Direct shear model device for monitoring side slope shear deformation

Abstract

The invention relates to the technical field of engineering, and discloses a direct shear model device for monitoring side slope shear deformation, which comprises a shear box, a loading system, a DIC monitoring system, a data acquisition system and a fixing device. In order to represent the shearing process of a soil body in a direct shear model test, a shear failure mode of the soil body is summarized, and a tempered glass structure is built. The shear box is mainly composed of two shear boxes of 2 * 1 * 0.5 (length, width and height) cubic meters and a shear box of 2 * 1 * 1 (length, width and height) cubic meters. The left large shear box is connected with the middle shear box through a rotatable shaft, and a detachable baffle is arranged at the bottom of the left large shear box. A buckle is arranged at the bottom of the shear box and used for fixing an optical fiber sensor for testing. According to the direct shear model device for monitoring the shear deformation of the side slope, a new idea is provided for meeting the requirements of start and extension research of a shear zone in side slope soil.

Description

Technical Field

[0001] The invention relates to the field of engineering technology, in particular to the field of laboratory simulation research, and more particularly to a direct shear model device for monitoring slope shear deformation. Background Art

[0002] Slope disasters are sudden and destructive. In severe cases, they can disrupt traffic, destroy buildings, and cause huge property losses to human society. In more serious cases, they can cause casualties. Among slope movements, landslide disasters are the most difficult to predict. Landslide movement is mainly controlled by the shear deformation behavior of the sliding zone. In-depth understanding of the deformation of the sliding surface is of great significance for slope stability assessment and landslide event warning.

[0003] In recent years, fiber optic sensing technology has been widely used in slope stability monitoring, especially the application potential and excellent performance of fiber Bragg grating (FBG) in slope stability monitoring. Fiber Bragg grating (FBG) is an optical device that uses the grating structure in the optical fiber to reflect and transmit light. When a broadband optical signal is input into the optical fiber, only light of a specific wavelength will be reflected back by the FBG, while light of other wavelengths will be transmitted. This specific wavelength is called the Bragg wavelength, which is related to the strain and temperature changes in the optical fiber. It has the advantages of good economic benefits, high measurement accuracy, quasi-distributed measurement and real-time monitoring, and is a low-cost and high-performance alternative to a number of commercial distributed fiber optic sensors. It is widely used to monitor the strain, temperature, vibration and other parameters of large buildings such as bridges and tunnels. It plays a very important role in slope stability monitoring. It is often used to monitor the deformation and displacement of slope disasters, and timely warn of the potential occurrence of disasters through data analysis to protect people's lives and property. Determining the relationship between FBG strain measurement and soil shear displacement is a difficult problem that must be solved for the development of FBG-based slope deformation monitoring systems.

[0004] It is difficult to establish comprehensive real-time monitoring of slope hazards on site, and monitoring the deformation of slope shear zones is crucial to understanding the dynamic process of slope evolution and evaluating slope stability.

[0005] Therefore, the present invention proposes a direct shear model device for monitoring slope shear deformation, which is used to simulate the actual state of the slope. The initial state and development process of the shear band in the soil are studied through direct shear model experiments, which has a very important impact on slope stability monitoring. Summary of the invention

[0006] To solve the above technical problems, the present invention provides a direct shear model device for monitoring slope shear deformation, which solves the need for determining the relationship between FBG strain measurement values ​​and soil shear displacement for developing a slope deformation monitoring system based on FBG.

[0007] The direct shear model device for monitoring slope shear deformation provided by the present invention comprises a shear box, a loading system, a DIC monitoring system, a data acquisition system and a fixing device: wherein the shear box is used to simulate the shear state that the soil may encounter under actual conditions; the loading system is used to load vertical stress and horizontal shear force; the DIC monitoring system is used to monitor in real time and capture the dynamic process of subtle displacement changes; the data acquisition system is used to measure the shear displacement and perform data recording and analysis.

[0008] Preferably, three shear boxes are used in the device, two of which have the same size and are fixed by a fixing device, and the other can slide along the sliding groove under the influence of shear force to achieve the effect of simulating shear displacement of the slope; the size of the third shear box is different from the first two in height, and is equipped with a removable baffle, which is connected to the fixed shear box with a rotatable shaft. When it is rotated clockwise to a certain angle, it can simulate a slope model with an inclined angle. When the two shear boxes overlap, the baffle is removed, and shear force is applied, so that deep displacement can be monitored synchronously; the shear joints located above and below and left and right can well simulate the shear movement of the soil sample along the joint during this process.

