Device and method for testing seabed landslide triggered by earthquake based on large vibration table

Abstract

The invention provides a test device and a test method for earthquake-triggered submarine landslide based on a large-scale vibration table, the test device comprises a vibration table test module, a waterproof module and a data dynamic acquisition module, the waterproof module is arranged around the vibration table test module, and the data dynamic acquisition module is arranged in the vibration table test module. The vibration table test module comprises a test model box, a foam plastic board, a gravel friction boundary and a vibration table; the waterproof module comprises a waterproof plate and waterproof cloth; the data dynamic acquisition module comprises an acquisition instrument, an acceleration sensor, a soil pressure sensor, a pore water pressure sensor, a stay wire type displacement sensor, a high-speed camera and a supporting rod. Through cooperation of the vibration table test module, the waterproof module and the data dynamic acquisition module, a technical blank in the field of simulation of earthquake triggered submarine landslide by a large vibration table is filled up, and reproduction and simulation of submarine landslide slope dynamic response and instability deformation and damage processes under the action of earthquake can be realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of marine geological disaster prevention and mitigation, and particularly relates to a test device and test method for earthquake-triggered submarine landslide based on a large-scale shaking table. BACKGROUND

[0002] As a typical marine geological disaster, submarine landslide has been found in almost all marine basins in the world, and submarine landslide triggered by earthquakes has been common. Earthquake-triggered submarine landslide refers to the phenomenon that the submarine slope loses stability locally or extensively under the action of earthquake load and moves downward along a certain slope surface. Unlike landslides on land, submarine landslides have the characteristics of slow slope, large scale, fast speed, long migration path and complex evolution process. Once it occurs, it is likely to destroy submarine and marine engineering infrastructure, trigger local tsunami secondary disasters, and even threaten the safety of people along the coast.

[0003] Existing exploration data shows that the coastal areas of China are located at the junction of the Eurasian plate, the Indian Ocean plate and the Pacific plate, with complex geological structure, high frequency and intensity of seismic activity. With the advancement of major offshore projects in China, the demand for submarine slope stability evaluation is increasing, and the accuracy requirement is also increasing. Therefore, from the perspective of disaster-causing effects, the study of the stability of submarine slopes under the action of earthquakes has important guiding significance for avoiding such marine geological disasters in future marine engineering activities.

[0004] However, the current slope stability and disaster evaluation in China is mainly limited to landslides on land, and the stability evaluation of submarine slopes, especially under the action of earthquakes, is still in its infancy and is basically based on the understanding of landslides on land. One of the main reasons for the slow progress in the study of submarine landslide stability is that the current in-situ testing and geophysical technology cannot capture the whole process of submarine landslide with high precision and for a long time, which makes a large number of scholars choose to use indoor tests with high controllability and low cost to reproduce the process of submarine landslide. However, conventional water channel tests are mainly used for the stability of submarine landslides under the action of waves, supergravity centrifugal simulation tests mainly focus on the flow evolution process after the landslide loses stability, and shaking table tests, as a common method for studying earthquakes, are rarely used in submarine landslides.

[0005] Therefore, it is necessary to design a test device for earthquake-triggered submarine landslide based on a large-scale shaking table to capture the whole process of the change of internal physical quantities and external deformation of submarine slopes from response to failure under the action of earthquakes, so as to reveal the dynamic response characteristics and failure mechanism of submarine slopes under the action of earthquakes. SUMMARY

[0006] The first object of the present application is to provide a test device for triggering submarine landslide by earthquake based on a large shaking table in view of the above-mentioned problems.

[0007] To achieve the above object, the present application adopts the following technical solutions.

[0008] The test device for triggering submarine landslide by earthquake based on a large shaking table comprises a shaking table test module, a waterproof module and a data dynamic acquisition module, the waterproof module is arranged around the shaking table test module, and the data dynamic acquisition module is arranged in the shaking table test module.

[0009] The shaking table test module comprises a test model box, a foamed plastic plate and a gravel friction boundary, the test model box is arranged on the shaking table, thick organic glass is arranged on both sides of the test model box, the foamed plastic plate is arranged on the inner walls of the test model box, and the normal direction of the foamed plastic plate is parallel to the seismic motion input direction.

