Characteristics and Inducing Mechanism of Typical Cutting Landslides under the Interaction of Earthquake and RainfallTaking Yunnan Yangbi Ms 6.4 Earthquake as an Example

Taking slopes along Dali–Yangbi–Yuner highway under construction as the research target, in response to the typical cut slope landslides caused by the 6.4 magnitude Yangbi earthquake in 2021, some methods such as electrical measurements and drones were used to conduct field investigation and test the characteristics of the cut slope landslide disasters. Based on the correlation between soil electrical parameters and damage factors established by indoor simulation experiments, the damage evolution law of cutting slopes was evaluated through relationship mapping, and the characteristics and inducing mechanism of typical cutting landslides caused by earthquakes were explored. The results show that slope excavation increases the risk of earthquake-induced landslides. Under the action of earthquakes, a through-going main crack forms at the top of the excavated surface of the road cut slope, with a maximum width and depth of 3−4 m. The degree of disaster caused by road cut landslides is influenced by seismic intensity and slope support. With the decrease of seismic intensity, the width and depth of cracks show a decrease trend. The increase of support measures can significantly reduce the risk of slope sliding. Under the influence of rainfall seepage, the soil damage degree of the earthquake damaged slope further increases along the depth direction of the crack. The damage factor in the trailing edge area is greater than 0.36, and the crack width rapidly increases from 2.9 m to 8.0 m. In summary, there is a positive correlation between insufficient support, seismic intensity, and the degree of slope damage, the unsupported slopes are significantly affected by earthquakes. There is a mutual promotion effect between earthquake and rainfall, and rainfall can greatly affect the stability of earthquake damaged slopes.