EXCAVATION METHOD FOR TUNNEL OF FLAT AND LARGE CROSS SECTION

摘要

PURPOSE: To safely and efficiently excavate a tunnel of flat and large cross section under a less vibration and a less noise, while excavator facility cost is reduced. ;CONSTITUTION: For the excavation of a tunnel of relatively flat and large cross section, a plurality of circular pilot tunnels 1 are excavated in advance within the upper semi-arch section 2 of a tunnel T on the operation of a tunnel excavator. Thereafter, the section 2 is shaped, expanded and excavated with a breaker. Then, a lower section 3 and the natural ground as an object for lowering the bed of an invert section 4 are slackened, and excavated with the breaker or an impact ripper, while being further slackened with blasting or a static breaking agent.;COPYRIGHT: (C)1995,JPO