STABILIZATION OF TUNNEL FACE USING FIBREGLASS DOWELS

Abstract

Cities nowadays are trying to incorporate the most advanced infrastructural facilities. But geographical and environmental limitations somewhat affect the sustainable development of the place. So the use of underground space for transit and serviceability purposes have been increasing in the last few two decades. These tunnels when passing through adverse ground 1 conditions at shallow depths, are more prone to face instability, a serious condition which pose risk to the entire tunneling activity. A detailed 3D simulation of the ground condition is done and face stability is studied using the introduction of fiberglass dowels. Excavation sequence is based on ADECO-RS method, but pre vaulting techniques are not considered. Simulations are carried out using PLAXIS 3D software. A wide range of dowel densities are considered for the analysis. Surface settlements before and after the installation of fiberglass dowels are studied. Further study is conducted regarding the optimization of the design using fiberglass dowels. Then the effect of dowels is compared with a simplified empirical solution. The work conducted helps to predict the risk factors that may arise due to the adverse ground conditions.