Mechanical-soil interface dynamic shear property measuring device and method

Abstract

The application provides a kind of mechanical-soil interface dynamic shear characteristic measuring device and method.The mechanical-soil interface dynamic shear characteristic measuring device includes chain test model, test frame, loading and control system and data acquisition system.The chain test model includes chain, to-be-measured shear plate, gear shaft, driving gear, driven gear, suspension plate, partition plate, test base and high-strength bolt.The loading and control system includes linear servo electric cylinder, servo motor, planetary reducer and servo motor driving device.The data acquisition system includes torque sensor, rotational speed sensor, thin film pressure sensor, linear displacement sensor and vertical force sensor.The measuring device and method of the application can test mechanical-soil interface dynamic linear shear characteristics under different conditions, and improve the defects such as bulldozing effect or uneven stress distribution in traditional tests.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of mechanical-soil interface dynamic shear characteristics determination device and method. BACKGROUND

[0002] The interaction of mechanical excavating tools or traction components with soil includes the extrusion deformation and shear behavior of soil, and to explore this complex problem, comprehensive and in-depth experimental research on the physical and mechanical properties of soil is needed, wherein the bearing capacity of soil involves the vertical deformation behavior of soil under normal pressure, and the shear behavior of soil involves the tangential slip deformation behavior of soil under the combined action of normal and tangential stress. In the field of ground mechanics, the dynamic interaction of structures such as scrapers, cutters, cutting teeth and traction components such as tracks and wheels with the soil interface is quite different from the shear loading conditions based on quasi-static in classical soil mechanics tests. The shear rate of soil during excavation or traction is at least 2-3 orders of magnitude higher than that in classical soil mechanics tests, so it is necessary to redesign the test scheme to conduct in-depth research on the dynamic shear characteristics of the mechanical-soil interface, and then optimize the soil cutting ability and earth moving efficiency of the mechanical excavating tool, and improve the ground passing performance of the traction component.

[0003] The direction of external force loading is one of the important factors affecting the dynamic shear characteristics parameters of soil. The field soil usually shows stratification characteristics, that is, the soil parameters such as water content and porosity change rapidly with the increase of burial depth, which makes the soil show anisotropy, so it needs to be tested within the shear plane that may actually occur. The existing soil shear strength test methods include ring shear, linear direct shear, uniaxial compression test, etc. Among them, the ring shear test method can measure the shear characteristics of soil under large strain conditions, and can partially simulate the shear effect of wheels or tracks on soil in the field of ground mechanics, so it is widely used. However, due to the different shear speeds inside and outside the shear ring in the ring shear test, the stress and displacement distribution on the ring radius is uneven, and the soft soil between the ring blades is pulled out of the ring due to centrifugal force, so that the space below the shear ring cannot be completely filled with sheared soil. The above factors may lead to the underestimation of the shear strength. The linear direct shear test can improve some defects of the ring shear test to some extent, but the "soil pushing effect" easily occurs during most linear direct shear tests, that is, when the soil in front of the shear device continuously accumulates and is pushed away, the measured horizontal force is the combined force of shear force and pushing force, which may overestimate the dynamic shear strength of soil and make it difficult to accurately control the shear rate. In addition, the linear direct shear test has high requirements for site and space, and is not suitable for narrow laboratory environment. Therefore, a new soil dynamic shear characteristics determination device needs to be developed to improve the defects of existing tests and devices. SUMMARY

[0004] In view of the problems existing in the prior art, the present application is proposed.

[0005] To solve the above technical problems, the application provides the following technical scheme: a mechanical-soil interface dynamic shear property measuring device, comprising a chain test model, a test frame, a loading and control system and a data acquisition system;

[0006] The chain test model comprises a chain, a shear plate to be measured, a gear rotating shaft, a driving gear, a driven gear, a suspension plate, a partition plate, a test base and high-strength bolts; the driving gear and the driven gear are arranged in an isosceles triangle shape; the gear rotating shaft is fixedly installed on the suspension plates located on both sides of the chain through a bearing with a seat and bolts; the chain is installed on the driving gear and the driven gear, and bolt holes are reserved on the outer side of the chain; the shear plate to be measured is fixed on the chain through the reserved bolt holes on the chain and the bolts; the suspension plates are located on both sides of the chain and are fixedly connected through high-strength bolts; the partition plate is arranged between the suspension plates; the test base is located between the two driven gears, and a chain guide rail is fixedly installed on the bottom of the test base; and the test base and the suspension plates are connected through high-strength bolts.