[0010] The waterproof module comprises a waterproof plate and a waterproof cloth, the waterproof plate is arranged on the side of the shaking table, and the waterproof cloth is arranged on the waterproof plate and the shaking table.

[0011] The data dynamic acquisition module comprises an acquisition instrument, an acceleration sensor, a soil pressure sensor, a pore water pressure sensor, a pull-wire type displacement sensor, a high-speed camera and a support rod, the acquisition instrument is connected with the sensors, and the support rod is arranged horizontally in the test model box.

[0012] In addition to the above technical solutions, the present application can also adopt or combine the following technical solutions.

[0013] As a preferred technical solution of the present application, the waterproof cloth is fixed by a G-shaped clamp.

[0014] As a preferred technical solution of the present application, the acceleration sensor is fixed on a wire mesh in advance.

[0015] As a preferred technical solution of the present application, the acceleration sensor, the soil pressure sensor and the pore water pressure sensor are fixed in the middle part of the support rod by inelastic fishing lines.

[0016] As a preferred technical solution of the present application, the pull-wire type displacement sensor is used in cooperation with a mass block, the mass block has a density similar to that of the submarine slope and is buried in the surface of the slope, and the pull wire of the pull-wire type displacement sensor is connected with the mass block.

[0017] As a preferred technical solution of the present application, the pull-wire type displacement sensor is fixed on the support rod by a G-shaped clamp.

[0018] As a preferred technical scheme of the present application, the high-speed camera is arranged outside the test model box and faces the test model box.

[0019] A second object of the present application is to provide a test method for triggering submarine landslides by earthquakes based on a large-scale shaking table.

[0020] To this end, the above object of the present application is achieved by the following technical scheme:

[0021] A test method for triggering submarine landslides by earthquakes based on a large-scale shaking table, which is based on the test device described above and comprises the following steps:

[0022] S1, soil sample pretreatment: the pretreatment methods of various types of soil samples include one or more of drying, crushing, sieving to remove impurities, and thorough mixing;

[0023] S2, test device performance detection and installation: install the waterproof module and the test model box to the shaking table surface, fill the empty box with water and apply seismic load to detect the airtightness of the test model box; all sensors in the data dynamic acquisition module need to be calibrated and zeroed, and connected to the acquisition instrument to detect whether they can be used normally;

[0024] S3, sensor embedding;

[0025] S4, submarine slope model making: when the slope soil sample is clay, the submarine slope model is made by on-site layer-by-layer ramming method. First, mix the soil sample with water according to the specified water content, and use the density control method to make the soil sample in layers. During the process, use a spatula to repeatedly cut until the shape meets the design. After the entire wet clay slope is formed in the air, slowly fill water from the slope foot through a water pipe with controllable flow rate until the specified water depth is reached, and wait for the slope to consolidate. When the slope is a sandy or silty slope, the submarine slope model is made by the sand rain method. The water surface height is always controlled to be 5 cm higher than the slope body. The relative density method is used to control the uniformity of the soil sample. After the soil body reaches the predetermined height, use a spatula to cut it to the shape that meets the design. After the model is formed, slowly fill water from the slope foot through a water pipe with controllable flow rate until the specified water depth is reached, and wait for the slope to consolidate.

[0026] S5, seismic motion input and result collection: during the test process, sensor data acquisition and high-speed camera PIV image acquisition are performed respectively, and appropriate sampling frequency is selected;

[0027] S6, model cleaning.

[0028] The application provides a test device and a test method for earthquake triggered submarine landslide based on a large vibration table, and has the following beneficial effects: the test device fills a technical blank in the field of physical simulation of marine geological disasters, especially in the field of large vibration table simulation of earthquake triggered submarine landslide, and can realize reproduction and simulation of dynamic response, instability deformation and destruction process of submarine landslide slope under the action of earthquake. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The application provides a test device for earthquake triggered submarine landslide based on a large vibration table.

[0030] Figure 2 The application provides a test device for earthquake triggered submarine landslide based on a large vibration table.

[0031] Figure 3a The application provides a test device for earthquake triggered submarine landslide based on a large vibration table.

[0032] Figure 3b The application provides a test device for earthquake triggered submarine landslide based on a large vibration table.

