On-site direct shear test device

Abstract

According to the scheme, the field direct shear test device comprises a balance weight platform, the top of the balance weight platform is provided with an area for placing a balance weight, the bottom of the balance weight platform is connected with the top of a shear frame, and the angle of the balance weight platform can be adjusted to keep the balance weight in a horizontal state; the shearing frame is a frame body with a rectangular section and is pressed into rock soil to obtain a complete sample; the balance weight is arranged on the balance weight platform; the linear driver is arranged on one side of the shearing frame, is positioned on the same straight line with the shearing frame and is used for providing shearing force; the displacement sensor is used for detecting the displacement of the sample; the data acquisition instrument is in communication connection with the linear driver and the displacement sensor; wherein a counterforce mechanism is arranged on one side, far away from the shearing frame, of the linear driver, and counterforce is provided for the linear driver through the counterforce mechanism. According to the method, the test efficiency can be greatly improved, the rule can be quickly searched through a large amount of data, and the original time-consuming, labor-consuming and money-consuming test is changed into a universal means.

Description

Technical Field

[0001] The present application relates to the field of in-situ testing of geotechnical engineering, and in particular to an on-site direct shear test device. Background Art

[0002] In geotechnical engineering, testing of rock and soil mechanical properties is primarily done through field testing and laboratory testing. Traditionally, determination of rock mass structural surfaces and soil-rock interface parameters has been largely based on laboratory testing. However, laboratory testing suffers from numerous drawbacks, including size effects, boundary effects, and sampling disturbance. In contrast, field testing involves less disturbance of soil samples, resulting in more accurate test results.

[0003] In-situ direct shear testing is a commonly used method in field testing. However, in practice, due to the natural presence of structural surfaces and weak surfaces such as joints and fissures in rock masses, and the fact that these interfaces are often not horizontal, in-situ direct shear testing of structural surfaces is extremely cumbersome, significantly increasing costs and man-hours.

[0004] Currently, there are several in-situ direct shear test devices available, such as CN204330502U - A Novel In-situ Direct Shear Test Device for Rock and Soil, CN111458238A - An Assembled In-situ Direct Shear Test Device and Method for Rock and Soil Slopes, and CN218036175U - Anchor-Tension-Based Direct Shear Test Device for Bedding Slopes. Most of these patented methods are unable to test structural surfaces. While some methods exist for testing structural surfaces of bedding slopes, they utilize time-consuming and labor-intensive anchoring methods that require anchoring to provide the required reaction force, resulting in excessively high labor costs. Test methods that do not require anchoring are also unsuitable for testing structural surfaces, resulting in a struggle between the two. Utility Model Content

[0005] The purpose of this application is to provide an on-site direct shear test device to address the above-mentioned problems existing in the prior art.

[0006] In order to achieve the above application objectives, this application adopts the following technical solutions: an on-site direct shear test device comprising:

[0007] The counterweight platform has an area on the top for placing the counterweight, and the bottom is connected to the top of the shear frame. The counterweight platform can be adjusted in angle to keep the counterweight in a horizontal state;

[0008] The shear frame is a frame with a rectangular cross section, which is pressed into the rock and soil to obtain a complete specimen;

[0009] A counterweight is provided on the counterweight platform;

[0010] A linear actuator is provided on one side of the shear frame and is located in the same straight line as the shear frame, and is used to provide shear force;

[0011] Displacement sensor, used to detect the displacement of the specimen;

[0012] A data acquisition device is communicatively connected with the linear drive and the displacement sensor;

[0013] A reaction force mechanism is provided on a side of the linear drive away from the shear frame, and a reaction force is provided to the linear drive through the reaction force mechanism.

[0014] Furthermore, the reaction mechanism is a bucket of an excavator.

[0015] Furthermore, the linear drive is a jack, and the jack is also connected to a hydraulic oil pump and a hydraulic sensor, and is communicatively connected to the data acquisition instrument through the hydraulic sensor.

[0016] Furthermore, the bottom of the counterweight platform is connected to the top of the shear frame through a positioning cover plate.

[0017] Furthermore, the positioning cover plate includes a base plate and an inclinometer. The base plate is provided with a limiting groove, through which the counterweight platform is limited. The inclinometer is used to display the inclination angle of the base plate.

