Study On Three-dimensional Reliability Analysis Of Long Soil Slope Based On Random Field Theory

The main problem in the slope engineering design is that a great deal ofuncertainties exists in the soil parameters. Even within nominally homogeneous soillayers, engineering soil properties may exhibit considerable variation from point topoint. For the uncertainty of the soil properties, the reliability theory is more scientificthan the traditional determination method. The two-dimensional limit equilibriummethod is usually applied to calculate the reliability of a typical cross section for thelonglinear earth slopes associated with embankments, dams or levees in practicalengineering, which ignores the influence of the end effect and the length of slope onthe reliability of the whole slope, obviously does not accord with the actualthree-dimensional (3-D) slope instability.According to the above problems, a simple and effective method based on thereliability theory and the random field theory is proposed to analysis the3-D reliabilityof long soil slope in this paper. And the procedure based on the simple Bishop methodis wrote by MATLAB software to assess the two-and three-dimensional risk of slopeinstability. According to the results computed by the procedure, the relationshipbetween3-D reliability and coefficient of variation of soil properties, horizontalcorrelation distances, critical width of the failure zoneand the total length of slopeispresented.The main conclusions of this paper can be summarized as follows: the safetyfactor of slope obtained by3-D method is larger than that obtained by2-D method.3-Dreliability index is significantly greater than the2-D reliability index, and the reliabilityindex will decrease when thecoefficient of variation of the cohesive force and internalfriction angle increases. The relationship between3-D reliability index and the widthof landslide is concave curve when the horizontal correlation distance is fixed, namelyexist a most likely width which makes the3-D reliability index minimum.The systemfailure risk of the slope approximately linearlyincreases as the total length of slopeincreases when the critical width of the failure zone is fixed.