[0033] Figure 4a The application provides a test device for earthquake triggered submarine landslide based on a large vibration table.

[0034] Figure 4b The application provides a test device for earthquake triggered submarine landslide based on a large vibration table.

[0035] Figure 5 The application provides a test device and a test method for earthquake triggered submarine landslide based on a large vibration table, and has the following beneficial effects: the test device fills a technical blank in the field of physical simulation of marine geological disasters, especially in the field of large vibration table simulation of earthquake triggered submarine landslide, and can realize reproduction and simulation of dynamic response, instability deformation and destruction process of submarine landslide slope under the action of earthquake.

[0036] In the figure: 101-vibration table test module; 102-waterproof module; 103-data dynamic acquisition module; 101a-test model box; 101b-foamed plastic plate; 101c-gravel friction boundary; 101d-vibration table; 102a-waterproof plate; 102b-waterproof cloth; 102c-G clamp; 103a-acquisition instrument; 103b-acceleration sensor; 103c-soil pressure sensor; 103d-pore water pressure sensor; 103e-pull line type displacement sensor; 103f-high-speed camera; 103g-inelastic fishing line; 103h-brace rod; 103i-wire mesh; 103j-mass block; 201-sea bottom slope model; 202-water. DETAILED DESCRIPTION

[0037] The application will be further described in detail with reference to the drawings and specific examples.

[0038] As Figures 1-2, 3a, 3b, a large-scale shaking table based on the trigger of submarine landslide test device, including shaking table test module 101, waterproof module 102, data dynamic acquisition module 103, shaking table test module 101 is provided with waterproof module 102, shaking table test module 101 is provided with data dynamic acquisition module 103,

[0039] The shaking table test module 101 includes a test model box 101a, a foam plastic plate 101b, a gravel friction boundary 101c, and a shaking table 101d. The test model box 101a is provided on the shaking table 101d and fixed by bolts. The test model box 101a is made of thick organic glass on both sides to facilitate the monitoring of model deformation and dynamic response by the high-speed camera 103f. The foam plastic plate 101b is arranged on the inner walls of the test model box 101a, with the normal direction parallel to the seismic input direction, for reducing the reflection of seismic waves at the boundary. The test model box 101a is provided with a gravel friction boundary 101c at the bottom for increasing the friction of the box bottom.

[0040] The waterproof module 102 includes a waterproof plate 102a and a waterproof cloth 102b. The waterproof plate 102a is arranged on the lateral side of the shaking table 101d and connected with the shaking table 101d by bolts. The height of the waterproof plate 102a should not be too high to prevent obstructing the capture of model morphology by the high-speed camera 103f. The waterproof plate 102a and the shaking table 101d are both provided with waterproof cloth 102b, which can be made of PVC fish pond cloth to ensure waterproofness.

[0041] The data dynamic acquisition module 103 includes an acquisition instrument 103a, an acceleration sensor 103b, a soil pressure sensor 103c, a pore water pressure sensor 103d, a pull wire displacement sensor 103e, a high-speed camera 103f, and a support rod 103h. The acquisition instrument 103a is connected with the sensors and controls the data acquisition to be always with a certain frequency. The support rod 103h is horizontally arranged at a predetermined position in the test model box 101a.

[0042] The waterproof cloth 102b is fixed by a G-shaped clamp 102c to be fixed in the waterproof plate 102a.

[0043] The acceleration sensor 103b is fixed on the wire mesh 103i in advance to prevent tilting.

[0044] The acceleration sensor 103b, the soil pressure sensor 103c, and the pore water pressure sensor 103d are all fixed in the middle part of the support rod 103h by inelastic fishing line 103g.

[0045] The pull wire displacement sensor 103e is used in cooperation with a mass block 103j. The mass block 103j has a density similar to that of the submarine slope and is buried in the surface of the slope. The pull wire of the pull wire displacement sensor 103e is connected with the mass block 103j.

[0046] The tensioned displacement sensor 103e is fixed on the strut 103h by the G-shaped clamp 102c.

[0047] The high-speed camera 103f is arranged outside the test model box 101a and faces the test model box 101a.

