A statistical review of the behaviour of concrete-face rockfill dams based on case histories

Abstract

The concrete-face rockfill dam (CFRD) has become a preferred dam type, but its design remains largely based on past experiences. Understanding the behaviour of CFRDs is critical to the design and safety assessments of these dams. The main objective of this study is to review the behaviour of CFRDs from the perspective of statistical analysis. A set of monitoring records and construction details of 87 case histories of in-service CFRDs constructed in the past 50 years is collected. The analysed data that are presented are based on a review of the literature. Detailed statistical analyses of post-construction crest settlement and face slab behaviour, settlement of the dam body during construction and leakage after reservoir filling are conducted on the basis of the above-mentioned case histories. Several suggested empirical relationships are obtained by regression analysis to estimate the deformation and seepage behaviour of CFRDs. Findings offer reliable insights into dam behaviour and provide an engineering analogy and reference for the planning, design and construction of CFRDs in the future. The statistical analyses also attempt to identify quantitatively the major influencing factors of the deformation of CFRDs, such as intact rockfill strength, foundation characteristics, valley shape and seepage flow. Intact rockfill strength and foundation characteristics are found to be the main influencing factors of dam deformation behaviour. The results from the statistical analysis of the case histories and the analyses performed are also presented herein.