Effect of freeze–thaw cycles on the deformation behavior of gravelly soil in the 300 m-high earth core rockfill dam

Abstract

Many high earth rockfill dams are currently being constructed in the alpine region of Southwest China. Since the effective working time is reduced by the cold climate, it is necessary to solve the problem of intermittent filling of the core wall at low temperature. However, freeze–thaw (FT) cycles in the filling process will change the deformation behavior of gravelly soil. For 300 m-high earth core rockfill dams, the deformation of gravelly soil is a crucial factor in predicting the long-term deformation and settlement after dam construction. To investigate the influence of FT cycles on the deformation characteristics, the deformation of the gravelly soil under different amounts of FT cycles was tested using an MTS-810 test system. The deformation characteristics were discussed, and a modified Burgers model was used to describe the deformation characteristics. The results show that the freeze–thaw action makes the coarse particles break, resulting in an increase in the fine content. The FT cycles can make the creep characteristics of gravelly soil more obvious. The creep strain has a large contribution to the total strain with the increasing in the FT cycles. It is thus suggested that the coverage of thermal insulation material would effectively prevent freezing of the gravelly soil and control the deformation.