[0009] Preferably, the loading system consists of a loading device and a cylinder: the loading device realizes the vertical stress in the actual process through external force, the pressure is controlled by the cylinder, and a pressure sensor is equipped to control the magnitude of the vertical stress; the cylinder at the shear box position is used to provide horizontal shear force to simulate the shear movement of the soil sample after the horizontal shear force is applied.

[0010] Preferably, the DIC monitoring system is connected to a computer via a network communication with a digital camera and a high-resolution motion camera, and uses professional software to process data. The DIC technology is based on the principle of image correlation and can monitor in real time and capture the dynamic process of subtle displacement changes. It is very suitable for non-contact measurement of strain and displacement of the entire experimental area.

[0011] Preferably, the data acquisition system includes a laser displacement meter and a computer terminal: the laser displacement meter is an instrument that uses laser technology to measure the distance between the surface of an object and a laser source, and is commonly used for non-contact measurement. It has high stability, strong anti-interference ability, and can respond quickly, and is suitable for dynamic monitoring. In this device, a laser displacement meter is used to measure shear displacement; the computer terminal integrates data recording and data analysis, and verifies the experimental results of the optical fiber sensor during the experiment by analyzing and processing the data of the DIC and laser displacement meter.

[0012] Preferably, the fixing device is composed of a steel structure bracket and a buckle: the steel structure bracket is stable and strong and can play a supporting role; the buckle is placed at the bottom of the shear box to fix the optical fiber used for testing to prevent other factors from interfering with the experimental results.

[0013] Preferably, the device is used to conduct systematic and simulated experiments on the optical fiber sensor required to be tested. The slope model can be simulated by adjusting the inclination of the large shear box on the left side. When the inclination is 90 degrees, the disassembly baffle is removed to simulate the shear force on the sensing optical fiber at different depths in a vertical state. When the middle shear box and the shear box on the right are spliced, a shear gap is left in the middle. By fixing the middle shear box, a horizontal shear force is applied to the shear box on the right side through a cylinder to simulate the shear force on the optical fiber sensor in a horizontal state. The DIC monitoring system and the data acquisition system process the collected data, and compare the strain value measured by the optical fiber sensor with the shear displacement of the soil through conversion, so as to further verify that the optical fiber sensor under study can achieve the required accuracy and function.

[0014] Compared with the related art, the direct shear model device for monitoring slope shear deformation provided by the present invention has the following beneficial effects:

[0015] 1. The direct shear model device for monitoring slope shear deformation provided by the present invention can help researchers understand the initiation and extension of shear bands in slope soil more efficiently, and can provide technical support for the detection and early warning of slope stability.

[0016] 2. The direct shear model device is an important experimental device, which plays an important role in slope research and prevention. The direct shear model experiment can be carried out in the laboratory, and the experimental conditions can be precisely controlled, which solves the problems of difficult detection and too many uncontrollable factors under field conditions. The device is simple and easy to operate, the experimental process can be repeated, the test cost is low, and it can be combined with other slope experiments. This device has the advantages of simplicity, economy and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a direct shear model device for monitoring slope shear deformation provided by the present invention;

[0018] Figure 2 is a plane schematic diagram of the direct shear model in Example 1;

[0019] Figure 3 is a schematic diagram of the structure of the DIC device in Example 2;

[0020] Figure 4 This is a block diagram of the principle of strain and displacement measurement achieved by DIC in Example 2;

[0021] Figure 5 is a schematic diagram of the laser displacement meter in Example 2;

[0022] Figure 6 This is the principle block diagram of the laser displacement meter in Example 2. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0024] The direct shear model device for monitoring slope shear deformation provided by the present invention comprises a shear box, a loading system, a DIC monitoring system, a data acquisition system and a fixing device, wherein:

[0025] (1) The shear box is a key component in the experimental device. Its design can simulate the shear state that the soil may encounter in actual conditions. A total of three shear boxes are used in this device, two of which have the same size (length, width and height are 2 meters, 1 meter and 0.5 meters respectively), and one is fixed by a fixing device, and the other can slide along the sliding groove under the influence of shear force to achieve the effect of simulating shear displacement of the slope. The size of the third shear box is different from the first two in height (length, width and height are 2 meters, 1 meter and 1 meter respectively), and is equipped with a removable baffle, which is connected to the fixed shear box with a rotatable shaft. When it is rotated clockwise to a certain angle, it can simulate a slope model with an inclined angle. When the two shear boxes overlap, the baffle is removed, the shear force is applied, and the deep displacement can be monitored synchronously. The shear box is made of tempered glass, with marking points and scales on the outside for easy visual observation. The tempered glass is transparent, strong and safe. The bottom is a steel structure with a grille to increase friction. The types of shear boxes include standard and specially designed shear boxes. Special shaped shear boxes can be designed for special experimental requirements. The design and manufacturing quality directly affect the accuracy and reliability of the experimental results. Therefore, when designing and using shear boxes, it is necessary to strictly follow the experimental standards and operating procedures.

