A soil mechanical property detection device

Abstract

This invention relates to the field of geotechnical testing technology and discloses a soil mechanical property testing device, including a base, a storage cylinder mounted on top of the base, an axial drive component located above the storage cylinder, and an upper pressure plate structure connected to its telescopic end; a mounting plate is provided on the axial surface of the connecting shaft, and a connecting arm is provided below the mounting plate. A push shaft passes through the bottom end of the connecting arm, and both ends of the push shaft extend into the guide grooves of the sliding plates on both sides of the storage cylinder; the sliding plates are fixed to the side pressure plate structure by push rods; when the axial drive component extends downward, it drives the push shaft to slide along the guide groove through the connecting shaft, mounting plate, and connecting arm, generating a horizontal component of the normal thrust that drives the sliding plate, push rod, and side pressure plate structure to move closer to the center of the storage cavity, realizing the coordinated application of longitudinal and transverse compressive loads by a single drive source; the device has a compact structure and can comprehensively acquire the mechanical response data of soil samples under multi-directional stress, providing reliable test basis for soil mechanical property evaluation.

Description

Technical Field

[0001] This invention relates to the field of geotechnical testing technology, and more specifically to a device for testing the mechanical properties of soil. Background Technology

[0002] As the most fundamental engineering material in geotechnical engineering, the accurate evaluation of soil's mechanical properties directly affects the reliability and safety of a series of engineering problems, such as slope stability analysis, foundation bearing capacity calculation, and tunnel surrounding rock support design. Accurately obtaining the strength, deformation, and stiffness of soil is crucial for geotechnical engineering investigation, design, and construction, and is of significant practical importance for saving construction time, reducing costs, and ensuring project quality. In particular, for new geotechnical engineering materials such as lightweight foamed soil, rigorous pressure testing is required before they are put into production and use to ensure that their mechanical properties meet engineering design requirements.

[0003] Currently, several devices have been proposed for testing the mechanical properties of soils such as foamed lightweight soil. For example, Chinese invention patent application CN202411441407.8 discloses a device and method for testing the mechanical properties of foamed lightweight soil. This device includes a base plate with a testing mechanism connected to the top. The testing mechanism includes a linear motor with its bottom connected to the base plate. A slide is fitted onto the surface of the linear motor, and a horizontal plate is connected to the right side of the slide. A single-axis motor is positioned above the horizontal plate, and a pressure sensor is connected to the shaft of the single-axis motor. This device, by incorporating a linear motor, slide, horizontal plate, single-axis motor, pressure sensor, first electric push rod, vertical pipe, and drill rod, enables the drill rod to move laterally and vertically, thereby adjusting its position and improving its flexibility. Drilling the ground with the drill rod facilitates drilling and testing of large areas of foamed lightweight soil layers to assess their ground strength, thus improving the applicability of the testing device to a certain extent. By replacing the drill rod with a pressure plate, pressure testing of the soil sample can be achieved.

[0004] However, the aforementioned existing technology still has the following shortcomings: the device can only apply pressure to the soil sample in the longitudinal direction (i.e., axial direction), and the data obtained is limited to the soil sample pressure change data in the axial force direction, lacking information on the lateral pressure data change in the circumferential direction when the soil sample is deformed under pressure; since there is a close coupling relationship between the axial deformation and lateral deformation of the soil during the compression process, it is difficult to fully and accurately reflect the true mechanical response characteristics of the soil based on a single axial pressure data, which to some extent affects the comprehensiveness of the experimental evaluation and the reliability of the test results. Summary of the Invention

[0005] The technical problem to be solved by this application is: how to simultaneously acquire the lateral pressure change data of the soil sample in the circumferential direction during the soil sample compression test, so as to overcome the shortcomings of the existing technology that can only measure single axial pressure data, resulting in insufficient experimental evaluation.

[0006] This invention provides the following technical solution: a soil mechanical property testing device, comprising a base, a storage cylinder mounted on top of the base for holding a soil sample to be tested, and an axial drive component positioned above the storage cylinder to provide axial driving force in the vertical direction; the telescopic shaft of the axial drive component is fixed to an upper pressure plate structure via a connecting shaft to apply an axial compressive load to the soil sample; a radially extending mounting plate is mounted on the axial surface of the connecting shaft, and a connecting arm arranged perpendicularly to the mounting plate is provided below the mounting plate; a pushing shaft extending in the front-rear direction passes through the bottom end of the connecting arm, pushing... The two ends of the feeding shaft extend into the obliquely opened guide grooves on the side wall of the slide plate on at least one side of the storage cylinder; the slide plate is fixed to one end of the push rod that moves through the side wall of the storage cylinder, and the other end of the push rod is fixed to the side pressure plate structure that is movably set on the side of the storage cavity; when the axial drive member extends downward, the driving force is transmitted to the pushing shaft through the connecting shaft, the mounting plate, and the connecting arm, causing the pushing shaft to slide along the guide groove to generate a normal thrust. Its horizontal component drives the slide plate to move closer to the center of the storage cavity along the push rod and the side pressure plate structure, so as to achieve the coordinated application of longitudinal and transverse compressive loads.

[0007] Furthermore, the storage chamber of the storage cylinder has a convex cross-section along the left and right directions, which provides a compression stroke margin for the upper pressure plate structure in the longitudinal direction and a feeding space for the side pressure plate structure in the transverse direction, so as to avoid interference between the two due to the superposition of displacements in their respective movement paths; when the upper pressure plate structure moves to the extreme low position in the longitudinal direction and the side pressure plate structure feeds to the extreme inward position in the transverse direction, the side wall of the upper pressure plate structure and the side wall of the side pressure plate structure form a vertically fitted and closed state, so that the effective volume of the storage chamber is compressed to the minimum.

[0008] Furthermore, the front sidewall of the storage cylinder has a front hatch, and the bottom edge of the front hatch is hinged to a door that can be opened and closed by flipping upwards. The door is provided with a locking structure for locking the front hatch in the closed state. The back side of the storage cylinder has a rear hatch with the same diameter as the front hatch and is arranged opposite to it. A bulldozer plate adapted to its contour is movably embedded in the rear hatch. The bulldozer plate is fixedly connected to the telescopic shaft of the unloading drive unit installed on the base. The unloading drive unit drives the bulldozer plate to move back and forth horizontally. The size of the front hatch and the rear hatch depends on the projection size of the effective pressing space enclosed by the upper pressure plate structure and the side pressure plate structure when they are vertically attached to the sidewalls on the plane where the hatch is located.

