Rock-soil direct shear type test equipment and test method

Abstract

The invention relates to the technical field of rock-soil tests, in particular to rock-soil direct shear type test equipment and a test method.The rock-soil direct shear type test equipment comprises a test bed, the top of the test bed is fixedly connected with a sliding plate, the top of the test bed is movably connected with two transposition plates, the top of the test bed is fixedly connected with a first electric cylinder, and the first electric cylinder is fixedly connected with a second electric cylinder; the top of the sliding plate is movably connected with a shear box, the shear box comprises a bottom box, two upper boxes and two lower boxes, the bottom of the lower box on the front side is fixedly connected with the bottom box, and the upper box on the front side is located on the top of the lower box on the front side. According to the rock-soil direct shear type test equipment and the test method, the horizontal opening and closing type shear box serves as a core, driving of the second electric cylinder and guiding of the limiting strip are matched, direct loading of a sample without a cutting ring and a water permeable piece and complete disassembling after testing are achieved, and through the double transposition plates connected through the transverse rod and a sliding rod guiding structure, the test efficiency is improved. And meanwhile, the next group of samples is preloaded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geotechnical test, in particular to a geotechnical direct shear test device and test method. BACKGROUND

[0002] It is known that the direct shear test is a classical laboratory test method for determining the shear strength of rock-soil, the core principle is to apply a fixed normal stress to the rock-soil sample, and gradually apply a horizontal shear force along the preset shear surface until the sample is sheared and destroyed, and then obtain the shear strength index, in order to determine the cohesion and internal friction angle of the rock-soil, the rock-soil sample is placed in the upper and lower shear boxes, a fixed normal stress is first applied to simulate the actual overburden pressure, and then a horizontal shear force is gradually applied along the preset shear surface, the relationship curve between the shear force and the shear displacement during the shearing process is recorded, the peak shear force is taken to determine the shear strength under the corresponding normal stress, and finally the relationship between the normal stress and the shear strength is fitted through the Mohr-Coulomb strength theory to obtain the calculation model of the rock-soil shear strength.

[0003] The existing geotechnical direct shear test is mostly to push the prepared rock-soil sample into the shear box through the cutting ring and the water-permeable sheet. Although this method can load the rock-soil sample, the edge of the rock-soil sample may have protrusions and other conditions during the manufacturing process, which may cause the edge tissue to peel off during the pushing of the water-permeable sheet, affecting the test results. At the same time, after the experiment, that is, after the rock-soil sample is destroyed, it is difficult to completely preserve the form of the rock-soil sample destruction, and it is easy to cause damage to the rock-soil sample when it is pushed out of the shear box, and it is difficult to observe the outer surface of the rock-soil sample after the test.

[0004] Based on the above-mentioned situation, we find that the existing geotechnical direct shear test is difficult to avoid the above problems at the same time, therefore, we propose a geotechnical direct shear test device which can simplify the loading process of rock-soil sample and shear box during the geotechnical direct shear test, and is not easy to cause damage to the rock-soil sample during loading, and can quickly and completely disassemble the rock-soil sample after the test to facilitate the observation of the damage condition. SUMMARY

[0005] (I) Technical problems solved

[0006] In view of the shortcomings of the prior art, the present application provides a geotechnical direct shear test device and test method, which has the advantages of simplifying the loading process of rock-soil sample and shear box during the geotechnical direct shear test, and is not easy to cause damage to the rock-soil sample during loading, and can quickly and completely disassemble the rock-soil sample after the test to facilitate the observation of the damage condition.

[0007] (II) Technical solutions

[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a direct shear test device and test method for soil and rock, including a test bench, a sliding plate fixedly connected to the top of the test bench, two shift plates movably connected to the top of the test bench, a first electric cylinder fixedly connected to the top of the test bench, and a shear box movably connected to the top of the sliding plate;

[0009] The shear box includes a base box, two upper boxes, and two lower boxes. The bottom of the front lower box is fixedly connected to the base box. The front upper box is located on top of the front lower box. The rear upper box and the rear lower box are used in conjunction with the front upper box and the front lower box, respectively. A back frame is fixedly connected to the rear side of the base box. A second electric cylinder is fixedly connected to the rear side of the back frame. The telescopic end of the second electric cylinder passes through the back frame and is fixedly connected to a push-pull bracket. Pin holes are opened on the inner sides of the upper and lower boxes. A top hook is fixedly connected to the right side of the front upper box.

