Multi-angle permeation direct shear test system

Abstract

The invention relates to the technical field of geotechnical tests, in particular to a multi-angle permeation direct shear test system. The multi-angle permeation direct shear test system comprises a loading module, a shearing module, a seepage device, a water adding module and a gas drying module, the loading module comprises a horizontal loading device and a vertical loading device, and the shearing module comprises an upper shearing box and a lower shearing box which are oppositely arranged up and down; the water adding module performs seepage on the soil sample through the seepage device, and the gas drying module performs aeration drying on the permeated soil sample through the seepage device. According to the invention, the seepage position and angle of the soil sample are adjusted through the seepage device, and the test sample does not need to be frequently replaced, so that the permeability test of the same soil sample in different directions and different positions, the direct shear test of the same soil sample with different water contents and the direct shear test of the same soil sample subjected to water seepage and drying can be realized, the test convenience is improved, and the test cost is reduced. And the test workload and time cost are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical testing, and in particular to a multi-angle penetration direct shear test system. Background Art

[0002] In the field of geotechnical testing, the permeability of soil is generally tested by using a geotechnical test permeameter to determine the permeability coefficient of the soil. When measuring the permeability value of the soil, the soil is first placed in a holding cylinder, and then water is supplied to the interior. The permeability capacity of the water flow and the time taken for a certain period of time are recorded to calculate the permeability value of the soil. When the permeameter in the prior art conducts a permeability test on the soil, the permeability direction of the soil sample is often relatively single. A single test can only measure the permeability in a specific direction, and it is impossible to fully evaluate the permeability of the soil sample in different directions, resulting in an incomplete understanding of the properties of the soil sample. When it is necessary to conduct permeability tests in different directions on the same soil sample, it is often necessary to repeat the test, which greatly increases the workload and time cost of the test.

[0003] The shear strength of soil is an important soil mechanical parameter in geotechnical engineering. Coarse-grained soil is widely used in engineering construction due to its excellent engineering properties. Therefore, it is particularly important to accurately and quickly measure the strength index of coarse-grained soil. In engineering practice, a direct shear apparatus is usually used to conduct shear tests on soil samples to obtain the shear strength parameters of the soil samples. In the laboratory, it is necessary to conduct shear tests on the same soil samples with different moisture contents to obtain the shear strength parameters of the soil samples under natural conditions. In the prior art, for shear tests on the same soil samples with different moisture contents, it is also necessary to repeatedly set up the test, which also increases the workload and time cost.

[0004] Therefore, how to use the same test device to conduct permeability test on the same soil sample and permeability shear test on soil samples with different moisture contents without frequent disassembly and replacement of the test device, thereby reducing the workload and time cost of frequent test settings in the prior art, is a technical problem faced by the prior art.

[0005] In addition, under certain natural environmental conditions, soil often experiences rainwater infiltration and drying many times, which has a great impact on the shear strength of the soil. Therefore, how to measure the shear strength parameters of soil samples that have experienced rainwater infiltration and drying is also one of the technical problems that need to be solved. Summary of the invention

[0006] In view of this, in order to overcome the defects in the above-mentioned prior art, the present invention provides a multi-angle penetration direct shear test system. The test system of the present invention can not only perform soil penetration tests on soil samples at different angles and directions, but also perform shear tests on soil samples at different moisture contents and on soil samples that have been infiltrated by rainwater and dried without the need to frequently disassemble and replace the soil samples.

[0007] To achieve the above-mentioned object, the present invention provides a multi-angle penetration direct shear test system, comprising a loading module, a shear module and a seepage device;

[0008] The loading module includes a horizontal loading device, a vertical loading device and a frame, the frame includes a left column, a right column and a crossbeam located between the left column and the right column, and the vertical loading device is fixedly arranged under the crossbeam;

[0009] The shear module comprises an upper shear box and a lower shear box which are arranged relatively to each other in the upper and lower directions. The upper shear box and the lower shear box are respectively fixedly connected to the left column and the right column through the horizontal loading device. The upper shear box is provided with an upper through hole, and the lower shear box is provided with a lower through hole. The upper through hole and the lower through hole are combined to form a sample slot.

[0010] The shearing module and the vertical loading device are located on the same vertical axis;

[0011] The seepage device comprises a water inlet and a water outlet, wherein the water inlet is arranged at the upper end of the seepage device, the water outlet is arranged at the lower end of the seepage device, the water inlet is communicated with the water outlet, and the water outlet is eccentrically arranged at the lower end of the seepage device;

[0012] The seepage device is detachably and rotatably arranged on the upper end of the upper shear box.

