A model test platform for debris flow microseismic monitoring

Abstract

A model test platform for debris flow microseismic monitoring, characterized in that it includes a structural part, a functional subsystem part, and a data processing part; the functional subsystem part is installed on the structural part, and the functional subsystem part is used to simulate the movement of debris flow and associated microseisms, and the data processing part analyzes and processes the monitoring data. Compared with the prior art, the present invention can perform high-precision synchronous observations on the movement characteristic parameters such as the flow configuration, accumulation form, and flow velocity during the movement of debris flow and microseismic parameters by means of microseismic monitoring and high-speed camera monitoring.

Description

Technical Field

[0001] The present invention relates to the field of engineering geology, and in particular to a model test system for microseismic monitoring of debris flow. Background Art

[0002] In recent years, affected by global climate change, large-scale landslides, debris flows and other catastrophic geological disasters have occurred frequently. Such large landslide-debris flow disasters pose a considerable threat to mountain residents. However, due to the characteristics of such disasters, such as unpredictability and great destructiveness, it is difficult to obtain complete and continuous data on their movement processes by traditional means, which restricts the scientific research on landslide-debris flow. However, during the movement process of landslide-debris flow, corresponding seismic wave signals will be generated and can be completely recorded by a seismic network within a certain range. It has become possible to study landslide-debris flow based on seismic network data. Seismic wave signals have the advantages of high time resolution and good continuity, and are gradually used by more and more researchers in the study of the movement process of landslide debris flow. However, due to the difficulty in obtaining the movement characteristic parameters of actual landslide events and the influence of the propagation path on the measured ground motion signals, the correlation between the dynamic characteristics of debris flow and the seismic wave signals triggered by it is still unclear, which greatly restricts the refined analysis of the measured debris flow ground motion signals. It is urgent to carry out relevant experimental studies to deeply reveal the internal relationship between the dynamic characteristics of debris flow and the seismic wave signals triggered by it. At present, the chute model test is the main test method for studying the movement and deposition process of debris flow, but it mainly focuses on the dynamic parameters of debris flow, such as particle flow velocity, flow configuration, etc. The microseismic monitoring method has not been effectively applied to such tests, and the relevant test and measurement systems are very scarce. Therefore, an effective test system is urgently needed to be developed.

[0003] The difficulties of such test systems are as follows:

[0004] (1) To achieve the free start-up of debris flow without interference, the baffle needs to be quickly withdrawn at the beginning of the test. How to improve the opening speed of the baffle and ensure the free start-up of debris flow without interference is the first difficulty of such test systems;

[0005] (2) After the baffle is opened at high speed, in order to avoid the baffle hitting other devices and damaging the test system, and at the same time avoid the baffle rebounding and affecting the start-up and flow state of the debris flow, how to brake and fix the baffle in time is the second difficulty of such test systems;

[0006] (3) The start-up and braking processes of the baffle will be accompanied by collisions and frictions, and the huge vibration signals generated by them will seriously affect the monitoring of the weak microseismic signals of the debris flow itself. How to eliminate the influence of such collisions and frictions on microseismic monitoring is the third key difficulty of such test systems;

[0007] When conducting full - process high - speed camera monitoring of model tests with larger sizes, the monitoring position of the high - speed camera is relatively far, resulting in higher lighting requirements. How to provide a high - brightness, uniform and non - stroboscopic lighting environment is the fourth difficulty of such test systems;

[0008] (5) Since the method of multi - source data monitoring using a micro - seismic monitoring system and a high - speed camera monitoring system is adopted, how to accurately synchronize the data of the two monitoring systems is the fifth difficulty of such test systems.

[0009] Therefore, there is an urgent need to invent a model test system for debris - flow micro - seismic monitoring to solve the above - mentioned difficult problems, reveal the whole - process dynamic characteristics of debris - flow and the laws of related micro - seismic signals, and provide a scientific basis for the theoretical research and disaster prevention of debris - flow. Summary of the Invention

[0010] Aiming at the deficiencies of existing research, the present invention provides a model test system for debris - flow micro - seismic monitoring, which realizes the correlation research of landslide - debris - flow seismic signals and their motion characteristics by performing high - precision synchronous observation on the motion characteristic parameters and micro - seismic parameters of debris - flow.

[0011] The technical solution of the present invention is as follows:

[0012] A model test platform for debris - flow micro - seismic monitoring, characterized in that it includes a structural part, a functional subsystem part, and a data processing part; the functional subsystem part is installed on the structural part, the functional subsystem part is used to simulate the movement of debris - flow and associated micro - seismic, and the data processing part analyzes and processes the monitoring data.

