Designing Tunnel Lining in Anhydritic Claystones. Intensity and Distribution of Swelling Forces

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.

Automated summary

This paper presents a procedure for designing tunnel linings in anhydritic formations, considering three-dimensional effects and spatial heterogeneity. The methodology is validated through the analysis of monitoring data from the Lilla tunnel lining. This approach can prevent conservatism in assuming uniform pressures against the lining and using two-dimensional models.