[0013] The vertical loading device can apply a vertical loading force to the shear module through the seepage device.

[0014] Furthermore, the horizontal loading device includes a force sensor, a horizontal driving unit and a horizontal loading unit. The horizontal driving unit is fixedly connected to the horizontal loading unit, the other end of the horizontal driving unit is fixedly connected to the left column / right column through a fixing plate, the other end of the horizontal loading unit is fixedly connected to the upper shear box / lower shear box through a fixing plate, and the force sensor is electrically connected to the horizontal driving unit.

[0015] Furthermore, the vertical loading device includes a vertical driving unit and a vertical loading unit, the vertical driving unit is fixedly connected to the vertical loading unit, and the other end of the vertical driving unit is fixedly connected to the crossbeam via a fixing plate.

[0016] Furthermore, the horizontal driving unit and the vertical driving unit are servo motors or servo cylinders, and the horizontal loading unit and the vertical loading unit are loading rods.

[0017] Furthermore, a permeable stone is arranged at the bottom of the lower through hole of the lower shear box, a filter plate is arranged above the permeable stone, a conducting pipe is arranged below the permeable stone, and a water tank is arranged directly below the lower shear box.

[0018] Furthermore, the seepage device includes an outer cover plate, an inner cover plate and a closed cavity located between the outer cover plate and the inner cover plate, the closed cavity is enclosed by the outer cover plate and the inner cover plate, the outer cover plate is provided with a water inlet, the inner cover plate is provided with a water outlet, the water inlet and the water outlet are both connected to the closed cavity, and the water outlet is eccentrically arranged on the inner cover plate.

[0019] Furthermore, the present invention also includes a water adding module, and the water adding module can be connected to the water inlet of the seepage device through a water inlet pipe.

[0020] Furthermore, the water adding module includes a water flow sensor, a water flow sensor display, pipe one, pipe two, a communicating vessel and a water injection tank, the two ends of the communicating vessel are respectively connected to pipe two and pipe one, pipe two is connected to the water injection tank, pipe one is connected to the water inlet of the seepage device, the water flow sensor is arranged at the connecting port between pipe two and the water injection tank, and the water flow sensor display screen is arranged on the water injection tank.

[0021] Furthermore, the present invention also includes a displacement sensor and a displacement receiver, wherein the displacement sensor is arranged at the edge of the lower shear box, and the displacement receiver is arranged at the edge of the upper shear box.

[0022] Furthermore, the present invention also includes a gas drying module, and the gas drying module can be connected to the water inlet of the seepage device through an air inlet pipe.

[0023] When the present invention performs a permeability test on a soil sample, the operation process is as follows:

[0024] The first step is to place the prefabricated soil sample in the sample groove formed by the upper through hole of the upper shear box and the lower through hole of the lower shear box;

[0025] The second step is to place the seepage device on the upper end of the upper shear box to cover the upper through hole, and rotate the seepage device according to the expected direction and position of infiltration, so that the water outlet below the seepage device corresponds to the expected infiltration position of the soil sample;

[0026] The third step is to connect the water adding module with the water inlet provided at the upper end of the seepage device through the water inlet pipe, and open the valve on the water inlet pipe to allow the soil sample to seep;

[0027] The fourth step is to record the water flow rate measured by the water flow sensor and the used seepage time for calculating the soil permeability value;

[0028] Step 5. When it is necessary to conduct a permeability test on other positions of the soil sample, repeat the above steps 2 to 4 to complete the permeability test on the required direction and position of the soil sample.

[0029] When the present invention performs a direct shear test on the same soil sample with different moisture contents, the operation process is as follows:

[0030] The first step is to place the prefabricated soil sample in a sample groove formed by the upper through hole of the upper shear box and the lower through hole of the lower shear box;

[0031] The second step is to place the seepage device on the upper end of the upper shear box to cover the upper through hole, and rotate the seepage device according to the expected direction and position of infiltration, so that the water outlet below the seepage device corresponds to the expected infiltration position of the soil sample;

[0032] The third step is to connect the water adding module to the water inlet provided at the upper end of the seepage device through the water inlet pipe, open the valve on the water inlet pipe to seep the soil sample, and obtain the soil sample with the expected moisture content by controlling the seepage pressure and seepage time;

[0033] The fourth step is to start the vertical loading device to apply a vertical loading force to the seepage device, and then start the horizontal loading device to apply a horizontal loading force to the upper shear box and the lower shear box;

[0034] The fifth step is to record the relative displacement between the upper shear box and the lower shear box during the shearing process through the displacement sensor and the displacement receiver, and collect data on the horizontal shearing process through the force sensor, so as to obtain the shear strength and seepage state of the soil sample during the shearing process, which is used to analyze the shear strength change characteristics of the soil sample under the coupling effect of the shear direction and the seepage direction;

[0035] Step 6. When it is necessary to perform penetration-direct shear test on other directions and positions of the soil sample, first unload the horizontal loading force applied by the horizontal loading device and the vertical loading force applied by the vertical loading device, so that the horizontal loading device and the vertical loading device return to their initial positions, and then repeat the above steps 2 to 5 to complete the penetration-direct shear test on the required direction and position of the soil sample.

