Research On The Mechanism Of Shallow Sliding Of Xiashu Soil Slope Under The Condition Of Wetting-drying Cycles

Xiashu soil as a special aeolian sedimentary soil,is widely distributed in low mountains,hills and other geomorphic units in Ningzhen area.In the rainy season every year,the Ningzhen area is the most frequent area of landslides in Jiangsu Province,which seriously affects the lives and property safety of residents,factory workers and tourists around the landslide.This is closely related to the widely distributed Xiashu soil slopes in the area.In order to accurately and reasonably evaluate the stability of the Xiashu soil slope under the action of rainfall,its shallow sliding mechanism is a key scientific problem,and there is still a lack of systematic research on such problems.This paper takes Xiashu soil of a slope in Zhenjiang as the research object,studies the mechanical properties of Xiashu soil under different wetting-drying cycles,moisture content and suction through unsaturated direct shear and circular shear tests,and obtains the strength parameters of Xiashu soil under wetting-drying cycles.On this basis,the stability evaluation method of Xiashu soil slope under the condition of wetting-drying cycle is constructed.The stability change rule of Xiashu soil slope under different wetting-drying cycle times,influence depth of wetting-drying cycle,slope height and slope rate is carried out by using Geo Studio software,and then the mechanism of shallow sliding is revealed.The main research results are as follows:(1)Under the condition of certain moisture content,suction can improve the mechanical properties of Xiashu soil;under the condition of different moisture content,suction has different influence on the strength parameters of Xiashu soil,and the cohesion of Xiashu soil is more affected by suction than by internal friction angle.(2)Under the action of wetting-drying cycle,Xiashu soil has cracks on its surface,and with the increase of the number of wetting-drying cycles,the cracks continue to develop;under the combined action of wetting-drying cycle and suction,the change of the mechanical characteristics of Xiashu soil is larger,Different mechanical parameters show different changing rules.(3)With the increase of the number of wetting-drying cycles,the peak strength and residual strength of Xiashu soil show a downward trend,and the corresponding strength parameters also show a downward trend;with the increase of water content,the peak strength and residual strength of Xiashu soil show a downward trend in varying degrees.(4)The influence depth of the wetting-drying cycle has an important influence on the stability of the Xiashu soil slope;at a higher influence depth of the wetting-drying cycle,the Xiashu soil slope exhibits shallow sliding characteristics;The stability of Xiashu soil slope gradually decreases with the increase of the number of wetting-drying cycles.With the same number of wetting-drying cycles and the influence depth of the wetting-drying cycles,the safety factor of the Xiashu soil slope decreases with the increase of the height of the slope;with the increase of the slope rate of Xiashu soil slope,the safety factor of Xiashu soil slope decreases gradually.