Evaluation Of Sensitivie Degree And Regression Analysis Of Instable Factors Of High Slope Of Loess Affected By Rainfall

Evaluation of high slope stability of loess is a major project research direction, the landslide which is caused by rain has the frequency high and the harm is quite big.The geological disasters for this have become attached great importance to the engineering problem,the loess area is even more. The rain is the main contributing factor among many affecting factors. Author selects the two forms of rainfall (almost the extreme of the loess region), range of values of Longxi loess is used to calculating parameter, and the stability of high loess slope is discussed in the paper.Using the Galerkin finite element method,author sloved saturated-unsaturated flow problem due to rainfall infiltration, and analyzed the rainfall infiltration seepage caused by the change with the help of MIDAS/GTS software. Analyzing effcts of the pore water pressure by saturated hydraulic conductivity and rainfall duration time caused and dicovering the rainfall infiltration law with the variation of saturated hydraulic. In this case, high slope stability of loess is analyzed with the Bishop method of slope stability analysis which considered the influence of pore water pressure and the rain. Author applys the simulation module of slope stability in the finite element analysis, obtained quantitatively the influence degree of rainfall intensity, rainfall duration time of soil slope stability;discussed the impact of the parameters to the safety factor.Based on the above work, using the distance analysis method,author improved evaluation of gray correlation analysis method and evaluated the sensitive degree of the instable factors on high slope stability of loess and taked into account nine major factors:severe natural,internal friction angle,cohesion, saturated permeability, volume moisture content; rainfall intensity, rainfall duration; slope height,slope angle. The results showed that:as the soil parameters, soil cohesion and internal friction angle is the biggest extent to the slope stability of loess and the weight is appropriate; rainfall intensity which caused the high unstability slope of loess is an important factor, the weight value is up to 11.3%;safety factor can be expressed as slope height and slope angle of the linear function, Fs=αβ+bh+c, where a, b,c are for the function of c,φ,γ,θ,ks,R,T. It can be seen that the high slope of loess upright limit height is 4.5m.