[0036] When the present invention simulates the direct shear test of soil that has undergone rainwater infiltration and drying, the operation process is as follows:

[0037] The first step is to place the prefabricated soil sample in a sample groove formed by the upper through hole of the upper shear box and the lower through hole of the lower shear box;

[0038] The second step is to place the seepage device on the upper end of the upper shear box to cover the upper through hole, and rotate the seepage device according to the expected direction and position of infiltration, so that the water outlet below the seepage device corresponds to the expected infiltration position of the soil sample;

[0039] The third step is to connect the water adding module to the water inlet provided at the upper end of the seepage device through the water inlet pipe, open the valve on the water inlet pipe to seep the soil sample, and obtain the soil sample with the expected moisture content by controlling the seepage pressure and seepage time;

[0040] The fourth step is to disconnect and remove the water inlet pipe of the water adding module from the water inlet provided at the upper end of the seepage device;

[0041] The fifth step is to connect the gas drying module to the water inlet provided at the upper end of the infiltration device through an air inlet pipe, and to ventilate and dry the soil sample infiltrated in the third step;

[0042] Step 6: start the vertical loading device to apply a vertical loading force to the seepage device, and then start the horizontal loading device to apply a horizontal loading force to the upper shear box and the lower shear box;

[0043] In the seventh step, the relative displacement between the upper shear box and the lower shear box during the shearing process is recorded by the displacement sensor and the displacement receiver, and data of the horizontal shearing process is collected by the force sensor to obtain the shear strength of the soil sample during the shearing process.

[0044] The beneficial technical effect brought by the technical solution of the present invention is: the multi-angle penetration direct shear test system of the present invention can not only perform a separate penetration test on a soil sample, but also perform a direct shear test on the same soil sample with different moisture contents, and can also perform a direct shear test on a soil sample that has undergone rainwater penetration and drying. When conducting a penetration test on a soil sample, the present invention can adjust the seepage position and angle of the soil sample through a seepage device, so that there is no need to frequently replace the sample, and the permeability performance test of the same soil sample in different directions and positions can be achieved, which can greatly reduce the test workload and time cost. When conducting a direct shear test on the same soil sample with different moisture contents, the present invention can adjust the seepage position and angle of the soil sample by rotating the seepage device, so as to obtain the same soil sample with different moisture contents and perform a shear test on it, and it is also necessary to repeatedly replace the test equipment and soil samples, which can also effectively reduce the workload and shorten the test time. At the same time, after the multi-angle penetration direct shear test system of the present invention performs a penetration test on the soil sample, by additionally setting up a gas drying device, it can simulate the soil body that has undergone rainwater penetration and drying in the natural environment, and measure the shear strength parameters of the soil sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to obtain the above and other advantages and features of the present invention, the present invention summarized above will be described in more detail below with reference to the specific embodiments of the present invention shown in the accompanying drawings. It should be understood that these drawings only show typical embodiments of the present invention and should not be regarded as limiting the scope of the present invention. Through the use of the accompanying drawings, the present invention will be described and explained in more detail; in the accompanying drawings:

[0046] Figure 1 It is an oblique view of a multi-angle penetration direct shear test test system of the present invention;

[0047] Figure 2 is a front view of the shear module and the seepage device of the present invention;

[0048] Figure 3 is a top view of the shear module and the seepage device of the present invention;

[0049] Figure 4 is a right side view of the shear module and the seepage device of the present invention;

[0050] Figure 5 It is a schematic diagram of the structure of the seepage device and the water adding module of the present invention;

[0051] Figure 6 It is a structural schematic diagram of the lower shear box of the present invention;

[0052] Figure 7 It is a front view of a multi-angle penetration direct shear test system of the present invention;

[0053] Figure 8 It is a top view of a multi-angle penetration direct shear test system of the present invention;

[0054] Fig. 9 It is a right view of a multi-angle penetration direct shear test system of the present invention.

