| Rainfall is one of the most important factors leading to the occurrence of landslides.In order to reduce the loss of in order to reduce losses,it is necessary to prevent and control rainfall-induced landslides.The landslide monitoring method based on elastic wave can greatly improve the reliability of landslide monitoring and provide a new research direction for landslide disaster prevention and mitigation.Although domestic and foreign scholars have carried out a lot of studies on the relationship between elastic wave and soil moisture content,deformation,there is still a lack of research on the influence of sensor arrangement,rainfall intensity and soil bedding structure on elastic wave velocity,and the response law of elastic wave under corresponding conditions still needs to be further clarified.In view of the above problems,this paper first briefly describes the damage mechanism,prevention and treatment method and test method of rainfall landslide.Then analyzes the research background,current status and significance of elastic wave in the slope to destroy early warning,and measure the physical mechanics indicators of test materials according to geotechnical test standards.Finally by use of a test system model of box foundation tests respectively,and two types of slope model test,the test results are as follows:(1)Through model box foundation bedding structure,experimental study on soil water content and the influence of elastic wave propagation distance on wave velocity.The results show that the elastic wave propagation velocity in tight soil is faster than that in loose soil,and the higher the density,the faster the wave velocity is.The higher density of soil at transmitting end,the faster the elastic wave velocity measured by the receiver nearest to the wave source.The change of soil density at transmitting end of elastic wave has a greater effect on wave velocity than that at receiving end.The increase of elastic wave distance will accelerate energy loss.It is recommended that the distance between elastic wave generator and receiver should not exceed 50 cm.(2)The failure process and elastic wave response law of the slope under rainfall were studied through homogeneous model test of slope.The results showed that slope experienced five stages during rainfall,including water accumulation and erosion at the toe,microcrack development in middle,tensile crack failure in upper part,and overall collapse.Although soil moisture content can reduce the elastic wave velocity,this effect is not obvious for the sudden drop of wave velocity caused by slope deformation and failure.(3)Three groups of heterogeneous slope model tests were used to analyze water content,wave velocity,failure mode and failure degree of slope during test process.It was found that the failure range and type of slope caused by rainfall were uncertain,and the continuous runoff would have an important impact on the stability of slope.The failure degree of slope varies with compaction degree of soil at the base slope,but the overall change trend with time is same.According to the laws of the elastic wave response curve,the current test under the condition of rainfall induce slope failure of elastic wave warning threshold.This means that if the elastic wave speed to reduce the rate of more than 8.5%,so will be released to the public in advance warning information. |
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