Reliability-Based Stability Analysis of a Baltic Cliff by the Combined Response Surface Method

The study presents a probabilistic stability analysis of a Baltic cliff in Jastrzębia Góra, Poland. Progressive slope erosion is a threat to adjacent buildings, so safety assessment of the slope is essential. The cliff shows a compound, multi-layered geological structure, which makes the analysis of its reliability a complex multivariate problem. A simple, straightforward computational procedure was proposed, incorporating the Response Surface Method (RSM) linked with the standard Monte Carlo (MC) simulation method and the Point Estimate Method (PEM). PEM samples make it possible to analyse the sensitivity of the cliff’s stability to variation in subsoil parameters and to reduce the number of random variables of the problem. The proposed methods were tested in two cases: a high failure probability (undrained state) and a moderate failure probability (drained case). The so-called combined Response Surface Method (CRSM) proposed here may be successfully applied in geotechnical computations characterized by dispersion and uncertainty of soil data as well as a relatively high damage probability.