Assessment of tunnel stability in layered ground

摘要

The stability of a circular tunnel in layered ground, with both fine-grained and coarse grainedsoils below the water table, is investigated experimentally and theoretically. Centrifuge tests have been carriedout at City University, London, investigating in detail tunnelling effects in layered ground, in terms of both soildisplacements and strains and in terms of the kinematics at failure. Also, analytical upper bound solutions forlayered ground which closely reflect the observed failure mechanism of the tunnel have been derived independently.The results from all different approaches have been compared by emphasising the effects of the differenthypotheses on the assessment of tunnel stability.