A shear test device and method for simulating the sea erosion of rock materials by seawater

Abstract

The invention provides a shear test device and method for simulating the seawater erosion effect on rock materials, and relates to the technical field of shear strength test devices. The device comprises a normal pressure plate, a tangential pressure plate, a bottom plate and a pressure detection side plate. The bottom plate is installed in a seawater simulation test box with an upper opening in a lifting and sliding manner, and the shear test block enters the seawater simulation test box or the shear test area through the lifting and lowering of the bottom plate. The side and bottom of the seawater simulation test box are respectively provided with a simulation pressure component and a water inlet and outlet. The invention can fully simulate the daily state of marine rocks and restore the influence of different variables in the marine environment on the shear strength of rocks to the greatest extent. The entire simulation test process is carried out in a set of devices, without the need to transfer the simulation test blocks and the simulation test control, and finally the pressure test of the test blocks is carried out autonomously, which reduces the workload of the experimenters and simplifies the structure, and is suitable for wide promotion.

Description

Technical Field

[0001] The present invention relates to the technical field of shear strength testing devices, and particularly to a shear experiment device and method for simulating the erosion of rock materials by seawater. Background Art

[0002] A direct shear apparatus and a rock shear test method with the publication number "CN115508182B" in the prior art include a rock sample clamping device, a normal direct shear mechanism, and a tangential direct shear mechanism. The rock sample clamping device includes two relatively arranged first shear boxes and second shear boxes for containing and clamping the rock sample. The normal direct shear mechanism abuts against the first shear box to apply a normal stress to the rock sample. The tangential direct shear mechanism abuts against the second shear box and is axially perpendicular to the normal direct shear mechanism to apply a tangential stress to the rock sample. Among them, a tangential stress adjusting device is provided between the tangential direct shear mechanism and the second shear box, and the magnitude of the tangential stress is adjusted through the tangential stress adjusting device to test the fault shear characteristics of the rock sample under different tangential stresses. This device conducts research on controlling the form of fault shear movement by controlling the shear stiffness of the device, and obtains the relevant laws of the fault shear movement mode under different tangential stresses.

[0003] However, there are still relatively obvious defects in the use of the above device: the above device can only complete the direct shear pressure test of conventional rock masses, and its detection means cannot meet the pressure experiment on marine rock masses, resulting in certain limitations in its experiments. Summary of the Invention

[0004] The purpose of the present invention is to provide a shear experiment device and method for simulating the erosion of rock materials by seawater to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A shear experiment device for simulating the erosion of rock materials by seawater includes a normal pressure plate, a tangential pressure plate, a bottom plate, and a pressure detection side plate. The normal pressure plate, the tangential pressure plate, the bottom plate, and the pressure detection side plate enclose a shear experiment area. A normal loading device and a tangential loading device are respectively installed on the sides of the normal pressure plate and the tangential pressure plate away from the shear experiment area. The tangential pressure plate and the pressure detection side plate are arranged in a staggered manner;

[0007] The bottom plate is installed in a seawater simulation experiment box with an upper opening in a lifting and sliding manner. A sealing plate is installed on the side of the seawater simulation experiment box in a translational sliding manner. When the sealing plate closes the upper opening of the seawater simulation experiment box, the inside of the seawater simulation experiment box is in a sealed state. A hydraulic telescopic cylinder is fixedly arranged below the seawater simulation experiment box. The telescopic arm of the hydraulic telescopic cylinder extends into the seawater simulation experiment box and is fixedly connected to the bottom plate. By lifting the bottom plate, the shear resistance test block enters the seawater simulation experiment box or the shear resistance test area;

[0008] The bottom plate is also provided with through holes arranged in an array. The side and bottom of the seawater simulation experiment box are respectively provided with a simulation pressurizing component and a water inlet and outlet. When the seawater simulation experiment box is in a sealed state, simulation pressurization is carried out inside through the simulation loading component, and water injection and drainage operations are carried out into the inside of the seawater simulation experiment box through the water inlet and outlet.

[0009] Preferably, both the normal loading device and the tangential loading device are hydraulic loading cylinders.