[0007] As a preferred scheme of the mechanical-soil interface dynamic shear property measuring device, the test frame comprises a steel frame, a support base, an acrylic transparent plate and a horizontal linear guide rail; the support base is installed on the bottom of the steel frame, the acrylic transparent plate is installed on the front side of the steel frame, and the soil to be measured is placed in the steel frame; the chain test model is placed on the soil to be measured; and the horizontal linear guide rail is installed on the top of the steel frame and used to control the horizontal position of the chain test model.

[0008] As a preferred scheme of the mechanical-soil interface dynamic shear property measuring device, the loading and control system comprises a linear servo cylinder, a servo motor, a planetary reducer and a servo motor driving device; the power output shaft of the servo motor is connected with the power input end of the planetary reducer through a rigid coupling, and the housings of the servo motor and the planetary reducer are connected through bolted flanges; the bottom of the linear servo cylinder is fixedly connected with the horizontal linear guide rail through screw threads, and the sliding block of the linear servo cylinder is connected with one side of the suspension plate through high-strength bolts; the servo motor driving device is installed on the top of the steel frame, and the servo motor driving device is connected with the linear servo cylinder and the servo motor through wires respectively, and is used for closed-loop control of the position, speed and gear rotating torque of the chain test model.

[0009] As a preferred scheme of the mechanical-soil interface dynamic shear property measuring device, the data acquisition system comprises a torque sensor, a rotating speed sensor, a thin film pressure sensor, a linear displacement sensor, a vertical force sensor, a traction force sensor, a miniature soil pressure cell, a data acquisition module, a computer module and a power module; the torque sensor is installed on the gear rotating shaft of the driving gear, the power input end of the torque sensor is connected with the power output shaft of the planetary reducer through a key, the power output shaft of the torque sensor is connected with the driving gear rotating shaft through a shaft sleeve, and the driving torque of the servo motor is detected; the rotating speed sensor is installed at the end of the driving gear and the driven gear rotating shaft respectively, and the rotating speed of the gear is detected; the thin film pressure sensor is pasted or embedded on the bottom surface and the side surface of the shear plate which may contact with the soil to be measured, and the actual normal pressure and the side soil movement resistance of the shear plate to be measured are detected; the linear displacement sensor is installed at one end of the linear servo cylinder, and the vertical distance between the chain test model and the soil to be measured is detected; the vertical force sensor is installed on the sliding block of the linear servo cylinder, and the normal pressure of the chain test model applied to the soil to be measured is detected; the traction force sensor is installed on the upper part of the horizontal linear guide rail, and the horizontal traction force of the chain test model during rotation is detected; the miniature soil pressure cells are placed at different depths of the soil to be measured, and the distribution and variation of the soil pressure of the soil to be measured under the condition of different sinking depths of the chain test model are tested.

[0010] As a preferred scheme of the mechanical-soil interface dynamic shear property measuring device, the input ports of the data acquisition module are connected with the sensors respectively; the output port of the data acquisition module is connected with the computer module; the computer module receives the real-time data of the sensors and performs automatic visual processing; and the power module supplies power for the torque sensor, the rotating speed sensor, the thin film pressure sensor, the linear displacement sensor, the vertical force sensor, the traction force sensor, the miniature soil pressure cell, the data acquisition module, the computer module, the linear servo cylinder, the servo motor, the planetary reducer and the servo motor driving device.

[0011] As a preferred scheme of the mechanical-soil interface dynamic shear property measuring device, the measuring device can be used for testing the mechanical-soil interface dynamic shear property parameters in an indoor soil tank or an outdoor construction site, and is used for studying the influence law of the soil parameters, the mechanical parameters and the driving conditions on the mechanical-soil interface dynamic shear properties (the maximum shear stress, the residual shear stress and the shear stress-slip displacement curve).

[0012] As a preferred scheme of the mechanical-soil interface dynamic shear property measuring device, the shear plate to be measured has different forms, which can be flexibly adjusted according to test requirements, and the size and shape of the shear plate to be measured are consistent with or proportionally reduced from the mechanical structure to be studied when the dynamic shear property of the soil is tested.

[0013] To solve the above technical problems, the present application provides the following technical scheme: a mechanical-soil interface dynamic shear property measuring method,

[0014] S1: Before the test, the size and shape of the shear plate to be measured are customized according to the type of the mechanical to be studied, and the shear plate to be measured is fixed on the chain in a certain arrangement mode through bolts;

[0015] S2: The vertical position of the chain test model is slowly and accurately adjusted by the linear servo cylinder through the loading and control system, so that the bottom of the chain test model is in horizontal contact with the surface of the soil to be measured. The vertical force sensor on the sliding block of the linear servo cylinder continuously records the vertical force applied to the soil to be measured by the whole chain test model, until the vertical force reaches a predetermined value and is controlled to remain unchanged;

[0016] S3: The servo motor is started to drive the gear shaft to rotate through the loading and control system, the torque sensor continuously records the driving torque of the servo motor, the rotation speed sensor continuously records the rotation speed of the gear, the film pressure sensor continuously outputs the resistance of the soil on the side of the shear plate to be measured, and the vertical force sensor continuously records the total normal pressure applied to the soil to be measured by the chain test model;

[0017] S4: The data acquisition module and the computer module comprehensively arrange and summarize all the received test data, and calculate the parameters related to the dynamic shear property of the mechanical-soil interface.

