condition parameters are as follows:

[0098] The rainfall area A is:

[0099] (6)

[0100] In the formula, b is the top area of ​​the adjustable tilt model box (m²), h is the top width of the adjustable tilt model box (m), and α is the slope angle of the adjustable tilt model box.

[0101] The water supply rate Q per unit time is:

[0102] (7)

[0103] In the formula, Q is the water supply per unit time (mL / h), I is the design rainfall intensity (mm / h), and A is the rainfall area (m²). 2 ).

[0104] The optimal moisture content ω op and maximum dry density ρ dmax The method to obtain it is as follows:

[0105] The water content ω of multiple sets of test soil samples was obtained by compaction test. The soil density ρ obtained by formula (8) was substituted into formula (9) to obtain the dry density ρ. d According to the following, with moisture content ω as the abscissa and dry density ρ as the ordinate, d Plot a compaction curve on the ordinate and perform curve fitting on the compaction data to obtain the fitted curve ρ of dry density as a function of moisture content. d =aω 2 +bω+c, take the first derivative of the fitted curve and set it equal to zero, i.e., ρ d If ω' = 0, the moisture content obtained by solving the problem is the optimum moisture content ω. op The dry density obtained by substituting the optimal moisture content into the fitted curve is the maximum dry density ρ. dmax ;

[0106] The formula for calculating soil density ρ is as follows:

[0107] (8)

[0108] m1: The total mass of the compacted bucket and soil after compaction.

[0109] m0: Mass of the compacted barrel before compaction.

[0110] V: Compacted barrel volume

[0111] a, b, and c are all constants;

[0112] According to formula (8), the soil density ρ obtained from the compaction test under different moisture contents ω can be calculated;

[0113] Soil dry density ρ d The calculation formula is:

[0114] (9)

[0115] During the experiment, different soil densities ρ and soil moisture contents ω were substituted into formula (9) to obtain the corresponding dry density ρ. d， Then, the compaction curve was plotted, and the optimal moisture content ω was determined. op and maximum dry density ρ dmax .

[0116] Experiment 1.

[0117] Test results under rainfall conditions with a slope gradient of 45°:

[0118] Infiltration direction: The slope surface responds before the interior of the slope, and the interior of the slope lags behind by about 150-200 minutes. The infiltration path is from the slope surface to the interior of the slope layer by layer.

[0119] Slope infiltration characteristics: At a depth of 30-40cm on the slope, the water content increases from 20.1% to 21.6-21.9% at 112 minutes, initiating a response; at a depth of 20cm, the water content increases from 20.0% to 21.6% at 144 minutes, initiating a response; and at a depth of 10cm, the water content increases from 20.1% to 22.8% at 200 minutes, initiating a response. The response at 30-40cm on the slope is earlier than that at 10cm.

[0120] Internal characteristics of the slope: all measuring points showed significant changes within 250-350 minutes, with the moisture content increasing from 17% to 23% within 50-100 minutes, an increase of 6%.

[0121] Infiltration saturation time: The slope surface reaches saturation in 200-300 minutes, and the interior of the slope body reaches saturation in 350-400 minutes.

[0122] Final moisture content: 34-36% for slope surface saturation and 24-25% for interior slope.

[0123] Experiment 2.

[0124] The slope angle was adjusted to 40°, and all other conditions were exactly the same as in Experiment 1. The results were as follows:

[0125] Infiltration direction: The slope surface responds before the interior of the slope, lagging by about 150-180 minutes. The infiltration path is from the slope surface to the interior of the slope layer by layer.

[0126] Slope infiltration characteristics: At a depth of 30-40cm on the slope, the water content increases from 20.1-20.2% to 22.3-24.3% at 112-144 minutes, indicating the start of a response; at a depth of 20cm, the water content increases from 20.1% to 21.8% at 144 minutes, indicating the start of a response; and at a depth of 10cm, the water content increases from 20.0% to 23.9% at 200 minutes, indicating the start of a response.

[0127] Internal characteristics of the slope: At a depth of 30-40cm, the moisture content increases from 17.0% to 22.3-23.3% after 300 minutes, indicating the start of a response. At a depth of 10-20cm, the response occurs after 350 minutes. The moisture content jumps from 17% to 22-23% within 50 minutes.

