Prioritizing highway tunnel risk factors with AHP method

In the risk evaluation of a highway tunnel, the recognized risk factors are categorized into two hierarchies. The first hierarchy consists of seven items, which are topography, geology, unfavorable geological condition, special stratigraphy, structural design, tunnel section and depth of embedment, shafts and pilot tunnels. An Analytic Hierarchy Process model is established to prioritize the risk factors in highway tunnels. In the decision making procedure, five experienced experts were organized and surveyed to give their judgments on the importance of different influencing factors to work out the priority. In order to verify the validity of the AHP analysis, two other experts were asked to give their comprehensive evaluation on the same question, results from the two processes are close to each other, this indicates that the AHP method adopted in prioritizing the risk factors of tunnel construction is effective and exercisable, it can be further developed to satisfy the requirements of the risk evaluation process for highway tunnels.