[0010] Preferably, the seawater simulation experiment box is fixedly installed on the side plate. Horizontal plates are also fixedly installed at both ends of the side plate. The hydraulic loading cylinder connecting the normal pressure plate is fixedly installed on the upper horizontal plate, and the hydraulic telescopic cylinder is fixedly installed on the bottom horizontal plate.

[0011] Preferably, the sealing plate is also fixedly connected to the telescopic arm of the sealing hydraulic telescopic cylinder. The fixed telescopic cylinder of the sealing hydraulic telescopic cylinder is fixedly installed on the side of the seawater simulation experiment box.

[0012] Preferably, the tangential loading device connecting the tangential pressure plate is also fixedly installed on the lifting block. The lifting block is movably installed on the lifting frame. Slide rails for accommodating both sides of the lifting block are provided on the lifting frame. A base is fixedly installed at the bottom of the lifting frame. A lifting drive telescopic cylinder is also fixedly installed on the base. The telescopic arm of the lifting drive telescopic cylinder is fixedly connected to the lifting block. The lifting movement of the tangential pressure plate is driven by the lifting movement of the lifting drive telescopic cylinder.

[0013] Preferably, the simulation pressurizing component includes a pressurizing cylinder. The pressurizing cylinder is communicated with the inside of the seawater simulation experiment box. A pressurizing piston plate is slidably arranged in the pressurizing cylinder in a translational manner. A pressurizing push plate is also fixedly installed on the side of the pressurizing piston plate away from the seawater simulation experiment box. When the tangential pressure plate is movably matched with the pressurizing push plate, the tangential pressure plate presses the inside by pushing the pressurizing push plate to slide towards the seawater simulation experiment box side. An extrusion spring is also installed in the pressurizing cylinder between the pressurizing piston plate and the seawater simulation experiment box.

[0014] A shear test method for simulating the erosion of rock materials by seawater using the above-mentioned shear test device for simulating the erosion of rock materials by seawater. This simulation test method includes three experimental methods, namely, conventional loading experiment, tidal simulation experiment, and seabed pressure simulation experiment.

[0015] Preferably, in the conventional loading experiment mode, it includes the following steps:

[0016] Step 1: Place the shear test block to be tested on the bottom plate.

[0017] Step 2: Enclose a shear test area by the normal pressure plate, tangential pressure plate, bottom plate, and pressure detection side plate, and apply tangential pressure through the tangential pressure plate to conduct a shear test.

[0018] Step 3: After the experiment is completed, the staff can clean up the crushed rocks.

[0019] Preferably, in the tidal simulation experiment mode, it includes the following steps:

[0020] Step 1: Place the shear test block to be tested on the bottom plate.

[0021] Step 2: Inject a certain amount of seawater into the seawater simulation test box through the water inlet and outlet. Simulate tidal immersion of the compression test block placed on the bottom plate by setting the lifting interval time of the bottom plate, and time it with a timer. When the tidal simulation experiment is completed, the bottom plate rises under program control and automatically completes the shear test.

[0022] Step 3: After the experiment is completed, the staff can clean up the crushed rocks.

[0023] Preferably, in the seabed pressure simulation experiment, it includes the following steps:

[0024] Step 1: Place the shear test block to be tested on the bottom plate.

[0025] Step 2: Inject a certain amount of seawater into the seawater simulation test box through the water inlet and outlet, and control the lifting of the bottom plate so that the shear test block is always in a fully immersed state. At this time, pressurize the seawater simulation test box through the simulation pressurization component to simulate the pressurization scenario of rocks at different depths on the seabed, and time it with a timer. When the seabed pressure simulation experiment is completed, the bottom plate rises under program control and automatically completes the shear test.

