## 3 Experimental Results
### Influence of Layer Orientation Effect on Mechanical Parameters  
The tensile strength, deformation, and splitting modulus are important parameters for the fracturing deformation of oil shale reservoirs. According to classical elastic mechanics, the tensile strength of the sample is calculated by Formula (1), and the calculation results are shown in Table 3.  
\[\sigma_{\text{t}}=\frac{2P}{\pi D_{\text{t}}}=0.636P/D_{\text{t}} \tag{1}\]  
where \(\sigma_{\text{t}}\) is the tensile strength (MPa), \(P\) is the failure load (N), and \(D_{\text{t}}\) is the diameter (mm) and thickness (mm) of the sample, respectively. Table 3 and Figure 6 show the tensile strength values of continental shale with different layer orientations. The test results show that, on the one hand, the tensile strength of continental shale with the same layer orientation is discrete to a certain extent. The dispersion of tensile strength increases with the increase of layer orientation. Compared with the average tensile strength, the maximum deviation of the tensile strength of continental shale is about 0.05%. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Mechanical Response Characteristics**} & \multirow{2}{*}{**Feature Point**} & \multicolumn{3}{c}{**Feature Point Threshold/KN**} \\ \cline{3-5}  & & \(\mathbf{\sigma}^{\circ}\leq\mathbf{\theta}\leq\mathbf{30^{\circ}}\) & \(\mathbf{30^{\circ}}\leq\mathbf{\theta}\leq\mathbf{60^{\circ}}\) & \(\mathbf{60^{\circ}}\leq\mathbf{\theta}\leq\mathbf{90^{\circ}}\) \\ \hline Compaction stage & Compaction closure point & \(\leq\)1.00 & 1.00–3.75 & 3.75–5.24 \\ Elastic stage & Crack cracking point & \(\leq\)1.80 & 1.80–6.05 & 6.05–8.93 \\ Failure stage & Strength failure point & 1.310–2.202 & 2.202–6.940 & 6.940–10.118 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Mechanical action stages and threshold values of characteristic points of samples with different layer orientations. Figure 5: Uniaxial compressive strength of continental shale. shale with different layer orientations is less than 17.1%. On the other hand, the tensile strength of continental shale with different layer orientations is significantly different. The tensile strength of continental shale increases with the increase of layer orientation. The tensile strength is the smallest when \(\theta=0^{\circ}\) (that is, the layer orientation is parallel to the loading direction), and the maximum is when \(\theta=90^{\circ}\). When \(\theta=0^{\circ}\)-\(30^{\circ}\), the tensile strength increases slowly, when \(\theta=30^{\circ}\)-\(45^{\circ}\), the tensile strength increases the fastest, and when \(\theta=45^{\circ}\)-\(90^{\circ}\), the tensile strength is close to a linear increase. Figure 7 shows the deformation characteristics of the stress peak at different layer orientations. It can be seen that the deformation at the peak of the stress presents an overall increasing trend with the increase of layer orientation. Among them, the deformation growth rate is faster in the interval \(\theta=0^{\circ}\)-\(45^{\circ}\), and the largest in the interval \(\theta=30^{\circ}\)-\(45^{\circ}\). However, the deformation growth rate slows down in the interval \(\theta=45^{\circ}\)-\(90^{\circ}\) and is the smallest in the interval \(\theta=60^{\circ}\)-\(90^{\circ}\). Obviously, as the layer orientation increases, the anisotropy between the lamination gradually increases, and the anisotropy exhibits the characteristics of first increasing and then slowing down. To quantify the layer orientation effect, the layer orientation effect coefficient \(\lambda\) (\(\theta\)), defined by [PERSON], is used to characterize it, as shown in Formula (2) [9]. Table 3 and Figure 8 show the calculation results of the mean layer orientation effect coefficient of the mechanical parameters of continental shale with different layer orientations.