A device and method for characterizing dynamic mechanical properties of surface soil

Abstract

This invention relates to a device and method for characterizing the dynamic mechanical properties of surface soil. The characterization device includes a frame, a power shaft fixing device, a thrust device, and a torque device. The thrust device drives a pressure plate or shear ring to apply vertical pressure to the soil, and the torque device drives the shear ring to apply shear force to the soil. The characterization method of this invention can perform conventional soil bearing or shear property tests; it can also introduce periodic fluctuations in movement speed and pressure, causing the pressure plate or shear ring to apply pressure to the soil and superimpose vibrations, thereby performing dynamic soil bearing or shear property tests. This method can characterize the mechanical properties of soil under dynamic conditions and can lay the foundation for subsequent research on the interaction mechanism between agricultural machinery wheels and rugged, soft ground in hilly and mountainous environments.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery and equipment technology, specifically to a device and method for characterizing the dynamic mechanical properties of surface soil. Background Technology

[0002] Hilly and mountainous areas are characterized by rugged terrain, loose soil, and high soil moisture content. However, the interaction mechanism between agricultural machinery wheels and the rugged, loose ground in hilly and mountainous areas remains unclear. This lack of theoretical guidance for chassis and tire design leads to poor maneuverability, weak ride comfort, and low stability of agricultural machinery in hilly and mountainous environments. Consequently, agricultural machinery is prone to vibration, getting stuck, and slipping during movement and operation, which hinders the development of agricultural mechanization in hilly and mountainous areas. To clarify the interaction mechanism between agricultural machinery wheels and rugged, loose ground in hilly and mountainous environments, it is necessary to characterize the mechanical properties of the surface soil under dynamic (vibration) conditions.

[0003] Currently, there are three methods for characterizing soil mechanical properties: cone penetration test, Bainck test, and geotechnical tests (direct shear, triaxial compression, etc.). Due to its ability to describe soil pressure-settlement relationships and shear stress-shear displacement behavior in situ, the Bainck test is the most suitable method for characterizing the mechanical properties of surface soils in hilly and mountainous areas. Chinese patent CN103115832B discloses a soil bearing capacity and shear test instrument. Based on the Bainck test principle, it can apply a vertical load to the pressure plate using weights to conduct soil bearing capacity tests, and can manually apply torque to the shear ring using a torsion wrench to conduct soil shear characteristic tests. However, because the vertical load and torque can only be manually adjusted, this patent has low accuracy in characterizing soil mechanical properties and is difficult to apply vibration loads to characterize dynamic soil mechanical properties. Chinese patent CN111735703B discloses a portable Bainck instrument with three servo drive systems. These systems control the vertical movement of linear electric cylinders to apply normal force to the soil, thereby independently measuring soil bearing capacity; and control a servo motor to drive the rotating shaft to apply shear force to the soil, thereby independently measuring soil shear characteristics. This patent employs a servo system to control the driving force, ensuring high accuracy in characterizing soil mechanical properties. However, it requires multiple mechanisms to characterize soil bearing and shear properties separately, resulting in a complex device structure. Furthermore, it does not address methods or devices for characterizing soil mechanical properties under dynamic conditions. Therefore, the current lack of a device and method for characterizing the dynamic mechanical properties of surface soil hinders research into the interaction mechanism between agricultural machinery wheels and the rugged, soft ground in hilly and mountainous areas, thus restricting the development of agricultural mechanization in these regions. Summary of the Invention

[0004] To address the problems existing in the prior art, the purpose of this 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, laying the foundation for subsequent research on the interaction mechanism between agricultural machinery wheels and rugged, soft ground in hilly and mountainous environments.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A device for characterizing the dynamic mechanical properties of surface soil includes a frame, on which a vertically arranged power shaft, pressure plate, shear ring, thrust device and torque device are provided;

[0007] The thrust device is connected to the power shaft and is used to drive the power shaft to move up and down; the torque device is connected to the power shaft and is used to drive the power shaft to rotate.

[0008] A shear ring or 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.

[0009] When performing conventional soil bearing capacity tests, the thrust device is used to output constant pressure so that the power shaft moves downward at a constant speed, driving the pressure plate to apply constant pressure to the soil.

