Risk-based stabilization planning for soil cut slopes

Abstract. Risk-based slope stabilization planning integrates the failure probability and the failure consequence systematically and shows promise for use in the practice. This paper attempts to develop a risk-based methodology for stabilization planning for deteriorating soil cut slopes. First, a framework of risk-based stabilization planning for slopes is proposed. Then the time-dependent reliability of deteriorating slopes is analyzed based on observed performance. Thereafter, the slope failure consequence is assessed in terms of expected numbers of fatality. After obtaining the time-dependent risk of slope failure, the time for slope stabilization is determined according to selected risk criteria. Finally, the effect of slope maintenance on the reliability of slopes is evaluated. Based on the analyses, the annual probability of failure of soil cut slopes would increase exponentially in the early stage of service if no maintenance were implemented. As a slope deteriorates, the risk of slope failure increases with time and may reach an intolerable level at a certain time. The risk of slope failure may also reach an intolerable level due to a change of elements at risk. The derived stabilization time depends on the factors that cause the slopes to deteriorate, consequence of slope failure, selected risk criteria, and vulnerability of the affected population.