Surface soil dynamic mechanical property characterization device and method thereof

Abstract

The invention relates to a surface soil dynamic mechanical property characterization device and method, the characterization device comprises a rack, a power shaft fixing device, a thrust device and a torque device, the thrust device can drive a pressing plate or a shearing ring to apply vertical pressure to soil, and the torque device can drive the shearing ring to apply a shearing effect to the soil. The characterization method disclosed by the invention can be used for executing a conventional pressure-bearing or shearing characteristic test of the soil; periodic fluctuation can also be introduced to the movement speed and pressure, so that the pressure plate or the shearing ring vibrates in a superposed manner when applying pressure to the soil, thereby executing the dynamic pressure-bearing or shearing characteristic test of the soil. The method can represent the soil mechanical characteristics under the dynamic condition, and can lay a foundation for the subsequent research on the interaction mechanism between the wheels of agricultural machines and tools and the rugged and soft ground under the hilly and mountain environment.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural machinery equipment, and in particular to a device and method for characterizing the dynamic mechanical properties of surface soil. Background Art

[0002] Hilly and mountainous areas have problems such as rugged ground, soft soil, and high soil water content. However, the interaction mechanism between the wheels of agricultural machinery and the rugged and soft ground in hilly and mountainous areas is still unclear, resulting in a lack of theoretical guidance for chassis and tire design, which leads to poor passability, weak ride quality, and low stability of agricultural machinery in hilly and mountainous areas. As a result, agricultural machinery is prone to vibration, sinking, and slipping during movement and operation, which restricts the development of agricultural mechanization in hilly and mountainous areas. In order to clarify the interaction mechanism between the wheels of agricultural machinery and the rugged and soft ground in hilly and mountainous environments, it is necessary to characterize the mechanical properties of the surface soil under dynamic (vibration) conditions.

[0003] At present, there are three methods for characterizing soil mechanical properties, namely cone penetration test, Bain test, and geotechnical test (direct shear, triaxial compression, etc.). Due to its ability to describe the soil pressure-settlement relationship and shear stress-shear displacement behavior in situ, the Bain test is the most suitable method for characterizing the mechanical properties of surface soil in hilly and mountainous areas. Chinese patent CN103115832B discloses a soil pressure and shear test tester. Based on the test principle of the Bain instrument, a vertical load can be applied to the pressure plate using a weight to conduct a soil pressure test, and a torque can be manually applied to the shear ring using a torque wrench to conduct a soil shear property test. Since the vertical load and torque can only be adjusted manually, the patent has low accuracy in characterizing soil mechanical properties, and it is difficult to apply a vibration load to characterize the dynamic mechanical properties of the soil. Chinese patent CN111735703B discloses a portable Bain instrument, which is designed with three servo drive systems, which respectively control the up and down movement of the linear electric cylinder to apply a normal force to the soil, thereby independently measuring the soil pressure characteristics; and control the servo motor to drive the rotating shaft to rotate to apply a shear force to the soil, thereby independently measuring the soil shear characteristics. The patent uses a servo system to control the driving force, which can ensure a high accuracy in the characterization of soil mechanical properties. However, multiple sets of mechanisms are required to characterize the soil pressure and shear properties respectively, which makes the device structure complex and does not involve a method and device for characterizing soil mechanical properties under dynamic conditions. Therefore, there is currently a lack of a device and method for characterizing the dynamic mechanical properties of surface soil, which hinders the study of the interaction mechanism between the wheels of agricultural machinery and the rugged and soft ground in hilly and mountainous areas, and restricts the development of agricultural mechanization in hilly and mountainous areas. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a device and method for characterizing the dynamic mechanical properties of surface soil, which can characterize the mechanical properties of soil under dynamic conditions and lay a foundation for subsequent research on the interaction mechanism between agricultural machinery wheels and rugged and soft ground in hilly and mountainous environments.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A device for characterizing the dynamic mechanical properties of surface soil comprises a frame, on which a vertically arranged power shaft, a pressure plate, a shear ring, a thrust device and a torque device are arranged; The thrust device is connected to the power shaft to drive the power shaft to move up and down; the torque device is connected to the power shaft to drive the power shaft to rotate; A shear ring or a pressure plate is selectively connected to the lower end of the power shaft, the pressure plate is used to apply vertical pressure to the soil, and the shear ring is used to apply shear force to the soil; When performing a conventional soil pressure-bearing property test, the thrust device is used to output a constant pressure so that the power shaft moves downward at a uniform speed, driving the pressure plate to apply a constant pressure to the soil; When performing a soil dynamic bearing property test, the thrust device is used to output vibration pressure to make the power shaft vibrate downward, driving the pressure plate to apply periodic fluctuating pressure to the soil; When performing a conventional soil shear property test, the thrust device is used to output a constant pressure and the torque device outputs a rotational torque, so that the power shaft drives the shear ring to apply a constant pressure to the soil while applying shear force; when performing a dynamic soil shear property test, the thrust device is used to output a vibration pressure and the torque device outputs a rotational torque, so that the power shaft drives the shear ring to apply a periodically fluctuating pressure to the soil while applying shear force.

