ABSTRACT
A project involved the construction of 2845 mm internal diameter liner using 200 mm thick fiber reinforced segmental liner. The contractor successfully installed segmental liner rings in the very stiff to hard clay with slickensides. For the successfully installed rings the contractor was able to inject grout behind the segments without difficulties using a grouting pressure of 0.40 MPa. In the tunnel stretch within interglacial deposits, the contractor experienced significant difficulties trying to inject grout. According to the GBR, these deposits consist of interbedded layers of cohesive and granular materials. The granular material was described as medium dense to very dense sand. Shortly after installing the first 4 rings in the granular material, the rings experienced excessive deformation with excessive diametric deformation as high as 3%. The paper discusses the causes of that large deformations in relation to the ground condition and the superior response of the FRC segmental liner under these ground conditions.