[0010] When performing soil dynamic bearing capacity tests, 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.

[0011] When performing conventional soil shear characteristic tests, the thrust device outputs constant pressure and the torque device outputs rotational torque, so that the power shaft drives the shear ring to apply constant pressure to the soil while applying shear force; when performing dynamic soil shear characteristic tests, the thrust device outputs vibration pressure and the torque device outputs rotational torque, so that the power shaft drives the shear ring to apply periodically fluctuating pressure to the soil while applying shear force.

[0012] 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, 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.

[0013] Furthermore, the frame includes a top plate, a sliding tie rod, and a bottom plate. The upper and lower ends of the sliding tie rod are fixed to the top plate and the bottom plate, respectively. 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 passes through the top plate. The middle of the bottom plate is provided with a through hole that allows a shearing ring or pressure plate to pass through.

[0014] Furthermore, a sliding upper crossbeam, a support rod, and a sliding lower crossbeam 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 crossbeam and the sliding lower crossbeam. The sliding upper crossbeam and the sliding lower crossbeam are respectively slidably connected to the sliding tie rod. A pair of tapered roller bearings are installed in the sliding upper crossbeam and the sliding lower crossbeam. The power shaft is installed in the tapered roller bearings, and the normal force sensor is connected to the sliding upper crossbeam.

[0015] Furthermore, the torque device includes a second servo motor, a torque sensor, and a right-angle commutator, which are horizontally mounted on one side of the power shaft and connected in sequence. The right-angle commutator is fixed on the sliding lower crossbeam and cooperates with the power shaft through a flat key to convert the horizontal torque output by the second servo motor into a vertical torque that is transmitted to the power shaft.

[0016] A method for characterizing the dynamic mechanical properties of surface soil includes the following steps:

[0017] When performing conventional soil bearing capacity tests, the thrust device outputs constant pressure, causing the power shaft to move downward at a uniform speed, thereby driving the pressure plate to apply constant pressure to the soil, exploring the correspondence between different pressures p and different depths z, and establishing the pz curve of conventional soil bearing capacity.

[0018] When performing soil dynamic bearing capacity test, the thrust device outputs vibration pressure, causing the power shaft to vibrate downwards, so as to drive the pressure plate to apply periodic fluctuating pressure to the soil, explore the correspondence between different pressures p and different depths z, and establish the soil dynamic bearing capacity pz curve.

[0019] When performing conventional soil shear characteristics tests, the thrust device outputs constant pressure and the torque device outputs rotational torque, so that the power shaft drives the shear ring to apply constant pressure to the soil while applying shear force. The corresponding relationship between rotation angle θ and torque T under different pressures p is explored, and the θ-T curve of conventional soil shear characteristics is established.

[0020] When performing dynamic shear characteristic tests on soil, the thrust device outputs vibration pressure and the torque device outputs rotational torque, causing the power shaft to drive the shear ring to apply periodic fluctuating pressure to the soil while simultaneously applying shear force. The corresponding relationship between rotation angle θ and torque T under different pressures p is explored, and the θ-T curve of dynamic shear characteristics of soil is established.

[0021] Furthermore, the steps for testing the conventional bearing capacity of soil are as follows: The movement speed *v* of the pressure plate and the vertical pressure *p* applied to the soil are set and transmitted to the programmable logic controller (PLC); the PLC generates constant analog signals for speed *v* and pressure *p*, and transmits them to the first driver in real time; the first driver controls the first servo motor to make the pressure plate move downwards at a constant speed *v*; when the pressure plate contacts the soil, the pressure value *p* fed back by the normal force sensor is... fThe pressure plate will continue to rise as it sinks deeper into the soil; the data acquisition system records that the position z and time t are both 0 at this point, and begins recording time t and velocity v. f When the pressure value p f Once the pressure setpoint p is reached, the first driver controls the first servo motor to keep the pressure plate moving downwards at a constant pressure p until the speed drops to 0; the data acquisition system stops recording time t and speed v. f The depth to which the pressure plate is embedded in the soil is determined to be... By performing the above steps multiple times to explore the correspondence between different pressures p and different depths z, the pz curve of the soil's conventional bearing capacity can be established.

