Geosynthetic material tensile test device

Abstract

The invention relates to a geosynthetic material tensile test device, and belongs to the technical field of geosynthetic material test equipment. Comprising a plurality of clamping mechanisms, a plurality of pressure adjusting mechanisms, a plurality of thrust adjusting mechanisms, a plurality of displacement mechanisms and a control mechanism. The multiple sets of clamping mechanisms sequentially clamp the two sides of the geosynthetics in the width direction in the length direction of the geosynthetics, the pressure adjusting mechanisms penetrate through the clamping mechanisms, the clamping mechanisms are slidably installed on the displacement mechanism, and the multiple thrust adjusting mechanisms are connected with the multiple sets of clamping mechanisms in a one-to-one correspondence mode. The two ends of the geosynthetics in the length direction are connected with tension equipment, a first pressure sensor is arranged between the geosynthetics and the clamping mechanism, and a second pressure sensor is arranged between the thrust adjusting mechanism and the clamping mechanism. According to the invention, the quantitative relation among the longitudinal tensile strength, the normal load and the transverse tensile strength of the geosynthetic material in the soil can be explored at a relatively low test cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geosynthetic material testing equipment, and particularly relates to a geosynthetic material tensile testing device. BACKGROUND

[0002] Geosynthetic materials are widely used in civil engineering, and their tensile properties are important indicators for evaluating material quality and applicability. In the process of testing the tensile properties of geosynthetic materials, the existing technology generally has the problem of necking caused by the difference between the test environment and the actual engineering working condition, that is, the phenomenon of sudden reduction of the local cross section of the material during the tensile process. This phenomenon can make the tensile strength data obtained by testing deviate significantly from the performance of the material under the actual stress state in the soil, and the specific hazards include (1) data distortion: necking causes local stress concentration of the material, and the test results in the air are 20%-40% lower than the actual strength in the soil, which cannot provide reliable basis for the design of reinforced soil structure. (2) Engineering hidden dangers: if the test results in the air are used for design, it may cause the geosynthetic materials such as geogrids and geotextiles to break prematurely in actual application, causing safety problems such as road settlement and dam leakage.

[0003] The existing standard air tensile test lacks the lateral confinement pressure existing in the soil. When the material is pulled, the lateral deformation of the geosynthetic material freely develops due to the absence of soil body constraint, resulting in local cross section contraction (necking), and the pulling force is concentrated at the necking place until the fracture. Some scholars found through comparative tests that when the normal load increases from 0 kPa to 150 kPa, the tensile strength of the geosynthetic material in the soil is 1.1-2.7 times higher than that in the air, which confirms the key role of lateral confinement pressure in inhibiting necking.

[0004] The bottleneck of the existing technology includes high verification cost and lack of quantitative means: although the existing soil tensile test device can simulate some working conditions, it has the following disadvantages: (1) it is necessary to eliminate friction by laying Teflon film, multiple layers of soil and other complex operations, and the cost of a single test is 3-5 times higher than that of air test. (2) only the phenomenon that "increasing pressure reduces necking" can be qualitatively observed, and the mathematical model of the quantitative relationship between the longitudinal tensile strength of the geosynthetic material in the soil, the normal load and the lateral tensile strength cannot be explored. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a geosynthetic material tensile testing device to explore the quantitative relationship between the longitudinal tensile strength of the geosynthetic material in the soil, the normal load and the lateral tensile strength at a lower test cost.

[0006] The technical scheme for solving the above technical problems of the present application is as follows: a geosynthetic tensile test device, comprising: multiple sets of clamping mechanisms, multiple pressure adjusting mechanisms, multiple thrust adjusting mechanisms, multiple displacement mechanisms, and a control mechanism; the multiple sets of clamping mechanisms are sequentially clamped on both sides of the geosynthetic in the width direction of the geosynthetic, the pressure adjusting mechanisms pass through the clamping mechanisms, the clamping mechanisms are slidingly installed on the displacement mechanisms, the thrust adjusting mechanisms are arranged in the clamping mechanisms and below the geosynthetic, the multiple thrust adjusting mechanisms are one-to-one connected with the multiple sets of clamping mechanisms, both ends of the geosynthetic in the length direction are connected with a tensile device, a first pressure sensor is arranged between the geosynthetic and the clamping mechanisms, a second pressure sensor is arranged between the thrust adjusting mechanisms and the clamping mechanisms, and the thrust adjusting mechanisms, the first pressure sensor, the second pressure sensor, and the tensile device are electrically connected with the control mechanism.