[0006] Furthermore, the thrust device includes a first servo motor, an electric cylinder and a normal force sensor, the first servo motor is fixed on the electric cylinder; the electric cylinder is fixed on the frame, the shaft end of the electric cylinder is connected to the normal force sensor; the normal force sensor is connected to the power shaft, and the power shaft is rotatably connected to the normal force sensor.

[0007] Furthermore, the frame includes a top plate, a sliding rod and a bottom plate. The upper and lower ends of the sliding rod are respectively fixed to the top plate and the bottom plate. The top plate and the bottom plate are arranged parallel to each other. The electric cylinder is fixed to the middle of the top plate and penetrates the top plate. A through hole is provided in the middle of the bottom plate to allow a shear ring or a pressure plate to pass through.

[0008] Furthermore, a sliding upper beam, a support rod and a sliding lower beam are provided between the top plate and the bottom plate, the upper and lower ends of the support rod are respectively fixed to the sliding upper beam and the sliding lower beam, the sliding upper beam and the sliding lower beam are respectively slidably connected to the sliding pull rod, and a pair of tapered roller bearings are installed in the sliding upper beam and the sliding lower beam; the power shaft is installed in the tapered roller bearings, and the normal force sensor is connected to the sliding upper beam.

[0009] Furthermore, the torque device includes a second servo motor, a torque sensor and a right-angle commutator which are horizontally arranged on one side of the power shaft and connected in sequence; the right-angle commutator is fixed on the sliding lower beam and cooperates with the power shaft through a flat key to convert the horizontal torque output by the second servo motor into a vertical direction and transmit it to the power shaft.

[0010] A method for characterizing the dynamic mechanical properties of surface soil comprises the following steps: When performing the soil conventional pressure bearing characteristic test, the thrust device outputs a constant pressure to make the power shaft move downward at a uniform speed, so as to drive the pressure plate to apply a constant pressure to the soil, explore the corresponding relationship between different pressures p and different depths z, and establish the soil conventional pressure bearing characteristic pz curve; When performing the soil dynamic bearing pressure test, the thrust device outputs vibration pressure to make the power shaft vibrate downward to drive the pressure plate to apply periodic fluctuating pressure to the soil, explore the corresponding relationship between different pressures p and different depths z, and establish the soil dynamic bearing pressure characteristic pz curve; When performing the conventional shear characteristic test of soil, the thrust device outputs a constant pressure and the torque device outputs a rotational torque, so that the power shaft drives the shear ring to apply a constant pressure and a shear force to the soil, explore the corresponding relationship between the rotation angle θ and the torque T under different pressures p, and establish the conventional shear characteristic θ-T curve of soil; When performing the soil dynamic shear characteristics test, the thrust device outputs vibration pressure and the torque device outputs rotational torque, so that the power shaft drives the shear ring to apply periodic fluctuating pressure to the soil while applying shear force, explore the corresponding relationship between the rotation angle θ and torque T under different pressures p, and establish the soil dynamic shear characteristics θ-T curve.

[0011] Furthermore, the steps of the conventional soil bearing property test are as follows: the movement speed v of the pressure plate and the vertical pressure p applied to the soil are set, and the signals are transmitted to the programmable logic controller; the programmable logic controller generates constant speed v and pressure p analog signals, and transmits them to the first driver in real time; the first driver controls the first servo motor to make the pressure plate move downward at a constant speed v as the control amount; when the pressure plate contacts the soil, the pressure value p fed back by the normal force sensor is f The pressure plate will continue to rise as its depth into the soil increases; the data acquisition system records that the position z and time t are both 0 at this time, and starts recording the time t and speed vf ; When the pressure value p f After reaching the pressure setting value p, the first driver controls the first servo motor to make the pressing plate continue to move downward with a constant pressure p as the control amount until the speed drops to 0; the data acquisition system stops recording the time t and speed v f ; Determine the depth of the pressure plate into the soil , and use this to establish the corresponding relationship between pressure p and soil depth z; repeat the above steps multiple times to explore the corresponding relationship between different pressures p and different depths z, and then the soil conventional bearing capacity pz curve can be established.

[0012] Furthermore, the steps of testing the dynamic bearing characteristics of soil are as follows: setting the movement speed v of the pressure plate, the vertical pressure p applied to the soil, the vibration frequency f, and the amplitude A, and transmitting them to the programmable logic controller; the programmable logic controller generates a periodic fluctuation speed and pressure The analog signal is transmitted to the first driver in real time; the first driver controls the first servo motor to make the pressing plate move at a periodically fluctuating speed. To control the downward vibration movement; when the pressure plate contacts the soil, the pressure value p fed back by the normal force sensor f The pressure plate will continue to rise as its depth into the soil increases; the data acquisition system records that the position z and time t are both 0 at this time, and starts recording the time t and speed v f ; When the pressure value p f After reaching the pressure setting value p, the first driver controls the first servo motor to make the pressure plate fluctuate periodically. To control the amount to continue to vibrate downward until the speed drops to near 0, the data acquisition system stops recording time t and speed v f ; Determine the depth of the pressure plate into the soil , and use this to establish the corresponding relationship between pressure p and soil depth z; repeat the above steps multiple times to explore the corresponding relationship between different pressures p and different depths z, and then the soil dynamic bearing capacity characteristic pz curve can be established.