[0022] Furthermore, the steps for testing the dynamic bearing capacity 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 these values ​​to the programmable logic controller (PLC); the PLC generates periodic fluctuations in speed. and pressure Analog signals are transmitted to the first driver in real time; the first driver controls the first servo motor, causing the pressure plate to 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 it sinks deeper into the soil; the data acquisition system records that the position z and time t are both 0 at this point, and begins recording time t and velocity v. f When the pressure value p f Once the pressure setpoint p is reached, the first driver controls the first servo motor to cause the pressure plate to fluctuate periodically. To control the downward oscillation until the velocity drops to near zero, the data acquisition system stops recording time t and velocity v. f The depth to which the pressure plate is embedded in the soil is determined to be... By performing the above steps multiple times to explore the correspondence between different pressures p and different depths z, the dynamic bearing capacity characteristic pz curve of the soil can be established.

[0023] Furthermore, the steps for testing the conventional shear properties of soil are as follows: The shear ring's movement speed *v*, the vertical pressure *p* applied to the soil, the rotational speed *ω*, and the rotational torque *T* are set and transmitted to a programmable logic controller (PLC); the PLC generates constant analog signals for speed *v* and pressure *p* and transmits them to a first driver in real time; the PLC generates analog signals for rotational speed *ω* and torque *T* and transmits them to a second driver in real time; the first driver controls a first servo motor to make the shear ring move downwards at a constant speed *v*; when the shear ring contacts the soil, the pressure value *p* fed back by the normal force sensor is... f It will continue to rise as the shear ring delves deeper into the soil; when the pressure value p f Once the pressure setpoint p is reached, the first actuator controls the first servo motor to keep the shear ring moving downwards at a constant pressure p until the speed drops to 0. The first actuator 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 point, and begins recording time t and rotational speed ω. f Torque value T f The second driver controls the second servo motor, causing the shearing ring to rotate at a speed ω as the control variable until the torque value T is reached. f No further additions are made, meaning the soil has been sheared at this point; the data acquisition system stops recording the recording time t and rotational speed ω. f Torque value T f The angle of rotation of the shear ring is determined as follows: By performing the above steps multiple times to explore the relationship between rotation angle θ and torque T under different pressures p, the θ-T curve of conventional soil shear characteristics can be established.

[0024] Furthermore, the steps for testing the dynamic shear properties of soil are as follows: setting the shear ring's movement speed v, 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 these values ​​to the programmable logic controller (PLC); the PLC generates periodic fluctuations in speed. and pressure Analog signals are generated and transmitted to the first driver in real time; the programmable logic controller generates analog signals of rotational 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 shearing ring move at a periodically fluctuating speed. To control the downward vibration motion; 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 delves deeper into the soil; when the pressure value p f Once the pressure setpoint p is reached, the first driver controls the first servo motor to cause the shear ring to operate at periodically fluctuating pressure. To control the downward oscillating motion until the velocity drops to near zero, the first actuator continues to control the shear ring to continuously apply periodically fluctuating pressure to the soil. The data acquisition system records that at this moment, both the rotation angle θ and time t are 0, and begins recording time t and rotational speed ω. f Torque value T f The second driver controls the second servo motor, causing the shearing ring to rotate at a speed ω as the control variable until the torque value T is reached. f No further increases are made; the data acquisition system stops recording time t and rotational speed ω. f Torque value T f The angle of rotation of shear ring 18 is determined to be... By performing the above steps multiple times to explore the relationship between rotation angle θ and torque T under different pressures p, the θ-T curve of soil dynamic shear characteristics can be established.

[0025] In summary, the present invention has the following advantages:

[0026] 1. It can provide not only the linear motion required for soil bearing capacity testing, but also the torsional motion required for soil shear capacity testing, making the soil mechanical property characterization device simple in structure, stable and reliable.

[0027] 2. The servo motor control system automates the entire characterization process, featuring simple operation and accurate measurement.

[0028] 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, soft ground in hilly and mountainous environments. Attached Figure Description

[0029] Figure 1 This is a three-dimensional structural schematic diagram of the surface soil dynamic mechanical property characterization device of the present invention.