[0048] Specifically, as shown in Figure 5 The test method for triggering submarine landslide by large-scale shaking table based on earthquake is implemented through the following steps:

[0049] S1, soil sample pretreatment: the pretreatment methods of various types of soil samples include one or more steps of drying, crushing, screening to remove impurities, and sufficient mixing;

[0050] Drying needs to be carried out by using an oven, which is to remove the original water content in the soil body, so as to facilitate the preparation of the subsequent slope and the control of water content;

[0051] Crushing is carried out by using a crusher, which is mainly aimed at the cohesive soil body with particle size far exceeding the real soil particle size;

[0052] Screening needs to be carried out by using a screen mesh that meets the test and soil particle size requirements, so as to remove impurities contained in the soil body;

[0053] Mixing needs to be carried out by using a mixer, and the soil body configuration and mixing with water need to be fully stirred in the mixer for about 2 hours

[0054] S2, performance detection and installation of test device: the waterproof module and the test model box need to be installed on the shaking table table first, the empty box is filled with water and the earthquake load is applied to detect the airtightness of the test model box; all the sensors in the data dynamic acquisition module need to be calibrated and zeroed, and connected with the acquisition instrument to detect whether they can be normally used, and only when the above two detection results are normal, the next operation can be carried out;

[0055] S3, sensor embedding: before the preparation of the submarine slope model, the acceleration sensor, soil pressure sensor and pore water pressure sensor are fixed in the specified position of the test model box, and are as far away from the boundary as possible to prevent the interference of boundary effect, after the preparation of the submarine slope model, the tensioned displacement sensor and the mass block are fixed at the specified position of the slope surface, during the model consolidation process, whether the submarine slope model is consolidated is confirmed by the embedded pore water pressure sensor, when the initial excess pore water pressure is completely dissipated, the model can start the subsequent shaking table test;

[0056] S4, preparation of submarine slope model: as Figure 4aAs shown, when the slope soil sample is clay, the seabed slope model is made by on-site layer-by-layer ramming method. The soil sample is mixed with water according to the specified water content, and the soil sample is made in layers by using the density control method. During the process, the spatula is repeatedly cut until the shape meets the design. After the entire wet clay slope is formed in the air, water is slowly injected from the slope foot through a water pipe with a controllable flow rate 202 until the specified water depth is reached, and the slope is allowed to consolidate. Figure 4b As shown, when the slope is a sand or silt slope, the seabed slope model is made by sand rain method. The water surface height is always controlled to be about 5 cm higher than the slope body. The soil sample is uniformly controlled by using the relative density method. After the soil body reaches the predetermined height, the spatula is cut until the shape meets the design. After the model is formed, water is slowly injected from the slope foot through a water pipe with a controllable flow rate 202 until the specified water depth is reached, and the slope is allowed to consolidate.

[0057] During the water injection process, a sponge can be placed in front of the water injection port to reduce the disturbance and erosion of the water flow on the model.

[0058] S5, seismic motion input and result collection: fix the high-speed camera at a position where the test process can be clearly captured, turn on the high-speed camera dedicated light source, confirm that the high-speed camera image is clear, input the seismic motion to the vibration table for testing, collect sensor data and high-speed camera PIV image during the test process, and select an appropriate sampling frequency.

[0059] S6, model cleaning: drain the water from the upper part of the slope model, observe and take pictures to record the shape change of the slope after the landslide body flows and the accumulation shape of the landslide soil body, then excavate the slope body, and if necessary, sample the relevant parts of the material for subsequent basic physical and mechanical property testing; finally, the slope body material is scooped out and washed with water to dry, and the next test is prepared.

[0060] The above specific embodiments are used to explain and illustrate the present application, and are only preferred embodiments of the present application, but not limit the present application. Any modification, equivalent replacement, improvement, etc. made to the present application within the spirit and protection scope of the claims falls within the protection scope of the present application.

