Assessment of Slope Stability Taking into Account the Uncertainty of Standard Seismic Impacts and Material Parameters of the Site

Assessing the risk of landslides as a result of intense seismic vibrations is an urgent problem in engineering geology. In this article, to assess slope stability, a method is proposed for normalizing the internal deformation of a slope, based on a probabilistic-stochastic approach. The cumulative Newmark displacement is considered as a normalized value, for which empirical relationships have been selected among the accumulated displacement, the level of seismic impact, and the critical acceleration specified by the material parameters of the slope. The method takes into account the uncertainties in the position of possible earthquake sources in the next 50 years in the vicinity of the studied slope, the magnitude of the event(s), and the level of seismic impact. The uncertainties in the physicomechanical parameters of the slope are also taken into account. Normative biases are estimated using reference exceedance probabilities (10 and 5%). The obtained values are compared with the threshold characteristics, and based on this, a decision is made on the slope stability to seismic loads. The value of 10 cm was taken as the lower threshold at which the slope can be considered stable. The technique was successfully tested on a well-studied area of the western slope of Mt. Bolshevik (the south of Sakhalin Island). The balanced estimate of the normative displacement for a 5% exceedance probability was slightly less than 10 cm. The study also provides recommendations for further improvement of the methodology.