The mechanical behaviors of the jointed rock masses during tunneling and lining are simulated using discontinuous deformation analysis (DDA). Two improvements for tunneling and lining are developed and implemented into the original DDA program and the process of the tunneling and lining are simulated using the advanced program. The influence of the joint direction on the deformation and the stresses distribution of the jointed rock masses are investigated during tunneling and lining. The effect of the excavation sequence on the stability of the rock around the tunnel is also simulated. From this study

it is found that the joint direction has primary impact on the deformation and the stress distribution. The excavation sequence has also impact on the deformation and the stability of rock masses. These results suggest that the advanced DDA can be applied to simulate the tunneling and lining behaviors of the complicated discon-tinuous rock masses.