Multifunctional testing device for geotextiles and testing method

Abstract

The application provides a multifunctional testing device for geotextile, and belongs to the technical field of geotextile performance testing. The device comprises a base, a supporting piece, a transmission assembly, a first distance measuring assembly and a second distance measuring assembly. The base is provided with a supporting rod and a sensor for detecting the axial stress of the supporting rod. The supporting rod comprises a fixed part and a moving part. When the moving part is stressed, it is suitable to move along the axial direction of the supporting rod relative to the fixed part, so as to adjust the distance between the fixed part and the moving part. The supporting piece is connected to the fixed part and the moving part, and is suitable to move along the radial direction of the supporting rod when the distance changes, so as to support and expand the geotextile. The transmission assembly is suitable to be stressed along the axial direction of the supporting rod and to drive the supporting rod to rotate relative to the base through motion conversion. The first distance measuring assembly is suitable to measure the distance between the fixed part and the moving part. The second distance measuring assembly is suitable to measure the distance between the supporting piece and the fixed part. The detection results are used to calculate the performance of the geotextile. The application can realize the integrated testing function of the tensile test and the interface friction test.

Description

Technical Field

[0001] The present invention relates to the technical field of geotextile performance testing, in particular to a multifunctional testing device and a testing method for geotextiles. Background Art

[0002] As an indispensable geosynthetic material in civil engineering and water conservancy projects, accurate acquisition of geotextiles' physical and mechanical parameters is crucial for engineering design. In related technologies, various geotextile performance parameters are measured separately using single-function testing devices. For example, tensile strength is independently tested using a tensile testing machine, while key technical indicators such as the interfacial friction coefficient between geotextiles and soil are independently tested using a pull-out testing machine. This not only requires large equipment investments, but also results in a cumbersome and inefficient testing process. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a multifunctional testing device and testing method for geotextiles, which can realize the integrated testing functions of tensile test and interface friction test.

[0004] The present invention provides a multifunctional testing device for geotextiles, comprising a base, a support member, a transmission assembly, a first distance measuring assembly, and a second distance measuring assembly. The base is provided with a support rod and a sensor for detecting axial force applied to the support rod. The support rod comprises a fixed portion and a movable portion, the fixed portion being rotatably connected to the base. When the movable portion is subjected to force, the movable portion is adapted to move relative to the fixed portion in the axial direction of the support rod to adjust the distance between the fixed portion and the movable portion. The support member connects the fixed portion and the movable portion and is adapted to move relative to the support rod in the radial direction of the support rod when the distance between the fixed portion and the movable portion changes, thereby supporting and expanding the geotextile. The transmission assembly is provided on the support rod, adapted to receive force in the axial direction of the support rod and drive the support rod and the support member to rotate relative to the base through motion conversion. The first distance measuring assembly is provided on the fixed portion and is directly opposite to the movable portion in the axial direction of the support rod to measure the distance between the fixed portion and the movable portion. The second distance measuring assembly is provided on the fixed portion and is directly opposite to the support member in the radial direction of the support rod to measure the distance between the support member and the fixed portion. Detection results of the sensor, the first distance measuring assembly, and the second distance measuring assembly are used to calculate and analyze the performance of the geotextile.

[0005] The multifunctional testing device of the present invention can support a geotextile and apply a radial load to expand it, thereby measuring the tensile performance parameters of the geotextile; it can also rotate the geotextile to cause it to rub against an object, thereby measuring its interfacial friction performance parameters. This multifunctional testing device integrates tensile and interfacial friction testing, enabling simultaneous acquisition of key geotextile indicators such as tensile modulus, stress-strain curve, tensile strength, and interfacial friction angle. This significantly simplifies the testing process, improves testing efficiency, and ensures the accuracy and reliability of the measured data.

[0006] According to some embodiments of the present invention, the support rod further includes a guide portion, the guide portion is fixedly connected to the fixed portion, and an end portion of the guide portion is detachably connected to the transmission assembly; the movable portion is slidably connected to the guide portion.

[0007] According to some embodiments of the present invention, the moving portion is provided with a pawl, and the guiding portion is provided with a tooth portion cooperating with the pawl, so as to enable the moving portion to move unidirectionally along the axial direction of the support rod.

[0008] According to some embodiments of the present invention, an elastic connecting member is provided between the movable portion and the fixed portion, and the elastic connecting member is adapted to limit the movement of the movable portion.

[0009] According to some embodiments of the present invention, the transmission assembly includes a first transmission member and a second transmission member, the second transmission member is circumferentially limitedly connected to the other end of the support rod, the first transmission member is cooperatively connected with the second transmission member, and the first transmission member moves axially relative to the support rod when subjected to axial force, and is suitable for driving the second transmission member to rotate, so as to drive the support rod to rotate relative to the base.

