# Mechanisms and Models of Attenuation of Shock Waves through Rock Formations
## 4 Discussion  
### Shock Wave Disturbance Roadway Mechanism  
The mechanism of the dynamic and static load superposition of rock burst is still recognized by most scholars. This theory explains the cause of rock burst and summarizes the natural and artificial factors that affect the intensity of rock burst. Among the natural factors, special geological structure and a thick hard roof are the most common reasons. Among the human factors, unreasonable working face layout and unreasonable measures to reduce rock pressure will also greatly increase the probability of rock burst. For example, in the process of coal mining, the hard roof is difficult to break in the process of mining. When it breaks, it releases substantial impact energy. The resulting shock wave instantly damages or destroys the underground facilities. According to previous research:  
1. When the shock wave spreads from the source to the surrounding rock of the roadway, the intensity gradually decreases.
2. There are different attenuation rates in rock formations with different properties.
3. During the transmission of the shock wave, the trend of the attenuation rate is decreasing.  
Figure 10: Shock wave YY\(-\)stress distribution characteristics through the roadway-surrounding rock. (**a**) The shock wave reaches the roadway roof (no support). (**b**) The shock wave reaches the roadway roof. (**c**) The shock wave reaches the two ribs of the roadway (no support). (**d**) The shock wave reaches the two ribs of the roadway (**e**) The shock wave reaches the floor of the roadway (no support) (**f**) The shock wave reaches the floor of the roadway.  
4. Anchor cables cannot adaptively change their anchorage strength to stabilize the roof when the shock wave reaches the roadway. The role of the anchor cable is that it creates a complete structure with the roof of the roadway to resist shock waves.  
Figure 11 shows the damage characteristics of a rock formation when a mining earthquake occurs in a hard roof. When the rock burst occurs in the roof, the energy is rapidly released and spread, with wide fractures spreading out from the source. The subsurface rock is intact and shock waves are easily transmitted from the source to the roadway-surrounding rock. Combined with the conclusions of Section 3:  
1. Due to the confines of the underground space, there is not enough space at the shock source for great displacements. The closer to the shock source, the higher the degree of damage to the rock.
2. For dynamic rocks, the roadway is a perfect free space. The rock damage is also dramatic here.
3. The subsidence of the roadway roof is an important factor in roadway damage.  
In the rock burst, not all rock formations are damaged, and we have focused on the damage to the roadway-surrounding rock. There are many influencing factors, such as the energy generated by the rock burst, the location of the roadway relative to the impact shock source and the support measures for the roadway. Based on these factors and conditions, a \"shock wave through-layer attenuation model\" is established and the equation for the attenuation of shock waves during a rock burst is derived.