Study Of Rainfall Infiltration And Its Effect On Stability Of Mawancun Landslide

It is prone to landslides,mudslides and other geological disasters owing to the typical loess hilly terrain,lower vegetation plant coverage,seriously weathering surfaces of the work area,and the rainfall is the key influence factor that induces geological disasters in the loess area.Based on the typical geological disaster in loess hilly area,the thesis studies the effect of rainfall on the landslide stability in working area,and its main research contents and achievements as follow:(1)Selecting five influence factors—the stratum lithology,the role of water,the direction of slope,relief,topography,this thesis uses GIS method of contribution weighting to divide the geological hazard susceptibility area into five grades: high susceptibility area,relatively high susceptibility area,middle susceptibility area,relatively low susceptibility area and low susceptibility area,and the areas with high and relatively high susceptibility taking up in total are about 69.80% of the entire area(2)Considering dynamic rainfall factor,the thesis evaluates the Ma Wancun landslide stability under 0~5mm/d?5~20mm/d?20~35mm/d?>35mm/d rainfall conditions by the half-quantitative method—the fuzzy comprehensive evaluation built on AHP.The result reveals that the stability of the Ma Wancun landslide corresponds different rainfall conditions.(3)The quantitative software Seep/w is used to simulate the changing mechanism of the volume moisture content and pore water pressure of unsaturated loess landslide under different rainfall intensity and rainfall duration.Combining the pore water pressure with Slope/w the software solves the safety factor of the landslide by Bishop method.The computed result shows that with 35 mm/d rainfall intensity the rainfall duration 48 h is the losing stability threshold of the Ma Wancun unsaturated loess landslide.