Automatic penetration type miniature in-situ direct shear apparatus

Abstract

The invention discloses an automatic penetration type miniature in-situ direct shear apparatus. The apparatus comprises a support frame, and a first driving module, a test module, a soil body cutting module and a sensor module which are arranged on the support frame, the support frame is anchored on the ground; the first driving module is fixed with the test module; a moving end of the first driving module is connected with the test module; the test module comprises a shell, a second driving module, a shear box and a valve; the shell is connected with the moving end of the first driving module; the second driving module is fixed in the shell; the upper end of the shear box is connected with the moving end; the valve is positioned at the lower end opening of the shear box; the two soil body cutting modules are symmetrically arranged at the lower end of the shell and are opened and closed through a driving motor to cut a soil body; the sensor module is used for collecting pressure data and displacement data in the test process. The test module can penetrate into a soil body in a narrow space or under a special geological condition, a direct shear test is completed in the in-situ soil body, disturbance in the sampling process is reduced, and wide application prospects are achieved.

Description

Technical Field

[0001] The present invention relates to the field of in-situ testing of geotechnical engineering, and particularly to an automated penetration-type micro in-situ direct shear apparatus. Background Art

[0002] In the field of geotechnical engineering, in-situ testing is one of the important means for evaluating the engineering properties of soil. In particular, the direct shear test, as a commonly used method for testing the mechanical properties of soil, can accurately reflect the shear strength characteristics of soil and is widely used in soil stability analysis, foundation design, and evaluation of soil behavior during construction. However, traditional direct shear tests usually need to be carried out in a laboratory environment, which requires taking out soil samples for treatment first, resulting in possible disturbance of the samples and affecting the accuracy of test results, especially in cases where soil samples are difficult to obtain or the environment is special.

[0003] Traditional in-situ direct shear test equipment is usually large, heavy, and complex to operate, making it difficult to meet the test requirements in narrow spaces or special geological conditions. Especially in complex engineering environments, such as urban underground pipelines, narrow underground operations, or testing in soft strata, existing equipment often cannot be flexibly and effectively tested. In addition, most existing equipment cannot achieve equal stress shear and cannot simulate actual engineering conditions.

[0004] To solve the above problems, in recent years, researchers have tried to design more portable and miniaturized direct shear test equipment. However, existing small equipment still has many problems, including cumbersome operation, insufficient measurement accuracy, low automation level, etc., and generally lacks the ability to automatically sample in-situ soil and complete tests, making it difficult to reduce disturbance and unable to effectively improve work efficiency. Therefore, there is an urgent need for a new type of equipment with a more compact structure, simple operation, capable of completing direct shear tests in-situ soil, and capable of automated operation. Summary of the Invention

[0005] In view of the above existing technical problems, the present invention proposes an automated penetration-type micro in-situ direct shear apparatus. The present invention provides a new type of equipment that can automatically complete in-situ direct shear tests in narrow spaces or special geological conditions. This equipment not only improves the degree of automation of operation, but also can minimize the disturbance to the soil, achieve equal stress shear, and improve test accuracy and work efficiency.

[0006] To achieve the above object, the technical solutions provided by the present invention are as follows:

[0007] An automated penetration-type miniature in-situ direct shear apparatus, comprising a support frame and a first drive module, a test module, at least two soil cutting modules and a sensor module provided thereon; the support frame is anchored to the ground; the first drive module is fixed to the support frame, and the moving end of the first drive module is connected to the test module for driving the test module to move in the vertical direction;

[0008] The test module is used for sampling and shear test, and the test module includes: a housing, a second drive module, a shear box and a valve; the housing is connected to the moving end of the first drive module; the second drive module is fixed inside the housing; the upper end of the shear box is connected to the moving end of the second drive module; the valve is arranged at the lower opening of the shear box; two soil cutting modules are symmetrically arranged at the lower end of the housing, and each soil cutting module includes: a drive motor, a connecting rod and a cutter; one end of the connecting rod is hinged to the lower end of the housing as a hinge end, the cutter is fixed to the other end of the connecting rod, and the drive motor drives the hinge end to rotate the connecting rod to realize the opening and closing of the two soil cutting modules; the sensor module includes: a pressure sensor and a displacement sensor, which are respectively used for collecting the pressure and displacement data during the shear box experiment; when the first drive module moves downward, the two soil cutting modules close and start cutting the soil; after reaching the specified depth, the first drive module stops, the two soil cutting modules open, the valve opens, the second drive module drives the shear box to move downward for sampling, after sampling, the valve closes, the second drive module drives the shear box to return to the original position; the test module starts the shear test, and after the experiment is over, the first drive module contracts and the test module retracts.