[0013] Compared with the prior art, the innovative points of the present invention:

[0014] (1) Different from traditional chute model tests, the present invention adopts synchronous joint monitoring of a high - speed camera monitoring system and a micro - seismic monitoring system, and can obtain a number of parameters of the whole process of landslide - debris - flow movement, including movement configuration, accumulation characteristics, dynamic characteristics, and corresponding seismic signal parameters, providing an indoor test method for the study of landslide - debris - flow seismic signals;

[0015] (2) The present invention adopts a detachable chute bottom plate and a chute support, and realizes the control of test variables simply and efficiently by replacing the bottom plate or the support;

[0016] (3) The present invention adopts a high - speed DC motor to increase the opening speed of the baffle, solving the problem of slow opening speed of the baffle;

[0017] (4) The present invention uses the method of driving the switch hammer to strike the limit switch by the baffle, effectively completing the braking and fixing of the baffle, protecting the baffle and other test devices, and ensuring the normal flow of the debris flow; (5) Different from the integral baffle used in traditional model experiments, the present invention adopts a test system with a separated chute and baffle. An independent aluminum alloy support system is used to install the baffle and control the motor, making it completely separated from the chute, avoiding the influence of the collision and friction during the starting and braking processes of the baffle on the microseismic signal of the granular flow, and solving this key problem. Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the overall chute and baffle system

[0019] Figure 2 It is a schematic diagram of the entire system structure

[0020] Figure 3 It is a schematic diagram of the chute model

[0021] Figure 4 It is a front view of the chute model

[0022] Figure 5 It is a schematic diagram of the baffle adjustment device

[0023] Figure 6 It is a detailed view of the baffle

[0024] Figure 7 It is a schematic circuit diagram of the control box

[0025] Figure 8 It is a schematic diagram of the synchronization of microseismic signals and high-speed camera data

[0026] Figure 9 shows a test case of acrylic material beads with a landslide inclination of 0°, a fluid mass of 600 g, and a particle size of 3.0 mm.

[0027] Figure 10 shows the microvibration signals recorded in the case.

[0028] Figure 11 shows the comparison of the seismic efficiency of acrylic material fluids with different particle sizes and the fitting results of the relationship between the particle size and seismic efficiency in acrylic material fluids.

[0029] Figure 12 shows the results of exploring the influence of fluid mass on the ratio of microvibration signal energy to maximum kinetic energy and conducting parallel tests with different fluid masses.

[0030] Notes on the labels in the figure:

[0031] 1 is the chute, 1-1 is the inner sample box, 1-2 is the chute side plate, and 1-3 is the chute bottom plate;

[0032] 2 is the stacking plate, 3 is the model base, and 4 is the chute bracket;

[0033] 5-1 is the baffle, 5-2 is the baffle adjustment frame, 5-2-1 is the adjustment frame cross beam, 5-2-2 is the adjustment screw, 5-2-3 is the fixator, 5-3 is the split bracket, 5-4 is the DC motor (the upper and lower long strip parts in the figure), 5-5 is the motor base (for fixing the motor), 5-6 is the coupling, 5-7 is the rotating shaft, 5-8 is the limit switch, 5-9 is the switch hammer, 5-10 is the control box, 5-10-1 is the power supply, 5-10-2 is the protection resistor, and 5-10-3 is the two-way switch;

[0034] 6-1 is the microseismic sensor, 6-2 is the constant current source, 6-3 is the signal acquisition instrument, and 6-4 is the first computer;

[0035] 7-1 is the side high-speed camera, 7-2 is the front high-speed camera, and 7-3 is the second computer;

[0036] 8 is the LED lighting system. Specific implementation mode

[0037] A model test platform for debris flow microseismic monitoring, characterized by comprising a structure part, a functional subsystem part, and a data processing part; the functional subsystem part is installed on the structure part, the functional subsystem part is used to simulate the movement of debris flow and associated microseisms, and the data processing part processes the monitoring data.

[0038] I. The structure part includes a test area and a support body

[0039] Among them, the test area includes the chute 1, the stacking plate 2, and the model base 3, where: the chute 1 includes an inner sample box 1-1, chute side plates 1-2, and a chute bottom plate 1-3, all made of transparent organic glass plates. Among them, the inner sample box 1-1 is adhesively fixed to the front ends of the two chute side plates 1-2 and is a starting storage device for granular materials; this model test platform includes multiple chute bottom plates 1-3, and the roughness of different chute bottom plates 1-3 is controlled by whether granular materials are pasted on their upper surfaces, and screw holes are also drilled at equal intervals below the chute bottom plates 1-3; the chute bottom plates 1-3 required for the test are connected to the chute side plates 1-2 with the inner sample box 1-1 installed to form the chute 1 model; the stacking plate 2, whose material is a transparent organic glass plate, has a rough stacking surface made by pasting granular materials on its upper surface;

[0040] Among them, the support body is a load-bearing structure, including the chute bracket 4 and the split bracket 5-3, which bear the load of the test area and the functional subsystem and provide an installation position. The chute bracket 4 is used to fix the chute 1 on the model base 3.