[0007] The beneficial effects of the present application are: the multiple sets of clamping mechanisms are sequentially clamped on both sides of the geosynthetic in the width direction of the geosynthetic, and the pressure adjusting mechanisms pass through the clamping mechanisms, which is beneficial to applying different pressures to the sides of the geosynthetic in the width direction through the pressure adjusting mechanisms, thereby simulating different normal loads on the geosynthetic in the soil layer, and the test cost is lower compared with the test of the prior art through complex operations such as laying a Teflon film and multiple layers of backfill; the first pressure sensor cooperates with the control mechanism, which is beneficial to detecting the pressure on the geosynthetic, the tensile device cooperates with the control mechanism, which is beneficial to gradually increasing the tension on the geosynthetic, thereby simulating the longitudinal stretching of the geosynthetic in the soil layer, and the quantitative relationship between the longitudinal tensile strength and the normal load of the geosynthetic in the soil layer is explored through multiple sets of pressure values and tension values; after the pressure that the geosynthetic can withstand reaches an extreme value, the thrust adjusting mechanism drives the clamping mechanism to displace along the displacement mechanism in the width direction of the geosynthetic, thereby applying an outward thrust to the geosynthetic in the width direction, and then simulating the lateral stretching of the geosynthetic in the soil layer, and the second pressure sensor cooperates with the control mechanism, which is beneficial to detecting the thrust on the geosynthetic, and the quantitative relationship between the longitudinal tensile strength, the normal load, and the lateral tensile strength of the geosynthetic in the soil layer is explored through multiple sets of thrust values and tension values.

[0008] On the basis of the above technical scheme, the present application can also be improved as follows.

[0009] Further, the clamping mechanism comprises two clamping members, the two clamping members are symmetrically clamped on both sides of the geosynthetic material in the width direction of the geosynthetic material, a plurality of clamping members are symmetrically clamped on both sides of the geosynthetic material in the width direction of the geosynthetic material, and the plurality of clamping members are symmetrically clamped on both sides of the geosynthetic material in the width direction of the geosynthetic material.

[0010] The beneficial effect of the above further scheme is that the two clamping members are symmetrically clamped on both sides of the geosynthetic material in the width direction of the geosynthetic material, which is beneficial to symmetrically exert pressure on both sides of the geosynthetic material in the width direction, thereby avoiding necking of the geosynthetic material due to asymmetric pressure under the action of tension, thereby affecting the accuracy of the quantitative relationship of the test.

[0011] Further, the clamping member comprises an upper clamp and a lower clamp, the upper clamp and the lower clamp are arranged at the top end and the bottom end of the geosynthetic material respectively, the pressure adjusting mechanism passes through the upper clamp and the lower clamp, the thrust adjusting mechanism is in abutment or separation with the lower clamp, and the lower clamp is slidably installed on the displacement mechanism.

[0012] The beneficial effect of the above further scheme is that the pressure adjusting mechanism is beneficial to adjust the tightness between the upper clamp and the lower clamp, thereby exerting different pressures on the geosynthetic material, and further simulating different normal loads on the geosynthetic material in the soil.

[0013] Further, the first pressure sensor is arranged between the upper clamp of one of the clamping members and the geosynthetic material, and between the lower clamp of the other clamping member and the geosynthetic material.

[0014] The beneficial effect of the above further scheme is that two first pressure sensors are arranged in a set of clamping mechanisms, which is beneficial to detect the pressure between the geosynthetic material and the upper clamp and the lower clamp, and by adjusting the pressure values detected by the two first pressure sensors in a set of clamping mechanisms to be the same size, it is beneficial to make both sides of the geosynthetic material in the width direction receive the same size of pressure, thereby improving the detection accuracy.

[0015] Further, the opposite side of the upper clamp and the lower clamp is provided with a rubber pad or a toothed structure.

[0016] The beneficial effect of the above further scheme is that the rubber pad or the toothed structure is beneficial to enhance the friction between the upper clamp, the lower clamp and the geosynthetic material, prevent slipping between the geosynthetic material and the upper clamp, the lower clamp during the process of tension exertion, and in addition, the rubber pad is also beneficial to avoid damage to the surface of the geosynthetic material due to excessive clamping force.

[0017] Further, the pressure adjusting mechanism comprises a threaded adjusting rod, a limiting stopper and an adjusting block, the limiting stopper is fixed at the top end of the threaded adjusting rod, the threaded adjusting rod passes through the upper clamp and the lower clamp, the limiting stopper abuts against the top end of the upper clamp, and the adjusting block is threadedly sleeved on the threaded adjusting rod and abuts against or separates from the bottom end of the lower clamp.

[0018] The above further scheme has the beneficial effect that the adjusting block is threadedly sleeved on the threaded adjusting rod, which is conducive to adjusting the clamping force between the upper clamp and the lower clamp by adjusting the position of the adjusting block on the threaded adjusting rod, and further adjusting the pressure applied by the upper clamp and the lower clamp to the geosynthetic material.

[0019] Further, the thrust adjusting mechanism comprises a driving cylinder, two push rods and two push blocks, the driving cylinder is electrically connected with the control mechanism, one end of the push rod is fixedly connected with the driving cylinder, the other end of the push rod is fixedly connected with one side of the push block, the other side of the push block abuts against or separates from the side wall of the lower clamp, and the second pressure sensor is arranged between the push block and the lower clamp.

[0020] The above further scheme has the beneficial effect that the driving cylinder is conducive to displacing the push block towards the lower clamp to abut against the side wall of the lower clamp by driving the push rod to push out, so as to simulate the lateral stretching of the geosynthetic material by applying an outward thrust to the lower clamp when the pressure adjusting mechanism cannot continue to apply greater pressure.

