Large-scale triaxial tests on behavior of gravelly soil at different shearing rates

The stress-strain behavior and shear strength of gravelly soil at different shearing rates were investigated through a triaxial consolidated-drained shear test on the gravelly soil of a core rockfill dam. The results show that regardless of the level of the shearing rate,the stress-strain behaviors of the gravelly soil exhibited various degrees of hardening and shear shrinkage under different confining pressures. As the shearing rate increased,the hardening gradually strengthened but the shrinkage weakened. The peak deviatoric stress( σ1- σ3)f decreased remarkably with the increase of the shearing rate,and the intensity index φ decreased significantly. In the range of testing shearing rates,the secant modulus E1 decreased with the increase of the shearing rate,and the bulk modulus K1 increased initially,and then decreased with the increase of the shearing rate.