ABSTRACT
Hokuriku Shinkansen Line’s Asahi Tunnel, a long mountainous tunnel of 7,549m in total length between points of 234 km 912 m and 242 km 461 m from Takasaki, has its entrance on the border with Niigata Prefecture (at Sakai, Asahi-machi, Shimoniikawa-gun, Toyama-ken) and ends at Takenouchi, Nanbo-chiku, the same town. The thickest earth covering along the tunnel is about 420m while the thinnest is 20 m right beneath Sasagawa River. Digging started from the mouth of a 3‰ (descending) heading toward the start point of works for building the tunnel of 3,030m in total length. The tunnel construction which began in March, 1998 is now under way for expected completion in November, 2004. For present construction works, a continuous belt conveyor system was introduced, instead of so-far used dump trucks, to carry muck out of the site.
