Abstract: Rockfill serves as the primary filling material in earth rock dams. Its wetting deformation characteristics have a significant influence on dam deformation during impoundment. Employing the single line method, we conducted extensive indoor triaxial wetting deformation tests under confining pressures of 0.5, 1.0, 2.0, and 3.0 MPa on two types of rockfill materials sourced from Lianghekou Hydropower Station. Results indicate a substantial increase in both axial and volumetric wetting deformations as stress levels and confining pressures escalate. This behavior aligns with wetting deformation patterns observed under medium and low confining pressures. Notably, under high isotropic confining pressure, volumetric wetting strain correlates linearly with confining pressure in double logarithmic coordinates, whereas axial wetting strain and confining pressure no longer meet a linear relationship. Moreover, at high unsymmetrical confining pressures, the ratio of volumetric wetting strain to axial wetting strain typically ranges from 0 to 2, exhibiting a nearly horizontal trend with increasing confining pressure. The six-parameter wetting model remains adept at accurately characterizing the axial and volumetric wetting deformation behaviors under varying stress levels and confining pressures.

Key words: rockfill, wetting deformation, single-line method, high confining pressure state, stress level