[0128] Infiltration saturation time: The slope surface reaches saturation in 200-300 minutes, and the interior of the slope body reaches saturation in 300-400 minutes.

[0129] Final moisture content: 35-36% for slope surface saturation and 24-25% for interior slope.

[0130] Experiment 3.

[0131] The slope angle was adjusted to 35°, and all other conditions were exactly the same as in Experiment 1. The results were as follows:

[0132] Infiltration direction: The slope surface responds before the interior of the slope, lagging by about 150-180 minutes. The infiltration path is from the slope surface to the interior of the slope layer by layer.

[0133] Slope infiltration characteristics: At a depth of 40cm, the water content increased from 20.3% to 22.8% at 112 minutes, indicating the start of a response; at a depth of 30cm, the water content increased from 20.1% to 24.7% at 144 minutes, indicating the start of a response; at a depth of 20cm, the water content increased from 20.1% to 28.2% at 200 minutes, indicating the start of a response; and at a depth of 10cm, the water content increased from 20.1% to 25.0% at 200 minutes, indicating the start of a response.

[0134] Internal characteristics of the slope: The water content at all depths jumped from 17.0% to 21.1-23.6% at 300 min. Among them, at a depth of 40 cm, the water content increased from 17.0% to 18.7% at 250 min.

[0135] Infiltration saturation time: The slope surface reaches saturation in 250-300 minutes, and the interior of the slope body reaches saturation in 350-400 minutes.

[0136] Final moisture content: 35-36% for slope surface saturation and 24-25% for interior slope.

[0137] The data above clearly demonstrates that the gentler the slope, the earlier and faster the infiltration within the slope; conversely, the steeper the slope, the greater the proportion of surface runoff and the slower the infiltration. However, the final moisture content is unrelated to the slope.

[0138] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A device for testing the seepage prevention effect of capillary-impeded cover layers on slopes, characterized in that: The system includes an adjustable-angle model box housed within a support frame, filled with a test soil sample. The upper part of the adjustable-angle model box, located on the upper surface of the test soil sample, is connected to a slope runoff collector. The side of the adjustable-angle model box, corresponding to the test soil sample, is connected to a lateral seepage collector. The bottom surface of the adjustable-angle model box is connected to a bottom seepage collector. A rainfall simulation system is installed on the support frame above the adjustable-angle model box. A data acquisition unit is installed inside the test soil sample, and the data acquisition unit is connected to a data processing system.

2. The device for testing the seepage prevention effect of capillary retardant cover layer on slopes according to claim 1, characterized in that: The tilt-adjustable model box includes a rectangular box body with the upper end in an open state. One side of the lower end of the rectangular box body is hinged to a hinge seat, and the other side of the lower end of the rectangular box body is hinged to the upper end of a lifting member. The lower ends of the hinge seat and the lower ends of the lifting member are connected to a support frame.

3. The device for testing the seepage prevention effect of capillary retardant cover layer on slopes according to claim 2, characterized in that: Multiple assembly hole groups are vertically spaced on the side of the rectangular box along its length, and the multiple assembly holes in each assembly hole group extend along the length of the rectangular box; the data acquisition unit includes multiple moisture sensors and multiple pore water pressure sensors installed at each assembly hole group, and each moisture sensor and pore water pressure sensor extends into the test soil sample through the corresponding assembly hole, and each moisture sensor and pore water pressure sensor is connected to the data processing system.

4. The device for testing the seepage prevention effect of capillary retardant cover layer on slopes according to claim 2, characterized in that: Multiple lateral collection hole groups are vertically spaced on two sides of the rectangular box along its width direction. Multiple lateral collection holes in each lateral collection hole group extend along the width direction of the rectangular box. The uppermost lateral collection hole group is connected to the slope runoff collector, and the next uppermost and lower lateral collection hole groups are connected to the lateral seepage collector.

5. The device for testing the seepage prevention effect of capillary retardant cover layer on slopes according to claim 2, characterized in that: Bottom collection holes are evenly distributed on the bottom surface of the rectangular box, and each bottom collection hole is connected to a bottom seepage collector.

