Designing Tunnel Lining in Anhydritic Claystones. Intensity and Distribution of Swelling Forces
Eduardo Alonso Pérez de Ágreda, A. Ramon-Tarragona, L. Verda
Abstract
Abstract The measured swelling pressures against tunnel linings range between a fraction of one MPa and 6–7 MPa. A strong spatial heterogeneity is often observed. The paper integrates these considerations into a procedure to design tunnel linings in anhydritic formations. Three-dimensional effects and proper consideration of heterogeneity is shown to be consistent with monitoring data of lining reinforcement stresses. The calculation methodology is illustrated in the case of the Lilla tunnel lining, which was monitored for more than 6 years. The described procedure leads to a rational design away from the conservatism of the assumption of uniform pressures against lining and two-dimensional modelling of tunnel cross-section.