[0009] Further, the shear box includes: a fixed upper box and a movable lower box; the fixed upper box and the movable lower box are connected by a slide rail to realize horizontal movement and non-separation in the vertical direction.

[0010] Further, the sensor module includes: a pressure sensor and a displacement sensor, the pressure sensor is arranged at the upper end of the fixed upper box, and the displacement sensor is fixed on the outer side wall of the movable lower box.

[0011] Further, the test module further includes: a third drive module, at least two air pumps and a loading plate; the third drive module is fixed inside the housing at the upper end of the shear box, one end of the pressure sensor is fixed to the moving end of the third drive module, the loading plate is fixed to the other end of the pressure sensor, and the loading plate coincides with the upper opening of the shear box; the two air pumps are symmetrically fixed on the inner walls of the housing on both sides of the movable lower box for pushing the movable lower box to move horizontally and reset.

[0012] Further, the support frame is a steel frame, and a backing plate is provided between the first drive module and the steel frame.

[0013] Further, a force transmission rod is provided between the first driving module and the test module to extend the length of the moving end of the first driving module protruding out.

[0014] Further, the valve includes at least two rectangular plates symmetrically hinged to the lower end of the shear box and a motor for driving the rectangular plates to rotate around the hinge end, so as to realize the closing and opening of the lower end opening of the shear box.

[0015] A method for using any one of the above-mentioned automatic penetration type micro in-situ direct shear instruments includes the following steps:

[0016] 1) Adjust the steel frame to be horizontal and fix it on the ground, and then adjust the centers of the first driving module, the force transmission rod, the second driving module, the third driving module, the loading plate, the fixed upper box, the movable lower box, and the soil cutting module to the same vertical line.

[0017] 2) Energize the first driving module to move downward, and the two soil cutting modules close and start cutting the soil.

[0018] 3) After reaching the specified depth, the first driving module stops, the two soil cutting modules open to the vertical state, the valve opens, the second driving module drives the shear box to move downward as a whole to penetrate the soil for sampling the soil to be measured. After the sampling is completed, the valve closes, and the second driving module drives the shear box to return to the position before sampling.

[0019] 4) The third driving module pushes the loading block downward to apply pressure to the soil to be measured, opens one side air pump to make it extend, and the other side air pump contracts, so that the movable lower box moves horizontally along the slide rail, causing the soil to be measured to undergo direct shear failure.

[0020] 5) After the experiment is completed, the air pump works in the reverse direction to make the movable lower box return to its original position along the slide rail, the first driving module contracts, the test module retracts, and the data of the pressure sensor and the displacement sensor are exported and analyzed. By analyzing the pressure-deformation curve, the shear strength indexes c of the soil to be measured can be obtained. According to Coulomb's law, there are two shear strength indexes of soil: 1. c, that is, the cohesion of the soil, with the unit of kPa; 2. That is, the internal friction angle of the soil, with the unit of degree.

[0021] The present invention has the following advantages:

[0022] (1) The present invention adopts automated operations to reduce human intervention: It uses an automated penetration design, combines an automatic soil-breaking and sampling mechanism of a second drive module, a soil cutting module, and a valve, and conducts shear tests through a test module. This device can automatically complete all aspects of the direct shear test, greatly reducing the complexity of manual operations and the interference of human factors. This makes the operation more simple and fast, reduces the technical requirements for operators, and improves the test efficiency.

