Abstract: Stress-deformation behaviour of a concrete-faced rockfill dam (CFRD) built on sand and gravel foundation is studied based on the in situ monitoring results and finite element analysis (FEA). The mechanical behaviour of the dam body and its impervious structures is investigated and the interaction between the CFRD and the overburden foundation is analyzed. Three-dimensional FEA is performed, with introducing the Duncan-Chang E-B model for gravel and rockfill and the Lagrange method for the interface, to evaluate the stress-deformation behaviour of the CFRD at the construction and filling stages of the reservoir. Comparative analysis shows that the maximum settlement occurred at the bottom height of the dam instead of the middle height and the maximum compressive stress distributed in the overburden. The overburden foundation has a significant effect on the stress-deformation behaviour of the dam body and impervious structures. The stress and deformation values computed using the FEA model are found to be consistent with the measured data for the construction stage. Numerical simulation is used to analyze the different factors influencing the behaviour of the dam body and cut-off wall. The results show that the staged-filling of the dam body will cause uneven deformation and stress concentration in the dam body, but can improve the stress and deformation behaviour of the cut-off wall to some extent; and the rapid dam construction rate results in a larger prestage stress and post-construction settlement which is not conducive to the construction and operation of the dam.

Key words: concrete-faced rockfill dam, stress-deformation behavior, monitoring, finite element analysis, overburden