A dual-state multifunctional soil creep test device for geosynthetics

Abstract

The present invention discloses a dual-state multifunctional soil creep test device for geosynthetics, comprising a test box I, a workbench II, a suspension device III, a fixture device IV, a horizontal force device V, a guide device VI, a hydraulic loading device VII, and a data acquisition device VIII, characterized in that: the test box I is located above the workbench II, the suspension device III is located above the test box I, the fixture device IV is provided with four groups, and the four groups of the fixture devices IV are respectively located around the test box I, and the horizontal force device V is also provided with four groups. The present invention can realize the creep of geosynthetics in the dual states of top pressure and tension in the soil or air, and introduces inverted thorns to realize the overall tensile expansion of the sample, which is used to study the creep performance of geosynthetics under real working conditions, and is more practical than the existing tensile creep test machine under single-state conditions.

Description

Technical Field

[0001] The invention relates to the technical field related to material performance testing, and in particular to a dual-state multifunctional soil creep testing device for geosynthetics. Background Art

[0002] The creep properties of geosynthetics are a hot topic in current research. The conventional horizontal tensile creep test method is often used to test the creep properties of geosynthetics. The measured creep properties are quite different from the main stress state of geosynthetics in some engineering applications, and cannot accurately reflect the creep properties of geosynthetics in the air or soil under normal top pressure and horizontal tension.

[0003] The existing test device can only reflect the creep characteristics under horizontal tension or top pressure state separately, and fails to combine the two. The soil creep test device can only be used for single-state unidirectional horizontal tension creep test, and cannot carry out bidirectional horizontal tension creep test in soil and creep test including top pressure state; the bidirectional tension creep tester can only be used for creep test under horizontal tension state in air, and cannot carry out bidirectional creep test and creep test in soil. However, the use of geosynthetics in actual engineering not only produces unilateral or bilateral creep in air under tension state, creep in soil under tension state or creep in air under top pressure state, but also the creep under top pressure state and tension state is combined in soil or air. Secondly, the existing bidirectional tension clamps separate from each other with tension, and the unclamped part of the material will shrink in the opposite direction of the tension direction, and the overall expansion of the geosynthetics cannot be achieved. In addition, after actual tests, the existing top pressure creep test device was found to have certain defects, such as stress concentration caused by the slippage of the top pressure block. Therefore, developing a geosynthetics dual-state creep test device in soil that can truly reflect the dual-state creep mechanical properties of geosynthetics in soil and is easy to operate has important engineering application value. Summary of the invention

[0004] The purpose of the present invention is to provide a dual-state multifunctional soil creep test device for geosynthetics to solve the problem that the existing test device mentioned in the above background technology can only reflect the creep characteristics under horizontal tension or top pressure state separately, and fails to combine the two. The existing two-way tension clamps separate from each other during stretching, and the unclamped part of the material will shrink in the opposite direction of the stretching direction, and the overall expansion of the geosynthetics cannot be achieved. After actual tests, the existing top pressure creep test device has certain defects.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a dual-state multifunctional soil creep test device for geosynthetics, comprising a test box I, a workbench II, a suspension device III, a fixture device IV, a horizontal force device V, a guide device VI, a hydraulic loading device VII, and a data acquisition device VIII, characterized in that: the test box I is located above the workbench II, the suspension device III is located above the test box I, the fixture device IV is provided with four groups, and the four groups of the fixture devices IV are respectively located around the test box I, the horizontal force device V is also provided with four groups, and the four groups of the horizontal force device V are respectively correspondingly located below the four groups of the fixture devices IV, the guide device VI is located at the upper end of the test box I, the hydraulic loading device VII is located at the upper end of the test box I, and the data acquisition device VIII is located at one side of the test box I;

[0006] The test box I comprises a box cover, a corner clamp and a box body. The box cover is provided with two groups, A and B. The box cover of group A is provided with a rigid edge and is fixed on the top of the box body. The box cover of group B is not provided with a rigid edge and can move in the vertical direction along the inside of the box body. The directional barrel is welded and fixed to the box cover. The corner clamp comprises an inverted thorn and a slide rail. The corner clamp is provided with four groups, and the four groups of corner clamps are respectively located at the four corners inside the box body;

[0007] The workbench II includes transparent glass, a conventional workbench, and a lever suspension frame. The transparent glass is located at the bottom of the test box I, and the lever suspension frame is vertically installed on one side of the upper end of the conventional workbench.

