## 6 Analysis of Pressure Measurement Experiments  
In this study, we conducted automatic monitoring experiments of shockwave emission for four combinations of storage tank volumes \(V_{t}\) of 3000 cm\({}^{3}\) (with a length of 60 cm) and 5000 cm\({}^{3}\) (with a length of 100 cm) and storage tank pressures \(P_{t}\) of 400 kPa and  
Figure 14: The pressure-monitoring screen of shockwave impact. From the maximum pressure values of the four experiments recorded in Table 1, we can see that in experiments 1 and 2 (\(V_{t}\) = 3000 cm\({}^{3}\)), the \(d_{emax}\) of the shockwave is 25 cm (\(p_{simax}\) = 0, \(i\) = 4, 5, 6). In experiments 3 and 4 (\(V_{t}\) = 5000 cm\({}^{3}\)), the \(d_{emax}\) of the shockwave is 30 cm (\(p_{simax}\) = 0, \(i\) = 5, 6). Therefore, the larger the storage tank volume, the farther the shockwave impacts the soil. Comparing experiment 1 (\(P_{t}\) = 400 kPa) with experiment 2 (\(P_{t}\) = 600 kPa), we can find that the \(p_{s1 max}\), \(p_{s2 max}\), and \(p_{s3 max}\) in the latter are all higher than those in the former. The greater the tank pressure, the greater the pressure of the shockwave impact. We can also get the same result by comparing the \(p_{s1 max}\), \(p_{s2 max}\), \(p_{s3 max}\), and \(p_{s4 max}\) in experiment 3 and experiment 4. Comparing the pressure measurement results of each experiment in Table 1 with the numerical simulation of the time-dependent pressure variation in Figure 8, we can find that in experiment 3, the maximum output pressure \(p_{omax}\) is 1036.3 kPa and the maximum pressure at the L1 position \(p_{s1 max}\) is 345.4 kPa. In numerical simulation, when we set the pressure at the shock tube inlet to 10 atm (about 1000 kPa), the shockwave pressure emitted from each hole can increase to 3.4 atm (about 340 kPa). We can see that the pressure measurement results of experiment 3 are consistent with the numerical simulation results in Figure 8.  
In the shockwave soil-loosening visual observation experiment in Section 4, we can observe that shockwaves are emitted from the output holes in eight directions and a top-down order. In the measurement experiment in Section 5, we buried the soil pressure sensors \(s_{p1}\), \(s_{p3}\), \(s_{p5}\), and \(s_{p6}\) in the emission directions of the output holes of the first circle (i.e., north, east, south, and west) according to the measurement plan in Figure 12. We buried \(s_{p2}\) and \(s_{p4}\) in the emission directions of the output holes of the second circle (northeast and southeast). The measurement results shown in Table 1 show that the maximum pressures measured by the sensors within the maximum emission distance \(d_{emax}\) are all greater than zero, and the pressure decreases as the distance increases. For example, in experiments 1 and 2, \(p_{s1 max}>p_{s2 max}>p_{s3 max}>0\), and in experiments 3 and 4, \(p_{s1 max}>p_{s2 max}>p_{s3 max}>p_{s4 max}>0\). This proves that shockwaves can be emitted from output holes in different directions. In addition, by comparing the positions of the maximum pressure of each curve in Figure 14, we can see that the positions of \(p_{s1 max}\) and \(p_{s3 max}\) detected by \(s_{p1}\) and \(s_{p3}\) are approximately 6505, while the positions of \(p_{s2 max}\) and \(p_{s4 max}\) detected by \(s_{p2}\) and \(s_{p4}\) are approximately 6535. This proves that the propagation of the shockwave first reaches \(s_{p1}\) and \(s_{p3}\) in the first circle, and \(s_{p2}\) and \(s_{p4}\) in the second circle arrive later.