Claims

1. A test device for triggering submarine landslides by earthquakes based on a large shaking table, characterized in that: Including vibration table test module (101), waterproof module (102), data dynamic acquisition module (103), the vibration table test module (101) is equipped with waterproof module (102) around, data dynamic acquisition module (103) is equipped with in the vibration table test module (101), The vibration table test module (101) includes test model box (101a), foam plastic plate (101b), gravel friction boundary (101c), vibration table (101d), the vibration table (101d) is equipped with test model box (101a), the test model box (101a) both sides are thick organic glass, the foam plastic plate (101b) is arranged in the inner wall both sides of test model box (101a), the normal direction is parallel to the ground motion input direction, the test model box (101a) bottom is equipped with gravel friction boundary (101c); The waterproof module (102) includes waterproof plate (102a) and waterproof cloth (102b), the vibration table (101d) is equipped with waterproof plate (102a) on the lateral side, and the waterproof plate (102a) and the vibration table (101d) are both equipped with waterproof cloth (102b); The data dynamic acquisition module (103) includes acquisition instrument (103a), acceleration sensor (103b), soil pressure sensor (103c), pore water pressure sensor (103d), pull wire type displacement sensor (103e), high-speed camera (103f) and support rod (103h), the acquisition instrument (103a) is connected with the sensor, and the support rod (103h) is transversely arranged in the test model box (101a).

2. The test apparatus for triggering submarine landslide by earthquake based on large-scale shaking table according to claim 1, characterized in that: The waterproof cloth (102b) is fixed by G-shaped clamp (102c).

3. The apparatus for testing the triggering of submarine landslides by earthquakes based on a large shaking table according to claim 1, characterized in that: The acceleration sensor (103b) is pre-fixed on the wire mesh (103i).

4. The apparatus for testing the triggering of submarine landslides by earthquakes based on a large shaking table according to claim 1, characterized in that: The acceleration sensor (103b), the soil pressure sensor (103c) and the pore water pressure sensor (103d) are all fixed in the middle part of the support rod (103h) through inelastic fishing line (103g).

5. The apparatus for testing the triggering of submarine landslides by earthquakes based on a large shaking table according to claim 1, characterized in that: The pull wire type displacement sensor (103e) is used in cooperation with the mass block (103j), the mass block (103j) is similar to the density of the submarine slope and is buried in the surface of the slope, and the pull wire of the pull wire type displacement sensor (103e) is connected with the mass block (103j).

6. The test apparatus for triggering submarine landslides by earthquakes based on a large shaking table according to claim 1 or 5, characterized in that: The pull wire type displacement sensor (103e) is fixed on the support rod (103h) through the G-shaped clamp (102c).

7. The apparatus for testing the triggering of submarine landslides by earthquakes based on a large shaking table according to claim 1, characterized in that: The high-speed camera (103f) is arranged outside the test model box (101a) and faces the test model box (101a).

8. A test method for triggering submarine landslides by earthquakes based on a large-scale shaking table, characterized in that: The method is based on the test device in any one of claims 1-7, and includes the following steps: S1, soil sample pretreatment: the pretreatment mode of various types of soil samples includes one or more steps of drying, crushing, screening and removing impurities, and thoroughly mixing; S2, test device performance detection and installation: install waterproof module and test model box to the vibration table surface, fill the empty box with water and apply seismic load to detect the airtightness of the test model box; all types of sensors in the data dynamic acquisition module need to be calibrated and zeroed, and connected with the acquisition instrument to detect whether they can be used normally; S3, sensor embedding; S4, seabed slope model making: when the slope soil sample is clay, the seabed slope model is made by on-site layer-by-layer ramming method. First, mix the soil sample with water according to the specified water content, and make the soil sample in layers by density control method. During the process, use a spatula to cut repeatedly until the shape meets the design. After the entire wet clay slope is formed in the air, slowly fill water from the slope foot through a water pipe with controllable flow rate until the specified water depth is reached, and wait for the slope to be consolidated. When the slope is sand or silt slope, the seabed slope model is made by sand rain method. The water surface height is always controlled to be higher than the slope body by 5 cm. The soil sample is controlled uniformly by relative density method. After the soil body reaches the predetermined height, use a spatula to cut until the shape meets the design. After the model is formed, slowly fill water from the slope foot through a water pipe with controllable flow rate until the specified water depth is reached, and wait for the slope to be consolidated; S5, seismic motion input and result collection: during the test, sensor data acquisition and high-speed camera PIV image acquisition are carried out respectively, and appropriate sampling frequency is selected; S6, model cleaning.

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