[0018] Furthermore, the counterweight platform includes adjusting bolts, a spirit level and a platform frame. The adjusting bolts are respectively located at the four feet of the platform frame and are used to adjust the angle of the platform frame to keep it in a horizontal state. The spirit level is provided on the platform frame to display the horizontal state of the platform frame.

[0019] Furthermore, the platform frame is made of steel, and its four legs form a square.

[0020] Furthermore, a cutting edge is provided at the bottom opening of the shear frame.

[0021] Furthermore, the counterweight is provided with a hanging lug.

[0022] Furthermore, the shear frame is a frame with a square cross-section.

[0023] Compared with the prior art, this application has the following beneficial effects:

[0024] 1. Strong Adaptability: The device can adapt to naturally occurring non-horizontal structural surfaces and weak surfaces in rock masses, overcoming the cumbersome procedures associated with previous devices for in-situ direct shear testing on such surfaces. For surfaces with varying inclination angles, the angle adjustment function of the counterweight platform ensures the horizontality of the counterweight, ensuring test accuracy and stability.

[0025] Second, easy operation: Instead of using time-consuming and labor-intensive anchoring methods to provide reaction force, the test utilizes reaction mechanisms such as excavator buckets, greatly simplifying the test operation steps and reducing labor costs. The counterweight platform is adjusted by adjusting bolts and a level gauge for angle adjustment, making operation intuitive and convenient, thereby improving test efficiency.

[0026] 3. Accurate Testing: Equipped with a displacement sensor and data acquisition instrument, the system can accurately detect specimen displacement and collect and record test data in real time, improving test accuracy and reliability. The inclinometer on the positioning cover and the level gauge on the counterweight platform help to precisely adjust the angle and level of the device, further ensuring the accuracy of test results.

[0027] 4. Flexible structure: The shear frame has a rectangular cross-section, and can be shaped in different shapes, such as square, to meet different test requirements. The counterweight is equipped with hanging ears for easy handling and installation, increasing the flexibility of the device.

[0028] In summary, the on-site direct shear test device for rock mass structural surface and soil-rock interface parameters of the utility model has significant advantages in adaptability, ease of operation, test accuracy and structural flexibility, and provides an efficient and reliable solution for the determination of rock mass structural surface and soil-rock interface parameters in geotechnical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of using the utility model to carry out on-site direct shear test of rock structure surface.

[0030] Figure 2 is a schematic diagram of the counterweight platform.

[0031] Figure 3 is a schematic diagram of the positioning cover.

[0032] In the figure, 1. counterweight platform; 11. adjusting bolt; 12. spirit level; 13. platform frame; 2. positioning cover; 21. bottom plate; 211. limit slot; 22. inclinometer; 3. shear frame; 4. counterweight; 5. jack; 6. hydraulic oil pump; 7. hydraulic sensor; 8. displacement sensor; 9. data acquisition instrument. DETAILED DESCRIPTION

[0033] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0034] Those skilled in the art should understand that, in the disclosure of this application, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms cannot be understood as limiting this application.

[0035] Example 1

[0036] like Figure 1-3 As shown, the on-site direct shear test device includes a counterweight platform 1, a positioning cover plate 2, a shear frame 3, a counterweight 4, a jack 5, a hydraulic oil pump 6, a hydraulic sensor 7, a displacement sensor 8 and a data acquisition device 9, which can be applied to on-site direct shear tests of rock structure surfaces and soil-rock interface parameters.

[0037] The counterweight platform 1 can be adjusted according to the inclination of the structural surface to keep the platform horizontal for placing the counterweight 4 and applying normal stress to the sample.

[0038] The positioning cover plate 2 is placed on top of the sample to evenly transfer the normal force exerted by the counterweight 4 and the counterweight platform 1 to the sample. At the same time, the counterweight platform 1 can be fixed to prevent it from sliding down with the inclination of the rock mass.

[0039] The shear frame 3 is a frame with a square cross section and a blade angle at the bottom, which is pressed into the rock mass to form a complete specimen.

[0040] The counterweight 4 is made of concrete with different weights, and a steel bar hanging lug is provided on the upper part for hanging, and can be stacked according to the weight required for the test.