[0010] A top cover is provided on the inner side between the two upper boxes. A dial indicator is fixedly connected to the top of the test bench. A main beam is slidably connected to the inner side of the test bench. A crossbeam is fixedly connected to the outer side of the main beam. A pressure column is fixedly connected to the bottom of the crossbeam.

[0011] Using the above technical solution, by setting up a shear box, soil and rock samples can be loaded quickly during use. The retraction of the second electric cylinder on the rear side of the back frame causes the upper and lower rear boxes, connected by a push-pull frame, to be pulled open along with the upper and lower front boxes. At this point, the space between the upper and lower front and rear boxes is large enough to directly accommodate the soil and rock sample. After placement, the second electric cylinder can push the upper and lower rear boxes back to close on top of the bottom box to load and fix the soil and rock sample. Then, by fixing the relative positions of the upper and lower ring boxes with pins, the top cover is locked inside the upper box, pressing its bottom firmly against the soil and rock sample. Subsequently, the first electric cylinder can move along the shift plate and slide... The shear box is pushed by pressing down on the left side of the lower box. After the main beam is pushed to the bottom, the main beam descends, causing the pressure column at the bottom of the crossbeam to press against the top cover. At this time, the top hook on the right side of the upper box presses against the dial indicator device, and the dial indicator device starts counting until the sample is sheared. The dial indicator reading can be used as the calculation standard. Since the shear box can be opened and closed in the horizontal direction, it can load and test soil and rock samples with irregular surfaces or even a certain degree of error. The loading process does not rely on changing the cutter or the permeable plate. After the test is completed, the upper and lower boxes can be moved back along the front lower and upper boxes, and the damaged soil and rock samples can be completely and quickly disassembled. The outer edge and the damaged surface can be observed relatively completely.

[0012] The present invention is further configured such that: a groove is provided on the top of the test bench, a side frame is fixedly connected to the bottom of the test bench, a slide rod is fixedly connected to the inner side of the side frame, the slide rod is located inside the groove, a slider is slidably connected to the outer side of the slide rod, the top of the slider is fixedly connected to a transposition plate, and a crossbar is fixedly connected between the two transposition plates.

[0013] By adopting the above technical solution, a crossbar is set to connect two sets of transposition plates. The groove cooperates with the side frame and the slide bar, which makes it easy for the two sets of transposition plates to slide horizontally along the slide bar to switch to the desired transposition plate. The transposition plate cooperates with the slide plate to form a complete slide for the shear box to move. During the test of a single shear box, another shear box and soil sample can be loaded in advance on the transposition plate that is not in cooperation with the slide plate, so as to facilitate quick switching after the test is completed.

[0014] The present invention is further configured such that: a narrow shell is fixedly connected to the top of the test bench, a limiting block is slidably connected to the inner side of the narrow shell, and the bottom of the limiting block is fixedly connected to the bottom of the inner side of the narrow shell by a spring.

[0015] By adopting the above technical solution, a narrow shell is set up so that when the switching plate is in the position that cooperates with the slider, two limiting blocks block the front and rear sides of the switching plate to prevent it from moving. When it is necessary to switch the switching plate, the switching plate will push the top of the arc-shaped limiting block when it slides in the horizontal direction and retract it into the narrow shell. The spring presses and stores force until the movement is completed, and the spring rebounds to make the limiting block return to the blocking position, so that the structure remains stable when it is not affected by external forces.

[0016] The invention is further configured such that: both the top of the slide plate and the top of the shift plate are provided with slots, and rollers are rotatably connected to the inner side of the slots.

[0017] By adopting the above technical solution, by setting up an empty groove to accommodate the roller, the rolling of the roller can reduce friction and reduce test error when the shear box slides along the slide and the transposition plate.

[0018] The present invention is further configured such that: a slide is fixedly connected to the bottom of the base box, the bottom of the slide is movably connected to the slide plate, a push plate is fixedly connected to the left side of the base box, and a magnetic block that cooperates with the push plate is fixedly connected to the telescopic end of the first electric cylinder.

[0019] By adopting the above technical solution, a pusher plate is set to contact and slide with the shift plate and the slide plate. The magnetic block, together with the pusher plate, facilitates the push-pull action of the shear box by the first electric cylinder. At the same time, when the shear box is subjected to a force perpendicular to the push-pull direction of the first electric cylinder, the shear box can be released from the first electric cylinder.

[0020] The present invention is further configured such that: a dovetail block is fixedly connected to the front side of the push-pull frame, and opening and closing frames are fixedly connected to the rear sides of the upper rear box and the lower rear box, and the inner side of the opening and closing frame is slidably connected to the dovetail block.

