The tunnels need to be big enough to accommodate the kinematic traffic envelope which comprises a 1.5 m breakdown lane, two 3.5 m wide traffic lanes and a 1.5 m walkway. Barriers separating traffic from the walkway are included in these dimensions. The height of the kinematic traffic envelope is a minimum of 5.3 m. An additional 2 m height above the kinematic traffic envelope is required for fans, lights, signs etc. The tunnel is to be driven from the south towards the north
You will need to work through the following steps to offer a robust tunnel support scheme.