A probabilistic systems methodology to analyze the importance of factors affecting the stability of rock slopes

A probabilistic expert semi-quantitative (PESQ) coding methodology is employed to assess the importance of factors that affect the stability of rock slopes within the rock engineering systems (RES) framework. With this newly proposed PESQ coding framework, uncertainties in the assignments of codes are expressed using probabilities that are assigned to each particular coding value. Rock slopes in the Khosh-Yeylagh region in Iran have been employed as an example case to illustrate the utilization of this method in rock slope engineering, and nine parameters are considered as the main factors modeling the stability of the slope system. In addition to the probabilistic coding, other typical RES procedures can also be performed non-deterministically, therefore allowing consideration of uncertainties in the RES analysis. The existence of “previous instabilities” has been found to be the most important parameter, therefore suggesting the importance of performing a site survey of similar slopes in the area; and “geology and lithology” and “mechanical properties of discontinuities” have also been found to be quite significant parameters. The degree of dominance or subordinance of parameters with respect to the slope system has also been interpreted probabilistically. The newly proposed approach could be a simple but efficient tool in evaluation of the parameters affecting the stability of rock slopes and hence be useful in decision making under uncertainties.