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...

An assessment of the relation between monitored settlements and the face stability of a slurry-TBM

During the boring of a tunnel in soft soils with a slurry TBM, support pressure is used to achieve equilibrium at the face of the TBM. When this equilibrium is not reached, when the face support pressure is too low or too high, settlements will occur. In this research settlement and pore water pressure measurements are used to monitor the...

Comparison of static and transient face stability: Case-study: The Rijnlandroute

Tunnel construction projects in the western part of the Netherlands are typically built in soft, heterogeneous ground conditions with low stiffness and high groundwater tables. The tunnelling technique used is the ‘slurry shield’ method, which uses a tunnel-boring machine (TBM). The TBM consists of a steel cylinder with a cutting wheel at the...