[0026] Step 3: After the experiment is completed, the staff can clean up the crushed rocks.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] The present invention can fully simulate the daily state of marine rocks, maximize the restoration of the influence of different variables in the marine environment on the shear strength of rocks. The entire simulation experiment process is carried out within a set of devices, eliminating the need for the transfer and control of simulation experiment blocks, and finally independently conducting the pressure test on the experiment blocks, which reduces the workload of experimental personnel and simplifies the structure, making it suitable for wide promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a three-dimensional schematic diagram of the overall structure of the present invention;

[0030] Figure 2 is a sectional schematic diagram of the overall structure of the present invention;

[0031] Figure 3 is a schematic diagram of the pressurized state of the seawater simulation experiment box of the present invention;

[0032] Figure 4 is a schematic diagram of the shear experiment block exposed above the liquid level surface of the present invention;

[0033] Figure 5 is a schematic diagram of the shear experiment block fully immersed in the liquid level surface of the present invention;

[0034] In the figure: 1 normal pressure plate, 2 tangential pressure plate, 3 bottom plate, 4 pressure detection side plate, 5 seawater simulation experiment box, 6 sealing plate, 7 hydraulic telescopic cylinder, 8 through hole, 9 water inlet and outlet, 10 hydraulic loading cylinder, 11 side plate, 12 horizontal plate, 13 sealed hydraulic telescopic cylinder, 14 lifting block, 15 lifting frame, 16 slide rail, 17 base, 18 lifting drive telescopic cylinder, 19 pressurizing cylinder, 20 pressurizing piston plate, 21 pressurizing push plate, 22 compression spring, 23 shear experiment block. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] Please refer to Figures 1 - 5 , the present invention provides a technical solution:

[0037] Embodiment 1:

[0038] A shear resistance experiment device for simulating the sea erosion effect of sea water on rock materials, comprising a normal pressure plate 1, a tangential pressure plate 2, a bottom plate 3 and a pressure detection side plate 4. The normal pressure plate 1, the tangential pressure plate 2, the bottom plate 3 and the pressure detection side plate 4 enclose a shear resistance experiment area. A normal loading device and a tangential loading device are respectively installed on the sides of the normal pressure plate 1 and the tangential pressure plate 2 away from the shear resistance experiment area. The tangential pressure plate 2 and the pressure detection side plate 4 are arranged in a staggered manner;

[0039] The bottom plate 3 is installed in a lifting and sliding manner in a sea water simulation experiment box 5 with an upper opening. A sealing plate 6 is installed on the side of the sea water simulation experiment box 5 in a translational sliding manner. When the sealing plate 6 closes the upper opening of the sea water simulation experiment box 5, the inside of the sea water simulation experiment box 5 is in a sealed state. A hydraulic telescopic cylinder 7 is fixedly arranged below the sea water simulation experiment box 5. The telescopic arm of the hydraulic telescopic cylinder 7 extends into the sea water simulation experiment box 5 and is fixedly connected to the bottom plate 3. By lifting the bottom plate 3, the shear resistance experiment block 23 enters the sea water simulation experiment box 5 or the shear resistance experiment area;

[0040] The bottom plate 3 is also provided with an array of through holes 8 arranged in an array. The side and bottom of the sea water simulation experiment box 5 are respectively provided with a simulation pressurization component and a water inlet and outlet 9. When the sea water simulation experiment box 5 is in a sealed state, simulation pressurization is carried out inside through the simulation loading component, and water injection and drainage operations are carried out inside the sea water simulation experiment box 5 through the water inlet and outlet 9.