[0018] As a preferred scheme of the mechanical-soil interface dynamic shear property measuring method, the mechanical-soil interface dynamic shear property measuring device can measure the parameters related to the dynamic shear property of the mechanical-soil contact interface: according to the measured data recorded by the torque sensor, the rotation speed sensor, the film pressure sensor and the vertical force sensor, the dynamic shear property of the mechanical-soil contact interface under different conditions can be obtained by using a first formula, wherein the first formula is:

[0019]

[0020] Wherein τ d is the dynamic shear stress of the mechanical-soil interface, τ max is the dynamic maximum shear stress of the soil, τ0 is the quasi-static shear stress of the soil, v is the dynamic shear rate, and k is the dynamic shear deformation coefficient.

[0021] In the study of the dynamic shear property of the mechanical-soil contact interface, τd The second formula is:

[0022]

[0023] Wherein T m is the driving torque of the servo motor, r0 is the radius of the driving gear, m is the number of the shear plates in contact with the soil to be measured, A is the area of the shear plate to be measured, τ f is the unit soil movement resistance on the side of the shear plate to be measured;

[0024] The τ0 in the first formula can be calculated by the third formula:

[0025]

[0026] Wherein c is the cohesion of the soil, N is the unit normal pressure of the shear plate to be measured, is the internal friction angle of the soil;

[0027] The v in the first formula can be calculated by the fourth formula:

[0028] v = 2πnr0

[0029] Wherein n is the rotational speed of the driving gear;

[0030] The N in the third formula can be calculated by the fifth formula:

[0031]

[0032] Wherein N w is the total normal pressure on the shear plate to be measured;

[0033] The τ max in the first formula can be measured by the chain test model 1, the maximum torque T max,0 of the servo motor (32) that makes the soil to be measured have a tendency to slip at the moment of starting is measured by the torque sensor (41), then T m =T max,0 , and τ max is obtained by the second formula.

[0034] As a preferred scheme of the mechanical-soil interface dynamic shear property determination method, the linear displacement sensor can record the vertical deformation of the soil to be tested, so as to analyze the bearing mechanical properties of the soil to be tested; the traction force sensor can record the horizontal traction force generated when the chain rotates, so as to analyze the motion trend of the chain test model, and further optimize the chain transmission parameters; and the miniature soil pressure cell can record the distribution and change of the soil pressure in the soil to be tested, so as to analyze the disturbance of the actual traction component or excavating machine to the surrounding soil and optimize the corresponding structure parameters.

[0035] The application has the following beneficial effects: 1. The chain test model is placed in an isosceles triangle shape, has a stable overall structure, occupies a small space, and is suitable for a laboratory environment. The servo motor and the linear servo cylinder device can realize the high-precision controllable dynamic linear shear behavior of the mechanical-soil interface.

[0036] 2. The introduction of the chain transmission mode greatly improves the bulldozing effect that is prone to occur in the traditional long-distance linear shear test, and also avoids the problems of the shear speed difference between the inside and outside of the shear ring and the stress unevenness on the ring radius in the traditional ring shear test.

[0037] 3. The shape, size and material of the shear plate to be tested can be flexibly customized according to the differences in test types and mechanical types, and the bolt holes provided on the chain are beneficial to the assembly and disassembly of the shear plate to be tested. Different types and groupings of the shear plate to be tested can simulate various use scenarios such as tracks, wheels and excavating machines.

[0038] 4. Since the suspension plate does not seal the space outside the chain and the shear plate to be tested, the film pressure sensor can be directly pasted or embedded on the shear plate to be tested and rotate with the chain without being stuck, so that the dynamic shear mechanical properties of the mechanical-soil contact interface under different shear rates and time conditions can be most directly and accurately tested. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor. Among them:

[0040] Figure 1 The figure is a schematic diagram of the overall structure of the mechanical-soil interface dynamic shear property determination device.