[0013] Furthermore, the steps of the conventional shear property test of soil are as follows: the movement speed v of the shear ring, the vertical pressure p applied to the soil, the rotation speed ω, and the rotation torque T are set, and transmitted to the programmable logic controller; the programmable logic controller generates a constant speed v and pressure p analog signal, and transmits it to the first driver in real time; the programmable logic controller generates an analog signal of the rotation speed ω and the torque T, and transmits it to the second driver in real time; the first driver controls the first servo motor to make the shear ring move downward at a constant speed v as the control amount; when the shear ring contacts the soil, the pressure value p fed back by the normal force sensor f It will continue to rise as the shear ring sinks deeper into the soil; when the pressure value pf After reaching the pressure setting value p, the first driver controls the first servo motor to make the shear ring continue to move downward with a constant pressure p as the control amount until the speed drops to 0. The first driver continues to control the shear ring to continuously apply a constant pressure p to the soil. The data acquisition system records that the rotation angle θ and time t are both 0 at this time, and starts to record the time t and the speed ω f , torque value T f The second driver controls the second servo motor to rotate the shear ring at a speed ω as the control amount until the torque value T f No longer increases, that is, the soil has been cut off at this time; the data acquisition system stops recording the recording time t and speed ω f , torque value T f ; Determine the angle of rotation of the shear ring , and use this to establish the corresponding relationship between the rotation angle θ and the torque T; perform the above steps multiple times to explore the corresponding relationship between the rotation angle θ and the torque T under different pressures p, and then the conventional shear characteristic θ-T curve of the soil can be established.

[0014] Furthermore, the steps of testing the dynamic shear characteristics of soil are as follows: setting the movement speed v of the shear ring, the vertical pressure p applied to the soil, the rotation speed ω, the rotation torque T, the vibration frequency f, and the amplitude A, and transmitting them to the programmable logic controller; the programmable logic controller generates a periodic fluctuation speed and pressure The analog signal is transmitted to the first driver in real time; the programmable logic controller generates analog signals of speed ω and torque T, and transmits them to the second driver in real time; the first driver controls the first servo motor to make the shear ring move at a periodically fluctuating speed To control the downward vibration movement; when the shear ring contacts the soil, the pressure value p fed back by the normal force sensor f It will continue to rise as the shear ring sinks deeper into the soil; when the pressure value p f After reaching the pressure setting value p, the first driver controls the first servo motor to make the shear ring fluctuate with periodic pressure. To control the amount of vibration, the machine continues to vibrate downward until the speed drops to near 0; the first drive continues to control the shear ring to continuously apply periodic fluctuating pressure to the soil. ; The data acquisition system records that the rotation angle θ and time t are both 0 at this time, and starts recording time t and speed ω f , torque value T f The second driver controls the second servo motor to rotate the shear ring at a speed ω as the control amount until the torque value T f No longer increases, the data acquisition system stops recording time t and speed ω f , torque value T f ; Determine the angle of rotation of the shear ring 18 , and establish the corresponding relationship between the rotation angle θ and the torque T; perform the above steps multiple times to explore the corresponding relationship between the rotation angle θ and the torque T under different pressures p, and then establish the soil dynamic shear characteristic θ-T curve.

[0015] In general, the present invention has the following advantages: 1. It can not only provide the linear motion required for the soil bearing pressure property test, but also provide the torsional motion required for the soil shear property test, so that the soil mechanical property characterization device has the characteristics of simple structure, good stability and high reliability.

[0016] 2. The servo motor control system is adopted to automate the whole characterization process, which has the characteristics of simple operation and accurate measurement.

[0017] 3. It has the ability to characterize the mechanical properties of soil under dynamic conditions, which can lay the foundation for subsequent research on the interaction mechanism between agricultural machinery wheels and rugged and soft ground in hilly and mountainous environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of the device for characterizing the dynamic mechanical properties of surface soil of the present invention.

[0019] Figure 2 It is a schematic diagram of the planar structure of the device for characterizing the dynamic mechanical properties of surface soil of the present invention.

[0020] FIG3 (a) is a schematic diagram of the structure of the pressing plate of the present invention.

[0021] FIG3( b ) is a schematic diagram of the structure of the shear ring of the present invention.

[0022] Figure 4 Schematic diagram of a control system according to an embodiment of the present invention.

