Comparative study of stochastic slope stability analysis based on conditional and unconditional random field

In this study, by coupling the conditional and unconditional random field with finite element methods, the stability of a real slope is investigated. In the first method, which is used for the case of an Unconditional Random Field (URF), the analysis is carried out similar to the approach of the Random Finite Element Method (RFEM) using the mean and standard deviation (std.) of soil parameters derived from all boreholes. In the second, which is a Conditional Random Field (CRF), the soil parameters are mapped onto the selected analysis section and are then predicted on the section mesh elements based on geostatistical estimations. As outputs of the stochastic analysis, the probability density functions of safety factor and maximum lateral displacement of the slope from the two methods are compared with each other. The results of this case study indicate that the use of the CRF affects not only the std. of the safety factor and maximum lateral displacement distribution but can also cause variations in the mean value. Furthermore, the system reliability index of the slope stability decreases when the analysis is done based on the URF.