Geotechnical studies and primary support design for a highway tunnel: a case study in Turkey

Abstract

The main aim of this study is to appraise the geotechnical characteristic of the rock masses and to propose the proper support design for the Cankurtaran Tunnel project situated in NE Turkey. the exhaustive engineering geological investigations were done to determine the characteristic of rock masses that primarily consist of volcanic and sedimentary rocks. the tunnel route was divided into 15 segments according to their lithological and structural properties. the rock mass rating (RMR) and Rock Mass Quality Index (Q) systems were used to determine the quality of rock masses and final tunnel lining support. To check the capacity of the suggested support units analytically, the convergence-confinement (CC) technique was applied. the efficiency of the support design, dimensions of the plastic zones and deformations were determined using the 2D and 3D numerical finite element method (FEM) modeling. the empirical support system suggested in this study reduced the total displacement and dimension of the plastic zone.