A geosynthetic tensile test device and method considering seepage action

Abstract

The application discloses a geosynthetic tensile test device and test method considering seepage effect and belongs to the technical field of geotechnical engineering test. The device comprises a model box system, a steel frame counterforce system, a horizontal tensile system and a seepage simulation system. The model box system is provided with a transparent side wall and a flexible leak-proof filler sleeve, can avoid filler leakage and is convenient for observation; the steel frame counterforce system is connected with a loading plate through a spherical hinge, uniform vertical load application is realized; the horizontal tensile system adopts a clamp, can firmly clamp the geosynthetic material and prevent stress concentration; the seepage simulation system can construct a stable seepage field with different hydraulic gradients through adjusting the water pressure adjusting piston of the water inlet and outlet cavities. The application solves the problem that the traditional tensile test cannot simulate seepage effect, and the test result is more in line with engineering practice. The device and method can be widely applied to performance test of geogrids, geotextiles and other materials, and can provide reliable basis for design of reinforced soil retaining walls, roadbed slopes and other projects.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering testing technology, specifically to a pull-out test apparatus and method for geosynthetics that takes into account seepage. Background Technology

[0002] Geosynthetics, such as geogrids and geotextiles, are widely used in reinforced soil retaining walls, roadbed slopes, and dams due to their excellent reinforcement, protection, and drainage functions. The interfacial friction characteristics of the reinforcement and soil are key parameters in the design of reinforced soil structures, and are typically determined through indoor pull-out tests.

[0003] However, in many practical engineering projects, such as reservoir bank slopes, river embankments, and roadbeds during the rainy season, reinforced soil structures are constantly exposed to seepage fields formed by groundwater or rainfall infiltration. Seepage not only alters the effective stress of the soil but also generates drag forces on the reinforcement, significantly changing the mechanical behavior of the soil-reinforcement interface. Studies have shown that compared to dry or static conditions, the apparent friction coefficient of the soil-reinforcement interface can change significantly under seepage conditions, with a reduction of 15% to 50% or even higher, depending on the soil type, density, and hydraulic gradient. Traditional pull-out test devices are only used under dry or static immersion conditions without a hydraulic gradient, which cannot simulate and quantify the key factor of seepage. This leads to a systematic overestimation of the interfacial strength under actual seepage conditions, resulting in significant deviations from actual engineering conditions.

[0004] Therefore, existing technologies need to be improved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that traditional pull-out test devices cannot simulate seepage fields. The purpose is to provide a pull-out test device and method for geosynthetics that takes into account seepage, and with the corresponding technical means, it has the advantage of good simulation effect.

[0006] This invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a pull-out test apparatus for geosynthetics that takes into account seepage, comprising,

[0008] A model box system, the model box system comprising a model box for containing filler and geosynthetic material, the model box including at least one transparent sidewall;

[0009] A steel frame reaction system is provided on the top of the model box, and the steel frame reaction system is connected to a loading plate that applies a loading force to the filler.

[0010] A horizontal pull-out system, the horizontal pull-out system including a horizontal actuator, the horizontal actuator being provided with a tie rod, the tie rod being connected to the geosynthetic material;

[0011] A seepage simulation system includes a water supply unit, an inlet chamber, and an outlet chamber. The inlet chamber and the outlet chamber are respectively located on both sides of the model box and are connected to the model box. The water supply unit provides water to the inlet chamber.

[0012] Furthermore, in this invention, the side wall of the aforementioned model box is provided with a slot, and one end of the geosynthetic material extends out from the slot and connects to the tie rod.

[0013] Furthermore, in this invention, the model box described above is provided with a flexible leak-proof filling sleeve on the inner side wall of the slot. The flexible leak-proof filling sleeve includes a clamping plate connected to the model box. The clamping plate is provided with flexible rubber clips, and two flexible rubber clips clamp the geosynthetic material.