[0023] (2) The present invention can achieve equal-stress shearing: By equipping a third drive module combined with a loading plate, the stress of the soil to be measured is evenly distributed to achieve equal-stress shearing; it helps to accurately evaluate the mechanical properties of the soil to be measured and optimize engineering design parameters, thereby improving the accuracy and reliability of engineering design and scientific research.

[0024] (3) The present invention is relatively small, lightweight, and suitable for narrow spaces and special geological conditions compared to traditional direct shear testers, such as underground pipelines, underground operation sites, or soft strata. This enables in-situ direct shear tests to be carried out in environments where conventional equipment cannot be used, solving the problem that traditional equipment is too large in size and cannot adapt to complex environments.

[0025] (4) The device of the present invention conducts tests in-situ on the soil body, minimizing disturbance to ensure test accuracy: This device effectively reduces the disturbance of the soil body during sampling and testing. This can more truly reflect the original mechanical properties of the soil body, avoid measurement errors caused by soil sample disturbance in traditional methods, and ensure the accuracy of test results. Description of the Drawings

[0026] By referring to the following detailed description with reference to the accompanying drawings, the above and other objects, features, and advantages of the exemplary embodiments of the present invention will become easily understandable. Among them:

[0027] In the drawings, the same or corresponding reference numerals represent the same or corresponding parts.

[0028] Figure 1 Schematic diagram of an automated penetration type micro in-situ direct shear tester according to an embodiment of the present invention;

[0029] Figure 2 Schematic diagram of the penetration process of an automated penetration type micro in-situ direct shear tester according to an embodiment of the present invention;

[0030] Figure 3 Schematic diagram of the shear process of an automated penetration type micro in-situ direct shear tester according to an embodiment of the present invention;

[0031] Figure 4 Schematic diagram of the valve structure of an automated penetration type micro in-situ direct shear tester according to an embodiment of the present invention;

[0032] Figure 5 Schematic diagram of the soil cutting module structure of an automated penetration-type miniature in-situ direct shear apparatus according to an embodiment of the present invention;

[0033] In the figure: 1: steel frame; 2: backing plate; 3: first driving module; 4: force transfer rod; 5: third driving module; 6: second driving module; 7: pressure sensor; 8: loading plate; 9: fixed upper box; 10: slide rail; 11: movable lower box; 12: air pump; 13: displacement sensor; 14: valve; 15: soil cutting module; 16: soil to be measured; 17: driving motor; 18: cutter; 19: outer shell. Specific implementation manners

[0034] 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 application, rather than all the embodiments.

[0035] According to a specific example of the present invention, an automated penetration-type miniature in-situ direct shear apparatus includes a support frame and a first driving module 3, a test module, at least two soil cutting modules 15, and a sensor module provided thereon;

[0036] The support frame is anchored to the ground; the first driving module 3 is fixed to the support frame, and the moving end of the first driving module 3 is connected to the test module;

[0037] The test module includes: an outer shell 19, a second driving module 6, a shear box, and a valve 14; the outer shell 19 is connected to the moving end of the first driving module 3; the second driving module 6 is fixed inside the outer shell 19; the upper end of the shear box is connected to the moving end of the second driving module 6; the valve 14 is provided at the lower opening of the shear box;

[0038] Two soil cutting modules 15 are symmetrically arranged at the lower end of the outer shell 19. Each soil cutting module 15 includes: a driving motor 17, a connecting rod, and a cutter 18; one end of the connecting rod is hinged to the lower end of the outer shell 19 as a hinged end, the cutter 18 is fixed to the other end of the connecting rod, and the driving motor 17 drives the hinged end to rotate the connecting rod to realize the opening and closing of the two soil cutting modules 15;

[0039] The sensor module is used to collect pressure and displacement data during the shear box experiment;

[0040] When the first driving module 3 moves downward, the two soil cutting modules 15 close and start cutting the soil. After reaching the specified depth, the first driving module 3 stops, the two soil cutting modules 15 open, the valve 14 opens, and the second driving module 6 drives the shear box downward for sampling. After sampling, the valve 14 closes, and the second driving module 6 drives the shear box to return to its original position. The test module starts the shear test. After the experiment, the first driving module 3 contracts and the test module retracts.