[0010] According to some embodiments of the present invention, the first transmission member includes a bearing, a guide rod, a limit member and a force plate, the bearing is arranged at the end of the guide part, and the inner ring of the bearing is cooperatively connected with the guide part; the guide rod is arranged on the outer ring of the bearing, and the axial direction of the guide rod is parallel to the axial direction of the support rod; the limit member is connected to the guide rod and is suitable for limiting the movement of the guide rod; the force plate is slidably connected to the guide rod, and the force plate is connected to the second transmission member by a thread; when the force plate is subjected to force, it moves along the axial direction of the guide rod and drives the second transmission member and the guide part to rotate.

[0011] According to some embodiments of the present invention, the multifunctional testing device further includes a connecting rod, which is constructed of at least two connecting rods, at least one connecting rod connecting the support member and the fixed part, and at least one connecting rod connecting the support member and the movable part; the connecting rod is suitable for rotating relative to the support member or the fixed part and the movable part.

[0012] According to some embodiments of the present invention, the connecting rod is constructed in two parts, the middle parts of the two connecting rods are hinged, one end of each connecting rod is rotatably and slidably connected to the support member, and a sliding groove is provided on the support member to cooperate with one end of the connecting rod.

[0013] The present invention also provides a method for testing the tensile strength of geotextiles, using the multifunctional testing device for geotextiles, and the testing method comprises the following steps:

[0014] Support and fix the geotextile, obtain the initial axial force of the support rod, the initial distance between the moving part and the fixed part, and the initial distance between the support member and the fixed part;

[0015] Apply pressure to the moving part one by one, and after the pressure stabilizes, record the maximum axial force of the support rod during the pressure application process, as well as the distance between the moving part and the fixed part, and the distance between the support member and the fixed part;

[0016] The data were corrected and calculated to obtain the hoop tensile stress and strain of the geotextile during the support expansion process;

[0017] The hoop tensile stress and strain data are used to draw a complete stress-strain curve and calculate the tensile modulus and tensile strength.

[0018] The present invention also proposes a method for testing the interfacial friction performance of geotextiles, using the multifunctional testing device described above, and the testing method comprises the following steps:

[0019] Support and fix the geotextile, and place the multifunctional testing device and the geotextile in the test soil so that the test soil covers the geotextile;

[0020] Obtain the initial axial force of the support rod;

[0021] Apply pressure to the moving part to move it downward a predetermined distance. After the pressure stabilizes, record the axial force of the support rod, the distance between the moving part and the fixed part, and the distance between the support member and the fixed part.

[0022] Apply pressure to the transmission assembly to drive the support rod and geotextile to rotate at a constant speed, and record the axial force on the support rod when the geotextile rotates at a constant speed;

[0023] Repeat the above steps, applying pressure to the moving part to move it downward by different predetermined distances, and applying pressure to the transmission assembly to drive the geotextile to rotate at a constant speed. After the pressure stabilizes each time, record the axial force on the support rod, as well as the distance between the moving part and the fixed part, and the distance between the support member and the fixed part; record the axial force on the support rod when the geotextile rotates at a constant speed;

[0024] Correct and calculate the data to obtain the radial load and torsional force on the geotextile;

[0025] The radial load and torsional force data were fitted to calculate the interface friction coefficient between the geotextile and the test soil.

[0026] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0028] Figure 1 is a schematic structural diagram of a multifunctional testing device according to some embodiments of the present invention;

[0029] Figure 2 is a top view of the structure of a multifunctional testing device according to some embodiments of the present invention;

[0030] Figure 3 is a schematic structural diagram of a multifunctional testing device according to some embodiments of the present invention without a supporting member;

[0031] Figure 4 is a schematic structural diagram of a fixing portion and a guide portion of a support rod according to some embodiments of the present invention;

[0032] Figure 5 is a schematic structural diagram of a moving portion of a support rod according to some embodiments of the present invention;

[0033] Figure 6 is a structural cross-sectional view of a moving portion of a support rod according to some embodiments of the present invention;

[0034] Figure 7 is a cross-sectional view of a support rod according to some embodiments of the present invention;

[0035] Figure 8 is a schematic structural diagram of a support member according to some embodiments of the present invention;

[0036] Figure 9 is a schematic structural diagram of a second transmission member according to some embodiments of the present invention;

[0037] Figure 10 is a top view of the structure of the bearing and guide rod of the transmission assembly according to some embodiments of the present invention;

[0038] Figure 11 is a schematic flow chart of a geotextile performance testing process according to some embodiments of the present invention;

[0039] Figure 12 is a schematic diagram of placing the multifunctional testing device of some embodiments of the present invention in a test soil;

[0040] Figure 13 It is a schematic diagram of the forces acting on the multifunctional testing device of some embodiments of the present invention when it is set in the test soil.

