Abstract
During excavation of a large-scale water storage tunnel in soft mudstone, rock deformations at the tunnel side wall have unexpectedly increased corresponding to the stepwise bench excavation. The conventional numerical analysis for designing tunnel supports could not predict such behaviors in advance. In this paper, some different numerical analyses for tunnel excavation in soft rock will be employed as the methods that can reasonably represent such rock mass mechanical behaviors. Analyses of large-scale cavern excavation in soft sedimentary rock will be carried out by them and all analysis results will be compared together with the measurement data in order to improve the prediction of tunnel deformational behaviors.
