## 5 Analysis of Test Results
### Macroscopic Analysis of Failure Patterns of the Test Section
Compared to the two test sections under the second and third conditions, the peak and residual values of the crown displacement of the conventional steel-bolt-reinforced test section are higher than those of the RDEA-bolt-reinforced test section. Taking the third condition test with an explosive charge amount of W = 10 kg as an example, the peak displacement of the conventional steel-bolt-reinforced test section is 13.694 mm (2.15 times that of the RDEA-bolt-reinforced test section), and the RDEA-bolt-reinforced test section is 6.37 mm. This phenomenon corresponds to the macroscopic failure modes of the two test sections and also reflects that the blast resistance of the RDEA bolt is better than that of the conventional steel bolt. The exponential fitted relationships between the crown displacement and the proportional distance \(R/W^{1/3}\) of the RDEA-bolt-reinforced test section and conventional steel-bolt-reinforced test section under different conditions are, respectively, as follows:  
\[\text{d}/\text{W}^{1/3}=2.11787(\frac{R}{W^{1/3}})^{-4.05} \tag{2}\]  
\[\text{d}/\text{W}^{1/3}=3.70727(\frac{R}{W^{1/3}})^{-2.06} \tag{3}\]  
In the equation:  
\(d\)--the displacement of the arch crown, m;  
\(W\)--the amount of explosive charge, kg;  
\(R\)--the distance between the arch crown and the blast center, m.  
Figure 13: Comparison diagram of the displacement of each test section under different explosive loads at the arch crown: (**a**) conventional steel-bolt-reinforced test section and (**b**) RDEA-bolt-reinforced test section. The fitted Equations (2) and (3) indicated that there is a negative exponential relationship between the crown displacement and the proportional distance \(R/W^{1/3}\) of each test section, and the peak displacement will decrease with the increase in the proportional distance. At the same time, it also indicates that when the reinforcement type of the cavern, the distance from the explosive center, and the amount of explosives are known, the peak displacement of the crown can be predicted by fitting the relationship equation. As given in Table 2, the total residual value of the crown displacement of the conventional steel-bolt-reinforced test section is 16.755 mm (2.28 times that of the total residual value of the crown displacement of the RDEA-bolt-reinforced test section) and that of the RDEA-bolt-reinforced test section is 7.344 mm. This indicated that the damage of the conventional steel-bolt-reinforced test section is more severe than that of the RDEA-bolt-reinforced test section. Comparing the peak and residual values of the crown displacement of the two test sections under the third condition (W = 10 kg), it was found that the proportion of the rebound displacement of the conventional steel-bolt-reinforced test section to the peak displacement was only 9.09%, while that of the RDEA-bolt-reinforced test section is 31.1%. The proportion of the displacement rebound of each test section reflects the difference in blast resistance performance between the caverns. This also indicated that the blast resistance performance of the RDEA-bolt-reinforced test section is better in this test, and the RDEA bolt played a role in restoring part of the displacement during the test process due to its good anchoring performance, while the blast resistance performance of the conventional steel-bolt-reinforced test section is poor. As shown in the displacement curve in Figure 13, the crown displacement of the two test sections tended to stabilize at the 90 ms mark after reaching the peak values in the three condition tests, indicating that the rock deformation has shown a significant lag phenomenon under the conditions of explosive dynamic loading.