LAUSR

This paper investigated the anisotropic permeability of columnar jointed rock masses at Baihetan hydropower station in Southwest China. Discrete element analysis is conducted to evaluate the hydraulic Representative Elemental Volume (REV) size of jointed rock masses. It is found to be 5m×5m and it is seven times of the column length. Research shows that permeability tensor of the jointed rocks exists. The maximum principle permeability is 3.47 × 10−14 m2 and the minimum principle permeability is 1.39 × 10−14 m2. The direction of maximum principle permeability is 72 degrees anticlockwise from the positive x-axis direction, which is along the same direction of the column length. A continuum hydro-mechanical coupling analysis is carried out on water infill of a tailrace tunnel in columnar basalt. An equivalent anisotropic mechanical model is applied in the numerical simulation. Anisotropic deformation and anisotropic permeability characteristics are investigated under the condition that the angle between maximum principle stress axis and maximum principle permeability axis is 72 degrees. Results show that anisotropic seepage field has an effort on anisotropic deformation field.