[0023] FIG. 5( a ) is a schematic diagram of a conventional soil bearing pressure characteristic test speed according to an embodiment of the present invention.

[0024] FIG5( b ) is a schematic diagram of the conventional soil bearing pressure test pressure according to an embodiment of the present invention.

[0025] FIG. 6( a ) is a schematic diagram of the test speed of the dynamic bearing capacity of soil according to an embodiment of the present invention.

[0026] FIG6( b ) is a schematic diagram of the soil dynamic bearing pressure characteristic test pressure according to an embodiment of the present invention.

[0027] FIG. 7( a ) is a schematic diagram of a conventional soil shear property test velocity according to an embodiment of the present invention.

[0028] FIG. 7( b ) is a schematic diagram of a conventional soil shear property test pressure according to an embodiment of the present invention.

[0029] FIG8( a ) is a schematic diagram of the test speed of soil dynamic shear characteristics according to an embodiment of the present invention.

[0030] FIG8( b ) is a schematic diagram of soil dynamic shear property test pressure according to an embodiment of the present invention.

[0031] In the figure: 1-first servo motor; 2-electric cylinder; 3-top plate; 4-normal force sensor; 5-sliding upper beam; 6-support rod; 7-sliding lower beam; 8-sliding bearing; 9-sliding pull rod; 10-bottom plate; 11-tapered roller bearing; 12-power shaft; 13-right angle commutator; 14-torque sensor; 15-second servo motor; 16-transition shaft; 17-pressure plate; 18-shear ring; 19-touch screen; 20-programmable logic controller; 21-first driver; 22-second driver; 23-data acquisition system. DETAILED DESCRIPTION

[0032] The present invention will be described in further detail below.

[0033] like Figure 1 , Figure 2 As shown, a device for characterizing the dynamic mechanical properties of surface soil includes a frame, a power shaft fixing device, a thrust device, a torque device, and a control system. The thrust device can drive the power shaft fixing device to move up and down, thereby driving the pressure plate 17 or the shear ring 18 to apply vertical pressure to the soil through the power shaft 12; the torque device can drive the power shaft 12 to rotate and provide torque to it, thereby driving the shear ring 18 to shear the soil.

[0034] The frame includes a top plate 3, a sliding rod 9, and a bottom plate 10. The bottom plate 10 is placed on the ground, four sliding rods 9 evenly arranged are fixed to the bottom plate 10 with screws, and the top plate 3 and the four sliding rods 9 are fixed with screws so that the top plate 3 and the bottom plate 10 are parallel.

[0035] The power shaft fixing device includes a sliding upper crossbeam 5, a support rod 6, a sliding lower crossbeam 7, a sliding bearing 8, a tapered roller bearing 11, and a power shaft 12. Each sliding pull rod 9 is equipped with two sliding bearings 8, and the sliding upper crossbeam 5 and the sliding lower crossbeam 7 are connected by screws and sliding bearings 8, so that the upper crossbeam 5 and the sliding lower crossbeam 7 can only move up and down; the sliding upper crossbeam 5 and the sliding lower crossbeam 7 are fixed by screws and support rods 6, so that the distance between the sliding upper crossbeam 5 and the sliding lower crossbeam 7 is constant; a pair of tapered roller bearings 11 are installed in the sliding upper crossbeam 5 and the sliding lower crossbeam 7; the power shaft 12 is installed in the tapered roller bearing 11, so that the power shaft 12 cannot move axially, but can only move up and down with the sliding upper crossbeam 5 and the sliding lower crossbeam 7, and the power shaft 12 is allowed to rotate.

[0036] The thrust device includes a first servo motor 1, an electric cylinder 2, and a normal force sensor 4. The first servo motor 1 is equipped with a reducer and fixed on the electric cylinder 2; the electric cylinder 2 is fixed on the top plate 3 by screws, and its shaft end extends through the round hole of the top plate 3; the shaft end of the electric cylinder 2 is connected to the normal force sensor 4 by a thread; the normal force sensor 4 is connected to the sliding upper crossbeam 5 by screws; driven by the first servo motor 1, the shaft end of the electric cylinder 2 can move up and down, and through the normal force sensor 4, the power shaft fixing device can be driven to move up and down, and then the power shaft 12 can be driven to move up and down; at the same time, the normal force sensor 4 can be used to record the real-time vertical load.

[0037] The torque device includes a right-angle commutator 13, a torque sensor 14, and a second servo motor 15, which are horizontally arranged on one side of the power shaft 12. The second servo motor 15 is connected to the torque sensor 14 through screws; the torque sensor 14 is connected to the right-angle commutator 13 through screws, and the right-angle commutator 13 is fixed on the sliding lower cross beam 7 through screws, and cooperates with the power shaft 12 through a flat key; under the drive of the second servo motor 15, its torque can be transmitted to the torque sensor 14, and then transmitted to the input end of the right-angle commutator 13; through the bevel gear inside the right-angle commutator 13, the torque direction can be converted from the horizontal direction to the vertical direction, and through the cooperation of the flat key, the torque is transmitted to the power shaft 12. Since the power shaft 12 is installed in the tapered roller bearing 11, the power shaft 12 can rotate in the tapered roller bearing 11 without axial movement. Therefore, the downward pressure applied by the thrust device to the power shaft 12 and the horizontal torque applied by the torque device to the power shaft 12 can be independent of each other and not affected. Therefore, vertical pressure and horizontal shear tests can be carried out simultaneously, which is conducive to achieving the characterization of various comprehensive mechanical properties of the surface soil.