[0009] Furthermore, the sliding plates are disposed on the outer wall surfaces of the front and rear hatches of the storage cylinder, and the sliding plates are provided with a slide rail structure extending laterally to guide the linear movement of the sliding plates in the horizontal direction; the two sliding plates on the same side are connected by a crossbar to form a rigid synchronous frame, one end of the push rod is fixed to the crossbar, and the crossbar and push rod are arranged relatively downward in the vertical direction to provide clearance space for the end of the push shaft to slide along the guide groove when the push shaft moves longitudinally with the connecting arm.

[0010] Furthermore, the push shaft has a length that is a short segment extending into the guide groove, and the connecting arm is forked, with its two forked arms respectively passing around the outer area between two opposing slide plates on the same side and fixed to the outer end of the corresponding push shaft.

[0011] Furthermore, the upper pressure plate structure includes an upper stacked plate directly connected to the connecting shaft, and a lower stacked plate disposed below the upper stacked plate and suspended via bolts movably passing through the perimeter of the upper stacked plate. In its natural state, the lower stacked plate forms a circumferentially continuous material guiding gap with the upper stacked plate. The bottom wall of the upper stacked plate is provided with an inverted conical protrusion, and the center of the lower stacked plate is provided with a groove that matches the inverted conical protrusion. When the upper stacked plate and the lower stacked plate are fully stacked, the inverted conical protrusion is embedded in the groove to seal the material guiding gap and to make the bottom surface of the lower stacked plate form a complete pressure plate plane. An upward through opening is provided along the side of the inverted conical protrusion, and a hopper is installed above the opening.

[0012] Furthermore, a base is provided below the base, and the base and the base are elastically connected by an elastic element to give the base a vertical floating degree of freedom relative to the base; a gantry frame is fixedly provided above the base, and an axial drive component is fixedly installed on the gantry frame; the side of the base and the longitudinal arm of the gantry frame form a sliding fit; a rotating shaft is rotatably installed on the upper surface of the base, and an eccentric wheel is fixedly sleeved on the shaft surface of the rotating shaft. The shaft end of the rotating shaft is poweredly connected to a motor installed on the base; the eccentric wheel has a protruding part, which intermittently pushes the bottom of the base during the rotation of the eccentric wheel, causing the base to move up and down relative to the base in the vertical direction, and the elastic force of the elastic element causes the base and its supporting components to vibrate up and down.

[0013] Furthermore, the connecting shaft and the telescopic shaft of the axial drive are connected by a sleeve. The sleeve has a shaft cavity, which is axially slidingly fitted with the outer peripheral wall of the connecting shaft, so that the connecting shaft can slide and extend along the shaft cavity of the sleeve.

[0014] Furthermore, the side pressure plate structure is a single pressure plate with a wall thickness, which is movably disposed on the side of the storage cavity; the push rod is rotatably disposed between the crossbar and the single pressure plate, and a transmission wheel is coaxially fixed at one end of the push rod near the crossbar. An annular groove is opened on the end face of the transmission wheel, and a toothed ring is arranged circumferentially in the annular groove; a drive pin is fixedly connected to the connecting arm. The drive pin is L-shaped and has teeth at its bottom end. The teeth can engage with the toothed ring in the annular groove during the initial descent of the connecting arm; the upper end of the drive pin slides through the connecting arm, and the side of the drive pin maintains a track-type coupling limit with the annular groove; a friction damping element is provided at the rotatable connection of the push rod to maintain the angular position of the transmission wheel and the push rod when the drive pin does not drive the transmission wheel.

[0015] Furthermore, the push rod has a through-cavity along the axial direction, with one end of the through-cavity used to connect to the cleaning medium supply source; the other end of the push rod extends into the transmission cavity inside the single pressure plate wall, and the end of the push rod located in the transmission cavity has a drain hole. A sloping cam is coaxially fixed on the axial surface of the push rod, and the sloping cam has a sloping surface on the side near the storage cavity; an overflow hole is opened on the side wall of the transmission cavity, and a sealing element moves through the overflow hole, forming an abutment fit with the sloping surface; the sealing element is integrally formed by a sealing plate, a neck plate, and an ear plate, the sealing plate is adapted to the overflow hole, the cross-sectional dimension of the neck plate is smaller than the diameter of the overflow hole, the ear plate is slidably disposed in the transmission cavity, and the ear plate is connected to the inner wall of the transmission cavity by a return spring; the sloping cam can rotate with the push rod to push the sealing element to slide axially through the sloping surface, so that the sealing plate opens or closes the overflow hole.

[0016] The technical effects and advantages of this invention are as follows: By controlling the downward extension of the axial drive component, the lower stack plate is pushed along the storage cavity of the storage cylinder via the connecting shaft to apply a longitudinal compressive load to the soil sample. Simultaneously, the mounting plate descends synchronously with the connecting shaft, causing the connecting arm and the push shaft to move downward. This generates a normal thrust at the contact surface between the pulley at the end of the push shaft and the guide groove. The horizontal component of this normal thrust guides the sliding plate to move the push rod and the single pressure plate towards the center of the cavity, applying a lateral compressive load to the soil sample. Thus, a single drive source achieves coordinated loading of longitudinal and lateral forces. The structure is compact and the operation is reliable. The pressure sensing module collects pressure data in real time during the longitudinal and lateral pressure application and transmits it to the data processing module for analysis and processing via electrical signals. It can simultaneously acquire data on the axial compression and lateral pressure changes of the soil sample, overcoming the shortcomings of existing technologies that can only measure single axial pressure data. It comprehensively reflects the coupled response characteristics of axial deformation and lateral deformation of the soil during compression, improving the comprehensiveness of experimental evaluation and the reliability of test results. It provides a reliable experimental basis for the accurate evaluation of the lateral deformation characteristics and lateral pressure coefficient of the soil. Attached Figure Description

[0017] Figure 1 This is a front view of the overall structure of the present invention.

[0018] Figure 2 This is a side view of the overall structure of the present invention.

[0019] Figure 3 This is a perspective view of the overall structure of the present invention.