[0041] Reference numerals:

[0042] Support rod 10; fixed portion 11; guide portion 12; axial groove 121; guide plate 122; movable portion 13; through groove 131; tooth portion 14; pawl 15; spring 16;

[0043] Support member 20; slide groove 21; connecting portion 22; connecting rod 30;

[0044] Transmission assembly 40; force plate 41; second transmission member 42; protrusion 421; bearing 43; guide rod 44;

[0045] Base 50; first distance measuring component 60; second distance measuring component 70;

[0046] Torsion box 80; test soil 90. DETAILED DESCRIPTION

[0047] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0048] Reference below Figures 1-13 A multifunctional testing device for geotextiles according to an embodiment of the present invention is described.

[0049] The application provides a multifunctional testing device for geotextile, which comprises a base 50, a supporting piece 20, a transmission assembly 40, a first distance measuring assembly 60 and a second distance measuring assembly 70, the base 50 is provided with a supporting rod 10 and a sensor for detecting the axial stress of the supporting rod 10; the supporting rod 10 comprises a fixed part 11 and a moving part 13, the fixed part 11 is rotatably connected with the base 50, and the moving part 13 is adapted to move relative to the fixed part 11 along the axial direction of the supporting rod 10 when the moving part 13 is stressed, so as to adjust the distance between the fixed part 11 and the moving part 13; the supporting piece 20 is connected with the fixed part 11 and the moving part 13, and is adapted to move relative to the supporting rod 10 along the radial direction of the supporting rod 10 when the distance between the fixed part 11 and the moving part 13 changes, so as to support and expand the geotextile outward along the radial direction of the supporting rod 10; the transmission assembly 40 is arranged on the supporting rod 10, and the transmission assembly 40 is adapted to be stressed along the axial direction of the supporting rod 10 and drive the supporting rod 10 and the supporting piece 20 to rotate relative to the base 50 through motion conversion; the first distance measuring assembly 60 is arranged on the fixed part 11 and faces the moving part 13 along the axial direction of the supporting rod 10, so as to measure the distance between the fixed part 11 and the moving part 13; the second distance measuring assembly 70 is arranged on the fixed part 11 and faces the supporting piece 20 along the radial direction of the supporting rod 10, so as to measure the distance between the supporting piece 20 and the fixed part 11; wherein the detection results of the sensor, the first distance measuring assembly 60 and the second distance measuring assembly 70 are used for calculating and analyzing the performance of the geotextile.

[0050] According to the multifunctional testing device, when the supporting piece 20 moves relative to the supporting rod 10 along the radial direction, the supporting radius of the supporting piece 20 can be changed, so that the geotextile can be set and fixed; when the moving part 13 is stressed along the axial direction, the distance between the moving part 13 and the fixed part 11 can be changed by moving relative to the fixed part 11 along the axial direction of the supporting rod 10, and when the distance is changed, the supporting piece 20 moves outward or inward along the radial direction of the supporting rod 10, the supporting piece 20 applies radial load to the geotextile to stretch it, at the same time, the force sensor can detect the axial stress of the supporting rod 10 in real time, the first distance measuring assembly 60 can measure the distance between the fixed part 11 and the moving part 13, and the second distance measuring assembly 70 can measure the distance between the supporting piece 20 and the fixed part 11, so that the tensile performance parameters of the geotextile can be obtained by calculation. Further, when the transmission assembly 40 is stressed, the supporting rod 10 is driven to rotate, the supporting rod 10 drives the geotextile to rotate through the supporting piece 20, so that the geotextile can be in contact with the soil during the test, and the geotextile can be in friction with the soil at all times during the rotation, based on the axial stress of the supporting rod 10, the distance between the supporting piece 20 and the fixed part 11, and the distance between the fixed part 11 and the moving part 13, the interface friction performance parameters of the geotextile can be obtained by calculation. The first distance measuring assembly 60 and the second distance measuring assembly 70 can be laser range finders.

[0051] The multifunctional testing device of the present invention can support a geotextile and apply a radial load to expand it, thereby measuring the tensile performance parameters of the geotextile; it can also rotate the geotextile to cause it to rub against an object, thereby measuring its interfacial friction performance parameters. This multifunctional testing device integrates tensile and interfacial friction testing, enabling simultaneous acquisition of key geotextile indicators such as tensile modulus, stress-strain curve, tensile strength, and interfacial friction angle. This significantly simplifies the testing process, improves testing efficiency, and ensures the accuracy and reliability of the measured data.

[0052] In some embodiments, a plurality of support members 20 are provided, spaced apart along the circumference of the support rod 10 and adapted to move synchronously. The plurality of support members 20 are spaced apart along the circumference of the support rod 10 and have equal support radii. When the support members 20 move radially relative to the support rod 10, the support radii of the plurality of support members 20 can be changed to support the geotextile and cause it to expand radially.

