Analysis of temporary support effectiveness in very softrock tunneling at Cisumdawu's Tunnel

Abstract

Temporary support aims to minimize deformation, it is installed immediately after excavation, especially in the case of softrock tunnels. In this study, Numerical modeling is used to analyze the optimization of the support system design, and then compared with the monitoring results. Based on numerical analysis, it is found that installation of pre-support before excavation is recommended, it can reduces deformation on the tunnel roof. This is advantageous, because pre-support decrease installation of other support. The use temporary support such as shotcrete and steel set, is enough to produce a more stable tunnel condition, especially for tunnel sections not affected by pre-support such as the tunnel floor.