[0055] In the figure: 1-frame, 2-lower-shear box, 3-upper-shear box, 4-outer cover, 5-pipeline one, 6-connecting vessel, 7-pipeline two, 8-vertical loading device, 9-horizontal loading device, 10-fixed plate, 12-internal chamber, 15-conducting pipe, 16-filter plate, 17-water tank, 18-circular tank, 20-inner cover, 22-force sensor, 23-connecting wire, 25-water flow sensor, 26-water flow sensor display, 27-displacement sensor, 28-displacement receiver. DETAILED DESCRIPTION

[0056] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. Directional terms such as "front", "back", "left", and "right" in the following description are not to be interpreted as limitations of the present invention. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0057] In order to make the purpose, technical scheme and beneficial effects of the present invention clearer, the following Figure 1-9 A multi-angle penetration direct shear test system provided by the present invention is further described in detail.

[0058] Please see attached Figure 1 and attached Figure 7-9 As shown, an embodiment of the present invention provides a multi-angle penetration direct shear test system, including a loading module, a shear module and a seepage device, the loading module includes a horizontal loading device 9, a vertical loading device 8 and a frame 1, the frame 1 includes a left column, a right column and a beam located between the left column and the right column, the two ends of the beam are respectively fixedly connected to the left column and the right column, the vertical loading device 8 is fixedly arranged under the beam, and preferably, the vertical loading device 8 is arranged in the middle of the beam.

[0059] The shear module includes an upper shear box 3 and a lower shear box 2 which are arranged relatively to each other in the upper and lower directions. The upper shear box 3 and the lower shear box 2 are respectively fixedly connected to the left column and the right column through the horizontal loading device 9. Preferably, the shear module is arranged in the middle of the frame 1, and the shear module and the vertical loading device 8 are located on the same vertical axis, so that the vertical loading device 8 is more balanced when applying the vertical loading force. The left and right horizontal loading devices 9 on both sides of the shear module are located in the same vertical plane, so that the horizontal loading device 9 is more balanced when applying the horizontal loading force.

[0060] In order to facilitate the installation of soil samples, the upper shear box 3 is provided with a through upper through hole, and the lower shear box 2 is provided with a through lower through hole. The upper through hole and the lower through hole are combined to form a sample slot, and the sample slot is used to hold the soil sample. Preferably, the shape of the sample slot can be a cylinder or a cuboid. Preferably, the shape of the upper shear box 3 and the lower shear box 2 can be a square.

[0061] The seepage device includes a water inlet and a water outlet, wherein the water inlet is arranged at the upper end of the seepage device, and the water outlet is arranged at the lower end of the seepage device, the water inlet is communicated with the water outlet, and the water outlet is eccentrically arranged at the lower end of the seepage device. The seepage device is detachably and rotatably arranged at the upper end of the upper shear box 3. After the soil sample is installed in the sample slot, the seepage device is installed at the upper end of the upper shear box 3. Since the water outlet is eccentrically arranged on the seepage device, the direction and position of the water outlet can be adjusted by rotating the seepage device, so that the water outlet corresponds to the expected infiltration position of the soil sample.

[0062] The horizontal loading device 9 and the vertical loading device 8 are retractable servo motors or servo cylinders. The vertical loading device 8 can apply a vertical loading force to the shear module through the seepage device, so that the seepage device pre-fixes the soil sample. At the same time, when the horizontal loading device 9 applies a horizontal loading force to perform a shear test on the shear module, the upper shear box 3 and the lower shear box 2 can be prevented from being displaced outside the shear direction.

[0063] As a further preferred embodiment, the horizontal loading device 9 in the present invention includes a force sensor 22, a horizontal driving unit and a horizontal loading unit, wherein the horizontal driving unit is fixedly connected to the horizontal loading unit, the other end of the horizontal driving unit is fixedly connected to the left column / right column via a fixing plate 10, the other end of the horizontal loading unit is fixedly connected to the upper shear box 3 / lower shear box 2 via the fixing plate 10, and the force sensor 22 is electrically connected to the horizontal driving unit. The force sensor 22 is electrically connected to the force sensor display screen via a connecting wire 23. The data collected by the force sensor 22 can be displayed via the force sensor display screen.

[0064] The vertical loading device 8 includes a vertical driving unit and a vertical loading unit. The vertical driving unit is fixedly connected to the vertical loading unit. The other end of the vertical driving unit is fixedly connected to the crossbeam through the fixing plate 10.