[0021] Further, two output shafts are symmetrically arranged on the side wall of the driving cylinder, and the two push rods are fixedly connected with the two output shafts one by one.

[0022] The above further scheme has the beneficial effect that it is conducive to synchronously driving the two push rods, so as to make the two push blocks abut against the side wall of the lower clamp synchronously, thereby increasing the accuracy of the test.

[0023] Further, the displacement mechanism comprises a base, a slide rail, a slide block and two baffles, the slide rail is fixed at the top end of the base along the width direction of the geosynthetic material, the slide block is slidingly installed on the slide rail, the top end of the slide block is fixedly connected with the bottom end of the lower clamp, and the two baffles are fixed at the two ends of the base one by one.

[0024] The beneficial effect of the further scheme is that the bottom end of the sliding block is slidingly installed on the slide rail, which is conducive to adjusting the geosynthetic material to a flat state before the test; in addition, the top end of the sliding block is fixedly connected with the bottom end of the lower clamp, which is conducive to the displacement of the clamping piece along the width direction of the geosynthetic material under the action of the pushing force of the pushing force adjusting mechanism, so that the geosynthetic material clamped by the clamping piece is subjected to an outward pushing force; the baffle is conducive to limiting the displacement of the sliding block and avoiding the sliding block from sliding out of the slide rail.

[0025] Further, the direction in which the tensile device exerts the pulling force is consistent with the length direction of the geosynthetic material.

[0026] The beneficial effect of the further scheme is that it is conducive to avoiding the generation of pulling force in other directions of the geosynthetic material in addition to the length direction, thereby avoiding the inaccuracy of the test results. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The overall structure side view is provided for the embodiment of the present application. Figure 2 The overall structure top view is provided for the embodiment of the present application.

[0028] Among them, Figure 2 The arrow in indicates the direction of the pulling force exerted by the tensile device on the length direction of the geosynthetic material.

[0029] In the drawings, the components represented by each reference numeral are listed as follows: 1, clamping piece; 2, pressure adjusting mechanism; 3, pushing force adjusting mechanism; 4, displacement mechanism; 5, geosynthetic material; 6, first pressure sensor; 7, second pressure sensor; 11, upper clamp; 12, lower clamp; 21, threaded adjusting rod; 22, limiting block; 23, adjusting block; 31, driving cylinder; 32, push rod; 33, push block; 41, base; 42, slide rail; 43, sliding block; 44, baffle. DETAILED DESCRIPTION

[0030] The principles and features of the present application are described below, and the examples are only used to explain the present application and are not used to limit the scope of the present application.

[0031] As Figure 1 and Figure 2As shown, the embodiment provides a geosynthetic tensile test device, comprising: a plurality of clamping mechanisms, a plurality of pressure adjusting mechanisms 2, a plurality of thrust adjusting mechanisms 3, a plurality of displacement mechanisms 4 and a control mechanism; a plurality of the clamping mechanisms are sequentially clamped on both sides of the geosynthetic material 5 in the width direction of the geosynthetic material 5 along the length direction of the geosynthetic material 5, the pressure adjusting mechanism 2 passes through the clamping mechanism, the clamping mechanism is slidingly installed on the displacement mechanism 4, the thrust adjusting mechanism 3 is arranged in the clamping mechanism and located below the geosynthetic material 5, a plurality of the thrust adjusting mechanisms 3 are connected with a plurality of the clamping mechanisms one by one, both ends of the geosynthetic material 5 in the length direction are connected with a tensile device, a first pressure sensor 6 is arranged between the geosynthetic material 5 and the clamping mechanism, a second pressure sensor 7 is arranged between the thrust adjusting mechanism 3 and the clamping mechanism, and the thrust adjusting mechanism 3, the first pressure sensor 6, the second pressure sensor 7 and the tensile device are electrically connected with the control mechanism.

[0032] It should be noted that in the embodiment, in addition to being communicatively connected with the thrust adjusting mechanism 3, the first pressure sensor 6, the second pressure sensor 7 and the tensile device, the control mechanism can also display the pressure value detected by the first pressure sensor 6, the thrust value detected by the second pressure sensor 7 and the tensile value applied by the tensile device in real time through the display. In order to ensure that the first pressure sensor 6 and the second pressure sensor 7 are not damaged under a larger pressure and thrust, the first pressure sensor 6 and the second pressure sensor 7 are selected to be F1119 pressure sensors (the maximum force is up to 120KN) of WIKA, Germany, or LCH series pressure sensors (the force range is 5KN to 1000KN) of NTS, Japan.

[0033] The longitudinal direction refers to the length direction of the geosynthetic material 5, the transverse direction refers to the width direction of the geosynthetic material 5, and the normal direction refers to the direction perpendicular to the top surface or bottom surface of the geosynthetic material 5.