[0021] By adopting the above technical solution, and by setting a dovetail block in conjunction with the opening and closing frame, the second electric cylinder can simultaneously push and pull the upper and lower boxes on the rear side, while the upper and lower boxes can move reasonably along the direction perpendicular to the push and pull direction of the second electric cylinder, so as to facilitate the shearing test.

[0022] The present invention is further configured such that: the left side of the rear upper box and the lower box and the right side of the front upper box and the lower box are fixedly connected to a frame, and the inner side of the frame is slidably connected to a limiting strip, the two limiting strips on the left are fixedly connected to the front upper box and the lower box respectively, and the two limiting strips on the right are fixedly connected to the rear upper box and the lower box respectively.

[0023] By adopting the above technical solution, and by setting a frame in conjunction with a limiting strip, the limiting strip can slide inside the frame to maintain a straight line movement when the upper and lower boxes on the rear side are pushed and pulled back and forth, making it less likely to tilt or rotate.

[0024] The present invention is further configured such that: a lower frame is fixedly connected to the bottom of the test bench, an upper frame is fixedly connected to the top of the main beam, and lead screws are rotatably connected to the inner sides of both the upper and lower frames; the bottom of the top lead screw is rotatably connected to the crossbeam; a threaded sleeve is threadedly connected to the outer side of the bottom lead screw; the threaded sleeve is fixedly connected to the main beam on the side near the main beam; a pin holder is threadedly connected to the outer side of the top lead screw; and a pin is fixedly connected to the bottom of the pin holder.

[0025] By adopting the above technical solution, when the bottom screw is driven to rotate, the main beam connected to it by the screw sleeve will rise and fall vertically along the test bench to adjust the vertical height of the crossbeam. When the top screw rotates, the upper frame will drive the pin frame connected to it to move vertically, so as to insert the pin into the pin hole or pull it out of the pin hole.

[0026] The present invention is further configured such that: a servo motor is installed at the bottom of the lower frame and the top of the upper frame; the output end of the top servo motor is fixedly connected to the top of the top lead screw; the output end of the bottom servo motor is fixedly connected to the bottom of the bottom lead screw; a sliding pin is slidably connected to the inner side of the pin frame; and the two ends of the sliding pin are fixedly connected to the upper frame and the crossbeam, respectively.

[0027] By adopting the above technical solution, a servo motor is set to control and drive the rotation of the top and bottom lead screws, and a sliding pin is set to limit the movement of the pin frame to prevent the structure from rotating or tilting.

[0028] A test method for a direct shear test device for soil and rock includes the following steps:

[0029] S1. Activate the second electric cylinder to retract the telescopic end. Drive the upper and lower boxes on the rear side to move backward along the limit strip and frame guide through the push-pull bracket. After opening the shear box, directly put in the soil and rock sample. Then control the second electric cylinder to push the rear box to reset and close. Drive the pin to insert into the pin hole to fix the box through the top servo motor. Cover the top cover and press it down. At the same time, use the crossbar to push the two sets of shift plates to slide along the slide bar. On the shift plate that does not cooperate with the slide plate, the shear box loading of the next set of samples is completed in advance. The limit block achieves the limit fixation of the shift plate through the spring rebound.

[0030] S2. The first electric cylinder uses a magnetic block to attract the shear box's pushing plate, pushing the shear box along the roller track on the top of the sliding plate and the shifting plate to below the main beam. The lower frame servo motor is started to drive the bottom screw to rotate, which drives the main beam to descend through the screw sleeve. This causes the pressure column at the bottom of the crossbeam to accurately press against the top cover and apply normal stress. At this time, the top hook of the upper box triggers the dial indicator to start counting, and then the shear test is carried out. The cooperation between the dovetail block and the opening and closing frame ensures that the box body adapts to the shear displacement, and the multiple limiting structure ensures the structural stability during the test.

[0031] S3. After the test, the top servo motor reverses and pulls out the pin. The first electric cylinder pulls the shear box back to the switching plate, controls the second electric cylinder to open the shear box again, and completely removes the damaged sample for morphological observation. The switching plate is switched to another pre-loaded shear box by sliding the crossbar, and the limit block is automatically reset and fixed.