[0041] The two functional subsystem parts include a split baffle system, a microseismic monitoring system, a high-speed camera monitoring system, and an LED lighting system 8.

[0042] Among them, the split baffle system includes a transparent plexiglass baffle 5-1, a baffle adjusting frame 5-2, a motor base 5-5, a coupling 5-6, a rotating shaft 5-7, and an electrical part, which is integrally installed on the split bracket 5-3; the electrical part includes a DC motor 5-4, a limit switch 5-8, a switch hammer 5-9, and a control box 5-10; one end of the transparent plexiglass baffle 5-1 is fixed to the rotating shaft 5-7, and the rotating shaft 5-7 is fixed to the baffle adjusting frame 5-2; the baffle adjusting frame 5-2 is installed on the split bracket 5-3 to adjust the position of the transparent plexiglass baffle 5-1; the baffle adjusting frame 5-2 includes an adjusting frame cross beam 5-2-1, an adjusting screw 5-2-2, and a fixator 5-2-3. The fixator 5-2-3 is fixed to the upper part of the adjusting screw 5-2-2, with a total of two pairs, which are respectively installed on both sides of the split bracket 5-3; the lower parts of the adjusting screws 5-2-2 are respectively fixed to both ends of the adjusting frame cross beam 5-2-1.

[0043] The DC motor 5-4 is fixed to the adjusting frame cross beam 5-2-1 through the motor base 5-5 and is connected to one end of the rotating shaft 5-7 through the coupling 5-6. When the DC motor 5-4 is powered on, it drives the rotating shaft 5-7 to rotate.

[0044] The switch hammer 5-9 is welded to the rotating shaft 5-7, and the welding angle has been designed in advance. It rotates together with the rotating shaft. After the baffle rotates a certain angle away from the granular material to achieve the purpose of opening the door and releasing the particles, at this time, the switch hammer also just turns to the position of the limit switch 5-8. The impact force of the rotation of the switch hammer is large enough to disconnect the limit switch 5-8, achieving the effect of automatically stopping the motor.

[0045] The limit switch 5-8 is fixed at a suitable position on the baffle adjusting frame 5-2. This position only needs to ensure that when the switch hammer 5-9 touches the limit switch, the rotation angle of the baffle is greater than 90 degrees. At this time, the baffle has rotated out of the inside of the chute and will not affect the flow of particles in the chute. The switch hammer 5-9 is fixed to the rotating shaft 5-7 so that when the transparent plexiglass baffle 5-1 is fully opened, the switch hammer 5-9 can contact the limit switch 5-8, thereby automatically cutting off the power supply of the DC motor 5-4 and stopping its rotation.

[0046] The control box 5-10 is a two-way circuit control box, which includes a power supply 5-10-1, a protection resistor 5-10-2 and a two-way switch 5-10-3, and is connected to the DC motor 5-4 and the limit switch 5-8 according to the circuit schematic diagram to supply power to the DC motor 5-4 and control its rotation direction. When the two-way switch 5-10-3 is rotated forward, the DC motor 5-4 rotates forward, releasing granular materials, and automatically cuts off the power after the switch hammer 5-9 contacts the limit switch 5-8 to avoid equipment damage. After the test is completed, the two-way switch 5-10-3 is rotated in the reverse direction, and the DC motor 5-4 drives the transparent acrylic baffle 5-1 to rotate reversely, realizing the perfect fit of the transparent acrylic baffle 5-1 with the inner sample box.

[0047] The microseismic monitoring system includes microseismic sensors 6-1, connecting cables, a constant current source 6-2, a signal acquisition instrument 6-3, and a first computer 6-4. The microseismic sensors 6-1 are installed on the chute bottom plate, chute side plate and stacking plate 2 according to requirements. The sensor threads are fully screwed into the reserved screw holes to prevent signal abnormalities caused by loose sensor installation. The input port of the constant current source 6-2 is connected to the microseismic sensor 6-1 through a connecting cable, and the output port is connected to the signal acquisition instrument 6-3 through a connecting cable. The signal acquisition instrument 6-3 is connected to the first computer 6-4 through a USB cable, and the microseismic signals are recorded by the first computer 6-4.