[0034] In the embodiment, the reason that the lateral thrust is applied to the geosynthetic material 5 by the thrust adjusting mechanism 3 is that: when the upper clamp 11 and the lower clamp 12 are clamped to apply pressure to the geosynthetic material 5 by the pressure adjusting mechanism 2, theoretically, the tighter the upper clamp 11 and the lower clamp 12 are clamped, the greater the pressure applied to the geosynthetic material 5. However, in the embodiment, the geosynthetic material 5 is arranged between the upper clamp 11 and the lower clamp 12, and when the upper clamp 11 and the lower clamp 12 are gradually close to a certain extent, the adjusting block 23 in the pressure adjusting mechanism 2 cannot continue to rotate on the threaded adjusting rod 21, so that the upper clamp 11 and the lower clamp 12 cannot be further close, and finally the geosynthetic material 5 cannot be applied with greater pressure. Or when the pressure applied to the geosynthetic material 5 increases to a critical value that can damage the geosynthetic material 5, it is not appropriate to further close the upper clamp 11 and the lower clamp 12, that is, it is not appropriate to increase the pressure applied to the geosynthetic material 5. In these two cases, the thrust adjusting mechanism 3 and the displacement mechanism 4 are introduced, that is, the lateral thrust is applied to the lower clamp 12 by the thrust adjusting mechanism 3, so that the upper clamp 11 and the lower clamp 12 are displaced in the width direction of the geosynthetic material 5 along the displacement mechanism 4 after stably clamping the geosynthetic material 5, thereby introducing a new variable "lateral tensile strength", and further exploring the quantitative relationship among the longitudinal tensile strength, the normal load and the lateral tensile strength of the geosynthetic material 5 in soil.

[0035] In fact, the exploration of the quantitative relationship among the longitudinal tensile strength, the normal load and the lateral tensile strength of the geosynthetic material 5 in the embodiment can be abstractly understood as follows: if a longitudinal tensile force is applied to the geosynthetic material 5 in the air (i.e. without applying pressure to the geosynthetic material 5), when the tensile force increases to a first value, the geosynthetic material 5 will produce necking, that is, the geosynthetic material 5 will locally contract from the lateral edge, and the width of the geosynthetic material 5 will be shortened. In this case, if a clamping force is applied to the geosynthetic material 5 in the width direction to clamp the geosynthetic material 5, then when the tensile force increases to the first value, the necking phenomenon will not occur. In addition, a thrust can be applied outward (i.e. away from the geosynthetic material 5) in the width direction of the geosynthetic material 5, so that when the tensile force increases to the first value, the necking phenomenon will not occur. The present application needs to explore the quantitative relationship among the tensile force, the pressure and the thrust in the above process.

[0036] As to why the clamping mechanism needs to be clamped on both sides of the width direction of the geosynthetic material 5, it is because the necking phenomenon often occurs from the lateral edge of the geosynthetic material 5.

[0037] The beneficial effects of the present application are that: a plurality of clamping mechanisms are sequentially clamped on both sides of the geosynthetic material in the length direction of the geosynthetic material, and the pressure adjusting mechanism passes through the clamping mechanism, which is conducive to applying different pressures to the sides of the geosynthetic material in the width direction by the pressure adjusting mechanism, thereby simulating the different normal loads that the geosynthetic material receives in the soil layer, and compared with the complex operation test of laying Teflon film, multi-layer filling and the like in the prior art, the test cost is lower; the first pressure sensor cooperates with the control mechanism, which is conducive to detecting the pressure received by the geosynthetic material, and the tensioning device cooperates with the control mechanism, which is conducive to gradually increasing the tension of the geosynthetic material, thereby simulating the longitudinal stretching of the geosynthetic material in the soil layer, and the quantitative relationship between the longitudinal tensile strength and the normal load of the geosynthetic material in the soil layer is explored through a plurality of pressure values and tension values; after the pressure that the geosynthetic material can withstand reaches an extreme value, the thrust adjusting mechanism drives the clamping mechanism to displace along the displacement mechanism in the width direction of the geosynthetic material, thereby applying an outward thrust to the geosynthetic material in the width direction, and then simulating the lateral stretching of the geosynthetic material in the soil layer, and the second pressure sensor cooperates with the control mechanism, which is conducive to detecting the thrust received by the geosynthetic material, and the quantitative relationship between the longitudinal tensile strength, the normal load and the lateral tensile strength of the geosynthetic material in the soil layer is explored through a plurality of thrust values and tension values.

[0038] Preferably, as shown in Figure 1 and Figure 2 , the clamping mechanism comprises two clamping pieces 1, the two clamping pieces 1 are correspondingly and symmetrically clamped on both sides of the geosynthetic material 5 in the width direction, a plurality of clamping pieces 1 are correspondingly and symmetrically clamped on both sides of the geosynthetic material 5 in the width direction, and a plurality of displacement mechanisms 4 are correspondingly and symmetrically clamped on both sides of the geosynthetic material 5 in the width direction. The thrust adjusting mechanism 3 is arranged between the two clamping pieces 1.

[0039] The beneficial effects of the above preferred scheme are that: the two clamping pieces are correspondingly and symmetrically clamped on both sides of the geosynthetic material in the width direction, which is conducive to symmetrically applying pressure to both sides of the geosynthetic material in the width direction, thereby avoiding necking of the geosynthetic material due to asymmetric pressure under the action of tension, thereby affecting the accuracy of the quantitative relationship of the test.