[0020] Figure 4 For the present invention Figure 3 A 3D view of the remaining part after removing half of the structure on the right.

[0021] Figure 5 For the present invention Figure 4 A three-dimensional view of the structural cross-section.

[0022] Figure 6 For the present invention Figure 5 A three-dimensional view from the other side of the structure.

[0023] Figure 7 This is a perspective view of the base, pedestal, elastic element, rotating shaft, and eccentric wheel of the present invention.

[0024] Figure 8 For the present invention Figure 5 A three-dimensional view showing further disassembly of the structure.

[0025] Figure 9 For the present invention Figure 8 A three-dimensional view showing further disassembly of the structure.

[0026] Figure 10 For the present invention Figure 9 Enlarged view of the structure at point A in the middle.

[0027] Figure 11 This is a perspective view of the lower stack plate, upper stack plate, lifting bolt, and hopper of the present invention.

[0028] Figure 12 For the present invention Figure 5 A 3D view after the structural state has changed.

[0029] The attached diagram is labeled as follows: 1. Base; 2. Storage cylinder; 3. Door; 4. Bulldozer blade; 5. Single pressure plate; 51. Transmission cavity; 52. Flow hole; 6. Lower stack plate; 7. Upper stack plate; 8. Lifting bolt; 9. Hopper; 10. Connecting shaft; 11. Sleeve; 12. Axial drive component; 13. Gantry frame; 14. Mounting plate; 15. Connecting arm; 16. Push shaft; 17. Slide plate; 171. Guide groove; 18. Push rod; 19. Transmission wheel; 20. Drive pin; 21. Unloading drive component; 22. Base; 23. Elastic component; 24. Rotating shaft; 25. Eccentric wheel; 26. Motor; 27. Inclined cam; 28. Sealing component; 29. ​​Return spring; 30. Data processing module. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The soil mechanical performance testing device involved in the present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1, see Figures 1 to 2 As shown, this invention provides a soil mechanical property testing device, including a base 1, a storage cylinder 2 installed on the top of the base 1 for containing and supporting the soil sample to be tested, an axial drive member 12 disposed above the storage cylinder 2 for providing controllable axial driving force in the vertical direction, and a pressure plate structure disposed at the telescopic end of the axial drive member 12 and capable of rising and falling with its telescopic movement to apply an axial compressive load to the soil sample stored in the storage cylinder 2; wherein, the telescopic end of the axial drive member 12 and the pressure plate structure are rigidly connected to achieve effective force transmission, so that the axial driving force output by the axial drive member 12 can be uniformly applied to the soil sample through the pressure plate structure. The upper surface forms a stable uniaxial compressive stress state within the storage cavity defined by the storage cylinder 2. The pressure plate structure is embedded with a pressure sensing module, which is in direct contact with the pressure-bearing surface of the soil sample. This module is used to sense and continuously collect the axial pressure data and corresponding deformation response information borne by the soil sample in real time throughout the entire pressure application process. The data is then converted into electrical signals and transmitted to the data processing module 30 via a preset signal transmission line for synchronous recording, analysis, and processing. This allows for the acquisition of key mechanical indicators such as the stress-strain response characteristics, compression modulus, and strength parameters of the soil sample under axial compression conditions, providing reliable experimental data support for the subsequent quantitative evaluation of soil mechanical properties.

