TUNNEL EXCAVATION METHOD, CONSTRUCTION METHOD OF TUNNEL BRANCH/CONFLUENT WIDTH EXPANDING PART USING THIS METHOD AND TUNNEL BRANCH/CONFLUENT WIDTH EXPENDING PART CONSTRUCTED THEREBY

摘要

PROBLEM TO BE SOLVED: To provide a construction method of a tunnel branch/confluent width expanding part, capable of shortening a construction period, capable of reducing construction cost, capable of excavating and carrying out the inside natural ground after constructing a structural skeleton, capable of rationalizing a structure by load reduction in a main track tunnel, capable of restraining influence on the peripheral ground, and capable of reducing the size in a required site width in response to the required inside of a branch/confluent part, by simplifying joining construction by reducing a connecting width between the main track tunnel and a ramp part tunnel.;SOLUTION: This method includes a process of connecting a connecting part 40 between the main track tunnel 10 and a pair of U-shaped tunnels 22 to a connecting part 42 of the pair of mutual U-shaped tunnels after the pair of U-shaped tunnels 22 are approached to the main track tunnel 10 by a U-shaped shield machine 20 forming the ramp part tunnel 12, and a process of forming the branch/confluent width expanding part 18 by excavating the natural ground between the pair of U-shaped tunnels 22.;COPYRIGHT: (C)2008,JPO&INPIT