AHP Approach for Risk Factors Prioritisation in Tunnel Construction

Tunnelling is amongst the most demanding infrastructure projects done in civil engineering industry. In addition to its severity of work, the construction being done in underground conditions makes it highly vulnerable to schedule delays, cost overruns, etc. Making risk analysis has been a very important aspect in tunnel construction. Due to the complexity of the tunnelling industry, each tunnelling project has numerous risk factors affecting the flow of construction work. The long list of factors is initially curtailed using Relative Importance Index (RII) then these risk variables are further prioritised based on the relative importance of expert opinion by using Analytic Hierarchy Process (AHP) approach. A literature analysis and real-life case studies in tunnel construction yielded 98 risk indicators. The list was then reduced to 75 by removing elements that were repetitive or overlapped. The remaining elements were grouped into clusters and rated using two methods: the Relative Importance Index and the Analytical Hierarchical Process. Tunnel projects are complicated and expensive infrastructure projects; hence the aim of this research is to improve current risk analysis practices by offering a more accurate framework for risk analysis and prioritisation.