[0040] Preferably, as shown in Figure 1 , the clamping piece 1 comprises an upper clamp 11 and a lower clamp 12, the upper clamp 11 and the lower clamp 12 are correspondingly arranged at the top end and the bottom end of the geosynthetic material 5, the pressure adjusting mechanism 2 passes through the upper clamp 11 and the lower clamp 12, the thrust adjusting mechanism 3 abuts or separates from the lower clamp 12, and the lower clamp 12 is slidably installed on the displacement mechanism 4.

[0041] The beneficial effect of the above preferred scheme is that the pressure adjusting mechanism is conducive to adjusting the tightness between the upper clamp and the lower clamp, thereby exerting different pressures on the geosynthetic material, and further simulating different normal loads on the geosynthetic material in the soil.

[0042] Preferably, as shown in the figure, the first pressure sensor 6 is arranged between the upper clamp 11 of one of the clamping members 1 and the geosynthetic material 5, and between the lower clamp 12 of the other clamping member 1 and the geosynthetic material 5. Figure 1

[0043] The beneficial effect of the above preferred scheme is that two first pressure sensors are arranged in a set of clamping mechanisms, which is conducive to detecting the pressure between the geosynthetic material and the upper clamp and the lower clamp, and adjusting the pressure values detected by the two first pressure sensors in the set of clamping mechanisms to the same size, so as to make the two sides of the geosynthetic material in the width direction receive the same pressure value, thereby improving the detection accuracy.

[0044] Preferably, as shown in the figure, the upper clamp 11 and the lower clamp 12 are provided with rubber pads or toothed structures on the opposite sides. Figure 1

[0045] It should be noted that in the preferred embodiment of the present application, the end face of the rubber pad in contact with the geosynthetic material 5 is engraved with cross anti-slip lines, the line depth is 0.5 mm, and it is suitable for conventional geotextiles; the tooth pitch of the toothed structure is 0.5-1 mm, the tooth depth is 0.3-0.6 mm, and the material is wear-resistant stainless steel, which is suitable for rough materials such as geogrids; In other preferred embodiments of the present application, if the geosynthetic material 5 is a smooth material such as a geomembrane, the clamping member 1 is a vacuum suction head, the vacuum suction head suctions the geosynthetic material 5, and the end face of the vacuum suction head suctions the geosynthetic material 5 is distributed with a plurality of suction holes with a diameter of 1-2 mm, the suction holes are connected with a micro vacuum pump through the vacuum suction head, the vacuum degree can reach 90 kPa, a negative pressure suction area is formed, and different suction forces are exerted on the geosynthetic material 5, thereby simulating different normal loads on the geosynthetic material 5 in the soil layer; If the geosynthetic material 5 is a high-elasticity material, the clamping member 1 is a puncture type chuck, the end face of the puncture type chuck close to the geosynthetic material 5 is arranged with a micro puncture needle, the needle diameter is 0.2-0.5 mm, the needle tip is blunted, and the puncture depth is controlled by an elastic pressing piece to be 0.1-0.3 mm.

[0046] ​​The beneficial effect of the above preferred scheme is that the rubber pad or the tooth structure is conducive to enhancing the friction between the upper clamp, the lower clamp and the geosynthetic material, preventing the geosynthetic material from slipping with the upper clamp and the lower clamp during the process of applying tension, and in addition, the rubber pad is conducive to avoiding damage to the surface of the geosynthetic material due to excessive clamping force.

[0047] Preferably, as shown in Figure 1 The pressure adjusting mechanism 2 comprises a threaded adjusting rod 21, a limiting block 22 and an adjusting block 23, the limiting block 22 is fixedly arranged at the top end of the threaded adjusting rod 21, the threaded adjusting rod 21 passes through the upper clamp 11 and the lower clamp 12, the limiting block 22 abuts against the top end of the upper clamp 11, and the adjusting block 23 is threadedly arranged on the threaded adjusting rod 21 and abuts against or separates from the bottom end of the lower clamp 12.

[0048] The beneficial effect of the above preferred scheme is that the adjusting block is threadedly arranged on the threaded adjusting rod, which is conducive to adjusting the clamping force between the upper clamp and the lower clamp by adjusting the position of the adjusting block on the threaded adjusting rod, and further adjusting the pressure applied to the geosynthetic material by the upper clamp and the lower clamp.

[0049] Preferably, as shown in Figure 1 The thrust adjusting mechanism 3 comprises a drive cylinder 31, two push rods 32 and two push blocks 33, the drive cylinder 31 is electrically connected with the control mechanism, one end of the push rod 32 is fixedly connected with the drive cylinder 31, the other end of the push rod 32 is fixedly connected with one side of the push block 33, the other side of the push block 33 abuts against or separates from the side wall of the lower clamp 12, and the second pressure sensor 7 is arranged between the push block 33 and the lower clamp 12.