[0065] A permeable stone is arranged at the bottom of the lower through hole of the lower shear box 2, a filter plate 16 is arranged above the permeable stone, a conducting pipe 15 is arranged below the permeable stone, and a water tank 17 is arranged below the shear module. The present invention facilitates water seepage through the permeable stone, and by arranging the filter plate 16, loose fine soil particles are filtered out, thereby avoiding clogging the conducting pipe 15. By arranging the water tank 17, it is convenient to guide the water after seepage through the conducting pipe 15 to the water tank 17, so that the infiltrated water can be recovered and recycled, thereby achieving the purpose of environmental protection.

[0066] The contact surface between the upper shear box 3 and the lower shear box 2 of the present invention is smooth to reduce the friction resistance during the shearing process, and the shearing direction is along the axial force direction of the horizontal loading device 9.

[0067] As a further preferred embodiment, please refer to the attached Figure 2-5 As shown, the seepage device in the present invention includes an outer cover plate 4, an inner cover plate 20 and a closed cavity between the outer cover plate and the inner cover plate, the closed cavity is enclosed by the outer cover plate 4 and the inner cover plate 20, the water inlet is arranged on the outer cover plate 4, the water outlet is arranged on the inner cover plate 20, the water inlet and the water outlet are both connected to the closed cavity, and the water outlet is eccentrically arranged on the inner cover plate 20. The longitudinal section of the seepage device is a frustum-shaped with a small top and a large bottom, and the inner cover plate 20 is located at the large end of the seepage device. During the test, after the soil sample is installed in the sample slot, the seepage device can be installed at the upper end of the upper shear box 3, and the size of the large end of the seepage device is larger than the size of the upper through hole of the upper shear box 3, so that the soil sample can be completely covered.

[0068] In order to facilitate the permeability test of soil samples, the multi-angle permeability direct shear test system of the present invention also includes a water adding module, which includes a water flow sensor 25, a water flow sensor display screen 26, a pipe 1 5, a pipe 2 7, a communication vessel 6 and a water injection box. The two ends of the communication vessel 6 are respectively connected to the pipe 2 7 and the pipe 1 5, the pipe 2 7 is connected to the water injection box, the pipe 1 5 is connected to the water inlet of the seepage device, and the water flow sensor 25 is arranged at the connecting port between the pipe 2 7 and the water injection box. When it is necessary to perform a permeability test on the soil sample, the valve switch on the water adding module is turned on, and the water flows from the water injection box through the pipe 2 7, the communication vessel 6, the pipe 1 5 and the seepage device in sequence, and flows out from the water outlet of the seepage device, and the permeability test is performed on the soil sample in the sample tank. The water flow sensor 25 is used to collect the water flow rate flowing out of the water injection box within a certain period of time, and the water flow sensor 26 is arranged on the water injection box to display the water volume and water temperature in the water injection box in real time.

[0069] In the direct shear test of soil samples with different moisture contents, in order to facilitate the collection of data during the shearing process, the present invention further includes a displacement sensor 27 and a displacement receiver 28, wherein the displacement sensor 27 is arranged at the edge of the lower shear box 2, and correspondingly, the displacement receiver 28 is arranged at the edge of the upper shear box 3. The displacement sensor 27 is used to emit a laser signal, and the displacement receiver 28 is used to receive the laser signal, and the shear displacement can be determined by measuring the distance swept by the laser signal.

[0070] The present invention collects and records the relative displacement between the upper shear box 3 and the lower shear box 2 during the shearing process through the displacement sensor 27 and the displacement receiver 28, and combines the data collected by the force sensor 22 for the horizontal shearing process to obtain the shear strength and seepage state of the soil sample during the shearing process, which is used to analyze the shear strength change characteristics of the soil sample under the coupling of the shear direction and the seepage direction.

[0071] As a further preferred embodiment, please refer to the attached Figure 2-5 As shown, the number of water inlets arranged above the seepage device can be multiple, preferably 4; the number of the pipes 1 5 matches the number of water inlets, preferably 4; the lower end of the communicating vessel 6 is provided with lower ports matching the number of the pipes 1 5, preferably 4; the upper end of the communicating vessel 6 is provided with an upper port connected to the pipe 2 7, and the communicating vessel 6 is provided with an internal chamber 12, which is respectively connected to the lower port and the upper port. The seepage device, the pipe 1 5, the communicating vessel 6 and the pipe 2 7 can all be detachably installed.

[0072] When performing a direct shear test on a soil sample, the seepage device is first installed on the upper end of the upper shear box 3, and then the pipe 1 5, the communicating vessel 6 and the pipe 2 7 are installed in sequence. After the installation is completed, the vertical fixing device 8 is started to apply a vertical loading force to the communicating vessel 6, so that the soil sample is fixed through the communicating vessel 6, the pipe 1 5 and the seepage device.