[0041] The jack 5 provides shear force for the specimen and is fixed behind the shear frame 3. An excavator bucket can be used to provide reaction force to it.

[0042] The hydraulic oil pump 6 is connected to the jack 5 through an oil pipe, and provides pressure to the jack 5 through the pressure rod pump oil, so that the jack 5 opens and pushes the sample.

[0043] The hydraulic sensor 7 is connected to the hydraulic oil pump 6. When the hydraulic oil pump 6 starts to pump oil and increase pressure, the hydraulic sensor 7 can collect oil pressure data. The oil pressure multiplied by the piston area and then divided by the cross-sectional area of ​​the shear frame 3 is the shear force value.

[0044] The displacement sensor 8 is fixed in front of the sample. When the sample is pushed by the jack 5, the displacement sensor 8 can collect data on the displacement of the sample.

[0045] The data acquisition instrument 9 is connected to the displacement sensor 8 and the hydraulic pressure sensor 7 via a data wire to obtain the displacement shear force curve of the sample during the shearing process.

[0046] like Figure 2 As shown, the counterweight platform 1 includes adjusting bolts 11, a level 12 and a platform frame 13. Made of steel, the four legs at the bottom are spaced 45 cm apart to form a square shape that can adapt to the inclination of the structural surface and always keep the platform frame 13 horizontal so that the counterweight 4 can be placed and loaded stably.

[0047] The adjusting bolts 11 are located at the four feet of the counterweight platform 1 and can be rotated to adjust the length to change the angle of the platform frame 13 to adapt to the inclination angle of the sample.

[0048] The level 12 contains a liquid bubble, which is fixed to the platform frame 13, and the reference surface is parallel to the platform frame 13. When the platform frame 13 is horizontal, the liquid bubble is centered.

[0049] like Figure 3 As shown, the positioning cover plate 2 includes a bottom plate 21 and an inclinometer 22. This ensures that the gravity of the counterweight 4 can act evenly on the top of the sample.

[0050] There is a limit groove 211 on the base plate 21 (the limit groove 211 is not limited to any form, it can be a rib, a groove, etc. that can play a limiting role). The bolt foot of the counterweight platform 1 can be fixed on the limit groove 211, so that the counterweight platform 1 will not slide downward with the inclination angle when placed on the base plate 21.

[0051] The inclinometer 22 can display the inclination angle of the bottom plate 21. During the test, the inclination angle of the bottom plate 21 is the inclination angle of the specimen, which can provide a reference for the subsequent calculation of shear force and normal force.

[0052] Example 2

[0053] Based on Example 1, this embodiment provides a method for testing using the device of Example 1, comprising the following steps:

[0054] S1: Use an excavator to level the test site and determine the inclination, dip and direction of the rock structure surface to be tested.

[0055] S2: Place the shear frame 3 along the structural surface at the test location to ensure that the shear frame 3 is pushed toward the slope foot in parallel with the structural surface, with the blade angle pointing downward.

[0056] S3: Covering the shear frame 3 with steel plates facilitates uniform compression and prevents damage to the shear frame 3. Then, use an excavator to statically press or slam the shear frame 3 onto the interface to be tested, minimizing disturbance and maintaining the original state of the rock and soil.

[0057] S4: After confirming that the shear frame 3 is perpendicular to the structural surface and embedded in the rock mass, fill the upper part with soil to fill the shear frame 3 to form a complete specimen.

[0058] S5: Excavate the rock and soil around the shear frame 3 to form a four-sided groove. The width of the groove in the front of the shear frame 3 in the pushing direction is slightly larger than 5 cm. The groove should expose the shear frame 3 so that it can be pushed freely.

[0059] S6: Replace the positioning cover plate 2, ensuring that the limit slots on the bottom plate 21 are in front of the shear frame 3 in the direction of push. At the same time, check the reading of the inclinometer 22 to ensure that the inclination angle is consistent with the structural surface. Then, place the counterweight platform 1 and rotate the adjusting bolt 11 to center the bubble of the spirit level 12.

[0060] S7: Install the jack 5 to apply the shearing reaction force, with the piston of the jack 5 close to the rear of the shear frame 3 in the pushing direction, and then install the displacement sensor 8, and fix the displacement sensor 8 in the front of the shear frame 3 in the pushing direction, with the sensor head close to the frame wall of the shear frame 3 and the direction parallel to the pushing direction.