[0030] Figure 2 This is a schematic diagram of the planar structure of the surface soil dynamic mechanical property characterization device of the present invention.

[0031] Figure 3(a) is a schematic diagram of the structure of the pressure plate of the present invention.

[0032] Figure 3(b) is a schematic diagram of the shear ring structure of the present invention.

[0033] Figure 4 This is a schematic diagram of the control system according to an embodiment of the present invention.

[0034] Figure 5(a) is a schematic diagram of the soil conventional bearing capacity test speed according to an embodiment of the present invention.

[0035] Figure 5(b) is a schematic diagram of the soil conventional bearing capacity test pressure according to an embodiment of the present invention.

[0036] Figure 6(a) is a schematic diagram of the soil dynamic bearing capacity test speed according to an embodiment of the present invention.

[0037] Figure 6(b) is a schematic diagram of the soil dynamic bearing capacity test pressure according to an embodiment of the present invention.

[0038] Figure 7(a) is a schematic diagram of the soil conventional shear characteristic test rate according to an embodiment of the present invention.

[0039] Figure 7(b) is a schematic diagram of the soil conventional shear characteristic test pressure according to an embodiment of the present invention.

[0040] Figure 8(a) is a schematic diagram of the soil dynamic shear characteristic test rate according to an embodiment of the present invention.

[0041] Figure 8(b) is a schematic diagram of the soil dynamic shear characteristics test pressure according to an embodiment of the present invention.

[0042] In the picture:

[0043] 1-First servo motor; 2-Electric cylinder; 3-Top plate; 4-Normal force sensor; 5-Sliding upper crossbeam; 6-Support rod; 7-Sliding lower crossbeam; 8-Sliding bearing; 9-Sliding tie rod; 10-Base plate; 11-Tap 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 Implementation

[0044] The present invention will now be described in further detail.

[0045] 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 drives the power shaft fixing device to move up and down, thereby driving the pressure plate 17 or shear ring 18 to apply vertical pressure to the soil via the power shaft 12. The torque device drives the power shaft 12 to rotate and provides torque to it, thereby driving the shear ring 18 to apply shear to the soil.

[0046] The frame includes a top plate 3, sliding rods 9, and a bottom plate 10. The bottom plate 10 is placed on the ground, and four evenly arranged sliding rods 9 are fixed to the bottom plate 10 with screws. The top plate 3 is also fixed to the four sliding rods 9 with screws so that the top plate 3 is parallel to the bottom plate 10.

[0047] The power shaft fixing device includes a sliding upper crossbeam 5, a support rod 6, a sliding lower crossbeam 7, sliding bearings 8, tapered roller bearings 11, and a power shaft 12. Each sliding 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 bearings 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.

[0048] 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 is fixed to the electric cylinder 2. The electric cylinder 2 is fixed to 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 threads. 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, it drives the power shaft fixing device to move up and down, thereby driving the power shaft 12 to move up and down. At the same time, the normal force sensor 4 can be used to record the real-time vertical load.

[0049] The torque device includes a right-angle commutator 13 horizontally mounted on one side of the power shaft 12, a torque sensor 14, and a second servo motor 15. The second servo motor 15 is connected to the torque sensor 14 via screws; the torque sensor 14 is connected to the right-angle commutator 13 via screws; the right-angle commutator 13 is fixed to the sliding lower crossbeam 7 via screws and engages with the power shaft 12 via a key; under the drive of the second servo motor 15, its torque can be transmitted to the torque sensor 14, and then 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 changed from the horizontal direction to the vertical direction, and through the engagement of the 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 to the power shaft 12 by the thrust device and the horizontal torque applied to the power shaft 12 by the torque device can be independent of each other and unaffected. This allows for simultaneous vertical pressure and horizontal shear tests, which is beneficial for characterizing various comprehensive mechanical properties of the surface soil.

[0050] The drive shaft 12 is connected to the transition shaft 16 by threads; the transition shaft 16 is connected to the pressure plate 17 by screws.