[0073] As a further preferred embodiment, in order to facilitate the simulation of the direct shear test on the soil body that has undergone rainwater infiltration and drying, the present invention further includes a gas drying module, which can be connected to the water inlet of the seepage device through an air inlet pipe. After the expected infiltration test is carried out on the soil sample, the gas drying module is connected to the water inlet provided at the upper end of the seepage device through the air inlet pipe, and the infiltrated soil sample is ventilated and dried, thereby obtaining a soil sample that has undergone rainwater infiltration and drying, and then the soil sample can be subjected to a direct shear test.

[0074] To further illustrate the multi-angle penetration direct shear test system described in the present invention, the method of using the present invention for different test purposes is described as follows.

[0075] When the present invention performs a permeability test on a soil sample, the operation process is as follows:

[0076] The first step is to place the prefabricated soil sample in a sample groove formed by the upper through hole of the upper shear box 3 and the lower through hole of the lower shear box 2;

[0077] The second step is to place the seepage device on the upper end of the upper shear box 3 to cover the upper through hole, and rotate the seepage device according to the expected direction and position of the seepage, so that the water outlet below the seepage device corresponds to the expected infiltration position of the soil sample;

[0078] The third step is to connect the water adding module with the water inlet provided at the upper end of the seepage device through the water inlet pipe, and open the valve on the water inlet pipe to allow the soil sample to seep;

[0079] The fourth step is to record the water flow rate collected by the water flow sensor 25 and the used seepage time, so as to calculate the soil permeability value.

[0080] When it is necessary to conduct a permeability test on other positions of the soil sample, repeat the second to fourth steps to complete the permeability test on the required direction and position of the soil sample.

[0081] When the present invention performs a direct shear test on the same soil sample with different moisture contents, the operation process is as follows:

[0082] The first step is to place the prefabricated soil sample in a sample groove formed by the upper through hole of the upper shear box 3 and the lower through hole of the lower shear box 2;

[0083] The second step is to place the seepage device on the upper end of the upper shear box 3 to cover the upper through hole, and rotate the seepage device according to the expected direction and position of the seepage, so that the water outlet below the seepage device corresponds to the expected infiltration position of the soil sample;

[0084] The third step is to connect the water adding module to the water inlet provided at the upper end of the seepage device through the water inlet pipe, open the valve on the water inlet pipe to seep the soil sample, and obtain the soil sample with the expected moisture content by controlling the seepage pressure and seepage time;

[0085] The fourth step is to start the vertical loading device 8 to apply a vertical loading force to the seepage device, and then start the horizontal loading device 9 to apply a horizontal loading force to the upper shear box 3 and the lower shear box 2;

[0086] The fifth step is to collect and record the relative displacement between the upper shear box 3 and the lower shear box 2 during the shearing process through the displacement sensor 27 and the displacement receiver 28, and collect data on the horizontal shearing process through the force sensor 22, so as to obtain the shear strength and seepage state of the soil sample during the shearing process, which is used to analyze the shear strength change characteristics of the soil sample under the coupling of the shear direction and the seepage direction.

[0087] When it is necessary to perform penetration-direct shear test on other directions and positions of the soil sample, first unload the horizontal loading force applied by the horizontal loading device 9 and the vertical loading force applied by the vertical loading device 9, so that the horizontal loading device 9 and the vertical loading device 8 return to their initial positions, and then repeat the above second to fifth steps to complete the penetration-direct shear test on the required direction and position of the soil sample.

[0088] When the present invention simulates the direct shear test of soil that has undergone rainwater infiltration and drying, the operation process is as follows:

[0089] The first step is to place the prefabricated soil sample in a sample groove formed by the upper through hole of the upper shear box 3 and the lower through hole of the lower shear box 2;

[0090] The second step is to place the seepage device on the upper end of the upper shear box 3 to cover the upper through hole, and rotate the seepage device according to the expected direction and position of the seepage, so that the water outlet below the seepage device corresponds to the expected infiltration position of the soil sample;

[0091] The third step is to connect the water adding module to the water inlet provided at the upper end of the seepage device through the water inlet pipe, open the valve on the water inlet pipe to seep the soil sample, and obtain the soil sample with the expected moisture content by controlling the seepage pressure and seepage time;

[0092] The fourth step is to disconnect and remove the water inlet pipe of the water adding module from the water inlet provided at the upper end of the seepage device;

