Development of a Risk-based Methodology for Rock Slope Analysis

The objective of this research is to develop a geotechnical risk assessment methodology to concurrently identify and quantify important risk elements in rock slopes. Thus, important geotechnical issues affecting a high rock slope were categorized into three major critical risk groups after a comprehensive literature review and field observation program. A set of knowledge-based fuzzy inference rules were established to set up membership functions and calculate risk index (RI) for each critical risk element (CRE). The CREs were ranked on the basis of the calculated RI. The developed risk algorithm was employed to assess the geotechnical risks associated with the right abutment slope of Vanyar dam, Iran. The analysis results showed that the presence of high water level (RI 4.47), shear strength of discontinuities (RI 4.27), and presence of shear or fault zones in the slope (RI 4.01) were the most critical elements which affected the slope stability, respectively. According to calculated risk indices the engineers should pay more attention to the underground water level in the dam abutments. The proposed method could provide scientific decision-making basis for varying risk levels associated with rock slope engineering and can be used as an aid in corresponding risk control measures. The obtained results indicated that the developed algorithm is beneficial in providing guidelines for design and remedial measures to improve slope construction and performance. The present study proposes a methodology based on a combination of project management, risk modelling, and geotechnical engineering.