[0048] The high-speed camera monitoring system includes a side high-speed camera 7-1, a front high-speed camera 7-2 and a second computer 7-3. The side high-speed camera 7-1 is fixed at a suitable distance from the side of the chute 1 model through a high-speed camera bracket to ensure that all contents of the chute 1 model can be monitored. The front high-speed camera 7-2 is fixed at a suitable position on the front of the chute 1 model through a camera bracket to ensure that the front conditions of the chute 1 and the stacking plate 2 can be monitored. The second computer 7-3 is connected to the two high-speed cameras through a USB cable to record the monitoring images.

[0049] In a further optimized solution, the high-speed camera monitoring system and the microseismic monitoring system should start monitoring synchronously. First, gently tap with a probe at a suitable position on the model base, and then rotate the control box switch to release the granular materials, which is convenient for time calibration of the microseismic signal data and the image monitoring data during the subsequent data processing.

[0050] The LED lighting system 8 is composed of multiple high-power non-flickering LED lights. Before the test starts, the LED lights are adjusted to evenly illuminate the chute 1 model, making the photos taken by the high-speed camera clear, ensuring that every granular material in the photos throughout the test is clearly distinguishable, which is convenient for subsequent image analysis.

[0051] III. Data processing part

[0052] The microseismic signal data and the high-speed camera data are synchronized by the probe tapping method. Before opening the two-way switch 5-10-3 to release the granular material, within the monitoring range of the high-speed camera, the model base 3 is tapped with a probe. Subsequently, the moment when the high-speed camera probe taps is synchronized with the moment when the microseismic signal shows obvious violent fluctuations, completing the data synchronization work. The probe should preferably be a metal rod with a fine end. The fine end of the metal rod facilitates accurately determining the time when the probe collides with the base from the image sequence captured by the high-speed camera. The high-signal-to-noise vibration wave generated by the rigid collision between the metal rod and the base is easily captured by the microseismic sensor, and the signal generation time can be accurately read from the waveform, facilitating the subsequent time synchronization of the two types of data.

[0053] The data processing part utilizes the recorded monitoring images and the recorded microseismic signals;

[0054] Multiple parameters of the entire process of landslide-debris flow movement can be obtained from the image sequence captured by the high-speed camera, including the movement configuration, accumulation characteristics, dynamic characteristics, and

[0055] The corresponding seismic signal parameters are obtained from the recorded microseismic signals;

[0056] Furthermore, the digital image correlation analysis method (Digital Image Correlation, abbreviated as DIC) is used to analyze the image sequence captured by the high-speed camera, and dynamic parameters such as the velocity field and displacement field of particle movement in the chute at any moment can be obtained. By comparing the image features at different time points, the movement configuration, accumulation characteristics, etc. of the particles in the chute during the flow process can be analyzed.

[0057] Furthermore, digital signal processing methods such as wavelet analysis and fast Fourier transform are used to analyze the microseismic signals, and signal parameters such as the amplitude, frequency, and power spectrum of the micro-vibration signals during the particle flow process can be obtained.

[0058] Specifically, screw holes are drilled at equal intervals on the side plates 1-2 of the chute to facilitate the subsequent installation of the microseismic sensor 6-1.

[0059] Specifically, on the upper surface of the accumulation plate 2, a rough accumulation surface is made by pasting granular materials, and screw holes are drilled at equal intervals in the lower part to facilitate the subsequent installation of the microseismic sensor 6-1.

[0060] Specifically, the model base 3 is a flat plate with a certain thickness, which is used to fix the accumulation plate 2 and the chute support 4. An empty groove is made in the middle of the base to facilitate the installation of the microseismic sensor 6-1.

[0061] Specifically, the chute support 4 is a multi-group L-shaped aluminum alloy support, which is used to fix the chute 1 on the model base 3. According to the angle of the chute 1 required for the model test, different sizes of chute supports 4 are used to fix the chute 1, thereby adjusting the chute 1 to the test angle.

[0062] Specifically, the separable support 5-3 is an aluminum alloy support, which is separably installed from the chute 1 to avoid partial collision with the chute 1 and affect the test data.

[0063] The working process is as follows:

[0064] After the test preparation work is completed, the high-speed camera monitoring system and the microseismic monitoring system are respectively turned on for monitoring. Since two different data acquisition systems are involved, there is a difference in the start and end times of the two types of data recorded at this time. The aforementioned probe tapping method needs to be used for time synchronization. After the probe taps, turn the control box switch forward. After the motor is powered on, it drives the baffle to rotate. When the baffle touches the limit switch, the motor stops rotating. While the baffle rotates and opens, the granular material in the inner sample box flows out along the chute. After the granular material is completely stationary, the monitoring ends and the data is saved. The data processing part is the platform software part, which analyzes and processes the monitored and saved data and outputs the experimental characteristic laws after analysis.

[0065] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0066] In the embodiment, the baffle 5-1 is made of transparent plexiglass.