[0032] (III) Beneficial Effects

[0033] Compared with the prior art, the present invention provides a direct shear test device and method for soil and rock, which has the following beneficial effects:

[0034] This direct shear test equipment and method for soil and rock utilizes a shear box to rapidly load soil and rock samples. The second electric cylinder on the rear of the back frame retracts, causing the upper and lower rear boxes, connected via a push-pull frame, to open along with the front upper and lower boxes. This creates ample space between the front and rear upper and lower boxes, accommodating the soil and rock sample. After loading, the second electric cylinder pushes the rear upper and lower boxes back to close on top of the bottom box, securing the sample. Then, pins secure the relative positions of the upper and lower boxes, locking the top cover inside the upper box and pressing its bottom firmly against the soil and rock sample. The first electric cylinder then moves along the shear box... The positioning plate and sliding plate push the shear box, specifically by pushing the left side of the lower box to the bottom of the main beam, after which the main beam descends, causing the pressure column at the bottom of the crossbeam to press against the top cover. At this time, the top hook on the right side of the upper box presses against the dial indicator device, and the dial indicator device starts counting until the sample is sheared. The dial indicator reading can be used as the calculation standard. Since the shear box can be opened and closed in the horizontal direction, it can be used to load and test soil and rock samples with irregular surfaces or even allow for a certain degree of error. Moreover, the loading process does not rely on changing the cutter or the permeable plate. After the test is completed, the upper and lower boxes can be moved back along the front lower and upper boxes, and the damaged soil and rock samples can be completely and quickly disassembled. The outer edge and the damaged surface can be observed relatively completely. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the main structure of the present invention;

[0036] Figure 2 This is a schematic diagram of the shear box structure in this invention;

[0037] Figure 3 This is a schematic diagram showing the disassembled shear box in this invention;

[0038] Figure 4 This is a schematic diagram of the rear of the shear box in this invention;

[0039] Figure 5 This is a schematic diagram of the connection of the shear box in this invention;

[0040] Figure 6 This is a rear view of the main structure in this invention;

[0041] Figure 7 This is a bottom view of the main structure in this invention;

[0042] Figure 8 This is a flowchart of the test method of the present invention.

[0043] In the diagram: 1. Test bench; 2. Slide plate; 3. Transposition plate; 4. First electric cylinder; 5. Shear box; 51. Bottom box; 52. Upper box; 53. Lower box; 54. Back frame; 55. Second electric cylinder; 56. Push-pull frame; 57. Pin hole; 6. Top cover; 7. Dial gauge device; 8. Main beam; 9. Crossbeam; 10. Pressure column; 11. Groove; 12. Side frame; 13. Slide rod; 14. Slider; 15. Crossbar; 16. Narrow shell; 17. Limiting block; 18. Roller; 19. Slide frame; 20. Push plate; 21. Magnetic block; 22. Dovetail block; 23. Opening and closing frame; 24. Frame; 25. Limiting strip; 26. Lower frame; 27. Upper frame; 28. Lead screw; 29. ​​Screw sleeve; 30. Pin holder; 31. Pin; 32. Sliding pin. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Example 1

[0046] Please see Figures 1-6 A direct shear test device for soil and rock includes a test platform 1, a sliding plate 2 fixedly connected to the top of the test platform 1, two shift plates 3 movably connected to the top of the test platform 1, a first electric cylinder 4 fixedly connected to the top of the test platform 1, and a shear box 5 movably connected to the top of the sliding plate 2.

[0047] The shear box 5 includes a base box 51, two upper boxes 52 and two lower boxes 53. The bottom of the front lower box 53 is fixedly connected to the base box 51. The front upper box 52 is located on the top of the front lower box 53. The rear upper box 52 and the rear lower box 53 are used in conjunction with the front upper box 52 and the front lower box 53, respectively. A back frame 54 is fixedly connected to the rear side of the base box 51. A second electric cylinder 55 is fixedly connected to the rear side of the back frame 54. The telescopic end of the second electric cylinder 55 passes through the back frame 54 and is fixedly connected to a push-pull bracket 56. Pin holes 57 are opened on the inner side of the upper box 52 and the lower box 53. A top hook is fixedly connected to the right side of the front upper box 52.

[0048] A top cover 6 is provided on the inner side between the two upper boxes 52. A dial gauge device 7 is fixedly connected to the top of the test bench 1. A main beam 8 is slidably connected to the inner side of the test bench 1. A crossbeam 9 is fixedly connected to the outer side of the main beam 8. A pressure column 10 is fixedly connected to the bottom of the crossbeam 9.

