EXCAVATION OF LARGE CROSS SECTION TUNNEL BY ADVANCED ROCK BOLT WORK EXECUTION

摘要

PURPOSE: To simultaneously execute a series of work in parallel by merging natural ground at the periphery of the outside of a predetermined excavating cross section with a plurality of lock bolts and by excavating its upper half part and discharging the earth and spraying concrete at the upper half part and by excavating its lower half part. ;CONSTITUTION: A pilot tunnel B is constructed in a predetermined excavating cross section A at its lower half part. Fixing materials are inserted in drilled holes for rock bolts. The rock bolts 4 are thrusted with the rock bolts 4 rotated. The rock bolts 4 are entirely stuck to natural ground. Next, processes, from a process for drilling holes for the rock bolts through a process for recovering joint rods for inserting the rock bolts 4 are repeated to merge the natural ground at the periphery of the outside of the predetermined excavating cross section A by means of a plurality of the rock bolts 4. Next, the upper half part A1 is excavated by means of a large shovel 7 to discharge earth by means of a belt conveyor 6. Concrete is sprayed at the inner surface wall. The lower half part A2 is excavated by means of the large shovel 7. Facilities such as the conveyor 6 in the tunnel are removed. Thus, working is done by simultaneously applying excavation, earth discharge, and concrete spraying in parallel.;COPYRIGHT: (C)1995,JPO