[0041] Embodiment 1:

[0042] An automated penetrative micro in-situ direct shear apparatus, see Figure 1 , comprising a support frame, a backing plate 2, a first driving module 3, a force transfer rod 4, a test module, a soil cutting module 15, and a sensor module; the test module includes: a housing 19, a third driving module 5, a second driving module 6, a shear box, a loading plate 8, a slide rail 10, an air pump 12, and a valve 14; the sensor module includes: a pressure sensor 7 and a displacement sensor 13; the shear box includes: a movable lower box 11, a fixed upper box 9. In this embodiment, the support frame is a steel frame 1, and the first driving module 3, the second driving module 6, and the third driving module 5 are all hydraulic cylinders.

[0043] See Figure 1 , the steel frame 1 is fixed to the ground, supporting the entire device and connected to the first driving module 3 to resist the reaction force transmitted by the first driving module 3. A backing plate 2 is provided between the first driving module 3 and the steel frame 1 to buffer the reaction force of the first driving module 3 acting on the steel frame 1. Before use, the steel frame 1 should be adjusted to be parallel to the horizontal plane and fixed to the ground.

[0044] See Figure 1 , Figure 2 , Figure 5 , the soil cutting module 15 is located at the lowermost end of the entire device, and is specifically composed of a driving motor 17, a connecting rod, and a cutter 18. One end of the connecting rod is hinged to the lower end of the housing 19, and the cutter 18 is connected to the other end of the connecting rod. The driving motor 17 is used to drive the hinged end of the connecting rod and the housing 19 to drive the connecting rod to rotate, realizing the opening and closing of the soil cutting module 15. The cutter 18 has the function of cutting the soil. After cutting, the driving motor 17 drives the connecting rod to rotate, so that the cutter 18 retracts to a vertical state, providing a channel for the shear box to take soil.

[0045] See Figure 1 , the first driving module 3 is connected to the test module through the force transfer rod 4, pushing the entire test module downward, and at the same time cooperating with the soil cutting module 15 to cut the soil and sending the test module to the specified test depth.

[0046] See Figure 1 , Figure 2 ,Figure 4 , the valve 14 is composed of a motor and two rectangular plates. The two rectangular plates are symmetrically arranged at the lower end of the movable lower box 11 and are respectively hinged to two symmetric side edges of the movable lower box 11. By driving the hinged ends of the two rectangular plates with the motor, the opening and closing of the two rectangular plates are realized, so as to close the lower opening of the shear box. During the penetration sampling process, the rectangular plates are driven by the motor to open to the vertical state. The second driving module 6 works to push the shear box downward for sampling. After sampling, the second driving module 6 contracts to make the shear box return to its original position, and the rectangular plates are driven by the motor to close.

[0047] Participate Figure 1 , the third driving module 5 is arranged above the shear box and fixed on the top inner wall of the housing 19, and can provide a vertical pressure during the direct shear test process.

[0048] See Figure 1 , a loading plate 8 is arranged above the fixed upper box 9. During the test process, the force of the third driving module 5 is transmitted to the tested soil mass 16 through the loading plate 8. The loading plate 8 can evenly transmit the stress at the boundary to the tested soil mass 16, so as to realize the equal stress shear of the tested soil mass 16.

[0049] See Figure 1 , Figure 2 , the connection between the fixed upper box 9 and the movable lower box 11 is realized through two slide rails 10 arranged in parallel between the fixed upper box 9 and the movable lower box 11. The movable lower box 11 can move horizontally along the telescopic direction of the air pump 12 together with the slide rails 10 and ensure that it will not fall off in the vertical direction.

[0050] See Figure 1 , Figure 3 , two air pumps 12 are symmetrically connected to the inner wall of the housing 19. When the air pumps 12 work, one air pump 12 extends and the other side contracts, pushing the movable lower box 11 to move horizontally, thereby causing the direct shear failure of the tested soil mass 16 in the shear box. After the test, the air pumps 12 on both sides work in the opposite direction to push the movable lower box 11 back to its original position.