[0049] By setting the shear box 5, the soil and rock sample can be quickly loaded during use. When the second electric cylinder 55 on the rear side of the back frame 54 retracts, the upper and lower boxes 52 and 53 connected to it via the push-pull bracket 56 are pulled open along the front upper and lower boxes 52 and 53. At this time, the space between the front and rear upper and lower boxes 52 and 53 is large enough to directly accommodate the soil and rock sample. After placement, the second electric cylinder 55 can push the rear upper and lower boxes 52 and 53 back to close on top of the bottom box 51 to load and fix the soil and rock sample. Then, after fixing the relative position of the upper box 52 and the lower box 53 by pin control, the top cover 6 is snapped into the inside of the upper box 52, and its bottom is pressed tightly against the soil and rock sample. Then, the first electric cylinder 4 can move along the shift plate 3... The shear box 5 is pushed by the sliding plate 2, specifically by pushing the left side of the lower box 53. After being pushed to the bottom of the main beam 8, the main beam 8 descends, causing the pressure column 10 at the bottom of the crossbeam 9 to press against the top cover 6. At this time, the top hook on the right side of the upper box 52 presses against the dial indicator device 7, and the dial indicator device 7 starts counting until the sample is sheared. The dial indicator reading can be used as the calculation standard. Since the shear box 5 can be opened and closed in the horizontal direction, it can be used to load and test soil and rock samples with irregular surfaces or even allow for a certain degree of error. The loading process does not rely on changing the blade or the permeable plate. After the test is completed, the upper box 52 and the lower box 53 on the rear side can be moved along the front lower box 53 and the upper box 52. The damaged soil and rock sample can be completely and quickly disassembled, and its outer edge and damaged surface can be observed relatively completely.

[0050] In this design, the left side of the rear upper box 52 and lower box 53, and the right side of the front upper box 52 and lower box 53, are all fixedly connected to a frame 24. Limiting strips 25 are slidably connected to the inner side of the frame 24. The two left-side limiting strips 25 are fixedly connected to the front upper box 52 and lower box 53 respectively, and the two right-side limiting strips 25 are fixedly connected to the rear upper box 52 and lower box 53 respectively. By setting the frame 24 in conjunction with the limiting strips 25, the limiting strips 25 can slide within the frame 24, allowing movement between the rear upper box 52 and lower box 53. When 53 is pushed or pulled back and forth, it maintains linear movement and is not prone to tilting or rotation. The bottom of the test bench 1 is fixedly connected to a lower frame 26, and the top of the main beam 8 is fixedly connected to an upper frame 27. Both the upper frame 27 and the lower frame 26 are rotatably connected to lead screws 28. The bottom of the top lead screw 28 is rotatably connected to the crossbeam 9, and the outer side of the bottom lead screw 28 is threadedly connected to a threaded sleeve 29. The threaded sleeve 29 is fixedly connected to the main beam 8 on the side closest to the main beam 8. The outer side of the top lead screw 28 is threadedly connected to a pin holder 30. A pin 31 is fixedly connected to the bottom of the pin frame 30. By setting the lower frame 26, when the bottom lead screw 28 is driven to rotate, the main beam 8 connected to it by the screw sleeve 29 will rise and fall vertically along the test bench 1 to adjust the vertical height of the crossbeam 9. When the top lead screw 28 rotates, the upper frame 27 will drive the pin frame 30 connected to it to move vertically, so as to insert the pin 31 into or pull it out of the pin hole 57. Servo motors are installed at the bottom of the lower frame 26 and the top of the upper frame 27. The output end of the top servo motor is fixedly connected to the top of the top lead screw 28, and the output end of the bottom servo motor is fixedly connected to the bottom of the bottom lead screw 28. A sliding pin 32 is slidably connected to the inner side of the pin frame 30. The two ends of the sliding pin 32 are fixedly connected to the upper frame 27 and the crossbeam 9, respectively. By setting the servo motor, the rotation of the top lead screw 28 and the bottom lead screw 28 is controlled and driven. The sliding pin 32 is used to limit the movement of the pin frame 30 to prevent the structure from rotating or tilting.

