Creep behavior of rockfill with soft rock under different relative densities

When soft rock is used as the dam embankment materials for high earth-rock dams, large creep deformation may occur, which is very unfavorable to the long-term stability of high earth-rock dams. Therefore, it is necessary to study the creep characteristics of rockfill with soft rock. The uniaxial creep tests are carried out on rockfill with soft rock under different relative densities by using a large odemeter, and the influences of relative density on creep characteristics of rockfill are discussed. The axial creep strain of rockfill decreases as the increase in the relative density. With the increase in the axial pressure, the influences of the relative density on the axial creep strain are more significant. The creep model of power function is used to fit the change curves of the axial creep strain with time. The attenuation index and the final creep strain are obtained. The functional relationship among the final creep strain, the attenuation index and axial pressure is discussed. It is found that the final creep strain and the attenuation index meet the hyperbolic function and power function relationship with the axial pressure, respectively, and a uniaxial creep model considering axial pressure is proposed. The relationship between the parameters of the creep model and the relative density shows that the relative density has small effects on the attenuation index. Based on a good linear relationship between the parameter related to the final creep strain in the model and the relative density, a uniaxial creep model related to both the axial pressure and the relative density is proposed, and the physical significance of each parameter of the model is discussed.