[0051] See Figure 1 , Figure 3 , the pressure sensor 7 is arranged above the fixed upper box 9, one end is connected to the third driving module 5, and the other end is connected to the loading plate 8, and the vertical pressure transmitted by the third driving module 5 is monitored in real time; the displacement sensor 13 is horizontally arranged on the side wall of the movable lower box 11, and the displacement change of the movable lower box 11 is monitored in real time. Through data analysis and processing, the shear strength indexes c of the in-situ soil mass are obtained. (According to Coulomb's law, there are two shear strength indexes of soil: 1. c, the cohesion of soil, or internal cohesion, with the unit kPa; 2. The internal friction angle of soil, with the unit degree).

[0052] Example 2:

[0053] The usage process of an automated penetration - type in - situ direct shear apparatus provided according to Example 1:

[0054] Before conducting a direct shear test using this device, the steel frame 1 should be adjusted to be horizontal and fixed to the ground first, and then the centers of the first driving module 3, the load transfer rod 4, the second driving module 6, the third driving module 5, the loading plate 8, the fixed upper box 9, the movable lower box 11, and the soil cutting module 15 should be adjusted to the same vertical line.

[0055] Power on to make the soil cutting module 15 start cutting the soil, and the first driving module 3 works. The two cooperate to make the entire test module move downward. When reaching the specified position, the soil cutting module 15 and the first driving module 3 stop working. The driving motor 17 drives the connecting rod to drive the cutter 18 to rotate outward until the soil cutting module 15 is in a vertical state.

[0056] Open the valve 14, and the second driving module 6 works to push the entire shear box downward for penetration sampling. After the sampling is completed, the valve 14 is closed, and the second driving module 6 contracts to restore the shear box to the position before penetration sampling.

[0057] As Figure 3 , turn on the switch of the air pump 12 to make it work, adjust the right - hand air pump 12 to extend and the left - hand air pump 12 to contract, so that the movable lower box 11 moves horizontally along the slide rail 10, and the tested soil mass 16 undergoes direct shear failure.

[0058] After the test is completed, adjust the switch of the micro - air pump 12 to work in the reverse direction, push the movable lower box 11 back to the initial position, and at the same time, the first driving module 3 contracts to retract the entire device.

[0059] After the test device is completely retracted, export and analyze the data of the pressure sensor 7 and the displacement sensor 13. By analyzing the pressure - deformation curve, the shear strength indexes c of the in - situ soil mass can be obtained.

[0060] The present invention is light and easy to contract. It can penetrate the direct shear test device into the in - situ soil mass in a narrow space or under special geological conditions, automatically sample through the combination of the soil cutting module 15, the first driving module 3, the second driving module 6 and the valve 14, and complete the direct shear test in the in - situ soil mass, minimizing the disturbance during the sampling process. At the same time, this device realizes equal - stress shear with the help of the loading plate 8, and has the advantages of being small and light, accurate measurement results, simple operation, and labor - saving, and is suitable for soil shear tests under various complex environments, having a wide application prospect.

[0061] As described above, it is only the preferred specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application, according to the technical solution and inventive concept of the present application, makes equivalent replacements or changes, and should be covered within the protection scope of the present application.

Claims

1. An automated penetration-type micro in-situ direct shear apparatus, characterized in that, It includes a support frame and a first driving module (3), a test module, at least two soil cutting modules (15) and a sensor module provided thereon; The support frame is anchored to the ground; the first driving module (3) is fixed to the support frame, and the moving end of the first driving module (3) is connected to the test module; The test module includes: a housing (19), a second driving module (6), a shear box and a valve (14); the housing (19) is connected to the moving end of the first driving module (3); the second driving module (6) is fixed inside the housing (19); the upper end of the shear box is connected to the moving end of the second driving module (6); the valve (14) is arranged at the lower opening of the shear box; Two soil cutting modules (15) are symmetrically arranged at the lower end of the housing (19), and each soil cutting module (15) includes: a driving motor (17), a connecting rod and a cutter (18); one end of the connecting rod is hinged to the lower end of the housing (19) as a hinge end, the cutter (18) is fixed to the other end of the connecting rod, and the driving motor (17) drives the hinge end to rotate the connecting rod to realize the opening and closing of the two soil cutting modules (15); The sensor module is used to collect pressure and displacement data during the shear box experiment; When the first driving module (3) moves downward, the two soil cutting modules (15) close and start cutting the soil; after reaching the specified depth, the first driving module (3) stops, the two soil cutting modules (15) open, the valve (14) opens, the second driving module (6) drives the shear box to move downward for sampling, after sampling, the valve (14) closes, and the second driving module (6) drives the shear box to return to its original position; the test module starts the shear test; after the experiment is over, the first driving module (3) contracts and the test module retracts.