[0032] See Figures 3 to 9 ,as well as Figure 12As shown, the telescopic shaft of the axial drive component 12 is fixedly connected to the upper pressure plate structure via the connecting shaft 10. The upper pressure plate structure is configured to reciprocate along the longitudinal direction of the storage cavity of the storage cylinder 2 to apply an axial compressive load to the soil sample contained in the storage cavity. A mounting plate 14 extending radially outward is fixedly sleeved on the axial surface of the connecting shaft 10, and a connecting arm 15 arranged perpendicular to its axis is fixedly disposed below the mounting plate 14. A push shaft 16 extending in a front-back direction is axially inserted through the bottom end of the connecting arm 15. The two ends of the push shaft 16 extend into guide grooves 171 obliquely opened on the side wall of the slide plate 17 located on at least one side of the storage cylinder 2. The slide plate 17 is fixedly connected to one end of a push rod 18 that movably penetrates the side wall of the storage cylinder 2, and the other end of the push rod 18 is fixedly connected to a side pressure plate structure movably disposed on the side of the storage cavity. The side pressure plate structure can be positioned horizontally relative to the side of the storage cavity. Wall movement; when the telescopic shaft of the axial drive component 12 extends downward in the vertical direction, its driving force is transmitted to the mounting plate 14, the connecting arm 15 and the push shaft 16 through the connecting shaft 10, causing the shaft end of the push shaft 16 to move along the inclined slide of the guide groove 171. A normal thrust is generated between the shaft end of the push shaft 16 and the contact surface of the guide groove 171. The horizontal component of this normal thrust pushes the slide plate 17 to drive the push rod 18 and the side pressure plate structure fixed to it to move towards the center of the storage cavity in a synchronous manner, thereby achieving the coordinated application of the transverse compressive load while the longitudinal compressive load is applied. The entire transmission process uses a single drive source, the axial drive component 12, as the power input. The lifting and lowering motion of the connecting shaft 10 simultaneously drives the linkage loading of the upper pressure plate structure and the side pressure plate structure. There is no need to set up an additional independent transverse force application mechanism. It has significant advantages such as compact structure, high transmission efficiency, consistent action sequence and reliable operation. Both the upper pressure plate structure and the side pressure plate structure are equipped with pressure-sensing modules. The sensing end face of the pressure-sensing module is kept in close contact with the pressure-bearing surface of the soil sample to ensure the authenticity of pressure transmission and response sensitivity. During the entire pressure application process, it senses and continuously collects the axial pressure data and corresponding compression deformation response information of the soil sample in real time at a preset high-frequency sampling rate. At the same time, it simultaneously acquires the lateral pressure change data in the lateral direction, forming a multi-dimensional force-deformation time history signal. The collected analog signal is converted into a stable and reliable electrical signal by the built-in amplification, filtering, and analog-to-digital conversion conditioning circuit, and then transmitted to the data processing module 30 through a preset signal transmission line. The data processing module 30 then executes the signal processing. Multi-channel synchronous recording, data fusion, and analytical processing are employed to achieve temporal matching and correlation analysis of axial and lateral pressure data. This allows for the simultaneous acquisition of the lateral pressure distribution along the circumference of the soil sample and its evolution under axial loading, based on the axial compression characteristics of the soil sample (including stress-strain curves and stiffness parameters). The collaborative acquisition of this bidirectional pressure data effectively overcomes the technical shortcomings of existing technologies that can only measure single axial pressure data, resulting in insufficient experimental evaluation. This provides comprehensive and reliable experimental evidence for the accurate evaluation of soil lateral deformation characteristics, Poisson's ratio, and static lateral pressure coefficient, significantly improving the comprehensiveness and reliability of soil mechanical property testing. The storage chamber of storage cylinder 2 has an approximately convex cross-section along the horizontal direction. This provides sufficient compression stroke margin for the upper pressure plate structure in the longitudinal direction and sufficient feeding space for the side pressure plate structure in the transverse direction. This ensures that both structures have sufficient compression stroke on the soil sample along their respective movement paths, avoiding interference or collision between the upper and side pressure plate structures due to the superposition of longitudinal and transverse displacements before reaching the preset compression peak value. This would affect the effective acquisition of experimental data and the stability of equipment operation. When the upper pressure plate structure moves longitudinally to its lowest position and the side pressure plate structure feeds laterally to its innermost position, the side walls of the upper and side pressure plate structures form a vertically fitted and closed state. At this time, the effective volume in the convex storage chamber is compressed to the minimum, and the soil sample is also compressed to its ultimate compacted volume. The front side wall of the storage cylinder 2 has a front hatch, the bottom edge of which is hinged to a door 3 that can be opened and closed upwards. This door is used to form a sealed fit with the front hatch when closed, and is equipped with a locking structure to maintain its closed and locked state during the experiment, preventing the soil sample from overflowing during the compression process. The back side of the storage cylinder 2 has a rear hatch with the same diameter as the front hatch and opposite in position. A bulldozer plate 4 that matches the contour of the rear hatch is movably embedded in the rear hatch. The bulldozer plate 4 is fixedly connected to the telescopic shaft of the unloading drive 21 installed on the base 1, and the unloading drive 21 drives the bulldozer plate 4 to move back and forth horizontally. The size of the front hatch and the rear hatch depends on the effective compression space formed by the upper pressure plate structure and the side pressure plate structure when they are vertically attached to the side wall. The projected dimensions of the surface are determined to ensure the smoothness and completeness of the pushing action. After the pressure test is completed, the locking structure is released and the front hatch is flipped downward to open. At this time, the telescopic axis of the unloading drive component 21 is extended forward, driving the bulldozer plate 4 to move forward from the rear hatch. The compressed soil sample is pushed forward through the opened front hatch as an unloading channel, so that operators or automated collection devices can easily obtain the tested soil sample for subsequent physical and mechanical property testing processes such as density, moisture content, particle size distribution, and microstructure analysis. This push-out unloading design greatly improves the convenience of soil collection and significantly reduces the residual rate of soil sample in the inner wall and corner areas of the convex storage cavity, avoiding disturbance or damage to the soil sample caused by manual scooping, and effectively ensuring the accuracy and representativeness of subsequent test data. Slide plates 17 are disposed opposite each other on the outer wall of the front and rear hatches of the storage cylinder 2. Each slide plate 17 is equipped with a matching slide rail structure at least at its connection point with the adjacent base 1 or the wall of the storage cylinder 2. This slide rail structure extends laterally to guide the slide plate 17 in low-friction linear motion in the horizontal direction, ensuring guiding accuracy and smooth movement during its movement. Two slide plates 17 on the same side are fixedly connected by a crossbar to form a rigid synchronous frame, ensuring that the two slide plates 17 on the same side maintain consistent displacement during lateral movement, avoiding additional torque or deflection caused by asynchronous movement. One end of the push rod 18 is fixedly connected to the crossbar, and the crossbar and push rod 18 are positioned relatively lower in the vertical direction to provide sufficient clearance for the end of the push shaft 16 to slide along the guide groove 171 when the push shaft 16 moves longitudinally with the connecting arm 15. This effectively prevents the push shaft 16 and push rod 18 from intersecting in space or mechanically interfering with each other, ensuring the independence and coordination of their respective movements. As an alternative implementation (not shown in the figure), the length of the push shaft 16 can also be set as a small segment extending into the guide groove 171. At the same time, the connecting arm 15 is set as a fork, so that its two fork arms bypass the outer area between the two opposing slide plates 17 on the same side and are fixed to the outer end of the corresponding push shaft 16. This bypass arrangement can also eliminate the spatial interference problem between the push shaft 16 and the push rod 18. Moreover, this structural form helps to set the position of the crossbar and the push rod 18 relatively close to the middle of the side pressure plate structure, so as to optimize the position of the force application point on the side pressure plate structure, make the transverse load transmission more balanced, and avoid additional bending moment or bias effect caused by the force application point deviating from the center of the side pressure plate structure, thereby improving the stress state and pressing uniformity of the side pressure plate structure. At the same time, the above arrangement scheme can be flexibly selected according to the actual installation space, processing technology requirements and transmission chain stiffness requirements to improve the assembly adaptability and structural optimization space of the device, so that the overall layout can meet the functional requirements while taking into account compactness, economy and manufacturability. A pulley is provided on the axial surface of the push shaft 16, which contacts the guide groove 171. This pulley acts as a rolling contact element, and its cylindrical outer circumferential surface forms a rolling fit with the linear inclined groove working surface of the guide groove 171. When the push shaft 16 descends synchronously with the connecting arm 15, the pulley rolls down along the inclined groove surface of the guide groove 171. During the rolling contact process, the pulley axis generates a normal thrust perpendicular to the contact surface of the guide groove 171 and inclined downward. This normal thrust is transmitted through the contact point between the pulley and the groove surface, and its horizontal component is used to drive the slide plate 17 to feed laterally. Since the pulley and the guide groove 171 are in rolling friction contact, the motion resistance and energy loss are effectively reduced, the power transmission efficiency is improved, and the vibration and abnormal noise caused by surface roughness in sliding contact are eliminated, making the transmission process more stable and smooth, and significantly reducing the wear rate of the contact surface, thus extending the service life and maintenance cycle of the components.