[0053] In addition, since the movement process of the moving part 13 relies on the action of axial external force, the transmission component 40 is also subject to the action of axial external force when transmitting motion. The external force required for the tensile performance test and the interface friction performance test of the geotextile of the present invention is consistent, and can be achieved in conjunction with a single driving device, further simplifying the testing process and device cost.

[0054] Furthermore, the multifunctional testing device of the present invention can adopt a dual-mode drive: it can work in conjunction with a continuously adjustable press, using it to change the pressurization of the moving part 13 or the transmission component 40 to carry out tests; it can also achieve motion control through direct motor drive, and during the test, the moving part 13 and the transmission component 40 are directly connected to the downward drive motor respectively.

[0055] Furthermore, the transmission assembly 40 is detachably connected to the support rod 10 to facilitate tensile performance testing.

[0056] It should be noted that, considering the influence of structural gravity and other factors, when conducting tests on the multifunctional testing device of the present invention, the support rod 10 is preferably arranged in a vertical direction, and the movable part 13 moves vertically downward close to the fixed part 11, driving the support member 20 to move radially outward to achieve support and expansion of the geotextile.

[0057] According to some embodiments of the present invention, the support rod 10 further includes a guide portion 12, the guide portion 12 is fixedly connected to the fixed portion 11, and the end of the guide portion 12 is detachably connected to the transmission assembly 40; the movable portion 13 is slidably connected to the guide portion 12. In this embodiment, Figure 3As shown, the guide portion 12 is provided to cooperate with the movable portion 13 to achieve relative movement between the movable portion 13 and the fixed portion 11. The extending direction of the guide portion 12 is consistent with the axial direction of the support rod 10. During testing, the guide portion 12 is provided above the fixed portion 11, and the movable portion 13 slides up and down along the guide portion 12.

[0058] In some embodiments, as Figure 4-7 As shown, the guide portion 12 is constructed as a cylindrical structure, and two arc-shaped guide plates 122 are formed by opening an axial groove 121, and the arc-shaped guide plates 122 extend axially along the support rod 10; the movable portion 13 is formed with two through grooves 131 that slide with the arc-shaped guide plates 122, and the movable portion 13 is sleeved with the guide portion 12 for relative sliding.

[0059] According to some embodiments of the present invention, the movable portion 13 is provided with a pawl 15, and the guide portion 12 is provided with a tooth portion 14 that cooperates with the pawl 15, so as to be suitable for the unidirectional movement of the movable portion 13 along the axial direction of the support rod 10. In this embodiment, the movable portion 13 and the guide portion 12 realize the unidirectional movement of the movable portion 13 through the cooperation of the pawl 15 and the tooth portion 14. Specifically, the movable portion 13 moves along the axial direction of the support rod 10 toward the fixed portion 11 under the condition of being subjected to an axial external force. When the geotextile expands to a predetermined state, the movable portion 13 can limit the movable portion 13 due to the unidirectional limiting effect of the tooth portion 14 and the pawl 15, so that it remains in this position, and the external force can be removed. This embodiment can maintain the stability of the multifunctional testing device during the test, help reduce test errors, and improve the accuracy of test results.

[0060] According to some embodiments of the present invention, an elastic connector is provided between the movable portion 13 and the fixed portion 11, and the elastic connector is suitable for limiting the movement of the movable portion 13. In this embodiment, by providing the elastic connector, a restraining force can be provided to the movable portion 13, so that the movable portion 13 is subjected to an elastic force in the opposite direction of the axial external force while being moved relative to the fixed portion 11 by the axial external force, which can play a certain buffering effect and improve the stability of the movable portion 13 during the movement process; at the same time, when the external force is removed, the elastic connector works in coordination with the pawl 15 and the tooth portion 14, and the movable portion 13 is subjected to the elastic force and the unidirectional limiting effect of the tooth portion 14 of the pawl 15, which can achieve position self-locking, thereby maintaining the stability of the multifunctional testing device during the parameter measurement process and improving the accuracy of the test results.

[0061] In some embodiments, as Figure 7 As shown, the elastic connector is constructed as a spring 16, one end of the spring 16 is connected to the fixed portion 11, and the other end is connected to the movable portion 13. In some embodiments, the spring 16 is disposed between the two guide plates 122 and connected to the space between the two through slots 131 of the movable portion 13.

[0062] According to some embodiments of the present invention, the transmission assembly 40 includes a first transmission member and a second transmission member 42. The second transmission member 42 is circumferentially limitedly connected to the other end of the support rod 10. The first transmission member and the second transmission member 42 are cooperatively connected. When the first transmission member is subjected to an axial force, it moves axially relative to the support rod 10 and is suitable for driving the second transmission member 42 to rotate, thereby driving the support rod 10 to rotate relative to the base 50. In this embodiment, motion conversion and force transmission are achieved through the cooperation of the first transmission member 42.