6. The device for testing the seepage prevention effect of capillary retardant cover layer on slopes according to claim 1, characterized in that: The rainfall simulation system includes a water storage tank located above an adjustable tilt model box. Simulated rain shower heads are evenly distributed on the lower surface of the water storage tank. The water storage tank is connected to the lower part of a water replenishment tank via a water supply pipe equipped with a control valve. The water replenishment tank is located at the upper end of the lifting mechanism.

7. The device for testing the seepage prevention effect of capillary retardant cover layer on slopes according to claim 6, characterized in that: A brilliant blue FCF tracer aqueous solution is injected into the water tank. A supplementary light is installed on the outside of the tilt-adjustable model box, and the part of the tilt-adjustable model box that is filled with the test soil sample is made of transparent plexiglass.

8. A method for testing the seepage prevention effect of capillary-impeded cover layers on slopes, characterized in that, Using the testing apparatus as described in any one of claims 1-7, the method includes the following steps: Step 1. Obtain the optimum moisture content and maximum dry density of the soil under a specific gradation through compaction tests, calculate the amount of soil required for the test, and prepare the soil sample; Step 2. Adjust the tilt angle of the adjustable tilt model box, the rainfall amount of the rainfall simulation system, and the accuracy of the data acquisition unit respectively; Step 3. The prepared soil sample is laid in layers in an adjustable tilt model box to form a test soil sample. The soil sample is laid in layers from top to bottom according to the particle size, and each layer is compacted and roughened between layers. Simultaneously, the data acquisition unit is assembled between the layers during the layer laying process. Step 4. Calculation and arrangement of rainfall parameters, including calculating the effective rainfall area and water supply per unit time of the test soil sample slope; Step 5. Continuous simulated rainfall test: The rainfall simulation system is supplied with constant pressure water to make the rainfall simulation system uniform and stable, and the movement path of water in the tilt-adjustable model box is observed at the same time. Step 6. Multi-path synchronous data acquisition: The dynamic data of water content and pore water pressure of the test soil sample are collected through the data acquisition unit, and the slope runoff, lateral seepage and bottom seepage are collected in three ways through the slope runoff collector, lateral seepage collector and bottom seepage collector. Step 7. Weigh the water volume of the slope runoff collector, lateral seepage collector, and bottom seepage collector respectively using an electronic balance, and record the time points of soil sample breakdown and saturation. Step 8. Test completion and result analysis: disassemble the device, clean the test soil sample, organize all time-series monitoring data, compare the working conditions under multiple slopes, and evaluate the seepage prevention effect of the capillary barrier cover layer.

9. A method for testing the seepage prevention effect of capillary retardant cover layer on slopes according to claim 8, characterized in that, The calculation methods for the required dry soil mass, water addition, wet soil mass, and soil volume when the compaction degree is a% for each layer are as follows: Based on the effective internal dimensions of the tilt-adjustable model box, the single-layer filling volume is calculated as follows: In i =L×W×h i (1) In the formula, L is the effective length of the tilt-adjustable model box, B is the effective width, and h is the effective length of the model box. i Let be the designed filling thickness of the i-th soil layer; The required dry soil mass for the i-th layer for: (2) Considering the optimal moisture content requirement, the required water addition for this layer is... for: (3) The mass m of the wet soil in each layer is: (4) Under the condition of compaction degree a%, the required soil volume ma for each layer is: (5) Based on formulas (1) to (5), calculate the amount of soil required for each layer under a certain compaction condition. After weighing and mixing the soil in each layer, fill the soil according to the design thickness to ensure that the compaction and moisture content of each layer of soil are controlled within the test requirements.

10. A method for testing the seepage prevention effect of a capillary-impeded cover layer on a slope according to claim 8, characterized in that, The calculation methods and formulas for rainfall condition parameters are as follows: The rainfall area A is: (6) In the formula, b is the top area of ​​the adjustable tilt model box (m²), h is the top width of the adjustable tilt model box (m), and α is the slope angle of the adjustable tilt model box. The water supply rate Q per unit time is: (7) In the formula, Q is the water supply per unit time (mL / h), I is the design rainfall intensity (mm / h), and A is the rainfall area (m²). 2 ).

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