## 4 Geotechnical Parameters  
Engineering rock mass quality is a comprehensive reflection of the complex engineering geological characteristics of rock mass. It not only objectively reflects the inherent physical and mechanical properties of rock mass structure but also provides a reliable basis for engineering stability analysis, the reasonable utilization of rock mass, and the correct selection of various rock mass mechanical parameters. Therefore, the geotechnical parameters of different rock masses were evaluated using laboratory testing and various empirical equations [42] based on Q, RMR, and GSI systems.  
The drifts located in the footwall of the ore body and the lithology were mainly besetization cataclasite. The physical and mechanical properties of intact rocks determined in the laboratory are shown in Table 3. The rock mass classification values for different study areas are given in Table 4. The rock mass classification values based on RMR are evaluated as fair for the \(-915\) m level, good for the \(-945\) m level, and poor for the \(-960\) m level. The rock mass classification values based on Q are evaluated as poor for the \(-915\) m level, good for the \(-945\) m level, and very poor for the \(-960\) m level. It can be seen that the Q results were more conservative than those of the RMR.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Level**} & **Wedge Name and** & \multirow{2}{*}{**Volume (m\({}^{3}\))**} & \multirow{2}{*}{**Weight (t)**} & \multirow{2}{*}{**Apex Height (m)**} & \multicolumn{2}{c}{**Factor of Safety**} \\ \cline{5-6}  & **Number** & & & & **Unsupported** & **Supported** \\ \hline \multirow{3}{*}{\(-915\) m} & Lower left wedge 2 & 5.384 & 14.828 & 5.88 & Stable & Stable \\  & Upper right wedge 7 & 4.648 & 12.802 & 5.77 & 0.535 & 276.662 \\  & Upper left wedge 8 & 0.0007 & 0.002 & 0.03 & 0 & 21,000.835 \\ \hline \multirow{3}{*}{\(-945\) m} & Lower left wedge 3 & 0.133 & 0.368 & 0.64 & 0.865 & 1124.283 \\  & Roof wedge 4 & 2.907 & 8.011 & 2.81 & 0.066 & 132.512 \\  & Floor wedge 5 & 5.955 & 16.412 & 3.56 & Stable & Stable \\  & Upper right wedge 6 & 0.166 & 0.457 & 0.68 & 0.686 & 1561.185 \\ \hline \multirow{3}{*}{\(-960\) m} & Floor wedge 2 & 1.601 & 4.414 & 1.64 & Stable & Stable \\  & Lower right wedge 3 & 0.117 & 0.323 & 0.48 & 0.237 & 419.598 \\ \cline{1-1}  & Upper left wedge 5 & 0.0015 & 0.004 & 0.05 & 0.200 & 7974.418 \\ \cline{1-1}  & Lower left wedge 6 & 0.125 & 0.343 & 0.49 & 0.756 & 683.126 \\ \cline{1-1}  & Roof wedge 7 & 0.513 & 1.413 & 1.24 & 0.043 & 517.726 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Detail information on wedge analysis.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameters** & **Unit** & \(-915\) m & \(-945\) m & \(-960\) m \\ \hline Unit weight, \(\rho\) & kg/m\({}^{3}\) & 2754 & 2756 & 2757 \\ Uniaxial compressive strength, \(\sigma_{c}\) & MPa & 80.81 & 93.78 & 93.46 \\ Tensile strength, \(\sigma_{t}\) & MPa & 4.91 & 4.16 & 3.9 \\ Deformation modulus, E & GPa & 14.73 & 13.66 & 15.02 \\ Poisson’s ratio, \(\mu\) & 0.21 & 0.18 & 0.19 \\ Cohen, \(c\) & MPa & 4.65 & 4.67 & 4.89 \\ Internal friction angle, \(\varphi\) & \({}^{\circ}\) & 34.54 & 33.22 & 32.31 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Physical and mechanical properties of intact rocks.  
The physical and mechanical parameters of rock mass reflect the stability and quality of rock mass, which are closely related to the rock hardness and the integrity of rock mass, which determine the basic quality of rock mass. One of the purposes of basic quality classifications of engineering rock mass is to determine the physical and mechanical parameters of the rock mass directly and quickly according to the grade of engineering rock mass, without a large number of tests [26]. The mechanics parameters of rock mass along the drift are summarized and listed in Table 5.