[0067] As Figure 1 、 Figure 2 shown, a model test system for debris flow microseismic monitoring according to the present invention is characterized in that the system includes: a chute 1, a stacking plate 2, a model base 3, a chute support 4, a separable baffle system, a microseismic monitoring system, a high-speed camera monitoring system, and an LED lighting system 8, wherein:

[0068] As Figure 3 、 Figure 4 shown, the chute 1 includes an inner sample box 1-1, chute side plates 1-2, and a chute bottom plate 1-3. The inner sample box 1-1 is made of a 5-mm-thick transparent plexiglass plate. The chute side plates 1-2 and the chute bottom plate 1-3 are both made of 10-mm-thick transparent plexiglass plates. One end of the two chute side plates 1-2 is adhered to the inner sample box, and then the chute bottom plate 1-3 is fixed to it with screws to form the chute 1;

[0069] The model base 3 is a thick flat plate with a hollow groove in the middle. The chute 1 is fixed on the model base 3 through the chute support 4, and then the stacking plate 2 is closely attached to the end of the chute 1 and fixed on the model base 3;

[0070] As Figure 1As shown, assemble the separate bracket 5-3 with screws, adjust the bracket position to ensure that the bracket does not collide with the chute 1 model and does not block the side high-speed camera 7-1 from monitoring the chute 1, and install a plurality of microseismic sensors 6-1 at appropriate positions of the chute 1 model. During the installation process, ensure that the sensors are fully tightened to avoid affecting their monitoring effect;

[0071] like Figure 5 and Figure 6 As shown, the DC motor 5-4 is installed on the motor seat 5-5, the motor seat 5-5 is fixed on the adjustment frame beam 5-2-1, and then the coupling 5-6 and the rotating shaft 5-7 are installed in sequence; in this embodiment, the speed of the DC motor 5-4 is 400r / min, and the rated voltage is 24V, so as to reduce the influence of the baffle 5-1 on the movement of the granular material; then the switch hammer 5-9 is screwed into the rotating shaft 5-7 and fixed with a nut; the transparent organic glass baffle 5-1 is connected to the rotating shaft 5-7 through a screw rod, and also fixed with a nut , to ensure that the baffle 5-1 does not loosen during the rotation process; at the same time, a limit switch 5-8 is installed at a suitable position of the adjusting frame beam 5-2-1 to ensure that when the baffle 5-1 rotates to a preset rotation angle, the switch hammer 5-9 can touch the limit switch 5-8 to achieve power-off braking of the baffle; the adjusting frame beam 5-2-1 is connected to the fixer 5-2-3 through the adjusting screw 5-2-2, and the adjusting frame beam 5-2-1 and the fixer 5-2-3 are preliminarily fixed with nuts to prevent them from falling from the adjusting screw 5-2-2; then Figure 5 The baffle adjustment device shown spans across the separate bracket 5-3;

[0072] like Figure 7 As shown, according to the circuit schematic diagram of the control box 5-10, connect the power supply 5-10-1, the protection resistor 5-10-2, the bidirectional switch 5-10-3, the DC motor 5-4 and the limit switch 5-8 to complete the preliminary assembly of the model ( Figure 1 shown);

[0073] like Figure 1 As shown, after the initial assembly of the model is completed, the baffle 5-1 needs to be adjusted to a suitable position by adjusting the baffle adjustment frame 5-2. This suitable position needs to meet the following requirements: first, the baffle 5-1 can be rotated to completely fit with the internal sample box 1-1 to form an initial storage device for granular materials, and the granular materials cannot leak out; second, during the process of the baffle 5-1 rotating to "open the door", it does not collide or rub with the slide 1 to avoid vibration of the slide 1 and influence on the microseismic signal; after the adjustment is completed, the baffle adjustment frame 5-2 is fixed by the fixer 5-2-3 to prevent the baffle adjustment frame 5-2 from shaking during the rotation of the baffle 5-1;

[0074] like Figure 2As shown in the figure, after the baffle 5-1 is adjusted, the installed microseismic sensor 6-1 is connected to the constant current source 6-2, the constant current source 6-2 is connected to the signal collector 6-3, and the signal collector 6-3 is connected to the first computer 6-4 loaded with LabVIEW software through a USB cable. The microseismic signal is collected through the LabVIEW software. In this embodiment, the sampling frequency is 500000Hz. Then, the front high-speed camera 7-2 is placed at a suitable position in front of the model to ensure that the front of the chute 1 and the stacking plate 2 can be monitored. Then, the side high-speed camera 7-1 is placed at a suitable position on the side of the model, aligned with the chute 1, to ensure that the side of the chute 1 can be monitored, and it is connected to the second computer 7-3 installed with the acquisition software i-SPEED Software Suite 2.0 through a USB cable. The parameters of the high-speed camera are set through the software, and then the camera is focused. In this embodiment, the shooting frame rate is set to 500fps. After the monitoring instruments are set up, turn on the LED light 8, adjust the position and angle of the light, and evenly illuminate the chute 1 to avoid local reflection or darkness of the chute 1 caused by uneven illumination, so that the high-speed camera can clearly capture the movement process of each granular material from the side;