[0014] Furthermore, in this invention, the aforementioned tie rod is connected to a clamp, the clamp including a clamping bar, a surrounding clamp, and a mounting plate. The mounting plate is connected to the tie rod, the surrounding clamp has a crescent-shaped cross-section, the surrounding clamp is connected to the mounting plate, and the geosynthetic material is inserted between the convex arc side of the surrounding clamp and the mounting plate. The geosynthetic material is wrapped around the concave arc side of the surrounding clamp and fixed by the clamping bar.

[0015] Furthermore, in this invention, the aforementioned clamping bar is provided with screws that are fixedly connected to the surrounding clamp.

[0016] Furthermore, in this invention, the water supply unit mentioned above includes a constant pressure water pump, the constant pressure water pump is connected to an inlet pipe, the outlet end of the inlet pipe is inserted into the inlet chamber, and the inlet pipe is sequentially provided with a constant pressure tank, a first pressure sensor and a first flow meter.

[0017] Furthermore, in this invention, the side wall of the aforementioned model box is provided with a first permeable stone wall connected to the water inlet chamber and a second permeable stone wall connected to the water outlet chamber. The water inlet chamber is provided with a first water pressure regulating piston, and the water outlet chamber is provided with a second water pressure regulating piston. By adjusting the height of the first water pressure regulating piston and the second water pressure regulating piston, the water level height of the water inlet chamber and the water outlet chamber can be independently adjusted in the vertical direction.

[0018] Furthermore, in this invention, a reaction frame is provided on the top of the model box, and the steel frame reaction system includes a vertical actuator disposed on the reaction frame. A spherical hinge is provided at the bottom of the vertical actuator, and the spherical hinge is connected to the loading plate.

[0019] Furthermore, in this invention, the bottom of the aforementioned water outlet cavity is connected to a water outlet pipe, and the water outlet pipe is sequentially equipped with a second flow meter and a second pressure sensor.

[0020] Secondly, the present invention provides a test method comprising the aforementioned geosynthetic material pull-out test apparatus considering seepage effects, and further comprising the following methods.

[0021] Equipment assembly preparation: Clean and assemble the model box system, steel frame reaction system, horizontal pull-out system, and seepage simulation system components, and complete the fixing and sealing inspection of pipelines, clamps, and leak-proof packing sleeves;

[0022] Layered filling and compaction of filler: Test filler is filled into the model box and manually compacted to the preset compaction degree to ensure that the geosynthetic material is dense with the filler;

[0023] Geosynthetic material fixing: The geosynthetic material is threaded through the leak-proof filling sleeve, and one end is fastened to the horizontal tie rod by a clamping bar, a circumferential clamp, and fine-tuned to the tension state;

[0024] Establishing a stable seepage field: Adjust the first water pressure regulating piston in the inlet chamber and the second water pressure regulating piston in the outlet chamber to the preset height, and start the constant pressure water pump to form a stable seepage field in the packing.

[0025] Horizontal pull-out and data acquisition: The horizontal actuator is activated to pull out the geosynthetic material. At the same time, the data acquisition and control system records the pull-out force, displacement, seepage pressure and flow rate data. Based on the recorded force-displacement curve and seepage parameters, the influence of seepage on the friction characteristics of the soil-reinforcement interface is analyzed.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention establishes an independent seepage simulation system. By adjusting the water levels in the inlet and outlet chambers, it can accurately simulate seepage fields under different hydraulic gradients, filling the gap in traditional pull-out tests that cannot simulate seepage effects, making the test results more consistent with engineering realities. This geosynthetic pull-out test device, which considers seepage effects, can not only control and adjust the seepage boundary conditions within the model chamber in real time, but also precisely control the hydraulic gradient, simulating the interaction between the reinforcement and soil interface under complex water-mechanical coupling stress states. It can also reflect the degree of influence of different seepage conditions on the frictional characteristics of the reinforcement-soil interface. This pull-out device can more realistically reflect the actual situation of reinforced soil structures under groundwater or rainfall infiltration environments, adapting to the needs of different engineering types such as reservoir bank slopes and flooded embankments, thereby improving the reliability and applicability of test results. It has significant implications for related scientific research and engineering practice.

