Research project: Interface characteristics in composite sprayed concrete lined tunnels
Over the last twenty years, sprayed concrete lined (SCL) tunnels have seen rapid development in their use, particularly for forming large underground spaces such as station concourses for urban metro lines. A waterproofing membrane is normally required around the tunnel, and a convenient way to achieve this is by a sprayed membrane applied to the inside of the primary SCL layer, before the secondary SCL is added. There is an uncertainty however in the extent of composite action that can be relied upon between the primary and secondary linings in these circumstances when the membrane is sandwiched between the two. This project is aimed at addressing this uncertainty. If it can be shown that composite action is present, an efficient utilisation of both primary and secondary linings in the complete structure should be possible, leading to significant savings in overall lining thickness and cost.