[0033] In Example 2, to optimize the ease of adding soil samples into the storage cylinder 2 and to ensure uniform distribution and compaction of the soil sample during the feeding process, thus avoiding adverse effects on the uniformity and accuracy of subsequent pressure testing due to localized accumulation or gaps, this application further optimizes the device design. See details below. Figures 5 to 7 and Figure 11 As shown: The upper pressure plate structure includes an upper stacked plate 7 rigidly fixedly connected to the connecting shaft 10, and a lower stacked plate 6 located below the upper stacked plate 7 and suspended by hanging bolts 8 movably passing through the perimeter of the upper stacked plate 7. In its natural state, the lower stacked plate 6 maintains a vertical gap with the upper stacked plate 7 due to gravity, forming a circumferentially continuous material guiding gap between them. When the upper stacked plate 7 moves downward under external force and completely overlaps with the lower stacked plate 6, the inverted conical protrusion on the bottom wall of the upper stacked plate 7 and the geometrically adapted groove in the center of the lower stacked plate 6 achieve precise embedding and fitting. The two form a complementary closure through the self-positioning effect of the conical surface, which can effectively seal the material guiding gap formed between the upper stacked plate 7 and the lower stacked plate 6 in the natural vertical state, and make the bottom surface of the lower stacked plate 6 form a complete and continuous... The pressure plate plane can apply a uniformly distributed longitudinal compressive load to the soil sample along the inner wall of the convex storage cavity of the storage cylinder 2; an upward through opening is provided on the side of the inverted conical protrusion along the bottom wall of the upper stacked plate 7, and a hopper 9 for feeding is installed above the opening. The hopper 9, as the feeding port, forms a continuous feeding channel from top to bottom with the guide gap; the soil sample to be tested is thrown into the hopper 9. Under its own gravity, the soil sample enters the area between the upper stacked plate 7 and the lower stacked plate 6 through the hopper 9 and the opening, and flows freely in the vertical direction without obstruction along the guide gap that is connected to the upper stacked plate 7 due to the natural hanging of the lower stacked plate 6. Finally, it flows smoothly into the storage cavity defined by the storage cylinder 2, thereby realizing the integrated integration of the feeding channel and the pressure structure; A base 22 is located below the base 1, and the two are elastically connected at the four corners via elastic members 23. These elastic members 23 provide both vertical support and elastic reset, allowing the base 1 to float vertically relative to the base 22. A gantry frame 13 is fixedly mounted above the base 22 to securely install the axial drive component 12, providing rigid support and positioning. The sides of the base 1 slide along the longitudinal arm of the gantry frame 13, which guides and constrains the lifting and lowering motion of the base 1, ensuring it moves only vertically without deflection or tilting. Within the space between the base 1 and the base 22, a rotating shaft 24 is rotatably mounted on the upper surface of the base 22. An eccentric wheel 25 is fixedly sleeved on the shaft surface of the rotating shaft 24. The shaft end of the rotating shaft 24 is connected to a motor 26 mounted on the base 22, which provides rotational driving force. The output shaft of the motor 26 is connected via a coupling to the torque... The torque is transmitted to the rotating shaft 24, which drives the rotating shaft 24 and the eccentric wheel 25 to rotate coaxially. The eccentric wheel 25 rotates periodically with its own axis as the center of rotation. During its rotation, the protruding part of the eccentric wheel 25 intermittently pushes the bottom of the base 1 upward, so that the base 1 obtains a periodic lifting driving force. When the pushing action of the eccentric wheel 25 is removed, the base 1 falls back under its own weight and the weight of the components it supports. At the same time, with the help of the elastic potential energy stored in the elastic element 23 due to the previous compression deformation, the elastic restoring force and the components it supports are released, so that the base 1 and the components it supports are shaken up and down together under the alternating action of elastic restoring force and gravity, forming a continuous high-frequency micro-amplitude vibration. This vibration is transmitted through the base 1 to the storage cavity above it, so that the soil sample that has been put into the cavity is compacted in the convex storage cavity, which promotes the rearrangement of soil particles, eliminates internal voids and hollow structures, and achieves uniform spreading and dense filling, providing a uniform initial sample state for the pressure test after loading. The connecting shaft 10 and the telescopic shaft of the axial drive 12 are connected via a sleeve 11. The sleeve cavity of the sleeve 11 forms an axial sliding fit with the outer peripheral wall of the connecting shaft 10, ensuring the relative freedom of movement between the two along the axial direction. During the vibration process, the connecting shaft 10 can slide axially along the shaft cavity of the sleeve 11, thereby forming a mechanical decoupling between the connecting shaft 10 and the axial drive 12. This causes the lifting and shaking action to terminate at the sleeve 11, and it will not be transmitted axially to the telescopic shaft end of the axial drive 12. This effectively blocks the transmission path of vibration energy to the precision transmission components (such as lead screw pairs, sealing rings, and guide bearings) inside the axial drive 12, preventing the sealing failure, guide wear, or decrease in positioning accuracy at the telescopic shaft end due to continuous impact load. This floating connection structure ensures that the axial drive 12 is always in a stable and smooth load state during operation, and its output end is not disturbed by external vibration, thus ensuring the reliability of equipment operation and service life under long-term use conditions.

