Abstract

This paper presents the proposed methods of DE(distinct element ) modelling to estimate the stability of tunnels injointed rock masses. First, the criterion to select the joint set(s) contributed to the discontinuous behaviour in a tunnelsection is proposed. Selected joint set(s) is(are) considered others to modify the elastic properties of rock blocks. The co mplex DE model with the average and the deviation of jointorientation and joint length for each joint set was compared to the simple model with only the average of joint orientationlt, the latter is suitable to the purpose of tunnel designbecause it can show the consistent behaviour of a jointed rock mass such as the locally discontinuous failure and theglobal anisotropic behaviour.