Realistic dynamic analysis of jointed rock slopes using DDA

A fully dynamic, two dimensional, stability analysis of a highly discontinuous rock slope is demonstrated in this paper using DDA. The analytically determined failure modes of critical keyblocks are clearly predicted by DDA. However, application of a fully dynamic analysis with no damping results in unrealistically large displacements that cannot be confirmed by field studies. With introduction of dynamic damping the calculated results can be made to match historic evidence. Our study shows that introduction of at least 5% dynamic damping is necessary to predict realistically the earthquake damage in a highly discontinuous rock slope with about 400 individual blocks. The introduction of dynamic damping is necessary to account for 2D limitations as well as for various energy loss mechanisms, which are not modeled in DDA.

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