[0029] Furthermore, the clamp of this invention adopts a crescent-shaped surrounding clamping structure, which, combined with screw fastening, can achieve a firm grip on the geosynthetic material, avoiding slippage and stress concentration during the pull-out process and ensuring the accuracy of the test data. Simultaneously, the flexible leak-proof filler sleeve effectively prevents filler leakage, ensuring the stability of the test. Attached Figure Description

[0030] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0031] Figure 1 This is a schematic diagram of a geosynthetic pull-out test device considering seepage effects according to the present invention;

[0032] Figure 2 This is a schematic diagram of the horizontal drawing system of the present invention;

[0033] Figure 3 This is a schematic diagram of the steel frame reaction system of the present invention;

[0034] Figure 4 This is a schematic diagram of the flexible leak-proof packing sleeve of the present invention.

[0035] The attached diagram shows the following components and their corresponding names: 1-Horizontal actuator, 2-Pull rod, 3-Clamp, 3a-Clamping bar, 3b-Circumferential clamp, 3c-Mounting plate, 4-Geosynthetic material, 5-Second water pressure regulating piston, 6-Flexible leak-proof filler sleeve, 6a-Clamping plate, 6b-Flexible rubber clamp, 7-Reaction frame, 8-Loading plate, 9-Vertical actuator, 10-Spherical hinge, 10a-Ball head bolt, 10b-Ball seat, 11-First flow meter, 12-First pressure sensor, 13-Inlet pipe, 14-First water pressure regulating piston, 15-Constant pressure tank, 16-Constant pressure water pump, 17-Inlet chamber, 18-First permeable stone wall, 19-Screw, 21-Second permeable stone wall, 22-Outlet chamber, 23-Second flow meter, 24-Second pressure sensor. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for explanation only and are not intended to limit the invention. The following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0037] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] Example 1

[0039] This embodiment 1 provides a pull-out test device for geosynthetics that takes into account seepage, such as Figures 1-4 As shown, it includes a model box system, a steel frame reaction system, a horizontal pull-out system, and a seepage simulation system.

[0040] Combination Figure 1 and Figure 4As shown, the model box system includes a model box for accommodating the filler and geosynthetic material 4. The model box includes at least one transparent sidewall (e.g., a transparent baffle made of acrylic or plexiglass) with the required optical transparency and surface flatness to allow direct observation of specimen deformation through the side of the box during the test, providing necessary observation conditions for particle image velocimetry, and facilitating observation of the interaction between the filler and geosynthetic material 4 during the test. A slot is provided on the left sidewall of the model box, allowing one end of the geosynthetic material 4 to extend from the slot and connect to the horizontal pull-out system. A flexible leak-proof filler sleeve 6 is provided on the inner sidewall of the slot. The flexible leak-proof filler sleeve 6 includes a clamping plate 6a connected to the model box, and the clamping plate 6a is equipped with flexible rubber clamps 6b. The two flexible rubber clamps 6b clamp the geosynthetic material 4, ensuring that the geosynthetic material 4 passes smoothly through while preventing the filler inside the model box from leaking out from the slot.

[0041] It should be noted that, in combination Figure 4 As shown, clamp 6a is fixed to the model box with screws, and the screw holes are sealed with sealant after installation. The side wall of the model box can be provided with multiple mounting holes of different heights, which can be used to adjust the gap between the two blades by adjusting the installation position of clamp 6a, so as to meet the test requirements of geosynthetic materials 4 with different thicknesses.

[0042] Furthermore, in combination Figure 1 and Figure 3 As shown, a steel frame reaction system is located at the top of the model box, and is connected to a loading plate 8 that applies a loading force to the filler. A reaction frame 7 is installed at the top of the model box, and the steel frame reaction system includes a vertical actuator 9 installed on the reaction frame 7. A spherical hinge 10 is installed at the bottom of the vertical actuator 9, and the spherical hinge 10 is connected to the loading plate 8. The spherical hinge 10 ensures that the loading plate 8 is evenly stressed, avoiding stress concentration. Figure 3 As shown, the spherical hinge 10 includes a ball head bolt 10a and a ball seat 10b. The ball head bolt 10a is connected to the vertical actuator, and the ball seat 10b is connected to the loading plate 8. The ball head bolt 10a and the ball seat 10b are connected to each other.

