Abstract：The response behaviour of rock salt under combined compression and shear impact loading are investigated by utilizing the S-Wave Tracing techniques，and correlative characteristics of dynamic damage are obtained by tracing changes of shear behavior during dynamic damage of rock salt. Impacting experiments with different impact velocities are conducted under combined compression and shear impact loading. Testing results show that (1) rock salt is in fracture phase when impacting velocity is more than 200 m/s，and (2) rock salt is in dynamic damage phase when impacting velocity is at 70～200 m/s. An important experimental phenomena is discovered for the first time in the impacting dynamic experiments，that is to say，there is another unloading shear wave before the unloading compress wave besides routine four impact waves in the process of compress-shear impact of rock salt，which is greatly different from other brittle materials.