[0061] S8: Connect the data wires of the hydraulic sensor 7 and the displacement sensor 8 to the data acquisition device 9, and check whether the working status of the sensors and the data acquisition device 9 is normal.

[0062] S9: Use an excavator to stably lift the counterweight 4 of the required weight onto the counterweight platform 1.

[0063] S10: Use the excavator bucket to provide reaction force for the jack 5, the data acquisition instrument 9 starts to record data, and at the same time the hydraulic oil pump 6 starts to increase pressure, so that the jack 5 opens and pushes the sample forward.

[0064] S11: When the displacement-shear force image on the data acquisition instrument 9 shows an obvious peak and then drops, or reaches the maximum range of the displacement sensor 8, the test ends.

[0065] S12: After the shear test is completed, use an excavator to check the shear surface properties, remove samples, clean up, etc.

[0066] Where, let the gravity of the counterweight 4 be G, the cross-sectional area of ​​the shear frame 3 be A, the inclination angle of the structural surface be θ, the jack oil pressure be x, and the jack piston radius be r. Then the normal force applied by the counterweight 4 to the specimen is:

[0067]

[0068] The shear stress on the specimen is:

[0069]

[0070] The parts not described in detail in this application are prior art, so this application does not describe them in detail.

[0071] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the elements may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0072] Although this document uses a lot of professional terms, it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of this application; interpreting them as any additional restrictions is contrary to the spirit of this application.

[0073] This application is not limited to the above-mentioned optimal implementation method. Anyone can derive various other forms of products based on the inspiration of this application. However, no matter what changes are made in their shape or structure, any technical solution that is the same or similar to that of this application falls within the scope of protection of this application.

Claims

1. An on-site direct shear test device, characterized in that: include: The counterweight platform has an area on the top for placing the counterweight, and the bottom is connected to the top of the shear frame. The counterweight platform can be adjusted in angle to keep the counterweight in a horizontal state; The shear frame is a frame with a rectangular cross section, which is pressed into the rock and soil to obtain a complete specimen; a counterweight, arranged on the counterweight platform; a linear actuator, provided on one side of the shear frame and in the same straight line as the shear frame, for providing shearing force; Displacement sensor, used to detect the displacement of the specimen; a data acquisition device, communicatively connected to the linear drive and the displacement sensor; Wherein, a reaction force mechanism is provided on a side of the linear drive away from the shear frame, and a reaction force is provided to the linear drive through the reaction force mechanism.

2. The on-site direct shear test device according to claim 1, characterized in that: The reaction force mechanism is a bucket of an excavator.

3. The on-site direct shear test device according to claim 1, characterized in that: The linear drive is a jack, and the jack is also connected to a hydraulic oil pump and a hydraulic sensor, and is communicatively connected to the data acquisition instrument via the hydraulic sensor.

4. The on-site direct shear test device according to claim 1, characterized in that: The bottom of the counterweight platform is connected to the top of the shear frame through a positioning cover plate.

5. The on-site direct shear test device according to claim 4, characterized in that: The positioning cover plate includes a base plate and an inclinometer. The base plate is provided with a limiting groove, through which the counterweight platform is limited. The inclinometer is used to display the inclination angle of the base plate.

6. The on-site direct shear test device according to claim 1, characterized in that: The counterweight platform includes an adjusting bolt, a spirit level and a platform frame. The adjusting bolts are respectively located at the four feet of the platform frame and are used to adjust the angle of the platform frame to keep it in a horizontal state. The spirit level is provided on the platform frame and is used to display the horizontal state of the platform frame.

7. The on-site direct shear test device according to claim 6, characterized in that: The platform frame is made of steel, and its four legs form a square.

8. An on-site direct shear test device according to any one of claims 1 to 7, characterized in that: A cutting edge is provided at the bottom opening of the shear frame.

9. An on-site direct shear test device according to any one of claims 1 to 7, characterized in that: The counterweight is provided with a hanging lug.

10. The on-site direct shear test device according to claim 9, characterized in that: The shear frame is a frame with a square cross-section.

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