[0008] The suspension device III includes a lever, a pressure hammer, a top pressure loading weight frame, a large roller, a roller connecting rod, a pressure plate, a pressure rod, and a top pressure block. The fulcrum of the lever is connected to the lever suspension frame, the pressure hammer is installed at the end of the lever, the top pressure loading weight frame is connected to the other end of the lever, the large roller is connected to the lever through the roller connecting rod, the pressure plate is located at the lower end of the large roller, the pressure rod is fixedly connected to the lower surface of the pressure plate, and the top pressure block is located at the bottom end of the pressure rod.

[0009] Preferably, the clamp device IV includes a clamp and a sleeve, and the clamp is divided into a primary side clamp and a secondary side clamp, the primary side clamp includes an upper clamp, a lower clamp, and bolts, the upper clamp and the lower clamp are fixedly connected by bolts, the clamping openings of the upper clamp and the lower clamp are square teeth, and the clamp is provided with an isolation sleeve, the isolation sleeve is sleeved on the outside of the primary side clamp, and there is no contact between the isolation sleeve and the primary side clamp, the secondary side clamp is welded to the primary side clamp, and one end of the secondary side clamp extends into the inverted thorn inside the angle clamp, the isolation sleeve includes a barrel body, a sleeve upper cover plate, a cover plate opening, a connecting plate, and a fixing screw, the barrel body is connected to the sleeve upper cover plate by a connecting plate and a fixing screw, the cross-section of the sleeve upper cover plate is L-shaped, and the cover plate opening is located on the side where the sleeve upper cover plate is vertically placed, and the clamp and the isolation sleeve are connected to the adjacent angle clamp by a sliding rail.

[0010] Preferably, the cover plate opening is no greater than 5 mm.

[0011] Preferably, the horizontal force-applying device V comprises a clamp support rod, a sleeve support rod, a tensile loading weight frame, a fixed pulley, a rope, and a tension movable frame. The clamp support rod is fixedly connected to the lower end of the lower clamp plate, the sleeve support rod is connected to the lower end of the cylinder body, the tensile loading weight frame is connected to the tension movable frame via a fixed pulley and a rope, and the tension movable frame is fixedly connected to the lower ends of the clamp support rod and the cylinder support rod.

[0012] Preferably, the guide device VI includes a vertical guide device and a horizontal guide device, the vertical guide device includes a directional barrel, the directional barrel is installed on the upper end of the box cover plate, the directional barrel includes an outer wall, a steel ball and an inner wall, and the steel ball is arranged on the inner wall; the horizontal guide device includes a small roller and a workbench guide rail, the small roller is fixedly installed at the bottom end of the tension moving frame, the workbench guide rail is provided with four groups, the four groups of workbench guide rails are respectively arranged around the conventional workbench, and the bottom end of the small roller is slidably connected to the workbench guide rail.

[0013] Preferably, the hydraulic loading device Ⅶ includes a support frame, a cross beam, and a hydraulic jack. The bottom of the support frame is connected to the workbench II, the top of the support frame is connected to the cross beam, the upper end of the hydraulic jack is connected to the cross beam, and the lower part of the hydraulic jack is connected to the box cover plate of group B.

[0014] Preferably, the data acquisition device VIII includes a first force sensor, a second force sensor, a third force sensor, a fourth force sensor, a first displacement sensor, a second displacement sensor and an acquisition device, the first force sensor is connected to the lower clamp, the second force sensor is located between the crossbeam and the hydraulic jack, the third force sensor is located between the pressure plate and the pressure rod, the fourth force sensor is connected to the tension moving frame, the first displacement sensor is located at the upper end of the pressure plate, the second displacement sensor is provided with four groups, and the four groups of the second displacement sensors are respectively located above the isolation sleeve, and the acquisition device is connected to the first force sensor, the second force sensor, the third force sensor, the fourth force sensor, the first displacement sensor and the second displacement sensor through a data line.

[0015] The present invention provides a dual-state multifunctional soil creep test device for geosynthetics, which has the following beneficial effects:

[0016] (1) The present invention is multifunctional and can realize not only dual-state creep test in air but also dual-state creep test in soil, as well as various other dual-state tests in air or soil, and has a wide range of applications.

[0017] (2) The setting of edge clamps and corner clamps can make the edges of geosynthetics be stretched at the same time, that is, the whole material expands.

[0018] (3) The present invention uses a large roller to apply the top pressure, which can ensure that the top pressure remains unchanged, and the top pressure block will not be offset or have stress concentration after being subjected to force; the top pressure block can be replaced with different shapes, and the force can be applied by using weights to load the force, so that the force is continuously applied and is not affected by power failure.

