Study on the Attenuation Mechanism of Unsaturated Residual Soil Under Rainfall Condition -A Case Study of the Tiller and Sediment Soil in Qishan Landslide, China

In the most area of the Southern part in China, the high-intensity and large-scale rainfalls would easily cause some natural disasters like landslide and mud slide in the area of which the geological conditions are not stable and could lead to mass casualty and a great loss in economy. The paper targets the tuff residual soil in Qishan, Yongtai city, Fujian Province of China as the investigated subject, getting the mineral composition of the soil mass through X-ray experiment, analyzing the micro structure and mineral compositions in soil mass in qualitative, getting the parameters of shear strength of the soil mass by taking quadruple shear test to the soil samples which were in different level of water content and wet-dry cycle times, making analysis to the micro structure of test samples by using electrical scanning, and using the Matlab software to make calculation about the micro-structural parameters to analyze it in quantitative and forming the fitting relations among water content, wet-dry cycle times, vertical load and micro-structural parameters of soil mass so that the intensity attenuation mechanism of the unsaturated residual soil under the condition of rainfall would be revealed.