[0041] In this embodiment, the normal pressure plate 1, the tangential pressure plate 2, the bottom plate 3 and the pressure detection side plate 4 are similar in structure to those in the prior art. The difference is that the functions of the bottom plate 3 and the tangential pressure plate 2 in this embodiment are not only used for the direct shear test of rocks, but also as a simulation experimental device for marine rocks. Among them, the bottom plate 3 is arranged in a lifting manner in the seawater simulation experimental box 5. Before the direct shear experiment, the shear-resistant test block 23 is simulated in the marine environment according to the experimental needs. The bottom plate 3 makes the shear-resistant test block 23 enter the seawater simulation experimental box 5 or the shear-resistant experimental area through lifting movement. And when it is in the seawater simulation experimental box 5, the immersion of the shear-resistant test block 23 is adjusted through the lifting movement of the bottom plate 3. Through the lifting movement, it can simulate the immersion of the rock during the rising and falling tides of the seawater in the marine tidal process, and at the same time, it can also simulate the all-weather immersion of the rock by the seawater at the seabed. Through the above method, the immersion process of seawater at different positions in the ocean can be simulated. At the same time, a simulation pressurization assembly is also arranged on the side of the seawater simulation experimental box 5. The seawater simulation experimental box 5 is pressurized through the simulation pressurization assembly, so as to simulate the immersion pressure of seawater at different depths at the seabed, so as to more comprehensively simulate the marine rock environment, and thus provide more experimental data that conforms to the real environment for the shear experiment. Among them, the simulation pressurization assembly includes a pressurizing cylinder 19. The pressurizing cylinder 19 is internally communicated with the seawater simulation experimental box 5. A pressurizing piston plate 20 is arranged to slide horizontally in the pressurizing cylinder 19. A pressurizing push plate 21 is fixedly installed on the side of the pressurizing piston plate 20 away from the seawater simulation experimental box 5. When the tangential pressure plate 2 is movably matched with the pressurizing push plate 21, the tangential pressure plate 2 pressurizes the inside of the seawater simulation experimental box 5 by pushing the pressurizing push plate 21 to slide towards the seawater simulation experimental box 5. An extrusion spring 22 is also installed in the pressurizing cylinder 19 between the pressurizing piston plate 20 and the seawater simulation experimental box 5. The tangential loading device connected to the tangential pressure plate 2 is also fixedly installed on the lifting block 14. The lifting block 14 is movably installed on the lifting frame 15. Slide rails 16 for accommodating both sides of the lifting block 14 are provided on the lifting frame 15. A base 17 is fixedly installed at the bottom of the lifting frame 15. A lifting drive telescopic cylinder 18 is also fixedly installed on the base 17. The telescopic arm of the lifting drive telescopic cylinder 18 is fixedly connected to the lifting block 14. The tangential pressure plate 2 is driven to move up and down through the lifting movement of the lifting drive telescopic cylinder 18. Through the cooperation of the above devices, the lifting adjustment of the tangential pressure plate 2 is realized, so that it is used as the direct shear device of the shear-resistant test block 23 on the one hand, and as the pushing mechanism of the simulation pressurization assembly on the other hand. To sum up, the bottom plate 3 and the tangential pressure plate 2 in this embodiment realize other functions besides direct shear, thus simplifying the structure of the device and improving the integration degree of the device. This device can fully adapt to the shear strength test of rocks in different marine environments. A main control MCU drive module is installed in the device, and is electrically connected to each electric drive element through the main control MCU drive module.In this embodiment, an 8-bit single-chip microcomputer of model S3P7588XZZ-COC8 produced by Samsung Corporation of South Korea is selected as the main control MCU driving module to drive and control the movement of each component. The experimenter only needs to place the shear test block 23 on the bottom plate 3 and set the lifting interval time of the bottom plate 3 according to the needs of the simulation environment, and the rest of the operations can be carried out automatically. The main control MCU driving module is also electrically connected to the timer. When the timer reaches the simulation experiment time, the sealing plate 6 is opened under the control of the main control MCU driving module. At this time, the bottom plate 3 rises, and the normal pressure plate 1, the tangential pressure plate 2, the bottom plate 3 and the pressure detection side plate 4 enclose a shear test area. The shear test block 23 is restricted in the shear test area, and the shear strength test of the shear test block 23 is carried out by the loading of the tangential pressure plate 2. The pressure detection side plate 4 on the opposite side is connected to the pressure detection device to record the data of the shear strength. The experimenter does not need to wait beside the device, which greatly reduces the experimental burden of the experimenter.

[0042] Embodiment Two:

[0043] Both the normal loading device and the tangential loading device are hydraulic loading cylinders 10.

[0044] The seawater simulation experiment box 5 is fixedly installed on the side plate 11. Horizontal plates 12 are also fixedly installed at both ends of the side plate 11. The hydraulic loading cylinder 10 connected to the normal pressure plate 1 is fixedly installed on the upper horizontal plate 12, and the hydraulic telescopic cylinder 7 is fixedly installed on the bottom horizontal plate 12.

[0045] The sealing plate 6 is also fixedly connected to the telescopic arm of the sealing hydraulic telescopic cylinder 13, and the fixed telescopic cylinder of the sealing hydraulic telescopic cylinder 13 is fixedly installed on the side of the seawater simulation experiment box 5.