[0093] The fifth step is to connect the gas drying module to the water inlet provided at the upper end of the infiltration device through an air inlet pipe, and to ventilate and dry the soil sample infiltrated in the third step;

[0094] Step 6: Start the vertical loading device 8 to apply a vertical loading force to the seepage device, and then start the horizontal loading device 9 to apply a horizontal loading force to the upper shear box 3 and the lower shear box 2;

[0095] In the seventh step, the relative displacement between the upper shear box 3 and the lower shear box 2 during the shearing process is recorded by the displacement sensor 27 and the displacement receiver 28, and data of the horizontal shearing process is collected by the force sensor 22 to obtain the shear strength of the soil sample during the shearing process.

[0096] The beneficial technical effect brought by the technical solution of the present invention is: the multi-angle penetration direct shear test system of the present invention can not only perform a separate penetration test on a soil sample, but also perform a direct shear test on the same soil sample with different moisture contents, and can also perform a direct shear test on a soil sample that has undergone rainwater penetration and drying. When conducting a penetration test on a soil sample, the present invention can adjust the seepage position and angle of the soil sample through a seepage device, so that there is no need to frequently replace the sample, and the permeability performance test of the same soil sample in different directions and positions can be achieved, which can greatly reduce the test workload and time cost. When conducting a direct shear test on the same soil sample with different moisture contents, the present invention can adjust the seepage position and angle of the soil sample by rotating the seepage device, so as to obtain the same soil sample with different moisture contents and perform a shear test on it, and it is also necessary to repeatedly replace the test equipment and soil samples, which can also effectively reduce the workload and shorten the test time. At the same time, after the multi-angle penetration direct shear test system of the present invention performs a penetration test on the soil sample, by additionally setting up a gas drying device, it can simulate the soil body that has undergone rainwater penetration and drying in the natural environment, and measure the shear strength parameters of the soil sample.

[0097] The above embodiments are preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any person skilled in the art may make some improvements without departing from the scope of the present invention, that is, any equivalent improvements made according to the present invention should be covered by the scope of the present invention.

Claims

1. A multi-angle penetration direct shear test system, characterized in that: It includes loading module, shear module and seepage device. The loading module includes a horizontal loading device, a vertical loading device and a frame, wherein the frame includes a left column, a right column and a crossbeam between the left column and the right column, and the vertical loading device is fixedly arranged under the crossbeam. The shear module comprises an upper shear box and a lower shear box which are arranged opposite to each other in the upper and lower directions. The upper shear box and the lower shear box are respectively fixedly connected to the left column and the right column through the horizontal loading device. The upper shear box is provided with an upper through hole, and the lower shear box is provided with a lower through hole. The upper through hole and the lower through hole are combined to form a sample slot. The shear module is located directly below the vertical loading device. The seepage device includes a water inlet and a water outlet, the water inlet is arranged at the upper end of the seepage device, the water outlet is arranged at the lower end of the seepage device, the water inlet is communicated with the water outlet, the water outlet is eccentrically arranged on the lower end of the seepage device, and the seepage device is detachably and rotatably arranged at the upper end of the upper shear box.

2. The multi-angle penetration direct shear test system according to claim 1 is characterized in that: The horizontal loading device includes a force sensor, a horizontal driving unit and a horizontal loading unit, wherein the horizontal driving unit is fixedly connected to the horizontal loading unit, the other end of the horizontal driving unit is fixedly connected to the left column / right column via a fixing plate, the other end of the horizontal loading unit is fixedly connected to the upper shear box / lower shear box via a fixing plate, the force sensor is electrically connected to the horizontal driving unit, the horizontal driving unit is a servo motor or a servo cylinder, and the horizontal loading unit is a loading rod. The vertical loading device includes a vertical driving unit and a vertical loading unit. The vertical driving unit is fixedly connected to the vertical loading unit. The other end of the vertical driving unit is fixedly connected to the crossbeam via a fixing plate. The vertical driving unit is a servo motor or a servo cylinder, and the vertical loading unit is a loading rod.

3. The multi-angle penetration direct shear test system according to claim 2 is characterized in that: A permeable stone is arranged at the bottom of the lower through hole of the lower shear box, a filter plate is arranged above the permeable stone, a conducting pipe is arranged below the permeable stone, and a water tank is arranged directly below the lower shear box.