[0043] It should be noted that in this embodiment 1, the vertical loading system has three parallel vertical actuators 9. The output end of each vertical actuator 9 acts on three identical loading plates 8, thereby contacting the top of the backfill sample. This arrangement allows the three vertical actuators 9 to be independently controlled to adjust the pressure distribution, and also to achieve synchronous load control, ensuring that the load is applied to the sample surface synchronously with the same frequency and phase, thus achieving uniform stress on the sample and effectively avoiding local stress concentration. The ball head bolt 10a and ball seat 10b can automatically adapt to the posture changes of the loading plate 8, effectively eliminating the eccentric bending moment caused by uneven sample surface or installation deviation of the vertical actuators 9, thereby ensuring that the vertical load is uniformly transferred to the sample surface and avoiding local stress concentration.

[0044] Combination Figure 1 and Figure 2 As shown, the horizontal pulling system includes a horizontal actuator 1, which is equipped with a pull rod 2. A force sensor and a displacement sensor are installed on the pull rod 2 to detect the pulling force and the pulling displacement.

[0045] Furthermore, to connect the tie rod 2 and the geosynthetic material 4, the tie rod 2 is connected to a clamp 3. The clamp 3 includes a clamping rod 3a, a surrounding clamp 3b, and a mounting plate 3c. The surrounding clamp 3b has a crescent-shaped cross-section, with a convex arc shape on the right side and a central angle of 270° on the left side. The mounting plate 3c is connected to the tie rod 2, and both ends of the surrounding clamp 3b are fixedly connected to the mounting plate 3c. A gap is left between the convex arc side of the surrounding clamp 3b and the mounting plate 3c to insert the geosynthetic material 4. The geosynthetic material 4 wraps around the surrounding clamp 3b from the top to the convex arc side, then to the bottom and concave arc sides, and is finally secured by the clamping rod 3a. The clamping rod 3a is equipped with screws 19 that are fixedly connected to the surrounding clamp 3b. Tightening the screws 19 ensures a firm grip on the geosynthetic material 4, preventing slippage and stress concentration during the pull-out process.

[0046] Combination Figure 1 As shown, the seepage simulation system includes a water supply unit, an inlet chamber 17, and an outlet chamber 22. The inlet chamber 17 and the outlet chamber 22 are respectively located on both sides of the model box and are connected to the model box. The water supply unit provides water to the inlet chamber 17.

[0047] Furthermore, the water supply unit includes a constant pressure water pump 16, which is connected to an inlet pipe 13. The outlet end of the inlet pipe 13 is inserted into the inlet chamber 17. The inlet pipe 13 is sequentially equipped with a constant pressure tank 15, a first pressure sensor 12, and a first flow meter 11. The constant pressure tank 15 can stabilize the water supply pressure, and the first pressure sensor 12 and the first flow meter 11 can monitor the pressure and flow data of the incoming water in real time.

[0048] The left and right side walls of the model box are provided with a first permeable stone wall 18 connected to the water inlet chamber 17 and a second permeable stone wall 21 connected to the water outlet chamber 22. The permeable stone walls have seepage pores, which can ensure that the water flows evenly into the model box, while preventing the filler from entering the water inlet chamber 17 and the water outlet chamber 22. To ensure the formation of a controllable and uniform stable seepage field, the key is that the hydraulic characteristics of the permeable stone must match those of the filler. The permeable stone wall selected in Embodiment 1 of this invention can be made of sintered stainless steel or porous alumina ceramic material, with typical parameters as follows: pore size range of 10-50 μm, porosity greater than 40%, thickness of 20-30 mm, and permeability coefficient not less than The permeability coefficient (Ks) of the permeable stone must be at least equal to the permeability coefficient (Ksoil) of the filling soil. The ratio is more than 1000 times (i.e., Ks / Ksoil ≥ 1000), ensuring that the head loss when water flows through the permeable stone is negligible, and the head difference in the seepage field almost entirely affects the filler sample. Simultaneously, the maximum pore size (Dmax) of the permeable stone is less than 1 / 10 of the minimum particle size (dmin) of the filler (i.e., Dmax < 0.1dmin). This design effectively prevents fine-particle filler from flowing into the cavity, ensuring long-term interface stability and smooth seepage. Through the above parameter adaptation, the permeable stone wall mainly serves to uniformly distribute water and stabilize the interface; the intensity, direction, and stability of the seepage field are precisely controlled by the pressure of the water supply unit and the cavity position.