[0041] Figure 2 The figure is an enlarged schematic diagram of the chain test model in the mechanical-soil interface dynamic shear property determination device. Figure 1

[0042] ​Figure 3 is a front enlarged schematic view of the test frame in Figure 1

[0043] Figure 4 is a side enlarged schematic view of the chain test model in Figure 1

[0044] Figure 5 are two different types of schematic views of the shear plate to be tested in Figure 1

[0045] Figure 6 is a side enlarged schematic view of the chain and gear in Figure 1

[0046] Figure, 1, chain test model; 2, test frame; 3, loading and control system; 4, data acquisition system; 11, chain; 12, shear plate to be tested; 13, gear rotating shaft; 14, driving gear; 15, driven gear; 16, suspension plate; 17, partition plate; 18, test base; 19, high-strength bolt; 21, steel frame; 22, support base; 23, acrylic transparent plate; 24, horizontal linear guide rail; 31, linear servo cylinder; 32, servo motor; 33, planetary reducer; 34, servo motor driving device; 41, torque sensor; 42, rotating speed sensor; 43, thin film pressure sensor; 44, linear displacement sensor; 45, vertical force sensor; 46, traction force sensor; 47, micro soil pressure cell; 48, data acquisition module; 49, computer module; 50, power module. DETAILED DESCRIPTION

[0047] In order to make the above objectives, features and advantages of the present application more apparent, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0048] In the following description, a lot of specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the spirit of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0049] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0050] As Figure 1 ​​​​As shown, the application is a mechanical-soil interface dynamic shear property testing device, which mainly comprises a chain test model 1, a test frame 2, a loading and control system 3, and a data acquisition system 4.

[0051] Referring to Figure 2 and Figure 4 , the chain test model 1 is placed in an isosceles triangle shape, has a stable overall structure, and occupies a small space. It mainly comprises a chain 11, a shear plate to be tested 12, a gear rotating shaft 13, a driving gear 14, a driven gear 15, a suspension plate 16, a partition plate 17, a test base 18, and a high-strength bolt 19. The driving gear 14 and the driven gear 15 are arranged in an isosceles triangle shape. The gear rotating shaft 13 is fixedly installed on the suspension plates 16 located on both sides of the chain through a bearing with a seat and a bolt. The chain 11 is installed on the driving gear 14 and the driven gear 15, and bolt holes are reserved on the outside of the chain 11. The shear plate to be tested 12 is fixed on the chain 11 through the reserved bolt holes on the chain and bolts. The reserved bolt holes are beneficial to the assembly and disassembly of the shear plate to be tested 12. The shape, size, and material of the shear plate to be tested 12 can also be flexibly customized according to the differences in test types and mechanical types, and have strong applicability. Different types and groupings of shear plates to be tested can simulate various use scenarios such as tracks, wheels, excavating machinery, etc. In addition, the introduction of the chain transmission mode greatly improves the bulldozing effect that is prone to occur in traditional long-distance linear shear tests, and also avoids the problems of shear speed difference between the inside and outside of the shear ring and stress unevenness on the ring radius in traditional ring shear tests.

[0052] The suspension plates 16 are located on both sides of the chain 11 and are connected and fixed through high-strength bolts 19. The partition plate 17 is arranged between the suspension plates 16, and is used for further reinforcing the chain test model 1 and also serving as a mud guard. The test base 18 is located between the two driven gears 15, and the test base 18 is fixedly installed with a chain guide rail at the bottom. The test base 18 is connected between the suspension plates 16 through high-strength bolts 19.

[0053] Referring to Figure 3 , the test frame 2 comprises a steel frame 21, a support base 22, an acrylic transparent plate 23, and a horizontal linear guide rail 24. The support base 22 is installed at the bottom of the steel frame 21, the acrylic transparent plate 23 is installed on the front side of the steel frame 21, and the soil to be tested is placed inside the steel frame 21. The chain test model 1 is placed on the soil to be tested. The horizontal linear guide rail 24 is installed at the top of the steel frame 21, and is used for controlling the horizontal position of the chain test model 1.

[0054] Referring to Figure 4The loading and control system 3 comprises a linear servo cylinder 31, a servo motor 32, a planetary reducer 33 and a servo motor drive device 34. The power output shaft of the servo motor 32 is connected to the power input end of the planetary reducer 33 through a rigid coupling, and the housings of the servo motor 32 and the planetary reducer 33 are connected through bolted flanges for controlling the chain transmission parameters; the bottom of the linear servo cylinder 31 is fixed to the horizontal linear guide rail 24 through screw connection, and the sliding block of the linear servo cylinder 31 is connected to one side of the suspension plate 16 through high-strength bolts 19 for accurately controlling the vertical distance between the chain test model 1 and the soil to be tested and applying a corresponding vertical force; the servo motor drive device 34 is installed on the top of the steel frame 21, and the servo motor drive device 34 is connected to the linear servo cylinder 31 and the servo motor 32 through wires for closed-loop control of the position, speed and gear torque of the chain test model 1, thereby realizing the high-precision controllable dynamic linear shear behavior of the mechanical-soil interface.

