Research On Stability Of Loose Deposit Slope Influenced By Earthquake And Rainfall

Landslide is a kind of relatively common geological disasters. Landslide is generally caused by many factors, including human activities, earthquake and rainfall,etc.Parts of southwestern China belong to the earthquake-prone area lying on the Mediterranean-Himalayan seismic belt.Earthquake tend to induce slope instability,bringing great damage to the lives and properties of human beings. Due to the unsuitable climate, It has greater and longer rainfall over the area of Southwest China.Statistics suggest that the probability of landslide is large under the condition of rainfall.Therefore,it has great value in academic research and engineering practice to have a excellent study on the influence mechanism to slope stability under earthquake and rainfall conditions.Loose deposit slopes are widely distributed over the area of Southwest of China.This type slope consists of a kind of special geological body that its material is between rock and soil with transitional properties. Plenty of Zhao Qiao secondary road slopes belong to this kind with large size, loose construction and high-permeability.Thus these slopes are accessible to buckling failure because of its particularity under conditions of earthquake and rainfall.The thesis is based on the typical landslide of a secondary road named Zhao Qiao.The model is built for in-depth analysis by means of the numerical simulation software Geo-Studio.A series of negative effects can be produced by increasing seismic accelerations and varied rainfalls.The analysis has given concern on the effects that can do harm on the slope stability.Some acknowledgements and conclusions are summarized as follows:① It is found that earthquake and rainfall can influence the distribution of stress,displacement and shear strain through a generalized analysis for mechanical responses of the slope to some extent. The extreme value of these responding parameters can be changed under conditions of earthquake and rainfall while the safety factor is decreasing. Thus the slope has a potential trend of collapse.② The seismic changing accelerations may have a great influence on the horizontal stress. A plastic stress distortion belt with developed plasticity can be produced near the boundary line between bedrock and loose accumulation body,implying that the area near the boundary line may be the most weak part of the wholeslope coupled with stress concentration.③ It is found that the saturation line tend to move from the foot part towards the inner part under conditions of varied rainfalls. And it is proved that as rainfall intensity gets larger, the elevation of every saturation line becomes higher, thus the slope is more unstable.This viewpoint is obtained by contrasting different varied rainfalls.④ Considering the analysis for max shear strain of the slope under conditions of earthquake and rainfall, it is easily to catch sight of a obvious belt-shaped area, which is very sensitive to outer conditions such as earthquake and rainfall. Therefore, the belt-shaped area plays an import role in the field of analysis in slope stability.Results of this thesis provide a amount of reference value which is fairly useful in analyzing the slope stability under conditions of earthquake and rainfall.This thesis raises some reliable suggestions as to how to design, construct and control the slope more effectively under conditions of frequent earthquake and heavy rainfall.