Tunnel squeezing risk assessment through multi-criteria decision making methods

Squeezing is an important phenomenon in tunneling which results in reduce in tunnel radius. Several methods are normally employed to predict this conditions in tunnels including empirical, semi-empirical and analytical techniques. This research is, however, examining the squeezing of tunnels using multicriteria decision making (MCDM) techniques in several classes ranging from “very low” to “very high”, employing 20 data points of Khimti Tunnel in Nepal. In order to do so, five influencing parameters comprising rock mass quality index (Q), overburden height (H), squeezing degree (N), tunnel diameter (D) and rock type have been taken into account. These parameters have been classified and the squeezing condition has been predicted for each tunnel section. The results have been compared to actual tunnel behavior and have then been discussed. In total, a good agreement was found between the predictions and the reality.