[0034] Example 3: How to further realize the automatic switching and coordinated control of the side pressure plate structure's functional states between "pressure sealing - cleaning and slag removal" working conditions, so as to achieve multi-mode coordinated operation of the device and ensure detection accuracy and equipment cleanliness; this application has made further optimized designs for the device, see details below. Figures 8 to 10 ,as well as Figure 12 As shown: The side pressure plate structure is a single pressure plate 5 with a wall thickness, which is movably disposed on the side of the storage cavity; the push rod 18 is rotatably disposed between the crossbar and the single pressure plate 5, and a transmission wheel 19 is coaxially fixed at one end near the crossbar; an annular groove is opened on the end face of the transmission wheel 19, and a toothed ring is arranged circumferentially in the annular groove; a drive pin 20 is fixedly connected to the connecting arm 15. The overall outline of the drive pin 20 is approximately L-shaped, and the teeth at its bottom end can mesh with the toothed ring in the annular groove in the initial stage of the drive pin 20 descending with the connecting arm 15, thereby converting the vertical linear motion of the drive pin 20 into the circumferential rotational motion of the transmission wheel 19; the sliding part extending horizontally at the upper end of the drive pin 20 movably passes through the connecting arm 15, and the longitudinally extending side of the drive pin 20 interacts with the transmission wheel 19. The annular groove maintains the track-type coupling contact, allowing the drive pin 20 to follow the horizontal floating displacement of the transmission wheel 19, thereby achieving motion coordination between the lifting displacement of the drive pin 20 and the horizontal sliding. In addition, the rotational connection between the push rod 18 and the crossbar or single pressure plate 5 is provided with an appropriate amount of mating friction or is equipped with a friction damping element. This frictional resistance is sufficient to keep the current angular position of the transmission wheel 19 and the push rod 18 unchanged when the transmission wheel 19 is not actively driven by the teeth of the drive pin 20, preventing unexpected deflection caused by vibration or gravitational torque, thereby ensuring the stability of the inclined cam 27 in the non-transmission state and its position holding ability, avoiding the sealing plate of the sealing member 28 from malfunctioning at unexpected times, and further improving the reliability of the transmission timing and the certainty of the action execution. The push rod 18 has a through-cavity along its axial direction. One end of the push rod is connected to an external source of cleaning medium, and a valve body for opening, closing, and flow regulation is provided on the connecting pipeline to control the on / off state and supply flow of the cleaning medium as needed. The other end of the push rod 18 extends into the transmission cavity 51 opened in the wall of the single pressure plate 5. The end of the push rod 18 located in the transmission cavity 51 has a drain hole, through which the cleaning medium is discharged and enters the inner cavity of the transmission cavity 51. At the same time, it is coaxially fixed on the axial surface of this end. A sloping cam 27 is provided, with a wedge-shaped sloping surface on the side of the cam 27 near the storage cavity. This sloping surface forms a sloping contact fit with the sealing member 28 that moves through the flow hole 52 in the side wall of the transmission cavity 51. The sealing member 28 is a stepped assembly structure integrally formed by a sealing plate, a neck plate, and an ear plate. The outer contour of the sealing plate is adapted to the shape of the port of the flow hole 52 to achieve complete sealing or partial opening of the flow hole 52. The cross-sectional dimension of the neck plate is smaller than that of the flow hole 52. The diameter is such that a circumferential flow gap is formed between the neck plate and the inner wall of the flow hole 52. The ear plate is slidably disposed in the transmission cavity 51 along the axial direction, and the ear plate and the inner wall of the transmission cavity 51 are elastically reset connected by a return spring 29. When the inclined cam 27 rotates with the push rod 18, the high point of its inclined surface near the sealing member 28 gradually intervenes and forms a blocking limit on the end of the ear plate of the sealing member 28. Under the pushing action of the inclined surface, the sealing member 28 overcomes the elastic force of the return spring 29 and moves axially towards The material storage chamber slides in the direction, causing the sealing plate to be gradually pulled out of the flow hole 52. At the same time, the neck plate enters the flow hole 52 and forms a through flow guide gap between it and the inner wall of the flow hole 52, providing a smooth fluid channel for the cleaning medium to flow from the transmission chamber 51 through the flow hole 52 into the material storage chamber. When the inclined cam 27 rotates in the opposite direction to remove the high point of the inclined surface, the sealing member 28 is reset under the elastic restoring force of the return spring 29, and the sealing plate re-closes the flow hole 52, restoring the sealing configuration under pressure.

[0035] Working principle of this invention: Soil sample preparation stage: Soil samples to be tested for mechanical properties are poured into hopper 9. Under their own weight, the soil samples flow freely vertically through the guide gaps between the upper and lower stacked plates 7 and 6, which are interconnected due to their staggered arrangement, and eventually flow into the convex storage cavity defined by the storage cylinder 2. In order to ensure that the soil samples flowing into the convex storage cavity are evenly distributed within the cavity and to avoid local accumulation or voids that could adversely affect the uniformity and accuracy of subsequent pressure testing, motor 26 is started. The output shaft of motor 26 drives rotating shaft 24 and eccentric wheel 25 to rotate coaxially via a coupling. This allows eccentric wheel 25 to rotate periodically around the axis of rotating shaft 24, intermittently lifting the base 1 upwards. The elastic restoring force stored in the elastic element 23 due to compression deformation allows the components supported on the base 1 to move up and down in unison, vibrating and compacting the soil sample within the convex storage cavity and spreading it evenly. During the lifting and vibrating process, the connecting shaft 10 can slide axially along the shaft cavity of the sleeve 11, thus forming mechanical decoupling. This prevents the vibration force from being transmitted axially to the axial drive element 12, avoiding impact damage to the telescopic shaft end of the axial drive element 12 and ensuring the reliability and service life of the equipment. The vibration operation ends when the convex storage cavity of the storage cylinder 2 is fully filled. At this point, the eccentric wheel 25 is stationary and forms a stable rigid support for the bottom of the base 1, providing a reliable bearing foundation for the subsequent pressure application stage.

[0036] The phase of coordinated pressure from both vertical and horizontal directions: The telescopic shaft of the axial drive component 12 extends downward in the vertical direction, which can drive the sleeve 11 to move downward synchronously. When the shaft end of the connecting shaft 10 is completely covered by the shaft cavity of the sleeve 11 and axially abuts, the connecting shaft 10 begins to move downward synchronously with the sleeve 11 and pushes the upper stacked plate 7 to gradually approach the top wall of the lower stacked plate 6. When the upper stacked plate 7 and the lower stacked plate 6 are completely stacked, the protrusion on the bottom wall of the upper stacked plate 7 and the groove on the center of the lower stacked plate 6 achieve precise matching and complementarity, thereby effectively sealing the originally misaligned and connected material guide gap between the upper stacked plate 7 and the lower stacked plate 6, and making the bottom surface of the lower stacked plate 6 form a complete pressure plate plane that can apply longitudinal compression load to the soil sample along the inner wall of the convex storage cavity of the storage cylinder 2. During this longitudinal compression process, the pressure sensing module senses and collects pressure data in real time, and transmits it to the data processing module 30 for analysis and processing via electrical signals to obtain the stress-strain response characteristics of the soil sample under axial compression conditions. Simultaneously, the mounting plate 14 descends synchronously with the connecting shaft 10, thereby driving the connecting arm 15 and the push shaft 16 to move downwards together. During the descent, the pulley at the end of the push shaft 16 interacts with the contact surface of the guide groove 171, thereby generating a normal thrust perpendicular to the contact surface of the guide groove 171 and inclined downwards. The horizontal component of this normal thrust guides the sliding plate 17 to drive the push rod 18 and the single pressure plate 5 located on the left or right side of the convex storage cavity to move towards the center of the cavity, thereby applying a lateral compressive load to the soil sample. During this lateral pressure application, the pressure sensing module also senses and collects pressure data in real time, and transmits it to the data processing module 30 for analysis and processing via electrical signals. This enables the simultaneous acquisition of lateral pressure change data in the lateral direction of the soil sample during the soil sample compression test, overcoming the shortcomings of existing technologies that can only measure single axial pressure data, resulting in insufficient experimental evaluation. This provides a reliable experimental basis for the accurate evaluation of the lateral deformation characteristics and lateral pressure coefficient of the soil.

