Abstract: Rockfill is the primary filling material for earth-rock dams, and its creep characteristics directly influence the magnitude of dam deformation after construction. We conducted indoor large-scale triaxial creep tests on two types of rockfill materials used in the gravel core wall of Lianghekou Hydropower Station. The findings are summarized as follows: 1) under low stress levels, the lateral strain exhibited positive values, whereas under high stress levels, the lateral strain became negative. 2) The test values at 30-year age extrapolated by using power function was utilized as the limit strain value for rockfill creep tests. Subsequently, the obtained residue creep demonstrated a robust power function relationship with time. 3) The final shear creep demonstrated a multiple relationship with shear stress, with the axial creep attenuation power index and shear creep attenuation power index being nearly equal. Moreover, the final axial creep was 1.5 times that of the final shear creep. Ultimately, we proposed a concise two-parameter power function creep model which features clear physical interpretations of model parameters and is highly practical for engineering applications. The findings provide valuable insights for the preliminary estimation of deformation following the construction of earth-rock dams.

Key words: high stress state, residue creep, final shear creep modulus, attenuation power index