[0063] According to some embodiments of the present invention, the first transmission member includes a bearing 43, a guide rod 44, a limit member and a force plate 41. The bearing 43 is arranged at the end of the guide portion 12, and the inner ring of the bearing 43 is cooperatively connected with the guide portion 12; the guide rod 44 is arranged on the outer ring of the bearing 43, and the axial direction of the guide rod 44 is parallel to the axial direction of the support rod 10. The limit member is connected to the guide rod 44 and is suitable for limiting the movement of the guide rod 44; the force plate 41 is slidingly connected to the guide rod 44, and the force plate 41 is connected to the second transmission member 42 by a thread; when the force plate 41 is subjected to force, it moves along the axial direction of the guide rod 44 and drives the second transmission member 42 and the guide portion 12 to rotate. In this embodiment, because a stopper (not shown) restricts the movement of guide rod 44 and the rotational freedom of force plate 41 is limited by guide rod 44, when force plate 41 is pressed downward, the second transmission member 42 is forced to rotate, thereby causing the support rod 10 and support member 20 to twist. At this time, the outer ring of bearing 43 remains relatively stationary with guide rod 44, while the inner ring rotates relative to the outer ring. This embodiment achieves motion conversion through the threaded connection between the circumferentially limited force plate 41 and the second transmission member 42, resulting in a simple structure and high stability. The stopper in this embodiment can be configured as part of the drive device that applies pressure to force plate 41, or it can be configured as an independent structure provided in the same system as base 50.

[0064] In some embodiments, for the two arc-shaped guide plates 122 formed by the guide portion 12, as shown in FIG. Figure 9 、 10 As shown, the inner ring of the bearing 43 is provided with a matching groove, which is circumferentially limited and connected with the guide portion 12, thereby achieving a stable connection with the guide portion 12; in addition, as shown Figure 9 As shown, the second transmission member 42 is formed with a protrusion 421, which cooperates with the axial groove 121 between the two arc-shaped guide plates 122 to achieve a circumferential limiting connection between the second transmission member 42 and the guide portion 12, so that the second transmission member 42 can drive the support rod 10 to rotate synchronously.

[0065] Furthermore, a limit bearing (not shown in the figure) is also provided on the base 50, and the limit bearing is connected to the fixing part 11 to realize a rotatable connection between the base 50 and the fixing part 11, and at the same time enables the support rod 10 to only transmit axial force to the base 50 without transmitting torque, and the force sensor can detect the axial force value.

[0066] According to some embodiments of the present invention, the multifunctional testing device further includes at least two connecting rods 30, at least one connecting rod 30 connecting the support member 20 and the fixed portion 11, and at least one connecting rod 30 connecting the support member 20 and the movable portion 13. The connecting rods 30 are adapted to rotate relative to the support member 20 or the fixed portion 11 or the movable portion 13. In this embodiment, when the movable portion 13 moves, the inclination angles of the multiple connecting rods 30 change, thereby driving the support member 20 to move horizontally.

[0067] According to some embodiments of the present invention, the connecting rod 30 is constructed in two parts, and the middle parts of the two connecting rods 30 are hinged. One end of each connecting rod 30 is rotatably and slidably connected to the support member 20, and a slide groove 21 is provided on the support member 20 to cooperate with one end of the connecting rod 30. In this embodiment, the two connecting rods 30 are hinged, and the slide groove 21 is provided on the support member 20 to cooperate with the movement of the connecting rod 30, which can increase the constraint points and improve stability, and at the same time make the structure more compact and optimize the structural layout. Furthermore, the two connecting rods 30 can be constructed to be equal in length and hinged in the middle position, so that the connection points of the two connecting rods 30 and the fixed part 11 and the movable part 13 are respectively at the same height as the two connection points of the connecting rod 30 and the support member 20, and the distance between the upper and lower connection points of the support member 20 is the same length as the distance between the connection points on the fixed part 11 and the movable part 13.

[0068] In some embodiments, the support member 20 is constructed as an arc-shaped plate, extending parallel to the axial direction of the support rod 10, and cooperating with the cylindrical geotextile.

[0069] like Figure 1-3 As shown, in some embodiments, the number of support members 20 is four and they are evenly spaced along the axial direction of the support rod 10. The number of second distance measuring assemblies 70 is four and they are arranged on the fixed portion 11 in a one-to-one correspondence with the support members 20. The first distance measuring assembly 60 is arranged above the fixed portion 11 and is located at the center of the support rod 10, facing the portion of the movable portion 13 in the vertical direction. Furthermore, the movable portion 13 has a limited range of movement. When the distance between the movable portion 13 and the fixed portion 11 is the largest, the multifunctional testing device has a minimum outer diameter, that is, the distance between the support member 20 and the center of the support rod 10 is the smallest. At this time, the four support members 20 can be sequentially contacted and connected in the circumferential direction to form a closed structure. There can also be a gap between two adjacent support members 20 to avoid structural interference or collision due to factors such as tolerance.