[0038] The power shaft 12 is connected to the transition shaft 16 via threads; the transition shaft 16 is connected to the pressure plate 17 via screws.

[0039] The pressure plate 17 can be replaced with a shear ring 18, as shown in FIG. 3(a) and FIG. 3(b), wherein the pressure plate 17 is used for soil pressure bearing test and the shear ring 18 is used for soil shear test.

[0040] Control system such as Figure 4 As shown, the touch screen 19 can set the test parameters such as the up and down movement speed v of the pressure plate 17 or the shear ring 18, the vertical pressure p applied to the soil, the rotation speed ω, the rotation torque T, the vibration frequency f, the amplitude A, etc.; the touch screen 19 transmits the test parameters to the programmable logic controller 20; the programmable logic controller 20 converts the test parameters into real-time motion analog signals and transmits them to the first driver 21 and the second driver 22; the first driver 21 uses the real-time motion analog signal as a reference value and uses the speed value v of the above-mentioned thrust device as a reference value. f(derived from the encoder of the first servo motor 1) and the pressure value p f (derived from the normal force sensor 4) as feedback, control the pressure plate 17 or the shear ring 18 to apply pressure to the soil; the second driver 22 uses the real-time motion analog signal as a reference value and the speed value ω of the torque device as a reference value. f (derived from the encoder of the second servo motor 15) and torque value T f (Torque sensor 14) is the feedback quantity, which controls the shear ring 18 to apply torque to the soil; at the same time, the feedback speed value v f , pressure value p f , speed value ω f , torque value T f All are transmitted to the data acquisition system 23 for storage and record.

[0041] This embodiment implements a method for characterizing the dynamic mechanical properties of surface soil through the above-mentioned device, and can execute conventional soil bearing pressure property test, dynamic soil bearing pressure property test, conventional soil shear property test, and dynamic soil shear property test.

[0042] The conventional soil pressure-bearing characteristic test is as follows: the conventional soil pressure-bearing characteristic test module is selected on the touch screen 19; the movement speed v of the pressing plate 17 and the vertical pressure p applied to the soil are set on the touch screen 19, and transmitted to the programmable logic controller 20; the programmable logic controller 20 will generate a constant speed v and pressure p analog signal, and transmit it to the first driver 21 in real time; as shown in Figures 5 (a) and 5 (b), the first driver 21 will control the first servo motor 1 to make the pressing plate 17 move downward at a constant speed v as the control amount; when the pressing plate 17 contacts the soil, the pressure value p fed back by the normal force sensor 4 is f The pressure plate 17 will continue to rise as the depth of the soil increases; the data acquisition system 23 will record that the position z and time t are both 0 at this time, and start recording the time t and speed v f ; When the pressure value p f After reaching the pressure setting value p, the first driver 21 controls the first servo motor 1 to make the pressing plate 17 continue to move downward with a constant pressure p as the control amount until the speed drops to 0, that is, it can no longer continue to fall; the data acquisition system 23 stops recording the time t and speed v f ; It can be determined that the depth of the pressing plate 17 into the soil is , and use this to establish the corresponding relationship between pressure p and soil depth z; repeat the above steps multiple times to explore the corresponding relationship between different pressures p and different depths z, and then the soil conventional bearing capacity pz curve can be established.

[0043] The soil dynamic bearing pressure characteristic test is as follows: the soil dynamic bearing pressure characteristic test module is selected on the touch screen 19; the movement speed v of the pressing plate 17, the vertical pressure p applied to the soil, the vibration frequency f, and the amplitude A are set on the touch screen 19, and transmitted to the programmable logic controller 20; the programmable logic controller 20 generates a periodic fluctuation speed and pressure The analog signal is transmitted to the first driver 21 in real time; as shown in FIG6 (a) and FIG6 (b), the first driver 21 controls the first servo motor 1 to make the pressing plate 17 move at a periodically fluctuating speed. To control the downward vibration movement; when the pressure plate 17 contacts the soil, the pressure value p fed back by the normal force sensor 4 f The pressure plate 17 will continue to rise as the depth of the soil increases; the data acquisition system 23 will record that the position z and time t are both 0 at this time, and start recording the time t and speed v f ; When the pressure value p f When the pressure setting value p is reached, the first driver 21 controls the first servo motor 1 to make the pressure plate 17 fluctuate periodically. The control quantity continues to vibrate downward until the speed drops to near 0, that is, it can no longer drop; the data acquisition system 23 stops recording the time t and speed v f ; It can be determined that the depth of the pressing plate 17 into the soil is , and use this to establish the corresponding relationship between pressure p and soil depth z; repeat the above steps multiple times to explore the corresponding relationship between different pressures p and different depths z, and then the soil dynamic bearing capacity characteristic pz curve can be established.