[0051] The pressure plate 17 can be replaced with a shear ring 18, as shown in Figure 3(a) and Figure 3(b). The pressure plate 17 is used for soil bearing capacity test, and the shear ring 18 is used for soil shear test.

[0052] Control system such as Figure 4 As shown, the touchscreen 19 can be used to set test parameters such as the vertical movement speed v of the pressure plate 17 or the shear ring 18, the vertical pressure p applied to the soil, the rotational speed ω, the rotational torque T, the vibration frequency f, and the amplitude A. The touchscreen 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 the speed value v of the aforementioned thrust device. f (Derived from the encoder built into the first servo motor 1) and pressure value p f (Based on the normal force sensor 4) as feedback, the pressure plate 17 or shear ring 18 is controlled to apply pressure to the soil; the second actuator 22 uses the real-time motion analog signal as a reference value, and the speed value ω of the aforementioned torque device is used as a reference value. f (Derived from the encoder built into the second servo motor 15) and torque value T f (Torque sensor 14) provides feedback to control the shear ring 18 to apply torque to the soil; simultaneously, it provides feedback on the velocity value v. f Pressure value p f Velocity value ω f Torque value T f All data are transmitted to the data acquisition system 23 for storage and recording.

[0053] This embodiment implements a method for characterizing the dynamic mechanical properties of surface soil using the above-mentioned device, which can perform conventional soil bearing capacity tests, dynamic soil bearing capacity tests, conventional soil shear capacity tests, and dynamic soil shear capacity tests.

[0054] The above-mentioned conventional soil bearing capacity test: Select the conventional soil bearing capacity test module on the touch screen 19; Set the movement speed v of the pressure plate 17 and the vertical pressure p applied to the soil on the touch screen 19, and transmit them to the programmable logic controller 20; The programmable logic controller 20 will generate constant speed v and pressure p analog signals, and transmit them 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, so that the pressure plate 17 moves downward at a constant speed v as the control quantity; 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 it sinks deeper into the soil; the data acquisition system 23 will record that the position z and time t are both 0 at this time, and will begin recording time t and velocity v. f When the pressure value pf Once the pressure setpoint p is reached, the first driver 21 will control the first servo motor 1 to make the pressure plate 17 continue to move downwards with a constant pressure p as the control variable until the speed drops to 0, i.e., it can no longer continue to descend; the data acquisition system 23 will stop recording time t and speed v. f It can be determined that the depth to which the pressure plate 17 is embedded in the soil is... By performing the above steps multiple times to explore the correspondence between different pressures p and different depths z, the pz curve of the soil's conventional bearing capacity can be established.

[0055] The above-mentioned dynamic soil bearing capacity test: Select the dynamic soil bearing capacity test module on the touch screen 19; set the movement speed v of the pressure plate 17, the vertical pressure p applied to the soil, the vibration frequency f, and the amplitude A on the touch screen 19, and transmit them to the programmable logic controller 20; the programmable logic controller 20 will generate periodically fluctuating speeds. and pressure The analog signal is transmitted to the first driver 21 in real time; as shown in Figures 6(a) and 6(b), the first driver 21 controls the first servo motor 1 to make the pressure 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 it sinks deeper into the soil; the data acquisition system 23 will record that the position z and time t are both 0 at this time, and will begin recording time t and velocity v. f When the pressure value p f Once the pressure setpoint p is reached, the first driver 21 will control the first servo motor 1 to make the pressure plate 17 fluctuate periodically. To control the downward oscillation until the velocity drops to near 0, meaning it can no longer descend, the data acquisition system 23 stops recording time t and velocity v. f It can be determined that the depth to which the pressure plate 17 is embedded in the soil is... By performing the above steps multiple times to explore the correspondence between different pressures p and different depths z, the dynamic bearing capacity characteristic pz curve of the soil can be established.