[0070] Furthermore, the support member 20 is formed with a plurality of connecting portions 22 on both sides of the axial direction. The connecting portions 22 are adapted to be selectively fixedly connected to the geotextile to ensure that the geotextile rotates synchronously when the support rod 10 rotates. The connecting portions 22 can be configured as threaded hole structures, etc.

[0071] The application further provides a testing method for the tensile strength of the geotextile, which adopts the multifunctional testing device, and comprises the following steps:

[0072] S1, supporting and fixing the geotextile: specifically, the geotextile to be tested is processed into a cylindrical sample with a diameter slightly larger than the minimum outer diameter of the multifunctional testing device and a length equal to the height of the support 20; the ring-shaped sample is sleeved on the outer periphery of the support 20; the moving part 13 is slightly pre-pressed to move downward, driving the support 20 to move radially outward until the support 20 is in close contact with the external geotextile, as shown in (a) of FIG. 1; Figure 11

[0073] obtaining the initial axial force of the support rod 10 F 0 and the initial distance between the moving part 13 and the fixed part 11 H 0 and the initial distance between the support 20 and the fixed part 11 B 0;

[0074] S2, sequentially applying pressure to the moving part 13: when the pressure is applied to the moving part 13, it is stopped after moving downward by a predetermined distance, and when the pressure is stable, the support 20 generates a radial load on the geotextile, the geotextile expands outward under stress, and there is a circumferential tensile action in the structure, at this time, the moving part 13 and the guide part 12 are self-locked and fixed, as shown in (b) of FIG. 1; Figure 11

[0075] repeating the above pressure applying step n times, and the pressure is increased sequentially;

[0076] recording the maximum axial force of the support rod 10 F n and the distance between the moving part 13 and the fixed part 11 H n and the distance between the support 20 and the fixed part 11 B n after the pressure is stable each time;

[0077] S3, correcting the data:

[0078] correcting the H n to the net distance between the upper and lower connecting points of the two connecting rods 30 : ,

[0079] wherein, Δh is the distance difference between the installation position of the first distance measuring assembly 60 and the center of the support rod 10, Δx is the correction value caused by the thickness of the related parts;

[0080] horizontal distance : , ​​

[0081] in, Δb is the distance difference between the installation position of the first distance measuring component 60 and the center of the support rod 10, Δy Correction value caused by the thickness of related parts;

[0082] S4. Use geometric relationships to convert axial force difference into radial pressure : ,

[0083] in, F 0 is the initial axial force of the support rod 10, F n is the maximum axial force of the support rod 10 when the pressure is applied for the nth time, H n ' is the corrected distance between the moving part 13 and the fixed part 11 when the pressure is applied for the nth time, B n ' is the corrected distance between the support member 20 and the fixing portion 11 when the pressure is applied for the nth time;

[0084] Calculate the hoop tensile stress of geotextiles during expansion based on classical material mechanics theory : ,

[0085] in, H is the height of the support member 20, t is the thickness of the geotextile;

[0086] The strain of geotextiles can be expressed by the change in circumference. : ,

[0087] in, B n ' is the corrected distance between the support member 20 and the fixing portion 11 when the pressure is applied for the nth time, B 0' is the initial correction distance between the support member 20 and the fixing portion 11;

[0088] The hoop tensile stress and strain data are used to draw a complete stress-strain curve and calculate the tensile modulus and tensile strength.

[0089] The method for testing the tensile strength of geotextiles of the present invention has an efficient testing process and high accuracy of the measurement results.

[0090] In some embodiments, when measuring the tensile strength of geotextiles, the multifunctional testing device can disassemble the transmission assembly 40 to facilitate the connection of the moving part 13 with the driving device.

