Abstract fd>{ UyU
Rock mass is inhomogeneous in nature. Data for underground structure designs are mainly obtained from site investigations and WH1 " HO
tests, but they are very limited. For this reason, uncertainty exists in the process of constructing underground structures in a rock C5I7\ 9F)
mass. In the design a tunnel support pattern, the most important parameters such as advance rate and excavation method must be iO?^y(phC
determined optimally. However, it is difficult to determine these parameters quantitatively. In addition, if these parameters are deter- 'F.P93
mined incorrectly, unexpected risk occurs such as the decrease in the tunnel stability or economic loss due to excessive amount of W4 d32+V
supports. `VO;\s$5j
In this study, a methodology to determine an optimal support pattern and advance rate for the design of a tunnel is introduced !8[A;+o3P
based on risk analysis. It can be confirmed quantitatively that the more the tunnel is supported, the higher the reliability index q@[F|EF=
becomes and the more stable the tunnel is predicted to be. Also an optimal support pattern and advance rate can be determined ?z l<"u
quantitatively by performing a risk analysis considering the construction cost and the cost of losses that can occur due to the col- -wV2
79^b
lapse of a tunnel. iz`>'wp C
2005 Elsevier Ltd. All rights reserved. *P`wuXn}
Keywords: Risk analysis; Factor of safety; Monte Carlo simulation; T