[0019] (4) The present invention uses a hydraulic jack to apply different normal loads to study the interaction mechanism between geosynthetics and soil under different load conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front view of the present invention;

[0021] Figure 2 A top view of the present invention;

[0022] Figure 3 is a side view of the present invention;

[0023] Figure 4 It is a front view of the present invention;

[0024] Figure 5 It is a top view of the present invention;

[0025] Figure 6 It is a front view of the soil creep box cover plate of the present invention;

[0026] Figure 7 A top view of the creep box cover plate in the soil of the present invention;

[0027] Figure 8 It is a front view of the cover plate of the creep box in air of the present invention;

[0028] Fig. 9 It is a top view of the cover plate of the creep box in air of the present invention;

[0029] Fig.10 It is a front view of the angle clamp of the present invention;

[0030] Fig.11 A top view of the angle clamp of the present invention;

[0031] Fig.12 This is a schematic diagram of the flexible inverted thorn of the present invention;

[0032] Fig.13 is a schematic diagram of the edge clamp of the present invention;

[0033] Fig.14 Schematic diagram of different top pressing block shapes of the present invention;

[0034] Fig.15 It is the lever balance and deflection θ position of the present invention.

[0035] In the figure: 1. Sample; 2. Soil; 3. Transparent glass; 4. Primary side fixture; 5. Secondary side fixture; 6. Isolation sleeve; 7. Box cover; 8. Directional barrel; 9. Angle clamp; 10. Box; 11. Rigid edge; 12. Outer wall; 13. Steel ball; 14. Inner wall; 15. Inverted thorn; 16. Slide rail; 17. Conventional workbench; 18. Lever suspension frame; 19. Workbench guide rail; 20. Lever; 21. Pressure hammer; 22. Top pressure loading weight frame; 23. Large roller; 24. Roller connecting rod; 25. Pressure plate; 26. Pressure rod; 27. Top pressure block; 28. Upper clamp; 29. Lower clamping plate; 30, bolts; 31, barrel; 32, sleeve upper cover plate; 33, cover plate opening; 34, connecting plate; 35, fixing screws; 36, clamp support rod; 37, sleeve support rod; 38, tensile loading weight rack; 39, fixed pulley; 40, rope; 41, tension moving rack; 42, small roller; 43, support rack; 44, crossbeam; 45, hydraulic jack; 46, first force sensor; 47, second force sensor; 48, third force sensor; 49, fourth force sensor; 50, first displacement sensor; 51, second displacement sensor; 52, acquisition equipment. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0037] Embodiment 1:

[0038] like Figure 1-15 As shown, the present invention provides a technical solution: a dual-state multifunctional soil creep test device for geosynthetics, comprising a test box I, a workbench II, a suspension device III, a fixture device IV, a horizontal force device V, a guide device VI, a hydraulic loading device VII, and a data acquisition device VIII, characterized in that: the test box I is located above the workbench II, and the test box I provides a necessary test environment for the tensile and compressive state of the sample 1 in the air or in the soil 2; the workbench II can provide a stable test platform for the test box I, the suspension device III is located above the test box I, and the suspension device III can apply continuous vertical top pressure to the sample 1, and the fixture device IV is provided with four groups, and the four groups of the fixture devices IV are respectively located at the four test boxes of the test box I Around, the geosynthetics sample 1 located in the soil 2 is stably clamped, four groups of isolation sleeves 6 protect the main side clamps 5 from contacting the soil 2, the horizontal force device V is also provided with four groups, and the four groups of horizontal force devices V are respectively located under the four groups of clamp devices IV, and can apply a continuous horizontal tensile force to the sample 1, the guide device VI is located at the upper end of the test box I, and provides a vertical force guide for the suspension device III, and provides a horizontal force guide for the four groups of horizontal force devices IV, the hydraulic loading device VII is located at the upper end of the test box I, and the hydraulic loading device VII provides a normal constraint for the creep test in the soil; the data acquisition device VIII is located on one side of the test box I, and the data acquisition device VIII can realize the function of data acquisition;

[0039] The test box I comprises a box cover plate 7, an angle clamp 9 and a box body 10. The box cover plate 7 is provided with two groups, A and B. The box cover plates 7 of group A are provided with a rigid edge 11, and the box cover plates 7 of group A are fixed above the box body 10 to prevent the box cover plates from moving vertically along the inside of the box body 10, and are used for dual-state creep tests in air. The box cover plates 7 of group B are not provided with a rigid edge 11, and the box cover plates 7 of group B can move vertically along the inside of the box body 10. After the hydraulic loading device Ⅶ is connected to the box cover plates 7, it is convenient to apply vertical loads for dual-state creep tests in soil. The directional barrel 8 is welded and fixed to the box cover 7, and the corner clamp 9 includes an inverted thorn 15 and a slide rail 16. The main side clamp 4 fits with the groove of the slide rail 16 and moves along the slide rail 16 to reduce the friction between the main side clamp 4 and the corner clamp 9. The inverted thorn 15 has a certain flexibility, which can make the unclamped part of the sample 1 enter in accordance with the tensile trend. However, after entering the interior of the corner clamp 9, the inverted thorn 15 pierces the sample 1, so that the sample 1 is fixed and cannot shrink. The corner clamp 9 is provided with four groups, and the four groups of the corner clamps 9 are respectively located at the four corners inside the box 10;

