Unlined Length Effect on the Tunnel Face Stability and Collapse Mechanisms in c-ϕ Soils: A Numerical Study with Advanced Mesh Adaptive Strategies

This paper presents a stability study on the collapse mechanisms of a plane-strain tunnel face in c-ϕ soils using the upper bound finite element method with rigid translatory moving elements (UBFELA-RTME) and nonlinear programming technique. Practical considerations are given to the unlined length influence behind the tunnel face. An advanced...