[0055] Reference Figures 2-4 The data acquisition system comprises a torque sensor 41, a rotational speed sensor 42, a thin film pressure sensor 43, a linear displacement sensor 44, a vertical force sensor 45, a traction force sensor 46, a miniature soil pressure cell 47, a data acquisition module 48, a computer module 49 and a power module 50. The torque sensor 41 is installed on the gear shaft 13 of the driving gear 14, the power input end of the torque sensor 41 is connected to the power output shaft of the planetary reducer 33 through a key, and the power output shaft of the torque sensor 41 is connected to the driving gear shaft 13 through a shaft sleeve for detecting the driving torque of the servo motor; the rotational speed sensors 42 are installed at the ends of the driving gear and the driven gear shafts 13 respectively for detecting the rotational speed of the gears; since the suspension plate 16 does not close the space outside the chain 11 and the shear plate 12 to be tested, the thin film pressure sensor 43 is directly pasted or embedded on the bottom surface and side surface of the shear plate 12 to be tested which may contact the soil to be tested and rotates with the chain 11 for detecting the actual normal pressure and the side soil movement resistance of the shear plate 12 to be tested; the linear displacement sensor 44 is installed at one end of the linear servo cylinder 31 for detecting the vertical distance between the chain test model 1 and the soil to be tested; the vertical force sensor 45 is installed on the sliding block of the linear servo cylinder 31 for detecting the normal pressure applied by the chain test model 1 to the soil to be tested as a whole; the traction force sensor 46 is installed on the upper part of the horizontal linear guide rail 24 for detecting the horizontal traction force of the chain test model 1 when the chain rotates; the miniature soil pressure cells 47 are placed at different depths in the soil to be tested to test the distribution and variation of the soil pressure in the soil to be tested under different settlement depths of the chain test model 1.

[0056] The input ports of the data acquisition module 48 are connected with the sensors respectively; the output ports of the data acquisition module 48 are connected with the computer module 49; the computer module 49 receives the real-time data of the sensors and performs automatic visualization processing; the power module 50 supplies power for the torque sensor 41, the rotation speed sensor 42, the thin film pressure sensor 43, the linear displacement sensor 44, the vertical force sensor 45, the traction force sensor 46, the miniature earth pressure cell 47, the data acquisition module 48, the computer module 49, the linear servo cylinder 31, the servo motor 32, the planetary reducer 33 and the servo motor driving device 34 respectively.

[0057] Reference Figure 5 Preferably, the to-be-tested shear plate 12 has different forms, which can be flexibly adjusted according to the test requirements. When the dynamic shear characteristics of the soil body are tested, the size and shape of the to-be-tested shear plate 12 are consistent with or are proportionally reduced from the mechanical structure to be studied.

[0058] A method for testing the dynamic shear characteristics of a mechanical-soil interface, characterized in that the method comprises the following steps:

[0059] S1: Before the test, the size and shape of the to-be-tested shear plate 12 are determined according to the type of the mechanical to be studied, and the to-be-tested shear plate 12 is fixed on the chain 11 in a certain arrangement mode through bolts;

[0060] S2: The vertical position of the chain test model 1 is slowly and accurately adjusted by the linear servo cylinder 31 started by the loading and control system 3, so that the bottom of the chain test model 1 is in horizontal contact with the surface of the to-be-tested soil body. The vertical force sensor 45 on the sliding block of the linear servo cylinder 31 continuously records the vertical force applied to the to-be-tested soil body by the chain test model 1, until the vertical force reaches a predetermined value and is controlled to remain unchanged;

[0061] S3: The gear shaft 13 is rotated by the servo motor 32 started by the loading and control system 3, the torque sensor 41 continuously records the driving torque of the servo motor 32, the rotation speed sensor 42 continuously records the rotation speed of the gear, the thin film pressure sensor 43 continuously outputs the movement resistance of the soil body on the side of the to-be-tested shear plate 12, and the vertical force sensor 45 continuously records the total normal pressure applied to the to-be-tested soil body by the chain test model 1;

[0062] S4: The data acquisition module 48 and the computer module 49 comprehensively arrange and summarize all the test data received, and calculate the parameters related to the dynamic shear characteristics of the mechanical-soil interface.