[0075] After the installation and adjustment of the model test system are completed, the test operation process is as follows:

[0076] First, reverse-rotate the two-way switch 5-10-3 of the control box to drive the baffle 5-1 to rotate reversely by the DC motor 5-4. At the same time, manually limit the rotation speed of the baffle 5-1 to prevent it from rotating too fast and colliding with the chute 1, damaging the chute 1 or the baffle 5-1. After the baffle 5-1 is completely attached to the inner sample box 1-1, close the two-way switch 5-10-3 to complete the "door closing" operation of the baffle 5-1;

[0077] Then pour the granular materials required for the test into the inner sample box 1-1 and level the surface to complete the sample loading operation;

[0078] Then check whether all instruments and software are working properly. After the inspection, the high-speed camera monitoring system and the microseismic monitoring system are started synchronously for monitoring. At the position where the high-speed camera 7-1 can capture on the model base 3, gently tap with a probe, and after a short delay (about 1S), rotate the two-way switch 5-10-3 forward to perform the "door opening" operation, release the granular materials, and close the two-way switch 5-10-3 after the "door opening" is completed; after the movement of the granular materials is completed, stop the monitoring and save the test data;

[0079] After the above single group test is completed, the granular materials on the chute 1 and the stacking plate 2 are cleaned, and the test variables such as the mass, particle size, and gradation of the granular materials are changed, and the next group of tests are continued according to the above steps; if the angle of the chute 1 needs to be changed, the chute bracket 4 needs to be disassembled and replaced, and after the chute 1 is adjusted to the target angle, the separate baffle system is adjusted according to the above operation again, and then the test is continued according to the test operation process;

[0080] like Figure 8 As shown in the figure, after the test, the moment when the probe touched the model base 3 recorded by the high-speed camera was synchronized with the moment when the microseismic signal began to fluctuate significantly. For example, in this case, the 830th photo taken by the high-speed camera (when the probe touched the base) was synchronized with the 468735th data point of the microseismic signal (the starting point of the sudden increase in signal amplitude), and data can be intercepted from the above recording points as valid data, thereby achieving time calibration and synchronization of the two types of data, which is convenient for subsequent data analysis of the particle motion parameters monitored by the high-speed camera and the signal parameters monitored by the microseismic monitoring.

[0081] The data analysis process of the present invention is described below by taking the mutual transformation law of kinetic energy, potential energy and microseismic energy of the particle system during particle flow as an example:

[0082] For example, Figure 9 This is a test case of acrylic beads with a landslide inclination of 0°, a fluid mass of 600 g, and a particle size of 3.0 mm. The lateral velocity field distribution was obtained by DIC analysis. The direction of the green arrow indicates the direction of movement of the particles in the area, and the length of the green line segment and the size of the arrow are linearly related to the size of its displacement. The longer the green line segment and the longer the arrow, the greater the displacement of the granular material in the area, and the greater its movement speed. According to formula (1), the kinetic energy of each pixel in the fluid captured by the high-speed camera is first solved, and then the kinetic energy of the entire fluid is calculated according to formula (2). Furthermore, the kinetic energy change of the entire fluid flow process can be analyzed according to the real-time position and velocity of the granular material during the flow of granular material at different times.

[0083]

[0084] Furthermore, the coordinates corresponding to each pixel in the fluid contour can be obtained through DIC calculation, and the gravitational potential energy of each pixel can be obtained according to formula (3).

[0085]

[0086] Where g = 9.8 m / s 2 , m is the mass, and h is the height relative to the reference point.

[0087] Finally, according to the correspondence between the pixel points and the true distance, and through summation calculation, the gravitational potential energy of the entire fluid can be obtained according to formula (4).

[0088]

[0089] Since the particulate matter flows from top to bottom in the vertical direction during the flow process, assuming that the initial time is t0, the change in gravitational potential energy from time t0 to time t is defined as:

[0090]

[0091] Figure 10 This is the micro-vibration signal recorded in this case. The energy of the micro-vibration signal comes from a part of the reduction in the gravitational potential energy of the fluid. As the energy conversion between dynamics and seismology, it plays a very important role. At the same time, the energy of the micro-vibration signal can be calculated according to formula (6).