[0040] The workbench II includes transparent glass 3, a conventional workbench 17, and a lever suspension frame 18. The transparent glass 3 is located at the bottom of the test box I, which is convenient for using an image acquisition device at the bottom to acquire images during the stress process of the geosynthetics. The lever suspension frame 18 is vertically installed on one side of the upper end of the conventional workbench 17.

[0041] The suspension device III includes a lever 20, a pressure hammer 21, a top pressure loading weight frame 22, a large roller 23, a roller connecting rod 24, a pressure plate 25, a pressure rod 26, and a top pressure block 27. The fulcrum of the lever 20 is connected to the lever suspension frame 18. The pressure hammer 21 is installed at the end of the lever 20 to play the role of a balancing lever. The top pressure loading weight frame 22 is connected to the other end of the lever 20, and a weight can be placed thereon to play the role of applying force for top pressure loading. The large roller 23 is connected to the top pressure loading weight frame 22 through the roller connecting rod. 24 is connected to the lever 20, the pressure plate 25 is located at the lower end of the large roller 23, the pressure rod 26 is fixedly connected to the lower surface of the pressure plate 25, and the top pressure block 27 is located at the bottom end of the pressure rod 26. The pressure plate 25 is subjected to a vertical downward force as the large roller 23 rolls, which is then transmitted to the top pressure block 27 by the pressure rod 26, and finally a top pressure is exerted on the sample 1. The top pressure block 27 can be replaced with top pressure blocks of different shapes to test the top pressure characteristics of geosynthetics under different top pressure contact surfaces.

[0042] The clamp device IV includes a clamp and a sleeve. The clamp is divided into a main side clamp 4 and a secondary side clamp 5. The main side clamp 4 includes an upper clamp plate 28, a lower clamp plate 29, and a bolt 30. The upper clamp plate 28 and the lower clamp plate 29 are fixedly connected by bolts 30. The clamping openings of the upper clamp plate 28 and the lower clamp plate 29 are square teeth. The clamp is provided with an isolation sleeve 6. The isolation sleeve 6 is sleeved on the outside of the main side clamp 4, and the isolation sleeve 6 does not contact the main side clamp 4, so as to protect the main side clamp 4 from contacting the soil 2. The secondary side clamp 5 is welded to the main side clamp 4, and one end of the secondary side clamp 5 The isolation sleeve 6 extends into the inverted thorn 15 inside the angle clamp 9, and includes a barrel 31, a sleeve upper cover plate 32, a cover plate opening 33, a connecting piece 34, and a fixing screw 35. The barrel 31 is connected to the sleeve upper cover plate 32 by the connecting piece 34 and the fixing screw 35. The cross-section of the sleeve upper cover plate 32 is L-shaped. The cover plate opening 33 is located on the side of the sleeve upper cover plate 32 that is vertically placed for the sample 1 to pass through. The clamp and the isolation sleeve 6 are connected to the adjacent angle clamp 9 by a slide rail 16 to reduce the friction force when the clamp device VI and the angle clamp 9 are relatively displaced.

[0043] The cover plate opening 33 is no higher than 5 mm.

[0044] The horizontal force-applying device V includes a clamp support rod 36, a sleeve support rod 37, a tensile loading weight frame 38, a fixed pulley 39, a rope 40, and a tension movable frame 41. The clamp support rod 36 is fixedly connected to the lower end of the lower clamp plate 29, and is used to support the clamp and enable the clamp to move therewith. The sleeve support rod 37 is connected to the lower end of the barrel body 31, and is used to support the sleeve and enable the sleeve to move therewith. The tensile loading weight frame 38 is connected to the tensile loading weight frame 41 through the fixed pulley 39 and the rope 40. The tensile loading weight frame 41 is fixedly connected to the lower ends of the clamp support rod 36 and the barrel support rod 37, and moves as weights are added to the tensile loading weight frame 38.

[0045] The guide device VI includes a vertical guide device and a horizontal guide device. The vertical guide device includes a directional barrel 8, which is installed on the upper end of the box cover plate 7. The directional barrel 8 includes an outer wall 12, a steel ball 13 and an inner wall 14. The steel ball 13 is arranged on the inner wall 14 to provide vertical force guidance for the suspension device III; the horizontal guide device includes a small roller 42 and a workbench guide rail 19. The small roller 42 is fixedly installed at the bottom end of the tension moving frame 41. The workbench guide rail 19 is provided with four groups. The four groups of workbench guide rails 19 are respectively arranged around the conventional workbench 17. The bottom end of the small roller 42 is slidably connected to the workbench guide rail 19 to provide horizontal force guidance for the four groups of horizontal force devices IV.

