Seismic response analysis of concrete-faced rockfill dams with dual mortar contact method

Abstract

Many high concrete-faced rockfill dams (CFRD) are constructed or planned with high seismic intensity. It is challenging to evaluate the resultant seismic response involving multi-body interactions. In this paper, a dual mortar contact method for multi-process sequential analysis accounting for staged construction, water storage, creep effects and seismic loading is presented. A complete derivation of the strong and weak forms, spatial and temporal discretizations, material and contact non-linearity treatments is provided as a solid basis to incorporate the rockfill constitutive behavior and stable algorithm for thin-walled inter-slab interfaces. The present method based on using nonconforming meshes is validated by the comparisons with conforming meshes and then applied to an ideal CFRD. The issues of post-earthquake extrusion damage, slab–slab separation and slab–cushion separation, which are major concerns in CFRDs, are discussed in detail. The additional extrusion stress of the concrete face during an earthquake can be up to 20 MPa and therefore calls for considerations in the design and safety assessment.