3D Numerical Study of Tunnel Advance Core Reinforcement : Application on Tunnel T4 from the Algerian East-West Highway

The study of the balance and stability of tunnels is a matter of great importance. Movements resulting from excavation work on face and surface level of the tunnel are yet hard to apprehend. Lately, various methods and techniques of tunnel reinforcement have emerged, aiming firstly at controlling the deformations and settlements and on the other hand at maintaining the stability of tunnelling. The purpose of this work is to study the influence of strengthening the tunnel advance core on the behavior of the surrounding massif by comparing two methods of reinforcement, one called umbrella arch method and the other ADECO-RS method; which consist of strengthening the tunnel face with fiber glass bolts. These two methods have been used during the excavation work for the tunnel “T4” of the east-west Algerian highway. Numerical simulation results using the finite element program “Plaxis 3D Tunnel” have helped to demonstrate the potential efficiency of the ADECO-RS method compared to the umbrella arch method.