## 4 Comparison of Prediction Accuracy
### Results and Analysis
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**No.** & **Rock Type** & **F/MPa\({}^{-2}\)** & **G/MPa\({}^{-2}\)** & **U/MPa\({}^{-1}\)** & **V/MPa\({}^{-1}\)** & **M/MPa\({}^{-2}\)** \\ \hline
1 & Bossier shale & \(5.01\times 10^{-5}\) & \(1.91\times 10^{-4}\) & \(9.67\times 10^{-3}\) & \(6.0487\times 10^{-3}\) & \(2.335\times 10^{-3}\) \\ \hline
2 & Vaca Muerta shale & \(1.35\times 10^{-4}\) & \(8.75\times 10^{-5}\) & \(4.337\times 10^{-3}\) & \(5.4687\times 10^{-3}\) & \(8.41\times 10^{-4}\) \\ \hline
3 & Anigiers Schist & \(2.88\times 10^{-7}\) & \(2.10\times 10^{-4}\) & \(1.4504\times 10^{-2}\) & \(7.0787\times 10^{-3}\) & \(9.34\times 10^{-3}\) \\ \hline
4 & Martinsburg Slate & \(4.78\times 10^{-7}\) & \(8.23\times 10^{-5}\) & \(7.847\times 10^{-3}\) & \(2.5387\times 10^{-3}\) & \(1.717\times 10^{-3}\) \\ \hline
5 & Austin Slate & \(4.35\times 10^{-7}\) & \(2.42\times 10^{-5}\) & \(3.017\times 10^{-3}\) & \(1.2187\times 10^{-3}\) & \(3.74\times 10^{-4}\) \\ \hline
6 & GreenRiver Shale 1 & \(6.96\times 10^{-6}\) & \(3.98\times 10^{-5}\) & \(4.337\times 10^{-3}\) & \(2.2347\times 10^{-3}\) & \(2.33\times 10^{-4}\) \\ \hline
7 & GreenRiver Shale 2 & \(4.35\times 10^{-7}\) & \(9.34\times 10^{-5}\) & \(5.366\times 10^{-3}\) & \(1.7117\times 10^{-3}\) & \(6.96\times 10^{-4}\) \\ \hline
8 & Quartz Phyllite & \(6.14\times 10^{-5}\) & \(2.90\times 10^{-4}\) & \(1.3808\times 10^{-2}\) & \(6.9047\times 10^{-3}\) & \(2.34\times 10^{-3}\) \\ \hline
9 & Carbona Phyllite & \(2.90\times 10^{-4}\) & \(2.10\times 10^{-4}\) & \(9.674\times 10^{-3}\) & \(1.001\times 10^{-2}\) & \(2.34\times 10^{-3}\) \\ \hline
10 & Micaceous Phyllite & \(3.11\times 10^{-5}\) & \(3.74\times 10^{-4}\) & \(1.5229\times 10^{-2}\) & \(1.0356\times 10^{-2}\) & \(9.34\times 10^{-3}\) \\ \hline
11 & Penrhyn Slate & \(8.23\times 10^{-5}\) & \(2.59\times 10^{-5}\) & \(2.814\times 10^{-3}\) & \(5.2797\times 10^{-3}\) & \(8.41\times 10^{-4}\) \\ \hline
12 & Tourmemire Shale & \(5.85\times 10^{-4}\) & \(8.41\times 10^{-4}\) & \(1.4504\times 10^{-2}\) & \(1.2618\times 10^{-2}\) & \(9.34\times 10^{-3}\) \\ \hline \end{tabular}
\end{table} 
Table 3: Fitting parameters of [PERSON]’s model. The mechanical behavior of anisotropic rock exhibits complex failure characteristics influenced not only by hydrostatic pressure but also significantly by the angular relationship between the axial loading direction and the bedding plane orientation. A comparative analysis of three distinct anisotropic strength criteria reveals that the SPW criterion uniquely demonstrates a distinctive shoulder-shaped pattern in its predicted strength variation curve across different bedding plane angles. This characteristic manifest as maintained consistency between theoretical predictions and actual strength changes within specific ranges of both low- and high-bedding plane angles. Notably, experimental measurements show a marked discrepancy between peak strength values at 0\({}^{\circ}\) and 90\({}^{\circ}\) bedding plane angles. Figure 4: Experimental data of Angiers Schist fit with three anisotropic models: (**a**) single plane of weakness model (**b**) [PERSON]’s model, and (**c**) patchy plane of weakness model. Figure 3: Experimental data of Bossier shale fit with three anisotropic strength models: (**a**) single plane of weakness model (**b**) [PERSON]’s model, and (**c**) patchy plane of weakness model. orientations, with perpendicular loading configurations (90\({}^{\circ}\)) generally yielding higher strength values than parallel loading scenarios (0\({}^{\circ}\)). This phenomenon arises because axial loading parallel to bedding planes predominantly induces tensile failure along weak planes, whereas perpendicular loading typically causes shear failure across bedding planes. Given that most rocks demonstrate substantially lower tensile strength compared to compressive resistance, this inherent material property fundamentally explains the observed strength hierarchy between different loading orientations relative to bedding planes.