[0026] (2) The loading system consists of a vertical loading device and a cylinder to simulate the vertical stress that the soil is subjected to in actual engineering. It usually simulates the deadweight of the soil or external load by applying a certain pressure. The cylinder provides horizontal shear force, and an automated control module can be added later.

[0027] (3) The DIC monitoring system is connected to the computer via a network communication with a digital camera and a high-resolution motion camera, and uses professional software to process data. Modern cameras and image acquisition equipment have high parameters, which can meet the requirements of recording fast deformation processes and quickly calculate through professional software. DIC technology can measure the deformation and displacement field of the entire surface of an object, including deformation gradient, strain and other parameters, and can obtain rich test data.

[0028] (4) The data acquisition system consists of a laser displacement meter and a computer. The laser displacement meter has strong anti-interference ability, high precision, and is less affected in extreme environments. The working principle of the laser displacement meter is based on laser ranging technology. The laser transmitter emits a laser beam, which is reflected when it encounters the surface of an object. The reflected laser is captured by the receiver and converted into an electrical signal. By measuring the time difference or phase difference between laser emission and reception, the distance between the laser beam and the surface of the object can be calculated. The computer integrates and processes the data.

[0029] (5) The fixture consists of a steel structure bracket and a clip. The steel structure has good plasticity and can be processed and formed as needed to meet various design requirements. It has high strength and can play a good supporting role. The clip is made of plastic, which is light, corrosion-resistant, simple and easy to operate, and can be recycled, which greatly reduces the impact on the experimental results.

[0030] Embodiment 1:

[0031] Take the direct shear model experiment as an example.

[0032] The shear box is a key component in the direct shear model test device. Its design can simulate the shear state that the soil may encounter in actual conditions. The function of the shear box is to hold the soil sample and ensure a closed shear environment during the experiment. This device uses three shear boxes with buckles at the bottom. The plan view is as follows: Figure 2 As shown, two of the shear boxes are of the same size, and one is fixed by a fixing device, and the other can slide along the sliding groove under the influence of shear force to achieve the effect of simulating shear displacement of the slope. The size of the third shear box is different from the first two in height, and it is equipped with a removable baffle, which is connected to the fixed shear box with a rotatable shaft. When it is rotated clockwise to a certain angle, it can simulate a slope model with an inclined angle. When the two shear boxes overlap, the baffle is removed, and shear force is applied, and deep displacement can be monitored synchronously. The experimental process is as follows: prepare the soil sample, fill it evenly, and avoid being too dry or wet to meet the experimental requirements. Perform equipment calibration, adjust the three shear boxes to the angle that meets the experimental conditions, ensure that the DIC monitoring system, loading device and data acquisition system operate normally, and apply vertical pressure to the loading system to avoid uneven compaction of the soil sample, which affects the experimental results. The cylinder applies horizontal shear force, and the shear rate is constant. Pay attention to safety during the operation, and the operation is strictly carried out according to the experimental steps. To ensure the reliability of the experiment, multiple tests should be carried out, and the temperature and humidity of the experimental environment should be paid attention to to reduce the impact on the experimental results. Follow the above experimental steps and precautions to ensure the accuracy and reliability of the experiment, thereby providing valid data.

[0033] Embodiment 2:

[0034] Take the DIC monitoring system and laser displacement meter as an example.

[0035] The structure diagram of the DIC monitoring system designed in advance can be found in Figure 3 The system is connected to the computer via network communication by a digital camera and a high-resolution motion camera for data processing. DIC technology is an advanced non-contact full-field deformation measurement technology with the advantages of non-contact measurement, full-field measurement, high precision, high resolution, and wide application range. DIC achieves displacement and strain measurement through the following steps. The principle block diagram is as follows Figure 4 As shown in the figure, the equipment is debugged before the experiment, and the surface images of the slope soil deformation at the beginning and end are captured using a digital camera and a high-resolution motion camera. The captured images are preprocessed, such as denoising, enhancement, and classification, to improve the quality. Feature points are set and marked in advance before the experiment, and the corresponding positions of these feature points are found after deformation. The position change of the feature points before and after deformation is determined by correlation function calculation, and the displacement field and strain field of the entire test area are calculated based on the displacement of the feature points. The deformation of the test area can be monitored in real time through the DIC monitoring system, and the observation of dynamic processes can be realized. The fiber Bragg grating (FBG) is tested through a direct shear model device, and the DIC and fiber Bragg grating (FBG) strain measurement values ​​are compared and verified with each other. It can greatly improve efficiency.

