Probability Analysis For Stability Of Slope Based On Random Field

Owing to the mineral,structure,and state of slope are all different to space and time, it is very complex, heterogeneous phenomenon. The parameters such as cohesion,angle of internal friction and gravity all have a certain randomicity. So factor of safety based on that soil,load and calculated model are certainty can not quantitatively,objectively reflect the true safe degree of slope. Probability analysis for stability of slope investigate geote-engineering problems taking random event and random course as object. This offset the shortage of certain method in a large degree. This paper state basic theory and probability analysis for stability of slope, and discuss pretreatment and model-building of geote-engineering parameters. Based balance equation of transfer coefficient method that widely used in domestic, applying checking point method recommended by JCSS, establish probability analysis for stability of slope model. Basing on variability of geote-parameters, introducing random field to method of probability for analyzing the stability of slope, gain result are more conformity with reality, and it more perfect reliability theory and probability method. Correlation distance is a very important parameter that random field theory concretely apply to slope project, it reflect certain self-correlation of geote-parameters. Taking PinPinXiang tea limited company of FuDing as example, analyze the relation between destroy probability and safe factor calculated with fixed value. Destroy probability calculated with model of random variable deviate high clearly, and destroy probability calculated with model of random field decrease greatly. When adopt random field, destroy probability decrease following with decrease of variance reduction coefficient. Dependable index decrease when increase of variable coefficient of cohesion and angle of internal friction of slope. When variable coefficient of cohesion and angle of internal friction range from 0.1 to 0.3, dependable index decrease particularly, and dependable index is more sensitive to variable coefficient of angle of internal friction. Rock and soil is particular material, the parameters of it have certain cross-correlation, so analysis for stability of slope must considerate cross-correlation of parameters. When cross-correlation between cohesion and angle of internal friction is positive, dependable index decrease following with increase of cross-correlation, and when cross-correlation between cohesion and angle of internal friction is negative, dependable index increase following with increase of cross-correlation. Probability analysis for stability of actual slope, variance reduction coefficient may take 0.5, thinking cross-correlation of cohesion and angle of internal friction, destroy probability of slope is 6.06%. It corresponds to factor of safety is 1.017.