[0063] The parameters related to the dynamic shear characteristics of the mechanical-soil contact interface can be calculated by the following steps: recording the normal pressure perpendicular to the shear plate 12 to be measured by the vertical force sensor 45, recording the driving torque of the servo motor 32 by the torque sensor 41, recording the driving gear speed by the rotation speed sensor 42, and recording the movement resistance of the soil on the side of the shear plate 12 to be measured by the thin film pressure sensor 43; obtaining the dynamic shear characteristics of the mechanical-soil contact interface under different conditions by using the first formula, the first formula being:

[0064]

[0065] wherein τ d is the dynamic shear stress of the mechanical-soil interface, τ max is the dynamic maximum shear stress of the soil, τ0 is the quasi-static shear stress of the soil, v is the dynamic shear rate, and k is the dynamic shear deformation coefficient.

[0066] In the first formula, τ d can be calculated by the second formula, the second formula being:

[0067]

[0068] wherein T m is the driving torque of the servo motor, r0 is the radius of the driving gear, m is the number of shear plates to be measured in contact with the soil to be measured, A is the area of the shear plate to be measured, τ f is the unit soil movement resistance on the side of the shear plate to be measured;

[0069] In the first formula, τ0 can be calculated by the third formula, the third formula being:

[0070]

[0071] wherein c is the cohesion of the soil, N is the unit normal pressure of the shear plate to be measured, and φ is the internal friction angle of the soil;

[0072] In the first formula, v can be calculated by the fourth formula, the fourth formula being:

[0073] v = 2 π n r0

[0074] wherein n is the driving gear speed;

[0075] In the third formula, N can be calculated by the fifth formula, the fifth formula being:

[0076]

[0077] wherein N w is the total normal pressure received by the shear plate to be measured;

[0078] In the first formula, τ​max The maximum torque T of the servo motor 32 at the starting moment, which tends to make the soil under test slip, can be measured by the torque sensor 41 through the chain test model 1 max,0 , and then T m =

[0079] T max,0 , τ max is obtained by the second formula.

[0080] The linear displacement sensor 44 can record the vertical deformation of the soil under test, so as to analyze the bearing mechanical properties of the soil under test; the traction force sensor 46 can record the horizontal traction force generated when the chain 11 rotates, so as to analyze the motion trend of the chain test model 1, and then optimize the chain transmission parameters; the miniature soil pressure cell 47 can record the distribution and change of the soil pressure in the soil under test, and can analyze the disturbance of the actual traction component or excavating machinery to the surrounding soil and optimize the corresponding structure parameters.

[0081] Importantly, it should be noted that the construction and arrangement of the present application shown in the various exemplary embodiments is merely illustrative. While only several embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described in this application. For example, elements shown as integrally formed can be constructed of multiple parts or elements, the position of elements can be reversed or otherwise varied, and the nature or number of elements or positions can be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present application. The order or sequence of any process or method steps can be varied or re-sequenced without materially affecting the application. Any "means plus function" clauses are intended to cover the structures described herein as performing the recited functionality and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes, and omissions can be made in the design, operating conditions, and arrangement of the exemplary embodiments without departing from the scope of the present application. Accordingly, the present application is not limited to the particular embodiments described and illustrated herein, but extends to equivalents of which the skilled artisan has knowledge of in light of the disclosure herein.

[0082] Furthermore, in order to provide a concise description of exemplary embodiments, all features of the actual implementation can not be described (i.e., those unrelated to the best mode of carrying out the present application currently under consideration or those unrelated to achieving the present application).

[0083] It is to be understood that the development of the particular implementations described herein was motivated by the desire to solve real-world problems, and as such the claimed implementations can be susceptible to further implementation while still being generically consistent with the descriptions provided herein. Specifically, although many of the examples provided herein describe particular implementations with reference to particular applications for illustration, those of ordinary skill in the art will recognize that the described implementations can be used in other applications and / or modified to be used in other applications and that the descriptions provided herein do not limit the claimed implementations to the applications described by way of example. Those skilled in the art will readily recognize a variety of applications for the claimed implementations.

[0084] It should be noted that the above examples are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, which should be covered by the claims of the present application.

