ABSTRACT
The technology of construction of in–situ pressed lining and the inherent conditions of lining interaction with surrounding earth mass are the major factors controlling the static performance of an underground structure. The experiments carried out at the Transportation Construction Research Institute (TCRI) during construction of metro and small–diameter utility tunnels have shed light on the stress state of in–situ pressed lining and its neighbourhood. State of ground stress and strain around the edge of compacted lining was analysed in models by the photoelasticity method. The enforced Codes of Practice recommend the design of in-situ pressed linings by methods of structural mechanics. Tunnel lining design by continuum mechanics techniques is based on the following mechanical model of lining interaction with the environment: an opening in elastic rock mass is supported around its perimeter with a lining made from elastic material; rock and lining strain is uniform along the contact line.
