Composite shell lining design analytical study of interface

Abstract: Traditionally, no bond has been assumed across waterproof membranes installed between primary and secondary tunnel linings. Spray-applied membranes offer the opportunity to consider some bond between the two linings, producing a composite action. The composite action has been verified through a significant laboratory testing programme from research from Pillai et.al. (2017)1 and an analytical study using finite element (FE) modelling software is presented in Green et. al. (2019), including a microscopic interpretation of the bond interface to understand load sharing facilitated by sprayed waterproof membranes. This paper presents a study on tensile and shear displacements along the interface when the tunnel lining deformation level reaches ULS.