When application manner of the mountain tunnel and the segment null mountain tunnel for semi-

摘要

PROBLEM TO BE SOLVED: To provide an economical execution method of a mountain tunnel superior in workability, and using special segments for an upper half temporary invert. SOLUTION: A tunnel upper half part is excavated, timbering 4 is assembled on a tunnel upper surface 1a and a tunnel side surface 1b, the plate-like first segment 5a is arranged in a tunnel width directional central part in a tunnel bottom surface 3c of an upper half part tunnel, and the plate-like second segment 5b is arranged in the both side parts. The first segment 5a and the second segment 5b adjacent to this segment are fastened, and the second segment 5b and the timbering 4 of the tunnel side surface 1b are connected. Banking 7 is performed on an upper surface of the upper half temporary invert 5 by assembling the first and second segments 5a and 5b, and the upper half part tunnel is advanced in boring by making heavy machinery travel on the banking 7. The banking 7 is removed when excavating a tunnel lower half part. The first and second segments 5a and 5b are removed, and are carried to the working face 2 side, and are successively diverted.