[0056] The above-mentioned conventional soil shear characteristics test: Select the conventional soil shear characteristics test module 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 constant speed v and pressure p analog signals, and transmit them to the first driver 21 in real time; In addition, the programmable logic controller 20 will generate rotation speed ω and torque T analog signals, and transmit them to the second driver 22 in real time; As shown in Figures 7(a) and 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 quantity; When the shear ring 18 contacts the soil, the pressure value p fed back by the normal force sensor 4 f It will continue to rise as the depth of the shear ring 18 embedded in the soil increases; when the pressure value p f Once the pressure setpoint p is reached, the first actuator 21 will control the first servo motor 1 to make the shear ring 18 continue to move downwards with a constant pressure p as the control variable until the speed drops to 0, i.e., it can no longer descend. The first actuator 21 continues to control the shear ring 18 to continuously apply a 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 will begin recording time t and rotational speed ω. f Torque value T f The second driver 22 will control the second servo motor 15 to make the shearing ring 18 rotate at a speed ω as the control variable until the torque value T is reached. f No further additions are made, meaning the soil has been sheared at this point; data acquisition system 23 stops recording the recording time t and rotational speed ω. f Torque value T f The angle of rotation of the shear ring 18 can be determined as follows: By performing the above steps multiple times to explore the relationship between rotation angle θ and torque T under different pressures p, the θ-T curve of conventional soil shear characteristics can be established.

[0057] The above-mentioned dynamic shear characteristic test of soil: Select the dynamic shear characteristic test module of soil on the touch screen 19; set the movement speed v of 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 on the touch screen 19, and transmit them to the programmable logic controller 20; the programmable logic controller 20 will generate periodically fluctuating speeds. and pressure Analog signals are generated and transmitted to the first driver 21 in real time; in addition, the programmable logic controller 20 generates analog signals of rotational speed ω and torque T and transmits them to the second driver 22 in real time; as shown in Figures 8(a) and 8(b), the first driver 21 controls the first servo motor 1 to make the shearing ring 18 move at a periodically fluctuating speed. To control the downward vibration motion; when the shear ring 18 contacts the soil, the pressure value p fed back by the normal force sensor 4... f It will continue to rise as the depth of the shear ring 18 embedded in the soil increases; when the pressure value p f Once the pressure setpoint p is reached, the first driver 21 will control the first servo motor 1 to cause the shear ring 18 to operate at periodically fluctuating pressure. To control the downward oscillating motion until the velocity drops to near zero, the first actuator 21 continues to control the shear ring 18 to continuously apply periodically fluctuating pressure to the soil. The data acquisition system 23 will record that the rotation angle θ and time t are both 0 at this moment, and will begin recording time t and rotational speed ω. f Torque value T f The second driver 22 will control the second servo motor 15 to make the shearing ring 18 rotate at a speed ω as the control variable until the torque value T is reached. f No further additions are made, meaning the soil has been sheared at this point; data acquisition system 23 stops recording time t and rotational speed ω. f Torque value T f The angle of rotation of the shear ring 18 can be determined as follows: By performing the above steps multiple times to explore the relationship between rotation angle θ and torque T under different pressures p, the θ-T curve of soil dynamic shear characteristics can be established.

[0058] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for characterizing the dynamic mechanical properties of surface soil, characterized in that: A device for characterizing the dynamic mechanical properties of surface soil is used. A device for characterizing the dynamic mechanical properties of surface soil includes a frame, on which a vertically arranged power shaft, pressure plate, shear ring, thrust device and torque device are provided; 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 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 conventional soil bearing capacity tests, the thrust device is used to output constant pressure so that the power shaft moves downward at a constant speed, driving the pressure plate to apply constant pressure to the soil. When performing soil dynamic bearing capacity tests, 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 conventional soil shear property tests, the thrust device is used to output constant pressure and the torque device outputs rotational torque, so that the power shaft drives the shear ring to apply constant pressure to the soil while applying shear force. When performing dynamic shear characteristics tests on soil, the thrust device is used to output 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. Includes the following steps, When performing routine soil bearing capacity tests, the thrust device outputs a constant pressure, causing the power shaft to move downwards at a uniform speed, driving the pressure plate to apply constant pressure to the soil, and exploring different pressures. p and different depths z The correspondence between them was established to establish the conventional compressive properties of soil. p - z curve; When performing soil dynamic bearing capacity tests, the thrust device outputs vibration pressure, causing the power shaft to vibrate downwards, driving the pressure plate to apply periodic fluctuating pressure to the soil, exploring different pressures. p and different depths z To establish the correspondence between them and to establish the dynamic bearing capacity characteristics of soil. p - z curve; When performing conventional soil shear property tests, the thrust device outputs constant pressure and the torque device outputs rotational torque, causing the power shaft to drive the shear ring to apply constant pressure and shear force to the soil, thus exploring different pressures. p Down rotation angle θ and torque T The correspondence between them was established to establish the conventional shear properties of soil. θ - T curve; When performing dynamic shear property tests on soil, the thrust device outputs vibration pressure and the torque device outputs rotational torque, causing the power shaft to drive the shear ring to apply periodic fluctuating pressure and shear force to the soil, thus exploring different pressures. p Down rotation angle θ and torque T To establish the correspondence between them and to establish the dynamic shear characteristics of soil. θ - T curve.

