Experimental Study on Dynamic Characteristics of Coarse-Grained Materials and Its Application on Numerical Analysis for Permanent Deformation of Rockfill Dams

The permanent deformation after earthquakes is an important seismic safety performance indicator for rockfill dams. Based on dynamic triaxial tests, taking grading reduced coarse-grained materials as the test object, the influence of factors including density, particle grading, confining pressure, consolidation stress ratio, and number of vibration cycles on its residual deformation was discussed. On this basis, a numerical model in power function form was established for elaborating the earthquake permanent deformation for rockfill dams, an assumed homogeneous rockfill dam and a practical core rockfill dam were taken as research objects, respectively; by conducting nonlinear dynamic Finite Element (FE) analysis and combining with the single factor sensitivity analysis, the relationship between the main influence factors and dam permanent deformation was explored, which indicated that the influence of above factors on the permanent deformation of rockfill dams is consistent with the relationship between these factors and the residual deformation of coarse-grained materials in the triaxial tests. Finally, a fitting analysis method searching for the maximum permanent deformation of rockfill dams under different seismic intensities was proposed. Then corresponding suggestions were recommended from both design and construction aspects to improve the seismic resistance of super-high rockfill dams, which may have reference significance for similar projects.