[0046] The hydraulic loading device Ⅶ includes a support frame 43, a cross beam 44, and a hydraulic jack 45. The bottom of the support frame 43 is connected to the workbench II, the top of the support frame 43 is connected to the cross beam 44, the upper end of the hydraulic jack 45 is connected to the cross beam 44, and the lower part of the hydraulic jack 45 is connected to the group B box cover plate 7 to apply normal constraints to the group B box cover plate 7.

[0047] The data acquisition device VIII includes a first force sensor 46, a second force sensor 47, a third force sensor 48, a fourth force sensor 49, a first displacement sensor 50, a second displacement sensor 51 and an acquisition device 52. The first force sensor 46 is connected to the lower clamping plate 29 to measure the magnitude of the tensile force on the test sample 1. The second force sensor 47 is located between the crossbeam 44 and the hydraulic jack 45 to measure the magnitude of the applied normal constraint force. The third force sensor 48 is located between the pressure plate 25 and the pressure rod 26 to measure the magnitude of the top pressure on the test sample 1. The fourth force sensor 49 is connected to the tension moving frame 41, and is used to monitor the horizontal force value. The first displacement sensor 50 is located at the upper end of the pressure plate 25, and is used to measure the top pressure displacement; the second displacement sensor 51 is provided with four groups, and the four groups of the second displacement sensors 51 are respectively located above the isolation sleeve 6, and are used to measure the displacement of the fixture. The acquisition device 52 is connected to the first force sensor 46, the second force sensor 47, the third force sensor 48, the fourth force sensor 49, the first displacement sensor 50 and the second displacement sensor 51 through a data line to facilitate data collection.

[0048] It should be noted that in a dual-state multifunctional soil creep test device for geosynthetics, when working, the four sets of main side clamps of the test box I move toward the outside of the test box I at the same time under the force of the weights on the tensile loading weight rack; since the main side clamps are welded to the secondary side clamps, the secondary side clamps move simultaneously with the main side clamps; when the main side clamps and the secondary side clamps move toward the outside of the test box, the sample is stretched and expanded accordingly; the four corners of the sample are not clamped by any clamps, but while the clamped part of the sample expands, it drives the unclamped sample to move toward the inside of the corner clamp, and the upper and lower thorns of the flexible inverted thorns pierce the sample, making it impossible for the unclamped part of the sample to shrink.

[0049] The workbench corresponding to the bottom of the test box is transparent glass. There is no filling soil when conducting tests in the air. An image acquisition device can be placed at the bottom of the test bench to acquire images of sample changes in the air test. When conducting tests in the soil, transparent soil can be used as filling soil, and an image acquisition device can be placed at the bottom of the test bench to acquire images.

[0050] When the weight of the weight rack remains unchanged, the pressure applied by the suspension device remains unchanged. The equilibrium position and the deflection angle θ position of the lever are as follows: Fig.15As shown, point A is the lever clamping part of the lever, i.e., the fulcrum, point B is the connecting hinge between the lever and the top pressure structure, point C is the weight loading end, and point D is the center of gravity of the pressure hammer. When the lever is in the equilibrium position CD, on the right side of the fulcrum A, there is no weight loading at point C, the top pressure structure is connected to point B of the lever and does not exert force on the geosynthetics; on the left side of the fulcrum A, the deadweight of the pressure hammer and the AD section of the lever can balance the lever. Assuming that the deadweight of the AC section of the lever is G1, the distance from its center of gravity to point A is L1, and the distance to point C is L3; the deadweight of the AD section is G2, and the distance from its center of gravity to point A is L2. According to the principle of lever balance, equation (1) can be obtained, C'D' is the position of the lever after the weight load is applied to the counterclockwise deflection angle θ from the equilibrium position, and equation (2) can be obtained, where is the applied weight load, is the force that the geosynthetics react to the top pressure block after being compressed and then transmitted to the lever; the distance of the hinge AB is L4. From equations (1) and (2), we can get equation (3), which shows that G, L1, L3, and L4 remain unchanged, so the size of remains unchanged and has nothing to do with the lever rotation angle θ, that is, under the same weight load, the top pressure on the geosynthetics remains unchanged.

[0051]

[0052] The weight racks of the suspension device III and the horizontal force application device V can apply weights at the same time, that is, they are subjected to constant forces in the normal and horizontal directions at the same time, so that creep tests under dual states of top pressure and tension can be realized.