[0037] Lateral pressure plate forming and resetting stage: Furthermore, the drive pin 20 can descend synchronously with the connecting arm 15; the teeth or friction part at the bottom of the drive pin 20 contacts the transmission wheel 19 during the descent and drives the transmission wheel 19 to rotate at a certain angle, causing the push rod 18 coaxial with the transmission wheel 19 and its shaft end and the inclined cam 27 located in the transmission cavity 51 to rotate together, causing the high point of the inclined cam 27 near the sealing member 28 to gradually remove its blocking and limiting effect on the sealing member 28; the sealing member 28, under the elastic restoring force of the return spring 29, moves towards the wall of the single pressure plate 5. The surface rebounds and resets until the sealing plate of the sealing component 28 completely seals the flow hole 52, and together with the wall of the single pressure plate 5, forms a complete pressure plate plane that can apply a lateral compressive load to the soil sample along the convex storage cavity of the storage cylinder 2, thereby achieving effective sealing and bearing action during the soil compaction stage; (Note: The sliding part of the drive pin 20 passes through the connecting arm 15, and the side of the drive pin 20 is kept in track-type coupling and limiting with the annular groove of the transmission wheel 19, thereby realizing the coordinated linkage between the lifting displacement and horizontal sliding of the drive pin 20). Conversely, when the device is fully reset to its initial state, that is, when the drive pin 20 rises synchronously with the connecting arm 15, the teeth or friction part at the bottom of the drive pin 20 can drive the transmission wheel 19 to rotate in the opposite direction by a certain angle after contacting it, so as to achieve reset. This causes the push rod 18, which is coaxial with the transmission wheel 19, and its shaft end and the inclined cam 27, which is located in the transmission cavity 51, to rotate in the opposite direction as a whole. This causes the high point of the inclined surface of the inclined cam 27 on the side close to the sealing member 28 to gradually intervene in blocking and limiting the sealing member 28. Under the pushing action of the inclined surface of the inclined cam 27, the sealing member 28 compresses the reset spring 29 and gradually pulls out to the outside of the flow hole 52, so that the guide gap between the neck plate of the sealing member 28 and the flow hole 52 is restored, providing a fluid channel for subsequent unloading and cleaning operations.

[0038] Unloading and cleaning stage: Subsequently, the soil sample after testing is removed from the convex storage chamber. The cleaning medium connected to the end of the push rod 18 can enter the transmission chamber 51 through the drain hole at the end of the push rod 18 after the corresponding valve body is opened, and then enter the convex storage chamber of the storage cylinder 2 through the flow hole 52. At this time, the eccentric wheel 25 can be opened to generate rotational vibration, and the soil sample residue remaining on the inner wall of the convex storage chamber is cleaned by water wave vibration. The synergistic effect of vibration excitation and fluid flushing effectively removes the attached residue, realizes the multi-mode collaborative operation of the device, and ensures the cleanliness and detection accuracy of the equipment under multiple cycle detection conditions.

[0039] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, in accordance with the technical plan and improved concept of the present invention, should be included under the protection of the present invention.

Claims

1. A soil mechanical property testing device, comprising a base (1), a storage cylinder (2) installed on the top of the base (1) for holding a soil sample to be tested, and an axial drive member (12) disposed above the storage cylinder (2) to provide axial driving force in the vertical direction; characterized in that: The telescopic shaft of the axial drive component (12) is fixed to the upper pressure plate structure via a connecting shaft (10) to apply an axial compression load to the soil sample; a radially extending mounting plate (14) is mounted on the axial surface of the connecting shaft (10), and a connecting arm (15) is arranged perpendicularly to the mounting plate (14) below it. A push shaft (16) extending in the front-back direction is passed through the bottom end of the connecting arm (15), and the two shaft ends of the push shaft (16) extend into the guide groove (171) obliquely opened on the side wall of the slide plate (17) of at least one side of the storage cylinder (2); the slide plate (17) and One end of the push rod (18) that runs through the side wall of the storage cylinder (2) is fixed, and the other end of the push rod (18) is fixed to the side pressure plate structure that is movably set on the side of the storage cavity. When the axial drive member (12) extends downward, the driving force is transmitted to the push shaft (16) through the connecting shaft (10), the mounting plate (14), and the connecting arm (15), which drives the push shaft (16) to slide along the guide groove (171) to generate normal thrust. Its horizontal component drives the sliding plate (17) to move in conjunction with the push rod (18) and the side pressure plate structure toward the center of the storage cavity, so as to achieve the coordinated application of longitudinal and transverse compression loads.

2. The soil mechanical property testing device according to claim 1, characterized in that: The storage chamber of the storage cylinder (2) has a convex cross-section along the left and right directions, which is used to provide a compression stroke margin for the upper pressure plate structure in the longitudinal direction and to provide a feeding space for the side pressure plate structure in the transverse direction, so as to avoid interference between the two due to displacement superposition in their respective movement paths; when the upper pressure plate structure moves to the extreme low position in the longitudinal direction and the side pressure plate structure feeds to the extreme inner position in the transverse direction, the side wall of the upper pressure plate structure and the side wall of the side pressure plate structure form a vertically fitted closed state, so that the effective volume of the storage chamber is compressed to the minimum.