4. The multi-angle penetration direct shear test system according to any one of claims 1 to 3, characterized in that: The seepage device comprises an outer cover plate, an inner cover plate and a closed cavity between the outer cover plate and the inner cover plate. The enclosed cavity is formed by enclosing the outer cover plate and the inner cover plate. The water inlet is arranged on the outer cover plate, and the water outlet is arranged on the inner cover plate. The water inlet and the water outlet are both connected to the closed cavity. The water outlet is eccentrically arranged on the inner cover plate.

5. The multi-angle penetration direct shear test system according to claim 4 is characterized in that: It also includes a water adding module, which can be connected to the water inlet of the seepage device through a water inlet pipe.

6. The multi-angle penetration direct shear test system according to claim 5 is characterized in that: The water adding module includes a water flow sensor, pipe 1, pipe 2, a communicating vessel and a water injection tank. The two ends of the communicating vessel are respectively connected to pipe 2 and pipe 1, pipe 2 is connected to the water injection tank, pipe 1 is connected to the water inlet of the seepage device, and the water flow sensor is arranged at the connecting port between pipe 2 and the water injection tank.

7. The multi-angle penetration direct shear test system according to any one of claim 6, characterized in that: It also includes a displacement sensor and a displacement receiver. The displacement sensor is arranged on the edge of the upper shear box or the lower shear box, and the displacement receiver is arranged on the edge of the corresponding lower shear box or the upper shear box.

8. The multi-angle penetration direct shear test system according to any one of claim 7, characterized in that: It also includes a gas drying module, which can be connected to the water inlet of the infiltration device through an air inlet pipe.

9. A method for using the multi-angle penetration direct shear test system according to claim 7, characterized in that: When conducting a direct shear test on the same soil sample with different moisture contents, the following steps are included: The first step is to place the prefabricated soil sample in a sample groove formed by the upper through hole of the upper shear box and the lower through hole of the lower shear box; The second step is to place the seepage device on the upper end of the upper shear box to cover the upper through hole, and rotate the seepage device according to the expected direction and position of infiltration, so that the water outlet below the seepage device corresponds to the expected infiltration position of the soil sample; The third step is to connect the water adding module to the water inlet provided at the upper end of the seepage device through the water inlet pipe, open the valve on the water inlet pipe to seep the soil sample, and obtain the soil sample with the expected moisture content by controlling the seepage pressure and seepage time; The fourth step is to start the vertical loading device to apply a vertical loading force to the seepage device, and then start the horizontal loading device to apply a horizontal loading force to the upper shear box and the lower shear box; The fifth step is to collect and record the relative displacement between the upper shear box and the lower shear box during the shearing process through the displacement sensor and the displacement receiver, and collect data on the horizontal shearing process through the force sensor, so as to obtain the shear strength and seepage state of the soil sample during the shearing process, which is used to analyze the shear strength change characteristics of the soil sample under the coupling effect of the shear direction and the seepage direction; Step 6. When it is necessary to perform penetration-direct shear test on other directions and positions of the soil sample, first unload the horizontal loading force applied by the horizontal loading device and the vertical loading force applied by the vertical loading device, so that the horizontal loading device and the vertical loading device return to their initial positions, and then repeat the above steps 2 to 5 to complete the penetration-direct shear test on the required direction and position of the soil sample.

10. A method for using the multi-angle penetration direct shear test system according to claim 8, characterized in that: The direct shear test of soil after water penetration and drying includes the following steps: The first step is to place the prefabricated soil sample in a test sample groove surrounded by the upper through hole of the upper shear box and the lower through hole of the lower shear box; The second step is to place the seepage device on the upper end of the upper shear box to cover the upper through hole, and rotate the seepage device according to the expected direction and position of infiltration, so that the water outlet below the seepage device corresponds to the expected infiltration position of the soil sample; The third step is to connect the water adding module to the water inlet provided at the upper end of the seepage device through the water inlet pipe, open the valve on the water inlet pipe to seep the soil sample, and obtain the soil sample with the expected moisture content by controlling the seepage pressure and seepage time; The fourth step is to disconnect and remove the water inlet pipe of the water adding module from the water inlet provided at the upper end of the seepage device; The fifth step is to connect the gas drying module to the water inlet provided at the upper end of the infiltration device through an air inlet pipe, and to ventilate and dry the soil sample infiltrated in the third step; Step 6: start the vertical loading device to apply a vertical loading force to the seepage device, and then start the horizontal loading device to apply a horizontal loading force to the upper shear box and the lower shear box; In the seventh step, the relative displacement between the upper shear box and the lower shear box during the shearing process is recorded by the displacement sensor and the displacement receiver, and data of the horizontal shearing process is collected by the force sensor to obtain the shear strength of the soil sample during the shearing process.

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