[0051] The working principle of this embodiment is as follows: When the extension end of the second electric cylinder 55 on the rear side of the back frame 54 retracts, the dovetail block 22 on the front side of the push-pull frame 56 pulls the opening and closing frame 23 of the upper box 52 and the lower box 53 on the rear side, causing the rear box to move backward along the guide of the front box. At this time, the limiting strip 25 on the inner side of the frame 24 slides synchronously, restricting the rear box to only move horizontally and linearly, forming a larger opening space to directly place the soil and rock sample. Then, the extension end of the second electric cylinder 55 extends to push the rear box to reset and close to wrap the sample. After the shear box 5 moves to the test position, the servo motor at the bottom of the lower frame 26 drives the bottom screw 28 to rotate, and the screw sleeve 29 drives the main beam 8 to rise and fall vertically along the test platform 1, thereby making the pressure column 10 at the bottom of the crossbeam 9 accurately press against the shear. The top cover 6 of the force box 5, along with the servo motor at the top of the upper frame 27, drives the top lead screw 28 to rotate. The pin frame 30 moves vertically along the sliding pin 32, causing the pin 31 to be inserted into the pin holes 57 of the upper box 52 and the lower box 53 to fix the box body. The sliding connection between the dovetail block 22 and the opening and closing frame 23 not only realizes the synchronous push and pull of the rear box body by the second electric cylinder 55, but also allows the box body to move slightly perpendicular to the push and pull direction during shearing. During the test, the cooperation between the frame 24 and the limiting strip 25 ensures that the box body always moves in a straight line, avoiding uneven force on the sample. The sliding pin 32 ensures that the pin 31 is accurately aligned with the pin hole 57. After the test, the servo motor reverses to pull out the pin 31, and the shear force box 5 can be opened and closed horizontally again to completely remove the damaged sample for observation.

[0052] Example 2

[0053] refer to Figures 1-7 A direct shear test device for soil and rock also includes a groove 11, wherein the groove 11 is formed on the top of the test platform 1, a side frame 12 is fixedly connected to the bottom of the test platform 1, a sliding rod 13 is fixedly connected to the inner side of the side frame 12, the sliding rod 13 is located inside the groove 11, a slider 14 is slidably connected to the outer side of the sliding rod 13, the top of the slider 14 is fixedly connected to the shift plate 3, and a crossbar 15 is fixedly connected between the two shift plates 3.

[0054] By setting a crossbar 15 to connect two sets of shift plates 3, and a groove 11 cooperating with a side frame 12 and a sliding rod 13, it is possible to allow the two sets of shift plates 3 to slide horizontally along the sliding rod 13 via a slider 14 to switch to the desired shift plate 3. The shift plate 3 cooperates with the sliding plate 2 to form a complete slide for the shear box 5 to move. During the test of a single shear box 5, another shear box 5 and a soil sample can be preloaded on the shift plate 3 that is not cooperating with the sliding plate 2, so as to facilitate quick switching after the test is completed.

[0055] The test bench 1 has a narrow shell 16 fixedly connected to its top. A limit block 17 is slidably connected to the inner side of the narrow shell 16. The bottom of the limit block 17 is fixedly connected to the bottom of the inner side of the narrow shell 16 via a spring. By setting the narrow shell 16, when the shift plate 3 is in position to engage with the slider 14, the two limit blocks 17 block and limit the front and rear sides of the shift plate 3, preventing it from moving. When the shift plate 3 needs to be switched, the shift plate 3 slides horizontally, pushing the top of the arc-shaped limit block 17 and causing it to retract into the narrow shell 16. The spring presses and stores force until the movement is complete, at which point the spring rebounds and the limit block 17 returns to its blocking position, ensuring the structure remains stable when not affected by external forces. The top of the slide plate 2 and the top of the shift plate 3 both have slots. A roller 18 is rotatably connected to the inner side of the slot. By accommodating the roller 18 in the slot, the shear box 5 moves along the slide rail and... When the shift plate 3 slides, the rolling of the roller 18 can reduce friction and thus reduce test error. The push plate 20 is set to contact and slide with the shift plate 3 and the slide plate 2. The magnetic block 21, in conjunction with the push plate 20, can facilitate the push-pull action of the shear box 5 by the first electric cylinder 4. At the same time, when the shear box 5 is subjected to a force perpendicular to the push-pull direction of the first electric cylinder 4, it can also loosen the shear box 5 from the first electric cylinder 4. The front side of the push-pull frame 56 is fixedly connected to the dovetail block 22. The rear sides of the upper box 52 and the lower box 53 are both fixedly connected to the opening and closing frame 23. The inner side of the opening and closing frame 23 is slidably connected to the dovetail block 22. By setting the dovetail block 22 in conjunction with the opening and closing frame 23, the second electric cylinder 55 can push and pull the upper box 52 and the lower box 53 of the rear side at the same time, and the upper box 52 and the lower box 53 can move reasonably along the push-pull direction perpendicular to the second electric cylinder 55, so as to facilitate the shear test.