[0044] The conventional shear characteristic test of the soil mentioned above: select the conventional shear characteristic test module of the soil on the touch screen 19; set the movement speed v of the shear ring 18, the vertical pressure p applied to the soil, the rotation speed ω, and the rotation torque T on the touch screen 19, and transmit them to the programmable logic controller 20; the programmable logic controller 20 will generate a constant speed v and pressure p analog signal, and transmit it to the first driver 21 in real time; in addition, the programmable logic controller 20 will generate an analog signal of the rotation speed ω and the torque T, and transmit it to the second driver 22 in real time; as shown in Figure 7 (a) and Figure 7 (b), the first driver 21 will control the first servo motor 1 to make the shear ring 18 move downward at a constant speed v as the control amount; when the shear ring 18 contacts the soil, the pressure value p fed back by the normal force sensor 4 f The pressure will continue to rise as the shear ring 18 sinks deeper into the soil; when the pressure value p fAfter reaching the pressure setting value p, the first driver 21 will control the first servo motor 1 to make the shear ring 18 continue to move downward with the constant pressure p as the control amount until the speed drops to 0, that is, it can no longer drop; the first driver 21 continues to control the shear ring 18 to continuously apply the constant pressure p to the soil; the data acquisition system 23 will record that the rotation angle θ and time t are both 0 at this time, and start recording the time t and the speed ω f , torque value T f The second driver 22 controls the second servo motor 15 to rotate the shear ring 18 at a speed ω as the control amount until the torque value T f No longer increases, that is, the soil has been cut off at this time; the data acquisition system 23 stops recording the recording time t, speed ω f , torque value T f ; It can be determined that the angle of rotation of the shear ring 18 is , and use this to establish the corresponding relationship between the rotation angle θ and the torque T; perform the above steps multiple times to explore the corresponding relationship between the rotation angle θ and the torque T under different pressures p, and then the conventional shear characteristic θ-T curve of the soil can be established.

[0045] The soil dynamic shear characteristic test is as follows: the soil dynamic shear characteristic test module is selected on the touch screen 19; the movement speed v of the shear ring 18, the vertical pressure p applied to the soil, the rotation speed ω, the rotation torque T, the vibration frequency f, and the amplitude A are set on the touch screen 19 and transmitted to the programmable logic controller 20; the programmable logic controller 20 generates a periodic fluctuation speed and pressure The analog signal is transmitted to the first driver 21 in real time; in addition, the programmable logic controller 20 will generate analog signals of the speed ω and the torque T, and transmit them to the second driver 22 in real time; as shown in Figure 8 (a) and Figure 8 (b), the first driver 21 will control the first servo motor 1 to make the shear ring 18 move at a periodically fluctuating speed. To control the downward vibration movement; when the shear ring 18 contacts the soil, the pressure value p fed back by the normal force sensor 4 f The pressure will continue to rise as the shear ring 18 sinks deeper into the soil; when the pressure value p f When the pressure setting value p is reached, the first driver 21 controls the first servo motor 1 to make the shear ring 18 move at a periodically fluctuating pressure. To control the amount of vibration to continue downward movement until the speed drops to near 0; the first driver 21 continues to control the shear ring 18 to continue to apply periodic fluctuating pressure to the soil The data acquisition system 23 will record that the angle θ and time t are both 0 at this time, and start recording time t, speed ω f , torque value T fThe second driver 22 controls the second servo motor 15 to rotate the shear ring 18 at a speed ω as the control amount until the torque value T f No longer increases, that is, the soil has been sheared off at this time; the data acquisition system 23 stops recording time t and speed ω f , torque value T f ; It can be determined that the angle of rotation of the shear ring 18 is , and establish the corresponding relationship between the rotation angle θ and the torque T; perform the above steps multiple times to explore the corresponding relationship between the rotation angle θ and the torque T under different pressures p, and then establish the soil dynamic shear characteristic θ-T curve.