[0053] The top pressure load must be checked before the test. The top pressure sensor is connected to the pressure rod, and the measured data includes the top pressure of the geosynthetics and the rolling friction between the pressure rod and the steel ball. Therefore, the data measured by the top pressure sensor includes the top pressure of the geosynthetics and the rolling friction between the pressure rod and the steel ball. The former is the measurement target value, and the latter is the system error value. Although the target value can be made more accurate by reducing the friction of the latter, this system error is inevitable. The error caused by the rolling friction between the pressure rod and the steel ball is eliminated in the following way. First, a creep test is performed without installing a geosynthetics sample, and the system error tensile value is obtained by the top pressure sensor. Then, a geosynthetics sample is installed for a creep test to obtain the initial value of the top pressure. The initial value of the top pressure minus the previously obtained system error top pressure value is the actual top pressure load on the geosynthetics.

[0054] The tensile load should be calibrated before the test. The tension sensor is connected to the lower clamp of the main side clamp, and the measured data includes the tension and friction of the main side clamp. On the one hand, the main side clamp is in contact with the geosynthetics, so the tension of the clamp is the real tension of the geosynthetics; secondly, the main side clamp is supported by the clamp support rod and the small pulley below it, and there is rolling friction between the small pulley and the workbench guide rail; in addition, the two sides of the main side clamp are connected to the angle clamp through the slide rail, and there is rolling friction between the main side clamp and the angle clamp. Therefore, the data measured by the tension sensor includes the tensile force of the geosynthetics, the rolling friction between the small pulley and the workbench guide rail, and the rolling friction between the main side clamp and the angle clamp. The first force is the measurement target value, and the latter two are the system error values. Although the target value can be made more accurate by reducing the friction of the latter two, this system error is inevitable. The error caused by the rolling friction between the small pulley and the worktable rail and between the main edge clamp and the angle clamp is eliminated in the following way. First, the creep test is performed without adding the geosynthetics sample, and the system error tension value is obtained by the tension sensor. Then the geosynthetics are added to perform the creep test to obtain the initial tension value. The initial tension value minus the previously obtained system error tension value is the actual force load on the geosynthetics.

[0055] In addition to the dual-state creep test in soil, this device can realize tests under various conditions such as top pressure creep test, bursting test, unidirectional creep test, bidirectional creep test, dual-state creep test in air, etc. on geosynthetics by different treatments of weights and placing or not placing soil in the test box.

[0056] Embodiment 2:

[0057] The dual-state creep test device for geosynthetics in soil includes the following experimental steps:

[0058] a. Initial tension check

[0059] Calibrate the system error when testing unclamped geosynthetics;

[0060] b. Initial state

[0061] Adjust the corresponding position relationship between the left, right, front and rear four sets of clamping devices and the corner clamps and temporarily fix them. Carefully put a small amount of soil into the test box. The height of the soil should not exceed the bottom of the isolation sleeve. Place the geosynthetics sample between the clamps and clamp it, and cover the sleeve with the upper cover plate.

[0062] c. Filling soil

[0063] Carefully fill and compact the lower part of the sample with soil to ensure that the sample is placed horizontally. Extend the top pressure block and the pressure rod into the test box and place them above the sample, so that they are in contact with the sample but temporarily without any force. Continue to fill the soil until it is about 20mm away from the box opening, leaving a certain space for the creep box cover in the soil to transmit the normal force of the hydraulic jack;

[0064] d. Cover the box

[0065] Pay attention to leveling the soil at the box mouth, aligning the bottom opening of the box cover plate with the directional barrel and passing the pressure rod, covering the box cover plate, and installing the hydraulic loading device on the upper part of the box cover plate;

[0066] e. Preparation for force application

[0067] Install the pressure plate on the pressure rod. Adjust the position of the pressure hammer to adjust the balance of the lever, keep the large roller and the pressure plate in a state without stress, align the small roller under the tension moving frame with the workbench guide rail, and connect the tension moving frame and the weight frame with a rope through the fixed pulley;

[0068] f. Parameter settings

[0069] Set the unit, measurement interval, calculation formula, etc. of the data measured by the sensor in the data processing device and start the test;

[0070] g. Add weight

[0071] According to the weight required for the test, carefully place the weights in the center of the five weight racks. At this time, make sure that the weights are placed at the same time, that is, the force is applied at the same time;

[0072] h. Soil collection

[0073] When the creep stretching reaches the target time, remove all weights at the same time, remove the hydraulic loading device, open the box cover, and take out the soil in the test box, taking care to minimize the soil from entering the fixture and the angle clamp;