[0092] (6)

[0093] In the formula, W el is the seismic energy, with the unit of J; ρ p is the density of the bottom plate, with the unit of kg / m 3 , τ is the energy dissipation characteristic value of the bottom plate, which is 0.01 s, and u z (t) is the moving speed of the bottom plate at time t, with the unit of m / s. Therefore, the energy of the micro-vibration signal under different working conditions can be calculated and analyzed through formula (6).

[0094] Define the seismic efficiency E f as the ratio of the energy of the micro-vibration signal to the reduction in the gravitational potential energy of the fluid during the flow process, that is, the proportion of the change in gravitational potential energy that is converted into seismic energy. When E f is larger, it indicates that a larger proportion of the reduction in gravitational potential energy is converted into seismic energy. Compare the seismic efficiencies of acrylic material fluids with different particle sizes, and fit the relationship between the particle size and the seismic efficiency in the acrylic material fluid. The results are as Figure 11 shown.

[0095] Define the ratio of the energy of the micro-vibration signal to the maximum kinetic energy of the fluid as E a =W el / max E k , to explore the influence of the fluid mass on the ratio of the energy of the micro-vibration signal to the maximum kinetic energy, parallel tests with different fluid masses are carried out. The results are as Figure 12As shown, when the fluid mass increases, the ratio of the energy of its micro-vibration signal to the maximum kinetic energy of the fluid decreases. The above highly regular results indicate that during the actual engineering application process, it is expected to indirectly invert the movement characteristics of debris flows by monitoring on-site seismic information through the test platform of the present invention, and this technology is of great significance for engineering disaster prevention and mitigation research.

Claims

1. A model test platform for debris flow microseismic monitoring, characterized in that, It includes a structural part, a functional subsystem part, and a data processing part; the functional subsystem part is installed on the structural part, and the functional subsystem part is used to simulate debris flow movement and associated microseismicity, and the data processing part analyzes and processes the monitoring data; The functional subsystem part includes a split baffle system, a microseismic monitoring system, a high-speed camera monitoring system, and an LED lighting system (8). With the help of microseismic monitoring and high-speed camera monitoring, the data processing part can then perform high-precision synchronous observation and analysis of the movement characteristic parameters such as the flow configuration, accumulation form, and flow velocity of the debris flow during movement, as well as microseismic parameters; The split baffle system includes a transparent plexiglass baffle (5-1), a baffle adjustment frame (5-2), a motor base (5-5), a coupling (5-6), a rotating shaft (5-7), and an electrical part, which is integrally installed on a split support (5-3); the electrical part includes a DC motor (5-4), a limit switch (5-8), a switch hammer (5-9), and a control box (5-10); one end of the transparent plexiglass baffle (5-1) is fixed to the rotating shaft (5-7), and the rotating shaft (5-7) is fixed to the baffle adjustment frame (5-2); the baffle adjustment frame (5-2) is installed on the split support (5-3) to adjust the position of the transparent plexiglass baffle (5-1); the baffle adjustment frame (5-2) includes an adjustment frame cross beam (5-2-1), an adjustment screw (5-2-2), and a fixator (5-2-3). The fixator (5-2-3) is fixed to the upper part of the adjustment screw (5-2-2), with a total of two pairs, which are respectively installed on both sides of the split support (5-3); the lower parts of the adjustment screws (5-2-2) are respectively fixed to both ends of the adjustment frame cross beam (5-2-1); The DC motor (5-4) is fixed to the adjustment frame cross beam (5-2-1) through the motor base (5-5) and is connected to one end of the rotating shaft (5-7) through the coupling (5-6). When the DC motor (5-4) is powered on, it drives the rotating shaft (5-7) to rotate; The switch hammer (5-9) is welded to the rotating shaft (5-7), and the welding angle has been designed in advance. It rotates with the rotating shaft. After the baffle rotates a certain angle with the rotating shaft to separate from the granular material and achieves the purpose of opening the door to release the particles, at this time, the switch hammer also just turns to the position of the limit switch (5-8). The impact force of the rotation of the switch hammer is large enough to disconnect the limit switch (5-8), achieving the effect of automatically stopping the motor; A probe is used for synchronous operation; The probe uses a metal rod with a fine end; The microseismic signal data and the high-speed camera data are synchronized by the method of probe tapping. Before opening the two-way switch (5-10-3) to release the granular material, within the monitoring range of the high-speed camera, use the probe to tap the model base (3). Subsequently, synchronize the moment when the high-speed camera probe taps with the moment when the microseismic signal shows a significant violent fluctuation to complete the data synchronization work; The data processing part includes: Through a fine probe, accurately determine the time when the probe collides with the base from the image sequence captured by the high-speed camera; the high-signal-to-noise vibration wave generated by the rigid collision of the metal rod and the base is captured by the microseismic sensor, and the signal generation time is accurately read from the waveform to synchronize the time of the two types of data. For the time calibration and synchronization of the two types of data, perform data analysis on the particle motion parameters monitored by the high-speed camera and the signal parameters monitored by microseismic monitoring. Multiple parameters of the entire process of landslide-debris flow movement can be obtained from the image sequence captured by the high-speed camera. By comparing the image features at different time points, analyze the motion configuration and accumulation characteristics of the particles in the chute during the flow process; finally, output the phenomena and characteristic laws as the research result platform.