[0049] Furthermore, the outlet of the constant pressure water pump 16 is connected to the constant pressure tank 15 via the inlet pipe 13, and the outlet of the constant pressure tank 15 is connected to the inlet chamber 17 via the inlet pipe 13. A first flow meter 11 and a first pressure sensor 12 are installed on the inlet pipe 13. Water is discharged from the outlet chamber 22 through the outlet pipe, which is equipped with a second flow meter 23 and a second pressure sensor 24. The constant pressure water pump 16 can be a magnetically driven centrifugal pump with a rated pressure range of 0.1 to 0.6 MPa and a rated flow range of 0.5 to... This range ensures sufficient water supply capacity and pressure margin when simulating various operating conditions, from slow seepage with low hydraulic gradients to rapid seepage with high hydraulic gradients (such as simulating critical piping conditions). The volume (Vtank) of the constant pressure tank 15 is designed based on the minimum stable flow rate of the water pump (Qmin) and the allowable pressure fluctuation range of the system (ΔP). The basic design formula is Vtank ≥ (QminΔt) / (β×ΔP / Pavg), where Δt is the response time of the control system, β is the compressibility coefficient of water, and Pavg is the average pressure.

[0050] The inlet chamber 17 is equipped with a first water pressure regulating piston 14, and the outlet chamber 22 is equipped with a second water pressure regulating piston 5. By adjusting the height of the first water pressure regulating piston 14 and the second water pressure regulating piston 5 in the inlet chamber 17 and the outlet chamber 22, the water level in the inlet chamber 17 and the outlet chamber 22 can be independently adjusted in the vertical direction, thereby accurately controlling the water level in the model box.

[0051] It also includes a data acquisition and control system, which is electrically connected to the first flow meter 11, the first pressure sensor 12, the second flow meter 23, the second pressure sensor 24, the tension sensor, and the displacement sensor, for real-time acquisition, storage, and processing of seepage pressure, flow rate, pull-out force, and displacement data.

[0052] Example 2

[0053] This embodiment provides a test method that uses the geosynthetic pull-out test device considering seepage in Embodiment 1.

[0054] Device assembly preparation: Clean and assemble the model box system, steel frame reaction system, horizontal pulling system, and seepage simulation system components. Complete the fixing and sealing inspection of pipelines, clamps 3, and leak-proof packing sleeves 6. Install the inlet chamber 17 and outlet chamber 22 at the predetermined height positions on both sides of the model box.

[0055] Layered filling and compaction of fill material and fixation of geosynthetic material: Fill material is layered on the bottom plate of the model box. When the filling reaches the predetermined height, geosynthetic material 4 is laid flat, ensuring that its pull-out end passes through the groove and is initially clamped by clamp 3. Continue filling the upper layer of fill material to the design height.

[0056] The actuator of the steel frame reaction system drives the loading plate 8 to apply a predetermined normal stress to the surface of the filler. The clamp 3 is electrically connected to the tension sensor of the horizontal pulling system. A PIV image acquisition system is arranged outside the transparent baffle. The position, focal length, and illumination of the high-speed camera are adjusted to ensure complete capture of the sample deformation area. All sensors are then connected to the data acquisition and control system.

