Risk analysis for determination of a tunnel support pattern

In this study, a methodology to determine an optimal support pattern and advance rate for the design of a tunnel is introduced based on risk analysis. It can be confirmed quantitatively that the more the tunnel is supported, the higher the reliability index becomes and the more stable the tunnel is predicted to be. Also an optimal support pattern and advance rate can be determined quantitatively by performing a risk analysis considering the construction cost and the cost of losses that can occur due to the collapse of a tunnel.