Effect of Overburden Depth and Stress Anisotropy on a Ground Reaction Caused by Advancing Excavation of a Circular Tunnel

The assumption of the Convergence–Confinement Method (CCM) is analysis interaction behavior support and ground a deep circular tunnel under an isotropic stress field. Aiming to improve this method, paper proposes discussion on influence overburden depth anisotropy. To consider effect, reaction in different depths due advancing excavation investigated. Under anisotropic conditions, analytical solutions stress/displacement plastic elastic regions can also be suitable for theoretical consistent manner. key factor study use confinement loss, which not only describe simulation effects but become superimposed value incremental procedure. In addition, calculation spreadsheets used estimate implement into executable computational solutions. check validity solution, finite element examine distribution around tunnel, especially along pressure line cross-section. Comparing solution calculated by procedure with result numerical shows trend.