[0046] In this embodiment, the layout of the corresponding mechanism and the driving mechanism are further improved and disclosed. Since the above installation method and driving method are relatively common in the prior art, they will not be elaborated here.

[0047] A shear test method for simulating the erosion of rock materials by seawater uses the above-mentioned shear test device for simulating the erosion of rock materials by seawater. This simulation test method includes three test methods, namely, conventional loading test, tidal simulation test, and seabed pressure simulation test.

[0048] Preferably, in the conventional loading test mode, it includes the following steps:

[0049] Step 1: Place the shear test block 23 to be tested on the bottom plate 3;

[0050] Step 2: By enclosing the normal pressure plate 1, tangential pressure plate 2, bottom plate 3, and pressure detection side plate 4 to form a shear resistance test area, and applying tangential pressure through the tangential pressure plate 2, the shear resistance test can be carried out.

[0051] Step 3: After the experiment is completed, the staff can clean up the crushed rocks.

[0052] Preferably, in the tidal simulation experiment mode, it includes the following steps:

[0053] Step 1: Place the shear resistance test block 23 to be tested on the bottom plate 3.

[0054] Step 2: Inject a certain amount of seawater into the seawater simulation test box 5 through the water inlet and outlet 9. By setting the lifting interval time of the bottom plate 3, the compression test block placed on the bottom plate 3 is simulated for tidal immersion, and timing is carried out by a timer. When the tidal simulation experiment is completed, the bottom plate 3 rises under program control and autonomously completes the shear resistance test.

[0055] Step 3: After the experiment is completed, the staff can clean up the crushed rocks.

[0056] Preferably, in the submarine pressure simulation experiment, it includes the following steps:

[0057] Step 1: Place the shear resistance test block 23 to be tested on the bottom plate 3.

[0058] Step 2: Inject a certain amount of seawater into the seawater simulation test box 5 through the water inlet and outlet 9, and control the lifting of the bottom plate 3 so that the shear resistance test block 23 is always in a fully immersed state. At this time, pressure is applied to the seawater simulation test box 5 through the simulation pressure component, so as to simulate the pressure scenarios of rocks at different depths in the seabed, and timing is carried out by a timer. When the submarine pressure simulation experiment is completed, the bottom plate 3 rises under program control and autonomously completes the shear resistance test.

[0059] Step 3: After the experiment is completed, the staff can clean up the crushed rocks.

[0060] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood 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 shear test device for simulating the seawater erosion of rock materials, comprising a normal pressure plate, a tangential pressure plate, a bottom plate and a pressure detection side plate, wherein the normal pressure plate, the tangential pressure plate, the bottom plate and the pressure detection side plate enclose a shear test area, and the normal pressure plate and the tangential pressure plate are respectively installed with a normal loading device and a tangential loading device on the side away from the shear test area, and the tangential pressure plate and the pressure detection side plate are staggered; characterized in that: The bottom plate is installed in a lifting and sliding manner in a seawater simulation experiment box with an upper opening. A sealing plate is installed in a translational and sliding manner on the side of the seawater simulation experiment box. When the sealing plate closes the upper opening of the seawater simulation experiment box, the seawater simulation experiment box is in a sealed state. A hydraulic telescopic cylinder is fixedly arranged below the seawater simulation experiment box. The telescopic arm of the hydraulic telescopic cylinder extends into the seawater simulation experiment box and is fixedly connected to the bottom plate. The shear test block enters the seawater simulation experiment box or the shear test area through the lifting and lowering of the bottom plate. The bottom plate is also provided with through holes arranged in an array, and the side and bottom of the seawater simulation experiment box are respectively provided with simulated pressurization components and water inlets and outlets. When the seawater simulation experiment box is in a sealed state, simulated pressurization is performed internally through the simulated loading component, and water is injected into and drained from the seawater simulation experiment box through the water inlets and outlets.

2. The shear test device for simulating seawater erosion on rock materials according to claim 1, characterized in that: The normal loading device and the tangential loading device are both hydraulic loading cylinders.