[0074] i. Test results

[0075] The data acquisition device records various data during the test. Soil is taken to the height of the sample, and the sample failure morphology is photographed and analyzed. The consistency of the sample failure state is verified by comparing it with the test results of other groups. The initial test result minus the system calibration value is the final test result;

[0076] j. Test completed

[0077] Remove the remaining soil, remove the damaged specimen, clean the test device, and prepare for the next set of tests;

[0078] Embodiment 3:

[0079] The dual-state creep test device for geosynthetics in air includes the following experimental steps:

[0080] a. Initial tension check

[0081] Calibrate the system error when testing unclamped geosynthetics;

[0082] b. Initial state

[0083] Adjust the corresponding position relationship between the left, right, front and rear four sets of clamping devices and the corner clamps and temporarily fix them. Carefully put a small amount of soil into the test box. The height of the soil should not exceed the bottom of the isolation sleeve. Place the geosynthetics sample between the clamps and clamp it, and cover the sleeve with the upper cover plate.

[0084] c. Cover plate

[0085] Put the top pressure block and the pressure rod into the test box and place them above the sample, so that they are in contact with the sample but temporarily without any force acting on them; align the bottom opening of the directional barrel of the creep box cover in the air with the pressure rod and pass it through, and cover the box cover;

[0086] d. Preparation for force application

[0087] Install the pressure plate on the pressure rod. Adjust the position of the pressure hammer to adjust the balance of the lever, and keep the large roller and the pressure plate in a state without force. Align the small roller under the tension mobile frame with the workbench guide rail, and use a rope to connect the tension mobile frame and the weight frame through the fixed pulley;

[0088] e. Parameter settings

[0089] Set the unit, measurement interval, calculation formula, etc. of the data measured by the sensor in the data processing device and start the test;

[0090] f. Add weight

[0091] According to the weight required for the test, carefully place the weights in the center of the five weight racks. At this time, make sure that the weights are placed at the same time, that is, the force is applied at the same time;

[0092] g. Open the box cover

[0093] When creep stretching reaches the target time, remove all weights at the same time and open the box cover;

[0094] h. Test results

[0095] The data acquisition device records various data during the test. Soil is taken to the height of the sample, and the sample failure morphology is photographed and analyzed. The consistency of the sample failure state is verified by comparing it with the test results of other groups. The initial test result minus the system calibration value is the final test result;

[0096] i. Test completed

[0097] Remove the damaged specimen, clean the test apparatus, and prepare for the next set of tests.

[0098] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A dual-state multifunctional soil creep test device for geosynthetics, comprising a test box I, a workbench II, a suspension device III, a fixture device IV, a horizontal force device V, a guide device VI, a hydraulic loading device VII, and a data acquisition device VIII, characterized in that: The test box I is located above the workbench II, the suspension device III is located above the test box I, the fixture device IV is provided with four groups, and the four groups of the fixture devices IV are respectively located around the test box I, the horizontal force-applying device V is also provided with four groups, and the four groups of the horizontal force-applying device V are respectively located below the four groups of the fixture devices IV, the guide device VI is located at the upper end of the test box I, the hydraulic loading device VII is located at the upper end of the test box I, and the data acquisition device VIII is located at one side of the test box I; The test box I comprises a box cover (7), an angle clamp (9) and a box body (10), wherein the box cover (7) is provided with two groups, A and B, wherein the box cover (7) of group A is provided with a rigid edge (11) and is fixed above the box body (10), wherein the box cover (7) of group B is not provided with a rigid edge (11) and the box cover (7) of group B can move in a vertical direction along the inside of the box body (10), wherein the angle clamp (9) comprises an inverted thorn (15) and a slide rail (16), wherein the angle clamp (9) is provided with four groups, and the four groups of angle clamps (9) are respectively located at the four corners inside the box body (10); The guide device VI comprises a vertical guide device, and the vertical guide device comprises a directional barrel (8), and the directional barrel (8) is welded and fixed to the box cover plate (7); The workbench II comprises transparent glass (3), a conventional workbench (17), and a lever suspension frame (18), wherein the transparent glass (3) is located at the bottom of the test box I, and the lever suspension frame (18) is vertically mounted on one side of the upper end of the conventional workbench (17); The suspension device III comprises a lever (20), a pressure hammer (21), a top pressure loading weight frame (22), a large roller (23), a roller connecting rod (24), a pressure plate (25), a pressure rod (26), and a top pressure block (27). The fulcrum of the lever (20) is connected to the lever suspension frame (18), the pressure hammer (21) is installed at the end of the lever (20), the top pressure loading weight frame (22) is connected to the other end of the lever (20), the large roller (23) is connected to the lever (20) through the roller connecting rod (24), the pressure plate (25) is located at the lower end of the large roller (23), the pressure rod (26) is fixedly connected to the lower surface of the pressure plate (25), and the top pressure block (27) is located at the bottom end of the pressure rod (26).

