Preliminary support design for Ankara subway extension tunnel

This paper presents the results of preliminary support design of the subway tunnel for Ankara subway project in accordance with some empirical and num erical methods, using the phase 2D finite element method (FEM). The 5 m dia meter subway tunnel will advance through slightly to moderately weathered d acite and weak zones. Rock masses were characterized in terms of rock mass rating (RMR), geological strength index (GSI) and Q System. Core samples we re tested in the rock mechanics laboratory to determine uniaxial compressiv e strength, deformability parameters, unit weight, tensile strength and tri axial compressive strength properties. Finally, rock mass strengths were de termined by empirical and numerical methods. Required support system was su ggested. (C) 2001 Elsevier Science B.V. All rights reserved.