Permanent tunnel lining monitoring system for the purpose of further design optimization

Abstract

Design background of temperature loading of tunnel linings given by the European and national standards in Czech Republic might be unnecessarily strict, while the considered temperature changes across the thickness of the tunnel lining should be notably lower than values recommended by standards. Due to these reasons, multiple tunnel structures actually under construction were selected for installation of newly designed specific monitoring system into the linings of these tunnels. Monitoring system is installed into three tunnel structures, its design is adjusted to ensure its similarity in all the structures. Monitored spots of the measurement system are situated in central and boundary segments. The system measures temperature profiles and strain in crown and wall of tunnel segments. Measurement should provide sufficient basis for statistical evaluation of temperature changes reached in tunnel linings during the extended period of time. Strain monitoring of lining provides complex information about overall deformation of structure caused by force and non-force effects of loads. Result of tunnel lining monitoring will be an adjusted design temperature profile for purpose of tunnel lining evaluation. Consideration of proper and realistic temperature gradient in design of tunnel linings should optimize thickness and reinforcement of lining, therefore the reducing final costs of newly constructed tunnels.