[0056] The working principle of this embodiment is as follows: The groove 11 on the top of the test bench 1, together with the slide rod 13 fixed by the bottom side frame 12, provides horizontal guidance for the slider 14. The crossbar 15 connects the two sets of switching plates 3 into a whole, so that the switching plate 3 can slide along the slide rod 13 through the slider 14, and then switch to form a complete slide track with the slide plate 2 for the shear box 5 to move. When a single shear box 5 is tested, the sample can be pre-loaded on the other set of switching plates 3 that is not in conjunction with the slide plate 2, so as to achieve quick switching after the test. The narrow shell 16 on the top of the test bench 1 is supported by a spring-loaded limiting block 17. When the switching plate 3 is in the working position, the limiting block 17 blocks the switching plate 3 from the front and rear sides to prevent it from loosening. When switching the switching plate 3, the switching plate 3 pushes the top of the arc-shaped limiting block 17 to retract it into the narrow shell 16, and the spring stores the force. After the repositioning is completed, the spring rebounds and pushes the limit block 17 to reset, ensuring the stability of the structure when there is no external force. The roller 18 is rotatably connected in the slot at the top of the sliding plate 2 and the repositioning plate 3, which can reduce friction and reduce test error when the shear box 5 slides. The push plate 20 on the left side of the bottom box 51 slides in contact with the sliding plate 2 and the repositioning plate 3. The magnetic block 21 at the telescopic end of the first electric cylinder 4 can attract the push plate 20, which facilitates pushing and pulling the shear box 5. When the shear box 5 is subjected to a force perpendicular to the pushing and pulling direction, the two can be flexibly released to avoid structural damage. The dovetail block 22 on the front side of the push-pull frame 56 slides in cooperation with the opening and closing frame 23 of the upper box 52 and the lower box 53 on the rear side, which not only realizes the synchronous pushing and pulling of the rear box by the second electric cylinder 55, but also allows the upper box 52 and the lower box 53 to move reasonably in a direction perpendicular to the pushing and pulling direction.

[0057] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. Those skilled in the art can make modifications to this embodiment without contributing any inventive step after reading this specification. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A direct shear test apparatus for soil and rock, comprising a test bench (1), characterized in that: The test bench (1) is fixedly connected to a slide plate (2), and the test bench (1) is movably connected to two shift plates (3). The test bench (1) is fixedly connected to a first electric cylinder (4), and the slide plate (2) is movably connected to a shear box (5). The shear box (5) includes a bottom box (51), two upper boxes (52) and two lower boxes (53). The bottom of the front lower box (53) is fixedly connected to the bottom box (51). The front upper box (52) is located on the top of the front lower box (53). The rear upper box (52) and the rear lower box (53) are used in conjunction with the front upper box (52) and the front lower box (53) respectively. A back frame (54) is fixedly connected to the rear side of the bottom box (51). A second electric cylinder (55) is fixedly connected to the rear side of the back frame (54). The telescopic end of the second electric cylinder (55) passes through the back frame (54) and is fixedly connected to a push-pull bracket (56). Pin holes (57) are opened on the inner side of the upper box (52) and the lower box (53). A top hook is fixedly connected to the right side of the front upper box (52). A top cover (6) is provided on the inner side between the two upper boxes (52). A dial gauge device (7) is fixedly connected to the top of the test bench (1). A main beam (8) is slidably connected to the inner side of the test bench (1). A crossbeam (9) is fixedly connected to the outer side of the main beam (8). A pressure column (10) is fixedly connected to the bottom of the crossbeam (9).

2. The direct shear test equipment for soil and rock according to claim 1, characterized in that: The test bench (1) has a groove (11) on its top. A side frame (12) is fixedly connected to the bottom of the test bench (1). A slide rod (13) is fixedly connected to the inner side of the side frame (12). The slide rod (13) is located inside the groove (11). A slider (14) is slidably connected to the outer side of the slide rod (13). The top of the slider (14) is fixedly connected to the shift plate (3). A crossbar (15) is fixedly connected between the two shift plates (3).

3. The direct shear test equipment for soil and rock according to claim 1, characterized in that: The top of the test bench (1) is fixedly connected to a narrow shell (16), and a limiting block (17) is slidably connected to the inner side of the narrow shell (16). The bottom of the limiting block (17) is fixedly connected to the bottom of the inner side of the narrow shell (16) by a spring.

4. The direct shear test equipment for soil and rock according to claim 1, characterized in that: The top of the slide plate (2) and the top of the shift plate (3) are both provided with slots, and rollers (18) are rotatably connected to the inside of the slots.

