Development of a framework for selection of a tunnel lining formwork system

Tunnels are considered special structures because of their uniqueness in analysis, design, and construction. During the construction of the tunnels, it is desirable to optimise the lining formwork system for the rapidity with quality, safety, and economy. The requirement of the tunnel leads to the change in the structure of the lining formwork system. However, the selection of lining formwork system is comprehensive and requires years of experience. This necessitates the development of a novel framework to select a lining formwork system for tunnelling projects. Therefore, this study attempts to develop a framework for selecting a lining formwork system using the Delphi method. For this purpose, guidelines of the Delphi Method are modified to select the experts based on their qualifications and experience. Then, ten experts are elected as a panellist. Subsequently, a total of 11 factors and 43 sub-factors are identified from the existing literature. Out of these, eight factors with their sub-factors are shortlisted using the Delphi method. Afterwards, Cronbach’s alpha is determined for the remaining eight factors to test reliability. The proposed framework can help practising engineers to select and optimise the lining formwork system.