# The Deformation Law of a Soft-Rock Cavern by Step Excavation in a Pumped Storage Power Station
## 3 Results
### The Influence of Support Measures on the Stability of the Surrounding Rock in Underground Caverns  
According to the mechanical parameters of the soft-rock mass and the mentioned support methods, the paper discussed the influence of support measures on the stability of the surrounding rock in underground caverns. Therefore, the finite difference method was used to simulate the step-by-step excavation of underground caverns and the displace \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Name** & **G\({}_{\mathbf{M}}\) (GPa)** & **G\({}_{\mathbf{K}}\) (GPa)** & **n\({}_{\mathbf{M}}\) (GPa h)** & **n\({}_{\mathbf{K}}\) (GPa h)** \\ \hline Sandstone & 489.6761 & 11.16571 & 2898.391 & 1.803093 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Rheological parameters used for the numerical model. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Name** & **Stress Level (MPa)** & **G\({}_{\mathbf{M}}\) (GPa)** & **G\({}_{\mathbf{K}}\) (GPa)** & **n\({}_{\mathbf{M}}\) (GPa h)** & **n\({}_{\mathbf{K}}\) (GPa h)** & **R\({}^{2}\)** \\ \hline Natural 0.5 MPa & 4 & 8.469547 & 16.43078 & 10,000 & 41.99804 & 0.686724 \\ Natural 0.5 MPa & 8 & 12.97276 & 15.10348 & 10,000 & 42.17472 & 0.665318 \\ ambient pressure & 12 & 15.3175 & 23.43532 & 10,000 & 45.79424 & 0.144663 \\ Recommended & 12.25327 & 18.32319 & 10,000 & 43.32233 & \\  & parameters & 12 & 492.7833 & 40.5884 & 9999.963 & 0.585766 & 0.12463 \\ Natural 3 MPa & 18 & 600 & 5.940712 & 10,000 & 0.09441 & 0.656332 \\ ambient pressure & 24 & 599.9999 & 4.435769 & 121.908 & 0.092265 & 0.994597 \\  & Recommended & 564.2611 & 16.98829 & 6707.29 & 0.257481 & \\ \hline Natural 6 MPa & 8 & 599.6736 & 12.07929 & 2807.976 & 1.645042 & 0.89486 \\ Natural 6 MPa & 16 & 368.2403 & 10.63802 & 2054.865 & 1.982264 & 0.885674 \\ ambient pressure & 24 & 501.1144 & 10.77981 & 3832.331 & 1.781973 & 0.861349 \\  & Recommended & 489.6761 & 11.16571 & 2898.391 & 1.803093 & \\  & parameters & 489.6761 & 11.16571 & 2898.391 & 1.803093 & \\ \hline \hline \end{tabular}
\begin{tabular}{c c c c c c c} \hline \hline
**Saturated 0.5** & 3 & 978,118.6 & 27.02992 & 49.910.3 & 0.02233 & 0.975636 \\ MPa confining & 4.5 & 599.999 & 11.58582 & 4500.291 & 0.494791 & 0.80275 \\ pressure & Recommended & 489.359.3 & 19.30787 & 27,205.29 & 0.25856 & \\ \hline \hline
\begin{tabular}{c} Saturated 3 MPa \\ confining \\ pressure \\ \end{tabular} & 6 & 58,205.47 & 0.981387 & 28.28857 & 0.004189 & 0.991984 \\  & Recommended & 58,205.47 & 0.981387 & 28.28857 & 0.004189 & \\  & parameters & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Plastic mechanical parameters of surrounding rocks in natural state. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Name** & **G\({}_{\mathbf{M}}\)** & **G\({}_{\mathbf{M}}\) (GPa)** & **G\({}_{\mathbf{K}}\) (GPa)** & **n\({}_{\mathbf{M}}\) (GPa h)** & **n\({}_{\mathbf{K}}\) (GPa h)** & **R\({}^{2}\)** \\ \hline \hline \multirow{5}{*}{Natural 0.5 MPa ambient pressure} & 12 & 492.7833 & 40.5884 & 9999.963 & 0.585766 & 0.12463 \\  & 18 & 600 & 5.940712 & 10,000 & 0.09441 & 0.656332 \\  & 24 & 599.9999 & 4.435769 & 121.908 & 0.092265 & 0.994597 \\  & Recommended & 564.2611 & 16.98829 & 6707.29 & 0.257481 & \\ \hline \hline \multirow{5}{*}{Natural 6 MPa ambient pressure} & 8 & 599.6736 & 12.07929 & 2807.976 & 1.645042 & 0.89486 \\  & 16 & 368.2403 & 10.63802 & 2054.865 & 1.982264 & 0.885674 \\  & 24 & 501.1144 & 10.77981 & 3832.331 & 1.781973 & 0.861349 \\  & Recommended & 489.6761 & 11.16571 & 2898.391 & 1.803093 & \\  & parameters & 489.6761 & 11.16571 & 2898.391 & 1.803093 & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Plastic mechanical parameters of surrounding rocks in natural state. ment trend of the surrounding rock after one year under the condition with or without support measures. The simulated displacement results of the midspan (y = \(-\)79.4 m) of the underground cavern and the whole underground cavern with or without support measures are shown in Figures 22 and 23.