5. The direct shear test equipment for soil and rock according to claim 1, characterized in that: The bottom of the base box (51) is fixedly connected to a slide (19), the bottom of the slide (19) is movably connected to the slide plate (2), the left side of the base box (51) is fixedly connected to a push plate (20), and the telescopic end of the first electric cylinder (4) is fixedly connected to a magnetic block (21) that works with the push plate (20).

6. The direct shear test equipment for soil and rock according to claim 1, characterized in that: The front side of the push-pull bracket (56) is fixedly connected to a dovetail block (22), and the rear sides of the upper rear box (52) and the lower rear box (53) are both fixedly connected to an opening and closing bracket (23). The inner side of the opening and closing bracket (23) is slidably connected to the dovetail block (22).

7. The direct shear test equipment for soil and rock according to claim 1, characterized in that: The left side of the rear upper box (52) and lower box (53) and the right side of the front upper box (52) and lower box (53) are fixedly connected to a frame (24). The inner side of the frame (24) is slidably connected to a limiting strip (25). The two limiting strips (25) on the left side are fixedly connected to the front upper box (52) and lower box (53) respectively, and the two limiting strips (25) on the right side are fixedly connected to the rear upper box (52) and lower box (53) respectively.

8. The direct shear test equipment for soil and rock according to claim 1, characterized in that: The bottom of the test bench (1) is fixedly connected to a lower frame (26), and the top of the main beam (8) is fixedly connected to an upper frame (27). The inner sides of the upper frame (27) and the lower frame (26) are rotatably connected to screw rods (28). The bottom of the top screw rod (28) is rotatably connected to the crossbeam (9), and the outer side of the bottom screw rod (28) is threadedly connected to a threaded sleeve (29). The threaded sleeve (29) is fixedly connected to the main beam (8) on the side close to the main beam (8). The outer side of the top screw rod (28) is threadedly connected to a pin holder (30), and the bottom of the pin holder (30) is fixedly connected to a pin (31).

9. A direct shear test device for soil and rock according to claim 8, characterized in that: Servo motors are installed at the bottom of the lower frame (26) and the top of the upper frame (27). The output end of the top servo motor is fixedly connected to the top of the top lead screw (28), and the output end of the bottom servo motor is fixedly connected to the bottom of the bottom lead screw (28). A sliding pin (32) is slidably connected to the inner side of the pin frame (30). The two ends of the sliding pin (32) are fixedly connected to the upper frame (27) and the crossbeam (9) respectively.

10. A test method for a direct shear test apparatus for soil and rock as described in any one of claims 1-9, characterized in that: Includes the following steps: S1. Start the second electric cylinder (55) to retract the telescopic end, and drive the upper box (52) and lower box (53) on the rear side to move backward along the guide bar (25) and the frame (24) through the push-pull bracket (56). After opening the shear box (5), directly put in the soil and rock sample, and then control the second electric cylinder (55) to push the rear box to reset and close. Drive the pin (31) through the top servo motor to insert into the pin hole (57) to fix the box. Cover the top cover (6) and press it down. At the same time, use the cross bar (15) to push the two sets of shift plates (3) to slide along the slide bar (13). On the shift plate (3) without the sliding plate (2), pre-complete the loading of the shear box (5) of the next set of samples. The limit block (17) realizes the limit fixation of the shift plate (3) through the spring rebound. S2. The first electric cylinder (4) attracts the push plate (20) of the shear box (5) through the magnetic block (21), and pushes the shear box (5) to move along the roller (18) slide of the top of the slide plate (2) and the shift plate (3) to the bottom of the main beam (8). The servo motor of the lower frame (26) is started to drive the bottom screw (28) to rotate, and the main beam (8) is driven to descend through the screw sleeve (29), so that the pressure column (10) at the bottom of the crossbeam (9) accurately presses against the top cover (6) to apply normal stress. At this time, the top hook of the upper box (52) triggers the dial indicator device (7) to start counting, and then the shear test is carried out. The cooperation between the dovetail block (22) and the opening and closing frame (23) ensures that the box body adapts to the shear displacement. The multiple limiting structure ensures the structural stability during the test. S3. After the test, the top servo motor reverses and pulls out the pin (31). The first electric cylinder (4) pulls the shear box (5) back to the switching plate (3). The second electric cylinder (55) is controlled to open the shear box (5) again. The damaged sample is completely removed for morphological observation. The switching plate (3) is slid through the crossbar (15) to switch to another set of pre-loaded shear boxes (5). The limit block (17) is automatically reset and fixed.

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