2. The method for characterizing the dynamic mechanical properties of surface soil 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. The method for characterizing the dynamic mechanical properties of surface soil according to claim 2, characterized in that: The frame includes a top plate, a sliding tie rod, and a bottom plate. The upper and lower ends of the sliding tie rod are fixed to the top plate and the bottom plate, respectively. 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 passes through the top plate. The middle of the bottom plate is provided with a through hole that allows a shearing ring or pressure plate to pass through.

4. The method for characterizing the dynamic mechanical properties of surface soil according to claim 3, characterized in that: Between the top plate and the bottom plate, there is a sliding upper crossbeam, a support rod, and a sliding lower crossbeam. The upper and lower ends of the support rod are fixed to the sliding upper crossbeam and the sliding lower crossbeam, respectively. The sliding upper crossbeam and the sliding lower crossbeam are slidably connected to the sliding tie rod. A pair of tapered roller bearings are installed in the sliding upper crossbeam and the sliding lower crossbeam. The power shaft is installed in the tapered roller bearings, and the normal force sensor is connected to the sliding upper crossbeam.

5. The method 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 mounted on one side of the power shaft and connected in sequence. The right-angle commutator is fixed on the sliding lower crossbeam and cooperates with the power shaft through a flat key to convert the horizontal torque output by the second servo motor into a vertical torque that is transmitted to the power shaft.

6. The method for characterizing the dynamic mechanical properties of surface soil according to claim 1, characterized in that: The steps for testing the conventional bearing capacity of soil are as follows: set the movement speed of the pressure plate. v and vertical pressure applied to the soil p And pass it to the programmable logic controller; Programmable logic controllers produce constant speed v and pressure p Analog signals are transmitted to the first driver in real time. The first driver controls the first servo motor, causing the pressure plate to move at a constant speed. v To ensure the pressure plate moves downwards at a constant speed; when the pressure plate contacts the soil, the pressure value fed back by the normal force sensor... p f It will continue to rise as the pressure plate sinks deeper into the soil; The data acquisition system records the current position. z and time t All values ​​are 0, and time recording begins. t and speed v f When the pressure value p f Reaching the pressure set value p Then, the first driver controls the first servo motor to make the pressure plate apply constant pressure. p To control the quantity to continue moving downwards until the velocity drops to 0, the data acquisition system stops recording the time. t and speed v f The depth to which the pressure plate is embedded in the soil is determined to be... And use this to create pressure p and the depth of the soil z The correspondence between them; repeat the above steps multiple times to explore different pressures. p and different depths z The correspondence between them can be used to establish the conventional compressive properties of soil. p - z curve.

7. The method for characterizing the dynamic mechanical properties of surface soil according to claim 1, characterized in that: The steps for testing the dynamic bearing capacity of soil are as follows: set the movement speed of the pressure plate. v Vertical pressure applied to the soil p Vibration frequency f ,amplitude A And pass it to the programmable logic controller; The speed at which the programmable logic controller generates periodic fluctuations and pressure Analog signals are transmitted to the first driver in real time. The first driver controls the first servo motor, causing the pressure plate to move at a periodically fluctuating speed. To control the downward vibration movement; when the pressure plate contacts the soil, the pressure value fed back by the normal force sensor. p f It will continue to rise as the pressure plate sinks deeper into the soil; The data acquisition system records the current position. z and time t All values ​​are 0, and time recording begins. t and speed v f When the pressure value p f Reaching the pressure set value p Then, the first driver controls the first servo motor to make the pressure plate fluctuate periodically. To control the downward oscillation until the velocity drops to near zero, the data acquisition system stops recording the time. t and speed v f The depth to which the pressure plate is embedded in the soil is determined to be... And use this to create pressure p and the depth of the soil z The correspondence between them; repeat the above steps multiple times to explore different pressures. p and different depths z By establishing the correspondence between them, the dynamic bearing capacity characteristics of the soil can be determined. p - z curve.

