The Effect of K0 on the Convergence of Tunnels in the Case of Synchronous and Asynchronous Installation of Support Systems

Abstract

One of the most important dates in numerical analysis of tunnels stability are in-situ stresses and also one of the factors which have a magnificent effect on these stresses is Ka- Consequently as K0 has a great influence on stresses and these stresses affect the appeared stress concentration so understanding the effect of K0 seems to be necessary. In this paper the effect of synchronous and asynchronous installation of composite support system which consist of bolt and shotcrete in different K0 ratios are studied on convergence of tunnels by phase2 software. Furthermore, the effect of K0=1(hyostatic stress condition) and ratios 1. 2, 1. 3, 1. 4 and 1. 5 of K0 are compared. The results show that as Ka increases the amount of displacements are decreased and synchronous installation is more effective than other moods of installation.