Abstract
Geotechnical surveys in the area of the Ena Tunnel have being carried out by Japan Highway Public Corporation from 1965. In the area of Nakatsugawa, the west side of the Ena Tunnel, 5 boring works were completed, and several physical characters of boring cores and bore holes were tested and measured.
From their resul ts, the geotechnical section of the west side of this tunnel is drawn. Considering difficulty of boring works and observation of boring cores, it seemed that geotechnical conditions in this area is not desirable for tunnel work beyond expection