2. The dual-state multifunctional soil creep test device for geosynthetics according to claim 1, characterized in that: The clamp device IV comprises a clamp and a sleeve, wherein the clamp is divided into a primary clamp (4) and a secondary clamp (5), wherein the primary clamp (4) comprises an upper clamp (28), a lower clamp (29), and a bolt (30), wherein the upper clamp (28) and the lower clamp (29) are fixedly connected by the bolt (30), wherein the clamping openings of the upper clamp (28) and the lower clamp (29) are square teeth-shaped, wherein the clamp is provided with an isolation sleeve (6), wherein the isolation sleeve (6) is sleeved on the outside of the primary clamp (4), and the isolation sleeve (6) and the primary clamp (4) are not in contact with each other, wherein the secondary clamp (5) and the primary clamp (4) are welded, and One end of the secondary edge clamp (5) extends into the inverted thorn (15) inside the angle clamp (9); the isolation sleeve (6) comprises a barrel (31), a sleeve upper cover plate (32), a cover plate opening (33), a connecting piece (34), and a fixing screw (35); the barrel (31) and the sleeve upper cover plate (32) are connected via the connecting piece (34) and the fixing screw (35); the cross-section of the sleeve upper cover plate (32) is L-shaped; the cover plate opening (33) is located on a side of the sleeve upper cover plate (32) that is placed vertically; the clamp and the isolation sleeve (6) are connected to the adjacent angle clamp (9) via a slide rail (16).

3. The dual-state multifunctional soil creep test device for geosynthetics according to claim 2, characterized in that: The cover plate opening (33) is no higher than 5 mm.

4. The dual-state multifunctional soil creep test device for geosynthetics according to claim 1, characterized in that: The horizontal force-applying device V comprises a clamp support rod (36), a sleeve support rod (37), a tensile loading weight frame (38), a fixed pulley (39), a rope (40), and a tension movable frame (41); the clamp support rod (36) is fixedly connected to the lower end of the lower clamp plate (29); the sleeve support rod (37) is connected to the lower end of the barrel (31); the tensile loading weight frame (38) is connected to the tension movable frame (41) via the fixed pulley (39) and the rope (40); and the tension movable frame (41) is fixedly connected to the lower ends of the clamp support rod (36) and the barrel support rod (37).

5. The dual-state multifunctional soil creep test device for geosynthetics according to claim 1, characterized in that: The guide device VI comprises a vertical guide device and a horizontal guide device. The vertical guide device comprises a directional barrel (8). The directional barrel (8) is mounted on the upper end of the box cover plate (7). The directional barrel (8) comprises an outer wall (12), a steel ball (13) and an inner wall (14). The steel ball (13) is arranged on the inner wall (14). The horizontal guide device comprises a small roller (42) and a workbench guide rail (19). The small roller (42) is fixedly mounted on the bottom end of the tension moving frame (41). The workbench guide rail (19) is provided with four groups. The four groups of the workbench guide rails (19) are respectively arranged around the conventional workbench (17). The bottom end of the small roller (42) is slidably connected to the workbench guide rail (19).

6. The dual-state multifunctional soil creep test device for geosynthetics according to claim 1, characterized in that: The hydraulic loading device VII comprises a support frame (43), a crossbeam (44), and a hydraulic jack (45); the bottom of the support frame (43) is connected to the workbench II, the top of the support frame (43) is connected to the crossbeam (44), the upper end of the hydraulic jack (45) is connected to the crossbeam (44), and the lower part of the hydraulic jack (45) is connected to the group B box cover plate (7).

7. The dual-state multifunctional soil creep test device for geosynthetics according to claim 1, characterized in that: The data acquisition device VIII comprises a first force sensor (46), a second force sensor (47), a third force sensor (48), a fourth force sensor (49), a first displacement sensor (50), a second displacement sensor (51) and an acquisition device (52), wherein the first force sensor (46) is connected to the lower clamping plate (29), the second force sensor (47) is located between the crossbeam (44) and the hydraulic jack (45), the third force sensor (48) is located between the pressure plate (25) and the pressure rod (26), the fourth force sensor (49) is connected to the tension movable frame (41), the first displacement sensor (50) is located at the upper end of the pressure plate (25), the second displacement sensor (51) is provided with four groups, and the four groups of the second displacement sensors (51) are respectively located above the isolation sleeve (6), and the acquisition device (52) is connected to the first force sensor (46), the second force sensor (47), the third force sensor (48), the fourth force sensor (49), the first displacement sensor (50) and the second displacement sensor (51) through a data line.

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