[0057] Horizontal Pulling and Data Acquisition: A seepage field is established, and the constant-pressure water pump 16 is started. Its built-in pressure feedback control system precisely adjusts the output water pressure. After pressure pulsation is eliminated by the constant-pressure tank 15, a constant water source is provided to the inlet chamber 17 through the inlet pipe 13. Water flows evenly into the packing material through the first permeable stone wall 18 at the front of the inlet chamber 17, forming a stable hydraulic gradient between the inlet chamber 17 and the outlet chamber 22. The vertical installation height of the inlet chamber 17 and the outlet chamber 22 are independently adjusted by the height adjustment device. When both are at the same horizontal height, a horizontal seepage field is formed; when there is a height difference, an inclined seepage field with a vertical component is formed; when one chamber is located at the top of the box and the other at the bottom, a vertical seepage field is formed.

[0058] During the above process, the influent flow rate and pressure are monitored in real time by the first flow meter 11 and the first pressure sensor 12, while the effluent parameters are monitored by the second flow meter 23 and the second pressure sensor 24. This allows for the active control of the hydraulic gradient (i=ΔH / L, where L is the seepage path length of the packing material between the two cavities) and the seepage direction of the seepage field.

[0059] Specifically: when regulation makes When ΔH=0, a horizontal seepage field is formed; when the adjustment makes... When ΔH>0, a downward seepage field is formed from back to front, with a hydraulic gradient i=ΔH / L; when the adjustment makes... At this time, a reverse upward seepage field is formed. By programming and controlling the piston connected to the electric actuator to operate in a specific timing sequence, the uniform rise / fall of the water level can be continuously simulated. and (synchronous changes) or a sudden drop in water level ( Rapidly decrease Complex working conditions such as (unchanged) are also possible. This precise, independent, and programmable control over the seepage direction and hydraulic gradient is something that traditional pull-out devices, which can only perform static immersion, cannot achieve, thus constituting the outstanding substantive feature of this invention.

[0060] Synchronous pull-out and PIV monitoring: After the seepage field stabilizes, the actuators and PIV image acquisition system are simultaneously activated to pull out the geosynthetic material 4 at a constant rate. The data acquisition and control system synchronously records the pull-out force, displacement, seepage pressure, flow rate data, and sample deformation image sequence. Based on the recorded force-displacement curves and seepage parameters, the influence of seepage on the frictional characteristics of the reinforcement-soil interface is analyzed.

[0061] By comparing and analyzing the pull-out force-displacement curves under different seepage conditions, the influence of seepage on the frictional properties of the reinforcement-soil interface is quantitatively evaluated. Steps three through five are repeated to conduct multi-condition tests, changing the seepage conditions or normal stress.

[0062] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. 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 present invention.

Claims

1. A geosynthetic tensile test apparatus that takes into account seepage action, characterized by, include, A model box system comprising a model box for accommodating filler and geosynthetic material (4), the model box containing at least one transparent sidewall; A steel frame reaction system is provided on the top of the model box, and the steel frame reaction system is connected to a loading plate (8) that applies a loading force to the filler. A horizontal pull-out system, the horizontal pull-out system including a horizontal actuator (1), the horizontal actuator (1) being provided with a tie rod (2), the tie rod (2) being connected to the geosynthetic material (4); The seepage simulation system includes a water supply unit, an inlet chamber (17) and an outlet chamber (22). The inlet chamber (17) and the outlet chamber (22) are respectively located on both sides of the model box and are connected to the model box. The water supply unit provides water to the inlet chamber (17).

2. The geosynthetic tensile test apparatus that considers seepage action according to claim 1, characterized by, The side wall of the model box is provided with a slot, and one end of the geosynthetic material (4) extends out from the slot and is connected to the tie rod (2).

3. The geosynthetic pull-out test apparatus considering seepage as described in claim 2, characterized in that, The model box is provided with a flexible leak-proof filling sleeve (6) on the inner side wall of the slot. The flexible leak-proof filling sleeve (6) includes a clamping plate (6a) connected to the model box. The clamping plate (6a) is provided with flexible rubber clips (6b). The two flexible rubber clips (6b) clamp the geosynthetic material (4).