[0050] The beneficial effect of the above preferred scheme is that the drive cylinder is conducive to displacing the push block to abut against the side wall of the lower clamp by driving the push rod to push out, so as to simulate the lateral stretching of the geosynthetic material by applying outward thrust to the lower clamp when the pressure adjusting mechanism cannot continue to apply greater pressure.

[0051] Preferably, as shown in Figure 1 The side wall of the drive cylinder 31 is symmetrically provided with two output shafts, and the two push rods 32 are fixedly connected with the two output shafts one by one.

[0052] It should be noted that in the embodiment, the drive cylinder 31 is connected with an air compressor that provides compressed gas, thereby providing power for the drive cylinder 31 to drive the output shaft, the push rod 32 and the push block 33 in sequence, and the control mechanism is electrically connected with the air compressor, thereby adjusting the thrust value that the drive cylinder 31 can apply.

[0053] The beneficial effect of the above preferred scheme is that it is beneficial to synchronously drive the two push rods, so that the two push blocks are in abutment with the side wall of the lower clamp at the same time, thereby increasing the accuracy of the test.

[0054] Preferably, as shown in Figure 1 The displacement mechanism 4 comprises a base 41, a slide rail 42, a slide block 43 and two baffles 44. The slide rail 42 is fixedly arranged on the top end of the base 41 along the width direction of the geosynthetic material 5. The bottom end of the slide block 43 is slidingly arranged on the slide rail 42, and the top end of the slide block 43 is fixedly connected with the bottom end of the lower clamp 12. The two baffles 44 are fixedly arranged on the two ends of the base 41.

[0055] The beneficial effect of the above preferred scheme is that the bottom end of the slide block is slidingly arranged on the slide rail, which is beneficial to adjust the geosynthetic material to a flat state before the test. In addition, the top end of the slide block is fixedly connected with the bottom end of the lower clamp, which is beneficial to displace the clamping member along the width direction of the geosynthetic material under the action of the pushing force of the pushing force adjusting mechanism, so that the geosynthetic material clamped by the clamped member is subjected to an outward pushing force. The baffles are beneficial to limit the displacement of the slide block, so as to prevent the slide block from sliding out of the slide rail.

[0056] Preferably, the direction in which the tension device applies the tension force is consistent with the length direction of the geosynthetic material 5.

[0057] It should be noted that in the present embodiment, the tension device is a tension testing machine, which is prior art.

[0058] The beneficial effect of the above preferred scheme is that it is beneficial to avoid that the geosynthetic material generates tension force in other directions except the length direction, thereby causing inaccurate test results.

[0059] The test processes of the two embodiments of the present application will be introduced below.

[0060] Preparation stage before the test: As shown in Figure 1 and Figure 2 A plurality of displacement mechanisms 4 are divided into two groups. The two groups of displacement mechanisms 4 are symmetrically arranged in the width direction of the geosynthetic material 5. The plurality of displacement mechanisms 4 in each group of displacement mechanisms 4 are sequentially placed on the horizontal platform in the length direction of the geosynthetic material 5, and the slide blocks 43 in the plurality of displacement mechanisms 4 are ensured to be in the same horizontal plane. Then, the lower clamps 12 in the plurality of clamping members 1 are fixedly arranged on the slide blocks 43 of the plurality of displacement mechanisms 4 one by one, so that there are a plurality of clamping members 1 sequentially abutting and arranged on the two side edges in the width direction of the geosynthetic material 5. For example, as shown in Figure 2 structure, Figure 2The six displacement mechanisms 4 (named as No. 1 displacement mechanism, No. 3 displacement mechanism, No. 5 displacement mechanism, No. 7 displacement mechanism, No. 9 displacement mechanism and No. 11 displacement mechanism respectively) are arranged on one side of the geosynthetic material 5 in the width direction, and six clamping pieces 1 (named as No. 1 clamping piece, No. 3 clamping piece, No. 5 clamping piece, No. 7 clamping piece, No. 9 clamping piece and No. 11 clamping piece respectively) are slidably arranged on each displacement mechanism 4, Figure 2 The six displacement mechanisms 4 (named as No. 2 displacement mechanism, No. 4 displacement mechanism, No. 6 displacement mechanism, No. 8 displacement mechanism, No. 10 displacement mechanism and No. 12 displacement mechanism respectively) are arranged on the other side of the geosynthetic material 5 in the width direction, and six clamping pieces 1 (named as No. 2 clamping piece, No. 4 clamping piece, No. 6 clamping piece, No. 8 clamping piece, No. 10 clamping piece and No. 12 clamping piece respectively) are slidably arranged on each displacement mechanism 4. The No. 1 clamping piece, the No. 3 clamping piece, the No. 5 clamping piece, the No. 7 clamping piece, the No. 9 clamping piece and the No. 11 clamping piece are sequentially abutted in the length direction of the geosynthetic material 5, the No. 2 clamping piece, the No. 4 clamping piece, the No. 6 clamping piece, the No. 8 clamping piece, the No. 10 clamping piece and the No. 12 clamping piece are sequentially abutted in the length direction of the geosynthetic material 5, the No. 1 clamping piece and the No. 2 clamping piece, the No. 3 clamping piece and the No. 4 clamping piece, the No. 5 clamping piece and the No. 6 clamping piece, the No. 7 clamping piece and the No. 8 clamping piece, the No. 9 clamping piece and the No. 10 clamping piece, and the No. 11 clamping piece and the No. 12 clamping piece are symmetrically arranged in the width direction of the geosynthetic material 5, and the sliders 43 in the No. 1 displacement mechanism to the No. 12 displacement mechanism are in the same horizontal plane; Then, the side edges of the geosynthetic material 5 in the width direction are placed between the upper clamps 11 and the lower clamps 12 of the clamping pieces 1, and the upper clamps 11 and the lower clamps 12 are moved closer to each other by rotating the adjusting blocks 23 to pre-clamp the side edges of the geosynthetic material 5 in the width direction. At this time, the first pressure sensors 6 detect the pressure values; Then, the sliders 43 in each of the two groups of displacement mechanisms 4 symmetrically arranged in the width direction of the geosynthetic material 5 are reversely slid on the sliding rails 42 to make the geosynthetic material 5 in a flat state and ensure that the geosynthetic material 5 is in a horizontal state. Finally, the tensioning device is connected at both ends of the geosynthetic material 5 in the length direction, and the tensioning direction is ensured to be consistent with the length direction of the geosynthetic material 5.