3. The shear test device for simulating seawater erosion on rock materials according to claim 2, characterized in that: The seawater simulation experiment box is fixedly mounted on the side panels, and horizontal panels are also fixedly mounted on both ends of the side panels. The hydraulic loading cylinder connected to the normal pressure plate is fixedly mounted on the upper horizontal panel, and the hydraulic telescopic cylinder is fixedly mounted on the bottom horizontal panel.

4. A shear test device for simulating seawater erosion of rock materials according to claim 1 or 3, characterized in that: The sealing plate is also fixedly connected to the telescopic arm of the sealed hydraulic telescopic cylinder, and the fixed telescopic cylinder of the sealed hydraulic telescopic cylinder is fixedly installed on the side of the seawater simulation experiment box.

5. The shear test device for simulating seawater erosion on rock materials according to claim 4, characterized in that: The tangential loading device connected to the tangential pressure plate is also fixedly installed on the lifting block, and the lifting block is movably installed on the lifting frame. The lifting frame is provided with slide rails for accommodating both sides of the lifting block. A base is fixedly installed at the bottom of the lifting frame, and a lifting drive telescopic cylinder is also fixedly installed on the base. The telescopic arm of the lifting drive telescopic cylinder is fixedly connected to the lifting block, and the tangential pressure plate is driven to perform lifting movement through the lifting movement of the lifting drive telescopic cylinder.

6. The shear test device for simulating seawater erosion on rock materials according to claim 5, characterized in that: The simulated pressurizing assembly includes a pressurizing cylinder, which is connected to the interior of the seawater simulation experiment box. A pressurizing piston plate is arranged in the pressurizing cylinder for translational sliding. A pressurizing push plate is also fixedly installed on the side of the pressurizing piston plate away from the seawater simulation experiment box. When the tangential pressurizing plate and the pressurizing push plate are movably cooperated, the tangential pressurizing plate pushes the pressurizing push plate to slide toward one side of the seawater simulation experiment box to perform a pressurizing operation on the interior. An extrusion spring is also installed in the pressurizing cylinder between the pressurizing piston plate and the seawater simulation experiment box.

7. A shear test method for simulating the seawater erosion of rock materials, using the shear test device for simulating the seawater erosion of rock materials according to any one of claims 1 to 6, characterized in that: The following steps are included in the normal loading experiment mode: Step 1: Place the shear test block to be tested on the base plate; Step 2: The shear test can be performed by enclosing the normal pressure plate, the tangential pressure plate, the bottom plate and the pressure detection side plate to form a shear test area, and performing tangential pressure through the tangential pressure plate; Step 3: After the experiment is completed, the staff will clean up the squeezed and crushed rocks.

8. A method for shear test of rock materials under simulated seawater erosion, using the shear test device for rock materials under simulated seawater erosion as claimed in any one of claims 1 to 6, characterized in that: The tidal simulation experiment mode includes the following steps: Step 1: Place the shear test block to be tested on the base plate; Step 2: inject a certain amount of seawater into the seawater simulation experiment box through the water inlet and outlet, and perform tidal simulation immersion on the compression test block placed on the bottom plate by setting the lifting interval of the bottom plate, and use the timer to count. When the tidal simulation experiment is completed, the bottom plate rises under program control and completes the shear test autonomously; Step 3: After the experiment is completed, the staff will clean up the squeezed and crushed rocks.

9. A method for shear test of rock materials under simulated seawater erosion, using the shear test device for rock materials under simulated seawater erosion as claimed in any one of claims 1 to 6, characterized in that: The following steps are included in the seabed pressurization simulation experiment: Step 1: Place the shear test block to be tested on the base plate; Step 2: Inject a certain amount of seawater into the seawater simulation test box through the water inlet and outlet, and control the lifting and lowering of the bottom plate so that the shear test block is always in a fully immersed state. At this time, the seawater simulation test box is pressurized through the simulated pressurization component to simulate the pressurization scenes of rocks at different depths on the seabed, and the timer is used for timing. When the seabed pressurization simulation experiment is completed, the bottom plate rises under program control and completes the shear test autonomously. Step 3: After the experiment is completed, the staff will clean up the squeezed and crushed rocks.

Images