3. The soil mechanical property testing device according to claim 2, characterized in that: The front side wall of the storage cylinder (2) is provided with a front hatch, and the bottom edge of the front hatch is hinged with a hatch (3) that can be flipped up and opened and closed. The hatch (3) is provided with a locking structure for locking the front hatch in the closed state. The back side of the storage cylinder (2) is provided with a rear hatch that is the same diameter as the front hatch and is opposite to it. A bulldozer plate (4) that is adapted to its contour is movably embedded in the rear hatch. The bulldozer plate (4) is fixedly connected to the telescopic shaft of the unloading drive (21) installed on the base (1). The unloading drive (21) drives the bulldozer plate (4) to move back and forth in the horizontal direction. The size of the front hatch and the rear hatch depends on the projection size of the effective pressing space enclosed by the upper pressure plate structure and the side pressure plate structure when they are vertically attached to the side wall on the plane where the hatch is located.

4. The soil mechanical property testing device according to claim 1, characterized in that: The slide plate (17) is placed on the outer wall of the front and rear hatches of the storage cylinder (2), and the slide plate (17) is provided with a slide rail structure extending in the horizontal direction to guide the slide plate (17) to move in a straight line in the horizontal direction; the two slide plates (17) on the same side are connected by a crossbar to form a rigid synchronous frame, one end of the push rod (18) is fixed to the crossbar, and the crossbar and the push rod (18) are arranged relatively downward in the vertical direction to provide clearance space for the shaft end of the push shaft (16) to slide along the guide groove (171) when the push shaft (16) moves longitudinally up and down with the connecting arm (15).

5. The soil mechanical property testing device according to claim 1, characterized in that: The length of the push shaft (16) is a small segment structure that extends into the guide groove (171). The connecting arm (15) is forked, with its two forked arms passing over the outer area between the two opposing slide plates (17) on the same side and fixed to the outer end of the corresponding push shaft (16).

6. The soil mechanical property testing device according to claim 1, characterized in that: The upper pressure plate structure includes an upper stacked plate (7) directly connected to the connecting shaft (10), and a lower stacked plate (6) located below the upper stacked plate (7) and suspended by bolts (8) that are movably inserted around the upper stacked plate (7). In its natural state, the lower stacked plate (6) forms a circumferentially through material guiding gap with the upper stacked plate (7). The bottom wall of the upper stacked plate (7) is provided with an inverted conical protrusion, and the center of the lower stacked plate (6) is provided with a groove that matches the inverted conical protrusion. When the upper stacked plate (7) and the lower stacked plate (6) are fully stacked, the inverted conical protrusion is embedded in the groove to block the material guiding gap and make the bottom surface of the lower stacked plate (6) form a complete pressure plate plane. An upward through opening is provided along the side of the inverted conical protrusion, and a hopper (9) is installed above the opening.

7. The soil mechanical property testing device according to claim 6, characterized in that: A base (22) is provided below the base (1), and the base (1) and the base (22) are elastically connected by an elastic element (23) so that the base (1) has a vertical floating degree of freedom relative to the base (22); a gantry frame (13) is fixedly provided above the base (22), and an axial drive element (12) is fixedly installed on the gantry frame (13); the side of the base (1) and the longitudinal arm of the gantry frame (13) form a sliding fit; a rotating shaft (23) is rotatably installed on the upper surface of the base (22). 4) An eccentric wheel (25) is fixedly sleeved on the shaft surface of the rotating shaft (24). The shaft end of the rotating shaft (24) is connected to the motor (26) installed on the base (22). The eccentric wheel (25) has a protruding part. During the rotation of the eccentric wheel (25), the protruding part intermittently pushes the bottom of the base (1), causing the base (1) to move up and down relative to the base (22) in the vertical direction. With the help of the elastic force of the elastic element (23), the base (1) and its supporting components will shake up and down.

8. The soil mechanical property testing device according to claim 7, characterized in that: The connecting shaft (10) and the telescopic shaft of the axial drive (12) are connected by a sleeve (11). The sleeve (11) has a shaft cavity, which is axially slidingly engaged with the outer peripheral wall of the connecting shaft (10), so that the connecting shaft (10) can slide along the shaft cavity of the sleeve (11).

9. The soil mechanical property testing device according to claim 4, characterized in that: The side pressure plate structure is a single pressure plate (5) with a wall thickness. The single pressure plate (5) is movably set on the side of the storage cavity. The push rod (18) is rotatably set between the cross bar and the single pressure plate (5). The end of the push rod (18) near the cross bar is coaxially fixed with a transmission wheel (19). The end face of the transmission wheel (19) is provided with an annular groove. A toothed ring is arranged circumferentially in the annular groove. A drive pin (20) is fixedly connected to the connecting arm (15). The drive pin (20) is L-shaped and has a toothed part at its bottom end. The toothed part can mesh with the toothed ring in the annular groove during the initial descent of the connecting arm (15). The upper end of the drive pin (20) slides through the connecting arm (15), and the side of the drive pin (20) is kept in track-type coupling limit with the annular groove. A friction damping element is provided at the rotation connection of the push rod (18) to maintain the angular position of the transmission wheel (19) and the push rod (18) when the drive pin (20) does not drive the transmission wheel (19).

10. The soil mechanical property testing device according to claim 9, characterized in that: The push rod (18) has a through-cavity along the axial direction. One end of the through-cavity is used to connect to the cleaning medium supply source. The other end of the push rod (18) extends into the transmission cavity (51) inside the wall of the single pressure plate (5). The end of the push rod (18) located in the transmission cavity (51) has a drain hole. A sloping cam (27) is coaxially fixed on the axial surface of the push rod (18). The sloping cam (27) has a sloping surface on the side near the storage cavity. An overflow hole (52) is opened on the side wall of the transmission cavity (51). A sealing member (28) moves through the overflow hole (52). The sealing element (28) forms an abutment fit with the inclined surface; the sealing element (28) is integrally formed by the sealing plate, neck plate and ear plate. The sealing plate is adapted to the flow hole (52). The cross-sectional size of the neck plate is smaller than the diameter of the flow hole (52). The ear plate is slidably disposed in the transmission cavity (51), and the ear plate is connected to the inner wall of the transmission cavity (51) by a return spring (29). The inclined cam (27) can rotate with the push rod (18) to push the sealing element (28) along the axial direction through the inclined surface, so that the sealing plate opens or closes the flow hole (52).

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