ESTIMATION BY IN-SITU MEASUREMENT OF EXCAVATION DISTURBANCE BY BLASTING IN SEDIMENTARY SOFT ROCK

Abstract

A drift has been excavated by blasting in sedimentary soft rock about 140m below the surface. In-situ measurement and numerical simulation have been performed to identify the rock zone where rock properties have been changed due to the drift excavation (Excavation Disturbed Zone=EDZ). The in-situ measurement has detected the EDZ with a width of about 1m around the drift. The EDZ has lower seismic velocity and elastic modulus and higher permeability than intact rock. The numerical simulation has suggested that it is necessary to consider excavation progress, rock stress and the EDZ for precise simulation of rock mass displacement.