2. The automated penetration-type miniature in-situ direct shear apparatus according to claim 1, wherein The shear box includes: a fixed upper box (9) and a movable lower box (11); the fixed upper box (9) and the movable lower box (11) are connected by a slide rail (10) to realize horizontal movement and not to separate in the vertical direction.

3. The automated penetration-type miniature in-situ direct shear apparatus according to claim 2, characterized in that, The sensor module includes: a pressure sensor (7) and a displacement sensor (13), the pressure sensor (7) is arranged at the upper end of the fixed upper box, and the displacement sensor (13) is fixed on the outer side wall of the movable lower box (11).

4. The automated penetration-type miniature in-situ direct shear apparatus according to claim 3, characterized in that, The test module further includes: a third driving module (5), at least two air pumps (12) and a loading plate (8); the third driving module (5) is fixed inside the housing (19) at the upper end of the shear box, one end of the pressure sensor (7) is fixed to the moving end of the third driving module (5), the loading plate (8) is fixed to the other end of the pressure sensor (7), and the loading plate (8) fits with the upper opening of the shear box; the two air pumps (12) are symmetrically fixed on the inner walls of the housing (19) on both sides of the movable lower box (11) and are used to push the movable lower box (11) to move horizontally and reset.

5. The automated penetration-type miniature in-situ direct shear apparatus according to claim 1, wherein The support frame is a steel frame (1), and a cushion plate (2) is provided between the first driving module (3) and the steel frame (1).

6. The automated penetration-type miniature in-situ direct shear apparatus according to claim 1, characterized in that, A force transmission rod (4) is provided between the first driving module (3) and the test module to extend the length of the protruding end of the moving end of the first driving module (3).

7. The automated penetration-type miniature in-situ direct shear apparatus according to claim 1, wherein The valve (14) includes at least two rectangular plates symmetrically hinged to the lower end of the shear box and a motor for driving the rectangular plates to rotate around the hinged end.

8. A method for using the automated penetration-type miniature in-situ direct shear apparatus according to any one of claims 1-7, characterized in that, The method includes the following steps: 1) Adjust the steel frame (1) to be horizontal and fix it on the ground, and then adjust the centers of the first driving module (3), the force transmission rod (4), the second driving module (6), the third driving module (5), the loading plate (8), the fixed upper box (9), the movable lower box (11), and the soil cutting module (15) to the same vertical line; 2) Energize to make the first driving module (3) move downward, and the two soil cutting modules (15) close and start cutting the soil; 3) After reaching the specified depth, the first driving module (3) stops, the two soil cutting modules (15) open to the vertical state, the valve (14) opens, the second driving module (6) drives the shear box to move downward as a whole to penetrate into the soil for sampling the tested soil (16). After the sampling is completed, the valve (14) closes, and the second driving module (6) drives the shear box to return to the position before sampling; 4) The third driving module (5) pushes the loading plate (8) downward to apply pressure to the tested soil (16), opens one side air pump (12) to make it extend, and the other side air pump (12) contracts, so that the movable lower box (11) moves horizontally along the slide rail (10), causing direct shear failure of the tested soil (16); 5) After the experiment is completed, the air pump (12) works in the reverse direction to make the movable lower box (11) return to its original position along the slide rail (10), the first driving module (3) contracts, the test module retracts, and the data of the pressure sensor (7) and the displacement sensor (13) are exported and analyzed.

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