## 3 Dynamic Tests with the Use of Hopkinson Split Pressure Bar (SHPB)
The tables present the results of eight dynamic tests performed for samples with different slenderness values (L/D) and different material parameters. The tables contain information about the maximum value of the obtained dynamic stresses (\(\sigma_{\text{max}}\)) and the corresponding maximum strains (\(\varepsilon_{\text{max}}\)) and strain rates. Another value calculated for each sample was Dynamic Increase Factor (DIF), which signifies the increase in rock strength due to dynamic loading with respect to static loading, which can be defined as below:  
\[\sigma_{S}(t)=\frac{A_{B}E_{B}}{2A_{S}}[\varepsilon_{I}(t)+\varepsilon_{R}(t)+ \varepsilon_{T}(t)] \tag{2}\]0  
Figures 11-13 present the courses of dynamic stresses for sandstone samples, assuming that slenderness L/D = 1. The average value of the samples' compressive strength (UCS), which was obtained as a result of static tests, is additionally marked with a horizontal line. The charts are accompanied by photos of samples after tests, which present the form of material destruction typical of a given test. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multicolumn{6}{c}{**Apricot Pink**} & \multicolumn{6}{c}{**Barwald**} & \multicolumn{6}{c}{**Kandla Grey**} \\ \hline \multirow{2}{*}{**Test**} & \(\sigma_{\text{max}}\) & \  
\[\sigma_{S}(t)=\frac{A_{B}E_{B}}{2A_{S}}[\varepsilon_{I}(t)+\varepsilon_{R}(t)+ \varepsilon_{T}(t)] \tag{2}\]1 Stress-strain response of Apricot Pink sandstone (L/D = 1). \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Apricot Pink**} & \multicolumn{4}{c}{**[PERSON]**} & \multicolumn{4}{c}{**Kandla Grey**} \\ \hline \multirow{2}{*}{**Test**} & \(\sigma_{\text{max}}\) & \(\varepsilon_{\text{max}}\) & \(\dot{\varepsilon}\) & \multirow{2}{*}{**DIF**} & & \multirow{2}{*}{**Test**} & \(\sigma_{\text{max}}\) & \(\varepsilon_{\text{max}}\) & \(\dot{\varepsilon}\) & \multirow{2}{*}{**DIF**} & & \multirow{2}{*}{**Test**} & \(\sigma_{\text{max}}\) & \(\varepsilon_{\text{max}}\) & \(\dot{\varepsilon}\) & \multirow{2}{*}{**DIF**} \\ \cline{2-2} \cline{8-11}  & **MPa** & **[-]** & **[1/s]** & & & & & **MPa** & **[-]** & **[1/s]** & & & **MPa** & **[-]** & **[1/s]** \\ \hline
2 & 308.9 & 0.022 & 108.6 & 2.45 & 3 & 259.4 & 0.0151 & 71.3 & 3.28 & 3 & 390.9 & 0.01 & 34.2 & 1.90 \\
3 & 310.7 & 0.02 & 87.6 & 2.47 & 5 & 268.2 & 0.0131 & 95.5 & 3.39 & 4 & 389.3 & 0.012 & 51.4 & 1.89 \\
4 & 294.7 & 0.021 & 85.6 & 2.34 & 6 & 274.7 & 0.0159 & 90.7 & 3.48 & 5 & 407.4 & 0.0094 & 40.9 & 1.98 \\
7 & 359.1 & 0.011 & 122 & 2.85 & 7 & 267.4 & 0.0174 & 112.9 & 3.38 & 6 & 440.33 & 0.0088 & 58.8 & 2.14 \\
9 & 317.5 & 0.017 & 173.5 & 2.52 & 8 & 279.7 & 0.0199 & 120.9 & 3.54 & 8 & 527.9 & 0.0071 & 56.9 & 2.56 \\
10 & 315.97 & 0.015 & 180 & 2.51 & 9 & 270.8 & 0.0137 & 125.3 & 3.43 & 10 & 544.7 & 0.0059 & 56.2 & 2.64 \\
11 & 331.2 & 0.012 & 150 & 2.63 & 10 & 264.7 & 0.0197 & 106.4 & 3.35 & 11 & 539.4 & 0.0058 & 66.1 & 2.62 \\
12 & 332.1 & 0.015 & 182 & 2.64 & 11 & 265.8 & 0.0188 & 143.7 & 3.36 & 12 & 556.1 & 0.0057 & 62.7 & 2.70 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Results of dynamic test for sandstone samples with L/D =1/2. Figure 12: Stress-strain response of Barwald sandstone (L/D = 1). In the case of Apricot Pink sandstone, the destruction of samples was usually accompanied by large amounts of dusty fraction, whereas the destruction of samples of the other two sandstones, characterized by lower porosity, was associated with a larger grain size of the material and a lower share of the dusty fraction. Due to the observed regularity, it was decided to perform a sieve analysis of the obtained excavated material (gradation test). The results of this analysis are shown in Figures 14-17. The performed grain analysis involved isolating six material fractions. For this purpose, sieves with mesh sizes of 10, 5, 2, 1, and 0.5 mm were used. The tests were carried out for minimum six samples of a given material.