[0061] Test stage of Example 1: First, the adjusting blocks 23 are rotated, and the pressure values detected by the first pressure sensors 6 are observed through the control mechanism to make the pressure values X1 detected by all the first pressure sensors 6 reach the first preset pressure value (the first preset pressure value is zero), i.e. to simulate that the geosynthetic material 5 is in the air and is not under pressure. Then the pulling device gradually increases the pulling force from zero until the test personnel observe that the geosynthetic material 5 generates necking phenomenon, and record the pulling force value Y1 applied by the pulling device at this time, taking X1 and Y1 as the first group of data.

[0062] Repeat the preparation stage before the above test, and in the next round of test stage, rotate the adjusting block 23 to make the pressure value X2 detected by all the first pressure sensors 6 reach the second preset pressure value, simulate the state that the geosynthetic material 5 is in the soil layer and is subjected to the second preset normal load; Then gradually increase the pulling force of the pulling device from zero until the test personnel observe that the geosynthetic material 5 generates necking phenomenon, and record the pulling force value Y2 applied by the pulling device at this time, taking X2 and Y2 as the second group of data.

[0063] Repeat the above operation multiple times to obtain multiple groups of data, and through discrete analysis of the multiple groups of data, the quantitative relationship Y=kX can be obtained, in which Y is the longitudinal tensile strength of the geosynthetic material 5 in the soil, X is the normal load of the geosynthetic material 5 in the soil, and k is the coefficient of the geosynthetic material 5, and the coefficient k is different for different materials of the geosynthetic material 5.

[0064] In the test stage of embodiment one, when the adjusting block 23 cannot continue to rotate on the threaded adjusting rod 21, i.e., the pressure value detected by the first pressure sensor 6 cannot continue to increase, or when the pressure of the geosynthetic material 5 increases to a critical value that can damage the geosynthetic material 5, stop rotating the adjusting block 23, fix the adjusting block 23 on the threaded adjusting rod 21, and record the maximum pressure value or the critical pressure value (the maximum pressure value or the critical pressure value is the maximum normal load m of the geosynthetic material 5 in the soil simulated in embodiment two) detected by the first pressure sensor 6, and start the test of embodiment two.

[0065] Test stage of embodiment two: Firstly, start the driving cylinder 31 to synchronously push out the two push blocks 33 until they are in abutment with the clamping pieces 1 on both sides of the geosynthetic material 5 in the width direction, and apply a pushing force, i.e., simultaneously apply a pushing force to the first clamping piece to the twelfth clamping piece in the width direction of the geosynthetic material 5, and detect the pushing force value by the second pressure sensor 7; Then gradually increase the pushing force applied by the driving cylinder 31 by the control mechanism, so that the pushing force value detected by all the second pressure sensors 7 reaches the first preset pushing force value a1, and then gradually increase the pulling force of the pulling device from zero until the test personnel observe that the geosynthetic material 5 generates necking phenomenon, and record the pulling force value b1 applied by the pulling device at this time, taking a1 and b1 as the first group of data; The preparation stage before the above test is repeated, and in the next round of test stage, the thrust value detected by all the second pressure sensors 7 reaches the second preset thrust value a2, and then the tension device gradually increases the tension from zero until the test personnel observe that the geosynthetic material 5 generates necking phenomenon, and record the tension value b2 applied by the tension device at this time, and take a2 and b2 as the second group of data; The above operation is repeated multiple times to obtain multiple groups of data, and through discrete analysis on the multiple groups of data, a quantitative relationship of b=m+ka can be obtained, in which b is the longitudinal tensile strength of the geosynthetic material 5 in the soil, a is the transverse tensile strength of the geosynthetic material 5 in the soil, k is the coefficient of the geosynthetic material 5, and the coefficient is different for different materials of the geosynthetic material 5, and m is the maximum normal load of the geosynthetic material 5 in the soil.

