In accretionary zone tunnel, heterogeneous rocks or variable geological conditions at the face produce serious problems and additional costs to the estimated cost. The seismic refraction method has been widely used in many tunnel projects in mountainous areas. But, it is usually difficult to do accurate rock-mass classification in the way of investigating.
In the present paper, high resolusion seismic refraction method was used in accretionary zone tunnel. Consequently, the precision of the classification was improved. But, we must pay attention to the evaluation result that an elasticity wave speed around face decreases too much according to a tunnel cutting.