[0091] The present invention also proposes a method for testing the interfacial friction performance of geotextiles, using the multifunctional testing device described above, and the testing method comprises the following steps:

[0092] S11. Support and fix the geotextile: Specifically, the geotextile to be tested is processed into a cylindrical sample with a diameter slightly larger than the minimum outer diameter of the multifunctional testing device and a length longer than the height of the support member 20; the annular sample is placed on the outer periphery of the support member 20; the moving part 13 is slightly pre-pressed to move it downward, thereby driving the support member 20 to move radially outward until the support member 20 is in close contact with the external geotextile, such as Figure 11 (a) Figure 11 As shown in (b); the portion of the geotextile that is higher than the support member 20 is folded over, and is fixedly connected to the support member 20 by a screw or other structure to prevent the geotextile from rotating relative to the support member 20;

[0093] Place the multifunctional test device and the geotextile in the torsion box 80, so that the torsion box 80 is flush with the bottom and top of the support 20, fill the torsion box 80 with test soil 90, so that the test soil 90 can cover the geotextile 360 ​​degrees, and then cap the test soil 90 after compaction. Figure 12 As shown;

[0094] S12, obtaining the initial axial force of the support rod 10 F 0;

[0095] S13, apply pressure to the moving part 13 to move it downward by a predetermined distance, remove the pressure after stabilization, and the moving part 13 and the guide part 12 are self-locking and fixed. At this time, the support member 20 generates a uniform horizontal load on the geotextile. N ,like Figure 13 As shown; record the axial force of the support rod 10 F 1, and the distance between the moving part 13 and the fixed part 11 H 1. The distance between the support member 20 and the fixing portion 11 B 1;

[0096] Apply pressure to the transmission assembly 40 to drive the support rod 10 and the geotextile to rotate at a constant speed, and record the axial force of the support rod 10 when the geotextile rotates at a constant speed. F 1 1 ;

[0097] S14. Repeat steps S11-S13 n times, apply pressure to the moving part 13 to move it down by different predetermined distances, and apply pressure to the transmission assembly 40 to drive the geotextile to rotate at a constant speed. After each pressure is stabilized, record the axial force of the support rod 10. F n , and the distance between the moving part 13 and the fixed part 11 H n , the distance between the support member 20 and the fixing portion 11B n ;

[0098] Each time the pressure is applied, the downward movement distance of the control moving part 13 is different, and the horizontal load of the support member 20 on the geotextile is also different;

[0099] S15. Correct the data:

[0100] Clearance : ,

[0101] in, Δh is the distance difference between the installation position of the first distance measuring component 60 and the center of the support rod 10, Δx Correction value caused by the thickness of related parts;

[0102] Horizontal distance : ,

[0103] in, Δb is the distance difference between the installation position of the first distance measuring component 60 and the center of the support rod 10, Δy Correction value caused by the thickness of related parts;

[0104] S16. Calculation of radial loads on geotextiles : ,

[0105] in, F 0 is the initial axial force of the support rod 10, F n is the axial force of the support rod 10 when the pressure is applied for the nth time, H n ' is the corrected distance between the moving part 13 and the fixed part 11 when the pressure is applied for the nth time, H is the height of the support member 20;

[0106] Calculating the torsional forces on geotextiles under radial load : ,

[0107] in, F n is the axial force of the support rod 10 when the pressure is applied for the nth time, F n n is the axial force of the support rod 10 during the n-th pressure rotation, B n ' is the corrected distance between the support member 20 and the fixing portion 11 when the pressure is applied for the nth time, H is the height of the support member 20, KThe ratio of the torsional force generated when the transmission assembly 40 is pressed down to the overburden pressure. This ratio is related to the thread angle, material, and main connecting rod material parameters, and is calibrated and determined before the test.

[0108] According to the following formula: ,

[0109] The data obtained from the test were calculated and fitted to obtain the interface friction coefficient of 90 between the geotextile and the test soil. μ .

[0110] The method for testing the interfacial friction performance of geotextiles of the present invention has an efficient testing process and high accuracy of the measurement results.

[0111] In some embodiments, in steps S1-S3, the multifunctional testing device may not be installed with the transmission assembly 40, so that the moving part 13 is connected to the driving device to support and fix the geotextile; in step S4, the transmission assembly 40 is installed.

[0112] Furthermore, the present invention's methods for testing the tensile and frictional properties of geotextile interfaces demonstrate that the multifunctional testing device can perform two tests simultaneously without interfering with or conflicting with each other. This parallel testing method enables simultaneous measurement of multiple material parameters, significantly improving experimental efficiency.

[0113] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0114] In the description of the present invention, "first feature" and "second feature" may include one or more of the features.

[0115] In the description of the present invention, "plurality" means two or more.

[0116] In the description of the present invention, a first feature being “on” or “under” a second feature may include the first and second features being in direct contact with each other, or the first and second features not being in direct contact with each other but being in contact with each other via another feature therebetween.

[0117] In the description of the application, above, over and on of a first feature to a second feature include the first feature directly above and obliquely above the second feature, or simply mean that the first feature is horizontally higher than the second feature.