[0046] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A device for characterizing the dynamic mechanical properties of surface soil, characterized in that: The machine comprises a frame on which a vertically arranged power shaft, a pressure plate, a shear ring, a thrust device and a torque device are arranged; The thrust device is connected to the power shaft to drive the power shaft to move up and down; the torque device is connected to the power shaft to drive the power shaft to rotate; A shear ring or a pressure plate is selectively connected to the lower end of the power shaft, the pressure plate is used to apply vertical pressure to the soil, and the shear ring is used to apply shear force to the soil; When performing a conventional soil pressure-bearing property test, the thrust device is used to output a constant pressure so that the power shaft moves downward at a uniform speed, driving the pressure plate to apply a constant pressure to the soil; When performing a soil dynamic bearing property test, the thrust device is used to output vibration pressure to make the power shaft vibrate downward, driving the pressure plate to apply periodic fluctuating pressure to the soil; When performing a conventional soil shear property test, the thrust device is used to output a constant pressure and the torque device outputs a rotational torque, so that the power shaft drives the shear ring to apply a constant pressure to the soil while applying a shear force; When performing a soil dynamic shear property test, the thrust device is used to output vibration pressure and the torque device is used to output rotation torque, so that the power shaft drives the shear ring to apply periodic fluctuating pressure to the soil while applying shear force.

2. A surface soil dynamic mechanical properties characterization device according to claim 1, characterized in that: The thrust device includes a first servo motor, an electric cylinder and a normal force sensor. The first servo motor is fixed on the electric cylinder; the electric cylinder is fixed on the frame, and the shaft end of the electric cylinder is connected to the normal force sensor; the normal force sensor is connected to the power shaft, and the power shaft is rotatably connected to the normal force sensor.

3. A surface soil dynamic mechanical properties characterization device according to claim 2, characterized in that: The frame includes a top plate, a sliding rod and a bottom plate. The upper and lower ends of the sliding rod are fixed to the top plate and the bottom plate respectively. The top plate and the bottom plate are arranged in parallel. The electric cylinder is fixed to the middle of the top plate and penetrates the top plate. The middle of the bottom plate is provided with a through hole allowing a shear ring or a pressure plate to pass through.

4. A surface soil dynamic mechanical properties characterization device according to claim 3, characterized in that: An upper sliding beam, a support rod and a lower sliding beam are provided between the top plate and the bottom plate. The upper and lower ends of the support rod are respectively fixed to the upper sliding beam and the lower sliding beam. The upper sliding beam and the lower sliding beam are respectively slidably connected to the sliding pull rod. A pair of tapered roller bearings are installed in the upper sliding beam and the lower sliding beam. The power shaft is installed in the tapered roller bearings, and the normal force sensor is connected to the upper sliding beam.

5. The device for characterizing the dynamic mechanical properties of surface soil according to claim 1, characterized in that: The torque device includes a second servo motor, a torque sensor and a right-angle commutator which are horizontally arranged on one side of the power shaft and connected in sequence; the right-angle commutator is fixed on the sliding lower beam and cooperates with the power shaft through a flat key to convert the horizontal torque output by the second servo motor into a vertical direction and transmit it to the power shaft.

6. A method for characterizing the dynamic mechanical properties of surface soil, characterized in that: The device for characterizing the dynamic mechanical properties of surface soil according to any one of claims 1 to 5 comprises the following steps: When performing the soil conventional pressure bearing characteristic test, the thrust device outputs a constant pressure, causing the power shaft to move downward at a uniform speed, driving the pressure plate to apply a constant pressure to the soil, exploring the corresponding relationship between different pressures p and different depths z, and establishing the soil conventional pressure bearing characteristic pz curve; When performing the soil dynamic bearing pressure test, the thrust device outputs vibration pressure to make the power shaft vibrate downward, driving the pressure plate to apply periodic fluctuating pressure to the soil, exploring the corresponding relationship between different pressures p and different depths z, and establishing the soil dynamic bearing pressure characteristic pz curve; When performing the conventional shear characteristic test of soil, the thrust device outputs a constant pressure and the torque device outputs a rotational torque, so that the power shaft drives the shear ring to apply a constant pressure and a shear force to the soil, explore the corresponding relationship between the rotation angle θ and the torque T under different pressures p, and establish the conventional shear characteristic θ-T curve of soil; When performing the soil dynamic shear characteristics test, the thrust device outputs vibration pressure and the torque device outputs rotational torque, so that the power shaft drives the shear ring to apply periodic fluctuating pressure to the soil while applying shear force, exploring the corresponding relationship between the rotation angle θ and torque T under different pressures p, and establishing the soil dynamic shear characteristics θ-T curve.

7. A method for characterizing the dynamic mechanical properties of surface soil according to claim 6, characterized in that: The steps of the conventional soil bearing property test are as follows: the movement speed v of the pressure plate and the vertical pressure p applied to the soil are set, and the signals are transmitted to the programmable logic controller; the programmable logic controller generates constant speed v and pressure p analog signals, and transmits them to the first driver in real time; the first driver controls the first servo motor to make the pressure plate move downward at a constant speed v as the control amount; when the pressure plate contacts the soil, the pressure value p fed back by the normal force sensor is f The pressure plate will continue to rise as its depth into the soil increases; the data acquisition system records that the position z and time t are both 0 at this time, and starts recording the time t and speed v f ; When the pressure value p f After reaching the pressure setting value p, the first driver controls the first servo motor to make the pressing plate continue to move downward with a constant pressure p as the control amount until the speed drops to 0; the data acquisition system stops recording the time t and speed v f ; Determine the depth of the pressure plate into the soil , and use this to establish the corresponding relationship between pressure p and soil depth z; repeat the above steps multiple times to explore the corresponding relationship between different pressures p and different depths z, and then the soil conventional bearing capacity pz curve can be established.

