ABSTRACT
Situated on the plate collision suture zone,Taiwan is marked with extreme topographic relieves and highly variable geological conditions. A long tunnel running under high rock cover can only be expected to have nothing but a vague geological picture of the area penetrated by the planned tunnel alignment, even though good quality geologic investigation had been performed. Nevertheless, geological investigations performed under various scales in accordance to requirements for the various study stages yielded results and information that proved to be of crucial importance in the construction of the Hsuehshan Tunnel, and the validity of this geological information was verified when the actual geology was finally revealed on the excavated walls of the tunnel. This paper presents an account on the results and methodologies for the investigations and site characterization performed for the Hsuehshan tunnel project in various stages.