Claims

1. A mechanical-soil interface dynamic shear property measuring apparatus, characterized by: It comprises a chain test model (1), a test frame (2), a loading and control system (3) and a data acquisition system (4); The chain test model (1) comprises a chain (11), a shear plate to be tested (12), a gear rotating shaft (13), a driving gear (14), a driven gear (15), a suspension plate (16), a partition plate (17), a test base (18) and high-strength bolts (19); the driving gear (14) and the driven gear (15) are arranged in an isosceles triangle; the gear rotating shaft (13) is fixedly installed on the suspension plates (16) located on both sides of the chain through a bearing with a seat and bolts; the chain (11) is installed on the driving gear (14) and the driven gear (15), and bolt holes are reserved on the outside of the chain (11); the shear plate to be tested (12) is fixed on the chain (11) through the reserved bolt holes on the chain and bolts; the suspension plates (16) are located on both sides of the chain (11) and are fixedly connected through the high-strength bolts (19); the partition plate (17) is arranged between the suspension plates (16); the test base (18) is located between the two driven gears (15), and chain rails are fixedly installed on the bottom of the test base (18); the test base (18) and the suspension plates (16) are connected through the high-strength bolts (19); The test frame (2) comprises a steel frame (21), a support base (22), an acrylic transparent plate (23) and a horizontal linear guide rail (24); the support base (22) is installed on the bottom of the steel frame (21), the acrylic transparent plate (23) is installed on the front side of the steel frame (21), and the soil to be tested is placed in the steel frame (21); the chain test model (1) is placed on the soil to be tested; the horizontal linear guide rail (24) is installed on the top of the steel frame (21) and is used for controlling the horizontal position of the chain test model (1); The loading and control system (3) comprises a linear servo cylinder (31), a servo motor (32), a planetary reducer (33) and a servo motor driving device (34); the power output shaft of the servo motor (32) is connected with the power input end of the planetary reducer (33) through a rigid shaft coupling, and the housings of the servo motor (32) and the planetary reducer (33) are connected through bolted flanges; the bottom of the linear servo cylinder (31) is fixedly connected with the horizontal linear guide rail (24) through screw threads, and the sliding block of the linear servo cylinder (31) is connected with one side of the suspension plate (16) through the high-strength bolt (19); the servo motor driving device (34) is installed on the top of the steel frame (21), and the servo motor driving device (34) is connected with the linear servo cylinder (31) and the servo motor (32) through wires, and is used for closed-loop control of the position, speed and gear rotating torque of the chain test model (1); The data acquisition system comprises a torque sensor (41), a rotating speed sensor (42), a thin film pressure sensor (43), a linear displacement sensor (44), a vertical force sensor (45), a traction force sensor (46), a miniature earth pressure cell (47), a data acquisition module (48), a computer module (49) and a power module (50); the torque sensor (41) is installed on the gear rotating shaft (13) of the driving gear (14), the power input end of the torque sensor (41) is connected with the power output shaft of the planetary reducer (33) through a key, the power output shaft of the torque sensor (41) is connected with the driving gear rotating shaft (13) through a shaft sleeve, and the torque sensor (41) is used for detecting the driving torque of the servo motor; the rotating speed sensors (42) are respectively installed on the end portions of the driving gear and the driven gear rotating shaft (13), and are used for detecting the rotating speed of the gears; the thin film pressure sensors (43) are pasted or embedded on the bottom surface and the side surface of the to-be-detected shear plate (12) which can contact the to-be-detected soil, and are used for detecting the actual normal pressure and the side soil movement resistance of the to-be-detected shear plate (12); the linear displacement sensor (44) is installed on one end of the linear servo electric cylinder (31), and is used for detecting the vertical distance between the chain type test model (1) and the to-be-detected soil; the vertical force sensor (45) is installed on the sliding block of the linear servo electric cylinder (31), and is used for detecting the normal pressure applied by the chain type test model (1) to the to-be-detected soil; the traction force sensor (46) is installed on the upper portion of the horizontal linear guide rail (24), and is used for detecting the horizontal traction force borne by the chain type test model (1) when the chain rotates; the miniature earth pressure cells (47) are placed in the to-be-detected soil at different depths at equal intervals, and are used for testing the distribution and variation law of the earth pressure of the to-be-detected soil under the condition of different settlement depths of the chain type test model (1).

2. The mechanical-soil interface dynamic shear property measuring apparatus according to claim 1, wherein: The input ports of the data acquisition module (48) are connected with the sensors respectively; the output port of the data acquisition module (48) is connected with the computer module (49); the computer module (49) receives the real-time data of the sensors and automatically performs visual processing; and the power module (50) supplies power for the torque sensor (41), the rotating speed sensor (42), the thin film pressure sensor (43), the linear displacement sensor (44), the vertical force sensor (45), the traction force sensor (46), the miniature earth pressure cell (47), the data acquisition module (48), the computer module (49), the linear servo electric cylinder (31), the servo motor (32), the planetary reducer (33) and the servo motor driving device (34).

3. The mechanical-soil interface dynamic shear property measuring apparatus of claim 1, wherein: The determination device can carry out the dynamic shear characteristic parameter test of the mechanical-soil interface in an indoor soil tank or an outdoor construction site, and is used for researching the influence law of the soil parameters, the mechanical parameters and the driving conditions on the maximum shear stress, the residual shear stress and the shear stress-slip displacement curve in the dynamic shear characteristics of the mechanical-soil contact interface.