2. The test platform according to claim 1, characterized in that, The structural part includes a test area and a support body: Among them, the test area includes a chute (1), a stacking plate (2), and a model base (3), where: the chute (1) includes an inner sample box (1-1), chute side plates (1-2), and a chute bottom plate (1-3), all made of transparent organic glass plates. The inner sample box (1-1) is adhesively fixed to the front ends of the two chute side plates (1-2) and is the starting storage device for granular materials; connect the required chute bottom plate (1-3) with the chute side plates (1-2) with the inner sample box (1-1) installed to form the chute (1) model; the stacking plate (2) is made of transparent organic glass plate, and its upper surface is pasted with granular materials to form a rough stacking surface. Among them, the support body is a load-bearing structure, including a chute support (4) and a split support (5-3), which bear the weight of the test area and functional subsystems and provide installation positions; the chute support (4) is used to fix the chute (1) on the model base (3).

3. The test platform according to claim 1, characterized in that, The control box (5-10) is a two-way circuit control box, including a power supply (5-10-1), a protection resistor (5-10-2), and a two-way switch (5-10-3), and is connected to the DC motor (5-4) and the limit switch (5-8) according to the circuit schematic diagram to supply power to the DC motor (5-4) and control its rotation direction. When the two-way switch (5-10-3) rotates forward, the DC motor (5-4) rotates forward, releasing the granular material, and automatically cuts off the power after the switch hammer (5-9) touches the limit switch (5-8); when the test is completed, rotate the two-way switch (5-10-3) in reverse, and the DC motor (5-4) drives the transparent organic glass baffle (5-1) to rotate reversely, realizing the complete fitting of the transparent organic glass baffle (5-1) with the inner sample box.

4. The test platform according to claim 1, characterized in that, The microseismic monitoring system includes a microseismic sensor (6-1), a connecting cable, a constant current source (6-2), a signal acquisition instrument (6-3), and a first computer (6-4); the input port of the constant current source (6-2) is connected to the microseismic sensor (6-1) through a connecting cable, and the output port is connected to the signal acquisition instrument (6-3) through a connecting cable; the signal acquisition instrument (6-3) is connected to the first computer (6-4) through a USB cable, and the microseismic signal is recorded by the first computer (6-4).

5. The test platform according to claim 1, characterized in that, The high-speed camera monitoring system includes a side high-speed camera (7-1), a front high-speed camera (7-2), and a second computer (7-3). The side high-speed camera (7-1) is fixed to the side of the chute (1) model through a high-speed camera bracket to ensure that all contents of the chute (1) model are monitored. The front high-speed camera (7-2) is fixed to the front of the chute (1) model through a camera bracket. The second computer (7-3) is connected to the two high-speed cameras to record the monitored images.

6. The test platform according to claim 2 or 3, characterized in that, The model test platform includes multiple chute bottom plates (1-3). The roughness of different chute bottom plates (1-3) is controlled by whether granular materials are pasted on their upper surfaces, and screw holes are also drilled at intervals below the chute bottom plates (1-3). Screw holes are drilled at intervals on the chute side plates (1-2) to facilitate the subsequent installation of microseismic sensors (6-1). The microseismic sensors (6-1) are installed on the chute bottom plate, chute side plates, and stacking plate (2) according to requirements. The threads of the sensors are fully screwed into the reserved screw holes to prevent signal abnormalities caused by loose installation of the sensors. The upper surface of the stacking plate (2) is pasted with granular materials to form a rough stacking surface, and screw holes are drilled at intervals below to facilitate the subsequent installation of microseismic sensors (6-1). The model base (3) is a flat plate with a certain thickness, used to fix the stacking plate (2) and the chute bracket (4). An empty groove is made in the middle of the base to facilitate the installation of microseismic sensors (6-1). The chute brackets (4) are multiple groups of L-shaped aluminum alloy brackets, used to fix the chute (1) to the model base (3). According to the angle of the chute (1) required for the model test, different sizes of chute brackets (4) are used to fix the chute (1), so as to adjust the chute (1) to the test angle. The split bracket (5-3) is an aluminum alloy bracket, which is installed in a split manner with the chute (1) to avoid affecting the test data due to partial collision with the chute (1).

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