[0036] It should be noted that a laser displacement meter is an instrument that uses laser technology to measure the distance or displacement between an object surface and a laser source, such as Figure 5 As shown in the figure, it is used to measure shear displacement. It is a tool that can measure without contacting the surface of the object. It has the advantages of high precision, real-time measurement and strong anti-interference performance. Its measurement principle is as follows Figure 6 As shown, it is often used in engineering applications to study the deformation behavior of materials under stress or temperature changes. Before use, it is necessary to calibrate to ensure measurement accuracy. At the same time, pay attention to the installation position of the laser displacement meter to avoid the installation position of the laser displacement meter affecting the experimental results.

[0037] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A direct shear model device for monitoring slope shear deformation, characterized in that: Includes shear box, loading system, DIC monitoring system, data acquisition system and fixture: Wherein, the shear box is used to simulate the shear state encountered by the soil in actual situations; The loading system is used to apply vertical stress and horizontal shear force; The DIC monitoring system is used to monitor and capture the dynamic process of subtle displacement changes in real time; The data acquisition system is used to measure shear displacement and perform data recording and analysis.

2. The direct shear model device for monitoring slope shear deformation according to claim 1, characterized in that: The device uses three shear boxes, two of which are of the same size, and one is fixed by a fixing device, and the other can slide along the sliding groove under the influence of shear force, so as to achieve the effect of simulating shear displacement of the slope; the size of the third shear box is different from the first two in height, and is equipped with a detachable baffle, which is connected to the fixed shear box with a rotatable shaft, and can simulate a slope model with an inclined angle when it is rotated clockwise to a certain angle. When the two shear boxes overlap, the baffle is removed, and the shear force is applied, so that the deep displacement can be monitored synchronously; The shear joints located at the top, bottom, left and right are used to simulate the shear movement of the soil sample along the joints during this process.

3. The direct shear model device for monitoring slope shear deformation according to claim 1, characterized in that: The loading system consists of a loading device and a cylinder: the loading device realizes the vertical stress in the actual process through external force, the pressure is controlled by the cylinder, and a pressure sensor is equipped to control the magnitude of the vertical stress; the cylinder at the shear box position is used to provide horizontal shear force to simulate the shear movement of the soil sample after the horizontal shear force is applied.

4. The direct shear model device for monitoring slope shear deformation according to claim 1, characterized in that: The DIC monitoring system is composed of a digital camera and a high-resolution motion camera connected to a computer via network communication and uses professional software for data processing. DIC technology is based on the principle of image correlation and can monitor in real time and capture the dynamic process of subtle displacement changes. It is suitable for non-contact measurement of strain and displacement of the entire experimental area.

5. The direct shear model device for monitoring slope shear deformation according to claim 1, characterized in that: The data acquisition system includes a laser displacement meter and a computer terminal: the laser displacement meter is used to measure shear displacement; the computer terminal integrates data recording and data analysis, and verifies the experimental results of the optical fiber sensor in the experimental process by analyzing and processing the data of DIC and laser displacement meter.

6. The direct shear model device for monitoring slope shear deformation according to claim 1, characterized in that: The fixing device is composed of a steel structure bracket and a buckle: the steel structure bracket is stable and strong and can play a supporting role; the buckle is placed at the bottom of the shear box and is used to fix the optical fiber used for testing to prevent other factors from interfering with the experimental results.

7. The direct shear model device for monitoring slope shear deformation according to claim 1, characterized in that: The device is used to conduct systematic and simulated experiments on the optical fiber sensor required to be tested. The slope model can be simulated by adjusting the inclination of the large shear box on the left. When the inclination is 90 degrees, the disassembly baffle is removed to simulate the shear force on the sensing optical fiber at different depths in a vertical state. When the middle shear box and the right shear box are spliced, a shear gap is left in the middle. By fixing the middle shear box, a horizontal shear force is applied to the right shear box through a cylinder to simulate the shear force on the optical fiber sensor in a horizontal state. The DIC monitoring system and data acquisition system process the collected data and compare the strain value measured by the fiber optic sensor with the shear displacement of the soil through conversion, further verifying that the fiber optic sensor under study can achieve the required accuracy and function.

Images