8. A method for characterizing the dynamic mechanical properties of surface soil according to claim 6, characterized in that: The steps of testing the dynamic bearing characteristics of soil are as follows: setting the movement speed v of the pressure plate, the vertical pressure p applied to the soil, the vibration frequency f, and the amplitude A, and transmitting them to the programmable logic controller; the programmable logic controller generates a periodic fluctuation speed and pressure Analog quantity signal, and transmit it to the first driver in real time; The first driver controls the first servo motor to move the platen at a periodically fluctuating speed. To control the downward vibration movement; when the pressure plate contacts the soil, the pressure value p fed back by the normal force sensor f The pressure plate will continue to rise as its depth into the soil increases; the data acquisition system records that the position z and time t are both 0 at this time, and starts recording the time t and speed v f ; When the pressure value p f After reaching the pressure setting value p, the first driver controls the first servo motor to make the pressure plate fluctuate periodically. To control the amount to continue to vibrate downward until the speed drops to near 0, the data acquisition system stops recording time t and speed v f ; Determine the depth of the pressure plate into the soil , and use this to establish the corresponding relationship between pressure p and soil depth z; repeat the above steps multiple times to explore the corresponding relationship between different pressures p and different depths z, and then the soil dynamic bearing capacity characteristic pz curve can be established.

9. A method for characterizing the dynamic mechanical properties of surface soil according to claim 6, characterized in that: The steps of the conventional soil shear property test are: setting the movement speed v of the shear ring, the vertical pressure p applied to the soil, the rotation speed ω, and the rotation torque T, and transmitting them to the programmable logic controller; the programmable logic controller generates a constant speed v and pressure p analog signal, and transmits it to the first driver in real time; The programmable logic controller generates analog signals of speed ω and torque T and transmits them to the second driver in real time; the first driver controls the first servo motor to make the shear ring move downward at a constant speed v as the control amount; when the shear ring contacts the soil, the pressure value p fed back by the normal force sensor f It will continue to rise as the shear ring sinks deeper into the soil; when the pressure value p f After reaching the pressure setting value p, the first driver controls the first servo motor to make the shear ring continue to move downward with the constant pressure p as the control amount until the speed drops to 0, and the first driver continues to control the shear ring to continuously apply the constant pressure p to the soil; The data acquisition system records that the rotation angle θ and time t are both 0 at this time, and starts recording time t and speed ω f , torque value T f The second driver controls the second servo motor to rotate the shear ring at a speed ω as the control amount until the torque value T f No longer increases, that is, the soil has been cut off at this time; the data acquisition system stops recording the recording time t and speed ω f , torque value T f ; Determine the angle of rotation of the shear ring , and establish the corresponding relationship between the rotation angle θ and the torque T; perform the above steps multiple times to explore the corresponding relationship between the rotation angle θ and the torque T under different pressures p, and then establish the conventional shear characteristic θ-T curve of the soil.

10. A method for characterizing the dynamic mechanical properties of surface soil according to claim 6, characterized in that: The steps of testing the dynamic shear characteristics of soil are as follows: setting the movement speed v of the shear ring, the vertical pressure p applied to the soil, the rotation speed ω, the rotation torque T, the vibration frequency f, and the amplitude A, and transmitting them to the programmable logic controller; the programmable logic controller generates a periodic fluctuation speed and pressure Analog quantity signal, and transmit it to the first driver in real time; The programmable logic controller generates analog signals of speed ω and torque T and transmits them to the second driver in real time; the first driver controls the first servo motor to make the shear ring move at a periodically fluctuating speed. To control the downward vibration movement; when the shear ring contacts the soil, the pressure value p fed back by the normal force sensor f It will continue to rise as the shear ring sinks deeper into the soil; when the pressure value p f After reaching the pressure setting value p, the first driver controls the first servo motor to make the shear ring fluctuate with periodic pressure. To control the amount of vibration, the machine continues to vibrate downward until the speed drops to near 0; the first drive continues to control the shear ring to continuously apply periodic fluctuating pressure to the soil. ; The data acquisition system records that the rotation angle θ and time t are both 0 at this time, and starts recording time t and speed ω f , torque value T f The second driver controls the second servo motor to rotate the shear ring at a speed ω as the control amount until the torque value T f No longer increases, the data acquisition system stops recording time t and speed ω f , torque value T f ; Determine the angle of rotation of the shear ring 18 , and establish the corresponding relationship between the rotation angle θ and the torque T; perform the above steps multiple times to explore the corresponding relationship between the rotation angle θ and the torque T under different pressures p, and then establish the soil dynamic shear characteristic θ-T curve.

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