ABSTRACT: In this paper the use of a novel design tool for the early stages of a tunnelling project is demonstrated. By applying this tool to evaluate the influence of support capacity and yield in a wide range of rock mass conditions, the authors demonstrate the link between the sensitivity of the tunnel lining design parameters and variations in the rock mass, and show how it can be quickly evaluated using simple graphical output.
The paper identifies that the stability of a tunnel in a weak rock mass is significantly greater than would be expected from initial modelling predictions. This led the authors to question the link between the rock mass deformation modulus and the confining stress. A series of case histories, both idealised and from published measured data are demonstrated to check the validity of the modified technique.