4. The mechanical-soil interface dynamic shear property measuring apparatus of claim 1, wherein: The to-be-tested shear plate (12) has different forms and can be flexibly adjusted according to test requirements. When the dynamic shear characteristics of the soil body are tested, the size and shape of the to-be-tested shear plate (12) are consistent with or are proportionally reduced from the mechanical structure to be studied.

5. A method of determining the dynamic shear properties of a mechanical-soil interface, characterized by: The mechanical-soil interface dynamic shear characteristic measuring device comprises the following steps: S1: Before the test, the size and shape of the to-be-tested shear plate (12) are customized according to the type of the mechanical structure to be studied, and the to-be-tested shear plate (12) is fixed on the chain (11) in a certain arrangement mode through bolts; S2: The vertical position of the chain test model (1) is slowly and accurately adjusted by the linear servo cylinder (31) through the loading and control system (3), so that the bottom of the chain test model (1) is in horizontal contact with the surface of the to-be-tested soil body. The vertical force sensor (45) on the sliding block of the linear servo cylinder (31) continuously records the vertical force applied to the to-be-tested soil body by the chain test model (1) as a whole, until the vertical force reaches a predetermined value and is controlled to remain unchanged; S3: The servo motor (32) drives the gear shaft (13) to rotate through the loading and control system (3), the torque sensor (41) continuously records the driving torque of the servo motor (32), the rotation speed sensor (42) continuously records the rotation speed of the gear, the diaphragm pressure sensor (43) continuously outputs the resistance of the soil body on the side of the to-be-tested shear plate (12), and the vertical force sensor (45) continuously records the total normal pressure applied to the to-be-tested soil body by the chain test model (1); S4: The data acquisition module (48) and the computer module (49) comprehensively arrange and summarize all the received test data, and calculate the parameters related to the dynamic shear characteristics of the mechanical-soil interface.

6. The method of claim 5, wherein: the mechanical-soil interface dynamic shear property is measured at a temperature of 20°C and a frequency of 10 Hz. The mechanical-soil interface dynamic shear characteristic measuring device can measure the parameters related to the dynamic shear characteristics of the mechanical-soil contact interface: according to the measured data recorded by the torque sensor (41), the rotation speed sensor (42), the diaphragm pressure sensor (43) and the vertical force sensor (45), the dynamic shear characteristics of the mechanical-soil contact interface under different conditions can be obtained by using the first formula, wherein the first formula is: where τ d is the dynamic shear stress at the mechanical-soil interface, τ max is the dynamic maximum shear stress of the soil, τ0is the quasi-static shear stress of the soil, v is the dynamic shear rate, and k is the dynamic shear deformation coefficient; In the study of the dynamic shear properties of the mechanical-soil contact interface, τ d may be calculated by the second formula, which is: wherein T m is the servo motor driving torque, r0 is the driving gear radius, m is the number of test shear plates in contact with the soil to be tested, A is the area of the test shear plate, τ f is the unit soil movement resistance on the side of the test shear plate; In the first formula, τ0 can be calculated by the third formula, wherein the third formula is: where c is the cohesion of the soil mass, N is the unit normal pressure of the shear plate to be measured, is the internal friction angle of the soil mass; In the first formula, v can be calculated by the fourth formula, wherein the fourth formula is: v = 2πnr0 Wherein n is the driving gear rotation speed; In the third formula, N can be calculated by the fifth formula, wherein the fifth formula is: where N w is the total normal force experienced by the shear panel under test; τ max The first formula τ max The maximum torque T max,0 measured by the torque sensor (41) at the moment of starting the servo motor (32) to make the soil under test have a tendency to slip can be measured by the chain test model 1 max,0 , and then T m = T max,0 , τ max is obtained by the second formula.

7. The method of claim 6, wherein: the mechanical-soil interface dynamic shear property is measured at a temperature of 20°C and a frequency of 10 Hz. The linear displacement sensor (44) can record the vertical deformation of the to-be-tested soil body, so as to analyze the pressure-bearing mechanical characteristics of the to-be-tested soil body; the traction force sensor (46) can record the horizontal traction force generated when the chain (11) rotates, so as to analyze the movement trend of the chain test model (1) and further optimize the chain transmission parameters; the miniature soil pressure cell (47) can record the distribution and change of the soil pressure in the to-be-tested soil body, and can analyze the disturbance of the actual traction component or excavating machinery to the surrounding soil body and optimize the corresponding structure parameters.

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