## 5 Analysis and Results
### Construction Time with Tunnel Support Types
Despite the higher number of holes drilled in Type 2 (96 holes) than Type 1 (88 holes), the reason that more basic construction time is needed in Type 1 is mainly because the drilling rate in Type 1 (177 cm/min) is slower than that in Type 2 (198 cm/min) due to the very hard rock mass quality, even though the drill length is the same for the two types. In other words, the drill times in Types 1 and 2 are 144 and 118 min, respectively, as shown in Table 6. The ratios of the basic construction time to the total construction time increase from 34% to 40% with higher tunnel support types, as the round length decreases considerably from 3.5 m \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Category**} & \multirow{2}{*}{**Operations**} & \multicolumn{6}{c}{**Tunnel Support Types**} \\ \cline{3-8}  & & **1** & **2** & **3** & **4** & **5** \\ \hline \multirow{8}{*}{Basic} & Drilling (min) & 144 & 118 & 71 & 61 & 62 \\ \cline{2-8}  & Charging and blasting & 88 & 94 & 89 & 102 & 119 \\ \cline{2-8}  & Rig time, incidental lost time for drilling and blasting (min) & 51 & 48 & 43 & 43 & 45 \\ \cline{2-8}  & \multirow{2}{*}{One round} & Ventilation (min) & 28 & 28 & 28 & 28 & 28 \\ \cline{2-8}  & & Loading and hauling (min) & 129 & 129 & 84 & 70 & 61 \\ \cline{2-8}  & \multirow{2}{*}{Scaling (min)} & Scaling (min) & 43 & 50 & 73 & 99 & 112 \\ \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} Correction time for tunnel \\ length and job training (min) \\ \end{tabular} } & 0 & 0 & 0 & 0 & 0 \\ \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} Subtotal time (min) \\ \end{tabular} } & Subtotal time (h) 1  & 6887 & 6679 & 9685 & 13,407 & 17,738 \\ \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} Tunnel \\ (3 km) \\ \end{tabular} } & Subtotal time (week) 2  & 57 & 55 & 80 & 110 & 146 \\ \hline \multirow{8}{*}{Standard} & \multirow{2}{*}{\begin{tabular}{c} One round \\ \end{tabular} } & Shotcrete (min) & 123 & 123 & 121 & 116 & 165 \\ \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} One round \\ \end{tabular} } & Rock bolt (min) & 20 & 46 & 62 & 71 & 75 \\ \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} One round \\ \end{tabular} } & Steel rib/Lattice (min) girder & - & - & - & 45 & 45 \\ \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} Forepoling (min) \\ \end{tabular} } & Forepoling (min) & - & - & - & - & 44 \\ \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} Subtotal time (min) \\ \end{tabular} } & Subtotal time (min) & 144 & 170 & 183 & 231 & 330 \\ \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} Tunnel \\ (3 km) \\ \end{tabular} } & Subtotal time (h) 1  & 2053 & 2422 & 4572 & 7716 & 13,730 \\ \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} Subtotal time (week) 2 \\ \end{tabular} } & 17 & 20 & 38 & 63 & 113 \\ \hline \multirow{8}{*}{Gross 3 & Final scaling (h) & 108 & 108 & 106 & 108 & 106 \\ \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} Water protection (h) \\ \end{tabular} } & Water protection (h) & 1571 & 1571 & 1581 & 1573 & 1585 \\ \cline{1-1} \cline{2-8}  & \multirow{2}{*}{\begin{tabular}{c} Tunnel \\ (3 km) \\ \end{tabular} } & Concrete lining (h) & 4438 & 4438 & 4441 & 4350 & 4355 \\ \cline{1-1} \cline{2-8}  & \multirow{2}{*}{\
\begin{tabular}{c} Subtotal time (h) \\ \end{tabular} } & 6117 & 6117 & 6128 & 6031 & 6046 \\ \cline{1-1} \cline{2-8}  & \multirow{2}{*}{
\begin{tabular}{c} Subtotal time (week) 2 \\ \end{tabular} } & 50 & 50 & 50 & 50 & 50 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Breakdown of each operation time. for Type 1 to 1.2 m for Type 5, even though the round cycle time needed for one blasting round, excluding the tunnel supports, decreases slightly from 482 min to 426 min with higher tunnel support types; in turn, the basic construction time (= round cycle time \(\times\) tunnel length/round length) increases.