## 4 Classification of Construction Time  
The construction time in this study is separated into five categories: basic, standard, gross, tunnel, and total according to tunnel support and operation types in Korea. Table 3 shows the definitions of these categories of construction time and the kinds of tunnel supports, as well as the operations for each construction time type. The basic construction time is the time spent on pure excavation operations such as drilling, charging, ventilation, loading and hauling, and scaling. The standard construction \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Tunnel Support Type** & **1** & **2** & **3** & **4** & **5** & **Remarks** \\ \hline \multirow{3}{*}{\begin{tabular}{c} RMR \\ (Q-value) \\ \end{tabular} } & RMR & 100–80 & 80–60 & 60–40 & 40–20 & 20–0 & RMR = 9-LN(Q \(>\) 44 ) \\  & (Q-value) & (Q \(>\) 54) & (54 \(>\) Q \(>\) 6) & (6 \(>\) Q \(>\) 0.6) & (0.6 \(>\) Q \(>\) 0.07) & (0.07 \(>\) Q) & by [PERSON] [36] \\ \hline \multirow{3}{*}{\begin{tabular}{c} Shotcrete \\ \end{tabular} } & Thickness & 5 & 5 & 8 & 12 & 16 & \begin{tabular}{c} Designed \\ (Including overbreak \\ and rebound) \\ \end{tabular} \\ \cline{2-7}  & Length & 3 & 3 & 4 & 4 & 4 & \\ \cline{2-7}  & Spacing & Random & 2 & 1.5 & 1.5 & 1.5 & \\ \cline{2-7}  & Interval & Random & 3.5 & 2 & 1.5 & 1.2 & \\ \hline \multirow{3}{*}{\begin{tabular}{c} Steel \\ rib/lattice \\ girder \\ \end{tabular} } & Interval & \multirow{3}{*}{(m)} & \multirow{3}{*}{-} & \multirow{3}{*}{-} & \multirow{3}{*}{-} & \multirow{3}{*}{1.5} & \multirow{3}{*}{1.2} \\  & (m) & & & & & \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} Foreppling \\ (m) \\ \end{tabular} } & Length & - & - & - & - & 4 & \\ \cline{2-7}  & Spacing & - & - & - & - & 0.5 & \\ \cline{2-7}  & Interval & - & - & - & - & 1.2 & \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Concrete \\ lining \\ \end{tabular} } & Thickness & \multirow{3}{*}{(cm)} & \multirow{3}{*}{30} & \multirow{3}{*}{} & \multirow{3}{*}{} & \multirow{3}{*}{} & \multirow{3}{*}{} \\  & (cm) & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Tunnel support specifications in Korea. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Categories** & **Definition** & **Included Operations** \\ \hline \multirow{7}{*}{
\begin{tabular}{c} Construction time \\ (week) \\ \end{tabular} } & Basic & \(\bullet\) Time spent for pure excavation & \(\bullet\) Drilling, charging, ventilation, loading \\  & & and hauling, scaling \\ \cline{2-5}  & Standard & \(\bullet\) Basic + & \(\bullet\) Shotcrete, rock bolts, steel ribs/lattice \\  & & \(\bullet\) Time spent for usual tunnel support & girder, forepoling \\ \cline{2-5}  & Gross & \(\bullet\) Standard + & \(\bullet\) Final scaling, water protection, \\  & & \(\bullet\) Time spent for permanent support & concrete lining \\ \cline{2-5}  & Tunnel & \(\bullet\) Gross + & \(\bullet\) Roads, electricity, etc. \\ \cline{2-5}  & & Time spent for installation & \(\bullet\) Site preparation, portal construction, and \\ \cline{2-5}  & Total & \(\bullet\) Tunnel + & \(\bullet\) unforeseen rock condition \\  & & \(\bullet\) Time spent for site preparation & \(\bullet\) Three months (13.5 weeks) before site \\  & & and mobilisation & preparation, 2 weeks for portal excavation, \\  & & & 1 week/km for demobilisation \\ \hline \hline \multicolumn{2}{c}{Advance rate (m/week)} & \multicolumn{2}{c}{\(\bullet\) Tunnel length advanced during each construction time except the tunnel and total construction time} \\ \hline \multirow{2}{*}{Others} & \multicolumn{2}{c}{\(\bullet\) Tunnel length: 3 km} \\  & & \(\bullet\) Working hours per week: 120 h (20 h/day \(\times\) 6 day/week) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Classification of construction time and operations in this study. time includes the implementation of the usual tunnel supports to ensure tunnel safety such as shotcrete, rock bolts, forepoling, steel ribs, and injection (grouting), as well as the basic construction time in the NTNU model.