[0066] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0067] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0068] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship of two elements, unless otherwise specifically limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0069] In the present application, unless otherwise explicitly specified and limited, a first feature is "on" or "under" a second feature can mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature is "over", "above" and "on top of" the second feature can mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. The first feature is "under", "below" and "underneath" the second feature can mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

[0070] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a 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 present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0071] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A geosynthetic tensile testing apparatus, characterized by, The device comprises: a plurality of clamping mechanisms, a plurality of pressure adjusting mechanisms (2), a plurality of thrust adjusting mechanisms (3), a plurality of displacement mechanisms (4) and a control mechanism; the plurality of clamping mechanisms are sequentially clamped on both sides of the geosynthetic material (5) in the length direction of the geosynthetic material (5), the pressure adjusting mechanism (2) passes through the clamping mechanism, the clamping mechanism is slidingly installed on the displacement mechanism (4), the thrust adjusting mechanism (3) is arranged in the clamping mechanism and below the geosynthetic material (5), the plurality of thrust adjusting mechanisms (3) are one-to-one corresponding to the plurality of clamping mechanisms, the two ends of the geosynthetic material (5) in the length direction are connected with a tension device, a first pressure sensor (6) is arranged between the geosynthetic material (5) and the clamping mechanism, a second pressure sensor (7) is arranged between the thrust adjusting mechanism (3) and the clamping mechanism, and the thrust adjusting mechanism (3), the first pressure sensor (6), the second pressure sensor (7) and the tension device are electrically connected with the control mechanism.

2. The geosynthetic tensile testing apparatus of claim 1, wherein, The clamping mechanism comprises two clamping pieces (1), the two clamping pieces (1) are one-to-one corresponding and symmetrically clamped on both sides of the geosynthetic material (5) in the width direction, and a plurality of clamping pieces (1) are one-to-one corresponding and slidingly installed on a plurality of displacement mechanisms (4) in the width direction of the geosynthetic material (5), and the thrust adjusting mechanism (3) is arranged between the two clamping pieces (1).

3. The geosynthetic tensile testing apparatus of claim 2, wherein, The clamping piece (1) comprises an upper clamp (11) and a lower clamp (12), the upper clamp (11) and the lower clamp (12) are one-to-one corresponding and arranged at the top end and the bottom end of the geosynthetic material (5), the pressure adjusting mechanism (2) passes through the upper clamp (11) and the lower clamp (12), the thrust adjusting mechanism (3) abuts or separates from the lower clamp (12), and the lower clamp (12) is slidingly installed on the displacement mechanism (4).

4. The geosynthetic tensile testing apparatus of claim 3, wherein, The first pressure sensor (6) is arranged between the upper clamp (11) of one of the clamping pieces (1) and the geosynthetic material (5) and between the lower clamp (12) of the other clamping piece (1) and the geosynthetic material (5).

5. The geosynthetic tensile testing apparatus of claim 3, wherein, Rubber pads or toothed structures are arranged on the opposite side walls of the upper clamp (11) and the lower clamp (12).

6. The geosynthetic tensile testing apparatus of claim 3, wherein, The pressure adjusting mechanism (2) comprises a threaded adjusting rod (21), a limiting block (22) and an adjusting block (23), the limiting block (22) is fixedly arranged at the top end of the threaded adjusting rod (21), the threaded adjusting rod (21) passes through the upper clamp (11) and the lower clamp (12), the limiting block (22) abuts against the top end of the upper clamp (11), and the adjusting block (23) is threadedly sleeved on the threaded adjusting rod (21) and abuts against or separates from the bottom end of the lower clamp (12).

7. The geosynthetic tensile testing apparatus of claim 3, wherein, The thrust adjusting mechanism (3) comprises a driving cylinder (31), two push rods (32) and two push blocks (33), the driving cylinder (31) is electrically connected with the control mechanism, one end of the push rod (32) is fixedly connected with the driving cylinder (31), the other end of the push rod (32) is fixedly connected with one side of the push block (33), the other side of the push block (33) is abutted with or separated from the side wall of the lower clamp (12), and the second pressure sensor (7) is arranged between the push block (33) and the lower clamp (12).

8. The geosynthetic tensile testing apparatus of claim 7, wherein, Two output shafts are symmetrically arranged on the side wall of the driving cylinder (31), and two push rods (32) are fixedly connected with the two output shafts in one-to-one correspondence.

9. The geosynthetic tensile testing apparatus of claim 3, wherein, The displacement mechanism (4) comprises a base (41), a sliding rail (42), a sliding block (43) and two baffles (44), the sliding rail (42) is fixedly arranged on the top end of the base (41) along the width direction of the geosynthetic material (5), the bottom end of the sliding block (43) is slidingly installed on the sliding rail (42), the top end of the sliding block (43) is fixedly connected with the bottom end of the lower clamp (12), and two baffles (44) are fixedly arranged on the two ends of the base (41) in one-to-one correspondence.

10. Geosynthetic tensile testing apparatus according to any one of claims 1-9, characterized in that The direction in which the tension device applies tension is consistent with the length direction of the geosynthetic material (5).

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