Potential impacts in soil slope of deformation and water content on elastic wave amplitude

Early warning during rainfall-induced landslides employs widely to save economic losses and casualties. Using elastic wave velocity for early warning benefits from the relationship between water content, shear deformation, and elastic wave velocity of unsaturated soil slope. Amplitude changes by means of the elastic wave in the soil can also reflect the physical properties. In this work, we proposed an idea to determine the impacts in the soil of water content and deformation on elastic wave amplitude to realize early warning. Model box tests were designed to study the action of one factor, volumetric water content, on the elastic wave amplitude. Slope model tests were aimed to consider the effects of volumetric water content and deformation on elastic wave amplitude during rainfall-induced landslides. The results show that the elastic wave amplitude non-linear decreased with the volumetric water content, which could be mutually verified from the data of the model box tests and the slope model tests. The deformation caused the wave amplitude to increase, and the range of the increase could reflect the range of the deformation. The statistical correlation coefficient quantified that the increase in wave amplitude was not directly related to the water content. The wave amplitude change can be represented more visibly by eliminating the residual after EMD decomposition, and it further verifies the above results. This work provides a new idea and a reliable basis for landslide prevention and mitigation and prediction.