8. The method for characterizing the dynamic mechanical properties of surface soil according to claim 1, characterized in that: The steps for testing the conventional shear properties of soil are as follows: setting the velocity of the shear ring. v Vertical pressure applied to the soil p Rotation speed ω Rotational torque T And pass it to the programmable logic controller; Programmable logic controllers produce constant speed v and pressure p Analog signals are transmitted to the first driver in real time. Programmable logic controller generates rotational speed ω and torque T The analog signal is transmitted to the second driver in real time; The first driver controls the first servo motor, causing the shearing ring to move at a constant speed. v To control the uniform downward movement of the shear ring; when the shear ring contacts the soil, the pressure value fed back by the normal force sensor... p f The pressure value will continue to rise as the shear ring delves deeper into the soil; p f Reaching the pressure set value p Then, the first driver controls the first servo motor to make the shearing ring operate at a constant pressure. p To control the flow of the shear ring until the velocity drops to zero, the first actuator continues to control the shear ring to maintain a constant pressure on the soil. p ; The data acquisition system records the turning point at this moment. θ and time t All values ​​are 0, and time recording begins. t Rotation speed ω f Torque value T f ; The second driver controls the second servo motor, causing the shear ring to rotate at a certain speed. ω Rotate to control the quantity until the torque value is reached. T f No further additions are made, meaning the soil has been sheared at this point; the data acquisition system stops recording. t Rotation speed ω f Torque value T f ; The angle of rotation of the shear ring is determined as follows: And use this to establish the rotation angle θ and torque T The correspondence between them; repeat the above steps multiple times to explore different pressures. p Down rotation angle θ and torque T By establishing the correspondence between them, the conventional shear properties of soil can be determined. θ - T curve.

9. The method for characterizing the dynamic mechanical properties of surface soil according to claim 1, characterized in that: The steps for testing the dynamic shear properties of soil are as follows: setting the movement speed of the shear ring. v Vertical pressure applied to the soil p Rotation speed ω Rotational torque T Vibration frequency f ,amplitude A And pass it to the programmable logic controller; The speed at which the programmable logic controller generates periodic fluctuations and pressure Analog signals are transmitted to the first driver in real time. Programmable logic controller generates rotational speed ω and torque T The analog signal is transmitted to the second driver in real time; The first driver controls the first servo motor, causing the shearing ring to move at a periodically fluctuating speed. To control the downward vibration motion; when the shear ring contacts the soil, the pressure value fed back by the normal force sensor... p f The pressure value will continue to rise as the shear ring delves deeper into the soil; p f Reaching the pressure set value p Then, the first driver controls the first servo motor, causing the shear ring to operate with periodically fluctuating pressure. To control the downward oscillating motion until the velocity drops to near zero, the first actuator continues to control the shear ring to continuously apply periodically fluctuating pressure to the soil. ; The data acquisition system records the turning point at this moment. θ and time t All values ​​are 0, and time recording begins. t Rotation speed ω f Torque value T f ; The second driver controls the second servo motor, causing the shear ring to rotate at a certain speed. ω Rotate to control the quantity until the torque value is reached. T f No further increases will be made; the data acquisition system will stop recording for a certain period of time. t Rotation speed ω f Torque value T f The angle of rotation of shear ring 18 is determined to be... And use this to establish the rotation angle θ and torque T The correspondence between them; repeat the above steps multiple times to explore different pressures. p Down rotation angle θ and torque T By establishing the correspondence between them, the dynamic shear characteristics of the soil can be established. θ - T curve.

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