Using Discontinuous Deformation Analysis to Investigate the Dynamic Stability of Tunnels in Jointed Rocks Under Earthquake Loading

Tunneling is one of the most important problems in rock mechanics that many numerical methods try to investigate. In general, static analysis methods are mainly used to investigate the stability of tunnels, which are not safe in dynamic conditions. This paper is illustrating the use of Discontinuous Deformation Analysis (DDA) in analyzing the stability of tunnels in jointed rocks under earthquake loading. To improve the capability of original DDA method to meet the requirements for analysis of rock tunnels under dynamic loading and time dependent (time history) loading, damping and energy loss have been added to the program. Some numerical examples have been illustrated to show the capability of the modified program. Good similarities between the field observations and the numerical results were observed. Blocks displacements and deformation of the roof of the tunnel matched with the field observations indicated the importance of the key blocks in tunneling