Framework for the estimation of overall probability of dam failure of ancient earth dams in Sri Lanka.

Abstract

Sri Lanka has a rich history of earth dam construction with over 300 large scale ancient earth dams in service, However, large number of ancient earth dams are suffering partial falier due to excessive seepage, piping and slope instability. The failure of an earth dam involves a probability of falier and therefore the individual probabilties estimated for different falier modes under various loading condition need to be combined The probability of failure tor each mode ,involves engineering assessment of the particular failure mechantsms. and looking for solutions that can reduce the probability of those falier modes or minimise the consequences of a failure. No standard framework is adopted in Sri Lanka for the estimation of overall probability of dam failure The objective of this paper is to develop a standard framework for the estimation of over orall probability of dam failure to be included in the quantitative risk assessment process for ancient earth dams in Sri Lanka. Critical loading conditions which are relevant to Sri Lanka are considered in the present study.