4. The geosynthetic pull-out test apparatus considering seepage as described in claim 1, characterized in that, The pull rod (2) is connected to a clamp (3), which includes a clamping bar (3a), a surrounding clamp (3b), and a mounting plate (3c). The mounting plate (3c) is connected to the pull rod (2). The surrounding clamp (3b) has a crescent-shaped cross section. The surrounding clamp (3b) is connected to the mounting plate (3c), and the geosynthetic material (4) is inserted between the convex arc side of the surrounding clamp (3b) and the mounting plate (3c). The geosynthetic material (4) is wrapped around the concave arc side of the surrounding clamp (3b) and fixed by the clamping bar (3a).

5. The geosynthetic pull-out test apparatus considering seepage as described in claim 4, characterized in that, The clamp (3a) is provided with screws (19) that are fixedly connected to the surrounding clamp (3b).

6. The geosynthetic pull-out test apparatus considering seepage as described in claim 1, characterized in that, The water supply unit includes a constant pressure water pump (16), which is connected to an inlet pipe (13). The outlet end of the inlet pipe (13) is inserted into the inlet chamber (17). The inlet pipe (13) is sequentially equipped with a constant pressure tank (15), a first pressure sensor (12), and a first flow meter (11).

7. The geosynthetic pull-out test apparatus considering seepage as described in claim 6, characterized in that, The side wall of the model box is provided with a first permeable stone wall (18) connected to the water inlet chamber (17) and a second permeable stone wall (21) connected to the water outlet chamber (22). The water inlet chamber (17) is provided with a first water pressure regulating piston (14), and the water outlet chamber (22) is provided with a second water pressure regulating piston (5). The independent water level adjustment of the water inlet chamber (17) and the water outlet chamber (22) in the vertical direction can be achieved by adjusting the height of the first water pressure regulating piston (14) and the second water pressure regulating piston (5).

8. The geosynthetic pull-out test apparatus considering seepage as described in claim 1, characterized in that, The top of the model box is provided with a reaction frame (7), and the steel frame reaction system includes a vertical actuator (9) provided on the reaction frame (7). The bottom of the vertical actuator (9) is provided with a spherical hinge (10), and the spherical hinge (10) is connected to the loading plate (8).

9. The geosynthetic pull-out test apparatus considering seepage as described in claim 1, characterized in that, The bottom of the water outlet chamber (22) is connected to the water outlet pipe, and the water outlet pipe is sequentially equipped with a second flow meter (23) and a second pressure sensor (24).

10. A test method, characterized in that, The geosynthetic pull-out test apparatus considering seepage as described in any one of claims 1-9 further includes the following method. Device assembly preparation: Clean and assemble the model box system, steel frame reaction system, horizontal pulling system, seepage simulation system and other components, and complete the fixing and sealing inspection of pipelines, clamps (3) and leak-proof packing sleeves (6); Layered filling and compaction of filler: Fill the model box with test filler and compact it manually to the preset compaction degree to ensure that the geosynthetic material (4) is compacted with the filler; Geosynthetic material fixing: The geosynthetic material (4) is threaded through the anti-leakage filling sleeve (6), and one end is fastened to the horizontal tie rod (2) through the clamp (3a) and the surrounding clamp (3b), and finely adjusted to the tension state; Establishment of a stable seepage field: Adjust the first water pressure regulating piston (14) of the inlet chamber (17) and the second water pressure regulating piston (5) of the outlet chamber (22) to the preset height, and start the constant pressure water pump (16) to form a stable seepage field in the packing; Horizontal pull-out and data acquisition: The horizontal actuator (1) is activated to pull out the geosynthetic material (4). At the same time, the data acquisition and control system records the pull-out force, displacement, seepage pressure and flow rate data. Based on the recorded force-displacement curve and seepage parameters, the influence of seepage on the friction characteristics of the soil-reinforcement interface is analyzed.

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