Evaluation Indices and Design Method to Determine the Rolling Density of Dam Shell Sandy Gravel Material

Abstract

Sandy gravel dams with clay core walls are a widely used dam type, and the rolling density of sandy gravel material is evaluated by the relative density Dr. Consequently, designing the optimal Dr value is related both to the safety and health of the dam body and the time and cost of construction, but finding the optimal Dr value has not yet been satisfactorily resolved. Here, eight evaluation indices—strength-related, deformation-related, and compatible deformation-related indices—are proposed, and relationships between the indices and the Dr value of shell material are studied through three-dimensional (3D) finite-element calculations. Three efficacy functions that correspond to the above three types of evaluation indices are defined, and multiobjective programming (MOP) is used to analyze the optimal Dr. The suggested constraint condition in MOP is Dr∈[0.75,1] rather than Dr∈[0,1]. Four MOP schemes based on different weight allocations for the three efficacy functions are suggested. The compatible deformation control scheme was the optimal design for the project, and the optimal designed relative density of sandy gravel is 0.862. The proposed design method meets strength, deformation, and compatible deformation requirements for the dam body.