[0118] In the description of the application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the application. In the description of the application, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0119] Although the embodiments of the application have been shown and described, it is understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for testing the interface friction performance of geotextiles, characterized in that: A multifunctional testing device for geotextiles is used, and the multifunctional testing device for geotextiles comprises: A base, on which a support rod and a sensor for detecting axial force on the support rod are provided; The support rod includes a fixed portion and a movable portion, wherein the fixed portion is rotatably connected to the base, and the movable portion is adapted to move relative to the fixed portion along the axial direction of the support rod when a force is applied, so as to adjust the distance between the fixed portion and the movable portion; a support member connecting the fixed portion and the movable portion and adapted to move relative to the support rod along a radial direction of the support rod when a distance between the fixed portion and the movable portion changes, so as to support and expand the geotextile; a transmission assembly, the transmission assembly being disposed on the support rod, the transmission assembly being adapted to receive force along the axial direction of the support rod and driving the support rod and the support member to rotate relative to the base through motion conversion; a first distance measuring component, which is disposed on the fixed portion and is aligned with the movable portion along the axial direction of the support rod, so as to be suitable for measuring the distance between the fixed portion and the movable portion; A second distance measuring component is provided on the fixing portion and is radially opposite to the support member along the support rod, so as to be suitable for measuring the distance between the support member and the fixing portion; The detection results of the sensor, the first distance measuring component and the second distance measuring component are used to calculate and analyze the performance of the geotextile; The test method comprises the following steps: Supporting and fixing the geotextile, and placing the multifunctional testing device and the geotextile in a test soil, so that the test soil covers the geotextile; Obtaining the initial axial force of the support rod; Applying pressure to the movable portion to move it downward by a predetermined distance, and recording the axial force of the support rod, the distance between the movable portion and the fixed portion, and the distance between the support member and the fixed portion after the pressure stabilizes; Applying pressure to the transmission assembly to drive the support rod and the geotextile to rotate at a constant speed, and recording the axial force on the support rod when the geotextile rotates at a constant speed; Repeat the above steps, successively applying pressure to the movable portion to move it downward by different predetermined distances, and successively applying pressure to the transmission assembly to drive the geotextile to rotate at a constant speed. After each pressure stabilizes, record the axial force on the support rod, the distance between the movable portion and the fixed portion, and the distance between the support member and the fixed portion; and record the axial force on the support rod when the geotextile rotates at a constant speed. Correct and calculate the data to obtain the radial load and torsional force on the geotextile; The radial load and torsional force data are fitted to calculate the interface friction coefficient between the geotextile and the test soil.

2. The method for testing the interfacial friction performance of geotextiles according to claim 1, characterized in that: The support rod also includes: The guide part is fixedly connected to the fixed part, and the movable part is slidably connected to the guide part; the end of the guide part is detachably connected to the transmission assembly.

3. The method for testing the interfacial friction performance of geotextiles according to claim 2, characterized in that: The moving part is provided with a pawl, and the guiding part is provided with a tooth part matched with the pawl, so as to be suitable for the moving part to move unidirectionally along the axial direction of the support rod.

4. The method for testing the interfacial friction performance of geotextiles according to claim 3, characterized in that: An elastic connecting member is provided between the movable portion and the fixed portion, and the elastic connecting member is suitable for limiting the movement of the movable portion.

5. The method for testing the interfacial friction performance of geotextiles according to claim 2, characterized in that: The transmission assembly includes a first transmission member and a second transmission member, the second transmission member is circumferentially limitedly connected to the other end of the support rod, the first transmission member is cooperatively connected with the second transmission member, and the first transmission member moves axially relative to the support rod when subjected to axial force, and is suitable for driving the second transmission member to rotate, thereby driving the support rod to rotate relative to the base.

6. The method for testing the interfacial friction performance of geotextiles according to claim 5, characterized in that: The first transmission member comprises: A bearing, the bearing being disposed at an end portion of the guide portion, the inner ring of the bearing being cooperatively connected to the guide portion; A guide rod, the guide rod being arranged on the outer ring of the bearing, the axial direction of the guide rod being parallel to the axial direction of the support rod; a limiting member connected to the guide rod and adapted to limit movement of the guide rod; The force-bearing plate is slidably connected to the guide rod, and the force-bearing plate is connected to the second transmission member through threads; when the force-bearing plate is subjected to force, it moves along the axial direction of the guide rod and drives the second transmission member and the guide part to rotate.

7. The method for testing the interfacial friction performance of geotextiles according to claim 1, characterized in that: The multifunctional testing device for geotextiles further comprises: At least two connecting rods, at least one of which connects the support member and the fixed part, and at least one of which connects the support member and the movable part; the connecting rod is suitable for rotating relative to the support member or the fixed part or the movable part.

8. The method for testing the interfacial friction performance of geotextiles according to claim 7, characterized in that: The connecting rod is constructed in two parts, the middle parts of the two connecting rods are hinged, one end of each connecting rod is rotatably connected to the support member, and one end of each connecting rod is slidably connected to the support member, and a sliding groove is provided on the support member to cooperate with one end of the connecting rod.

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