Anti-extrusion Failure Design for High CFRD

Abstract

Several cases of extrusion failure have occurred in high concrete face rock-fill dams (CFRDS) across the world, leading to dam leakage and threatening safety operation. It reveals insufficient understanding of concrete face deformation characteristics in previous studies. Based on the analysis of concrete face extrusion failure characteristics and compressive joint structure setting of multiple CFRDS, this paper proposes that concrete face’s insufficient capacity to withstand the extrusion deformation along the dam axis is the root cause for concrete face extrusion failure. Concrete face compressive joint width adaptation to longitudinal strain along the dam axis is an important way to prevent extrusion failure of the concrete face. The principle for CFRDconcrete face compressive joint adaptation to extrusion deformation is then proposed. Anti-extrusion failure design method is proposed, and mathematical expression of compressive joint width design is established. based on design and operation of CFRDprojects such as Hongjiadu CFRDin China, Dongqing CFRDin China and Nam Khan2 CFRDin Laos, the method was verified to be reasonable and reliable, which means important reference value for the construction of 200m and 300m CFRD in the future.