## 3 Analysis of Test Results
### Basic Physical Parameters and Wave Velocity Determination of Coal Stone Samples
#### 3.1.1 Basic Physical Parameters
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline
**Temperature** & **Sample ID** & **Size (Diameter \(\times\)** & **Density** & **Initial** & **Drying** & **Saturation** & **F Wave** & **Average** & **Uniaxial** & **F Poisson/s** & **Impact** & **Experimental** \\ \(F\) & **Single ID** & **Size (Diameter \(\times\)** & **High/mm** & **High/mm** & **Wave**  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline
**Temperature** & **Sample** & **Size (Diameter \(\times\)** & **Density** & **Initial** & **Drying** & **Sweet** & **Wave** & **Saturation** & **P** **Wave** & **Average** & **Uniaxial** & **Elastic** & **Poisson’s** & **Impact** & **Experimental** \\ /C & **ID** & **Height/mm** & **p/g/cm3** & **Speed** & **Veloco-** & **Wave** & **Velocity** & **Wave** & **Complexity** & **Moulus** & **Flan** & **Sped** & **Result** \\  & & & & & & & & & & & & & & \\  & & & & & & & & & & & & & & \\  & & & & & & & & & & & & & & \\  & DR-0.1 & 50 \(\times\) 50 & 2.67 & 2.21 & 2.11 & — & 2.42 & — & — & — & — & 9.38 & impact fracture \\  & & DR-0.2 & 50 \(\times\) 50 & 2.71 & 2.21 & 2.03 & — & 2.40 & — & — & — & 14.02 & impact smash \\  & & DR-0.3 & 50 \(\times\) 50 & 2.71 & 2.19 & 2.13 & — & 2.38 & — & — & — & 17.30 & impact smash \\  & & DR-0.4 & 50 \(\times\) 100 & — & — & — & — & — & 39.36 & 8.64 & 0.23 & impact smash \\
0 & & SR-0.1 & 50 \(\times\) 50 & 2.70 & 2.10 & 1.98 & 2.30 & 2.60 & — & — & — & 9.12 & impact smash \\  & & SR-0.2 & 50 \(\times\) 50 & 2.67 & 2.10 & 2.08 & 2.24 & 2.64 & 2.61 & — & — & 14.02 & impact smash \\  & & SR-0.3 & 50 \(\times\) 50 & 2.67 & 2.10 & 1.95 & 2.17 & 2.60 & — & — & — & 17.81 & impact smash \\  & & SR-0.4 & 50 \(\times\) 100 & — & — & — & — & — & 20.83 & 8.82 & 0.21 & impact smash \\ \hline  & DR-10.1 & 50 \(\times\) 50 & 2.74 & 2.19 & 2.04 & — & 2.50 & — & — & — & 10.61 & impact fracture \\  & & DR-10.2 & 50 \(\times\) 50 & 2.66 & 2.19 & 2.10 & — & 2.28 & 2.37 & — & — & — 13.80 & impact smash \\
10 & & DR-10.3 & 50 \(\times\) 50 & 2.73 & 2.19 & 1.90 & — & 2.32 & — & — & — & 17.87 & impact smash \\  & & SR-10.1 & 50 \(\times\) 50 & 2.70 & 2.08 & 1.85 & 2.19 & 2.40 & — & — & — & 9.69 & impact smash \\  & & SR-10.2 & 50 \(\times\) 50 & 2.73 & 2.08 & 1.77 & 2.20 & 2.60 & 2.51 & — & — & 13.91 & impact smash \\  & & SR-10.3 & 50 \(\times\) 50 & 2.75 & 2.08 & 1.91 & 2.31 & 2.52 & — & — & — & 10.30 & impact smash \\  & & DR-20.1 & 50 \(\times\) 50 & 2.70 & 2.19 & 1.96 & — & 2.29 & — & — & — & 10.39 & impact smash \\  & & DR-20.2 & 50 \(\times\) 50 & 2.75 & 2.18 & 2.02 & — & 2.34 & — & — & — & 15.80 & impact smash \\  & & DR-20.3 & 50 \(\times\) 50 & 2.72 & 2.17 & 1.98 & — & 2.38 & — & — & 38.50 & 8.72 & 0.25 & impact smash \\
20 & & SR-20.4 & 50 \(\times\) 50 & 2.72 & 2.08 & 2.07 & 2.38 & 2.43 & — & — & — & 9.92 & impact smash \\  & & SR-20.1 & 50 \(\times\) 50 & 2.71 & 2.07 & 2.02 & 2.41 & 2.44 & — & — & — & 14.76 & impact smash \\  & & SR-20.3 & 50 \(\times\) 50 & 2.69 & 2.07 & 1.95 & 2.34 & 2.41 & — & — & 18.32 & impact smash \\  & & SR-20.4 & 50 \(\times\) 100 & — & — & — & — & — & — & 23.19 & 8.75 & 0.23 & impact smash \\ \hline1.2 Characteristics of the Wave Velocity Measurements at Different Temperatures and Saturation Levels  
In this study, after several measurements of the sample, the average wave speed was used and plotted as a graph of the variation in the wave speed of the longitudinal wave. Figure 7 shows the ultrasonic wave velocity diagram of the dry and saturated coal and rock samples at different temperatures. As shown in the figure, the degree of wave speed can directly reflect the degree of material densification. The ratio of coal samples (1.68-2.01 km/s) to rock samples (2.24-2.61 km/s) shows that the degree of densification of coal is lower than that of rock. The wave speeds of all coal and rock samples showed a trend of initially increasing, then decreasing, and then increasing as the temperature decreases. The inflection points were at \(0\,^{\circ}\)C and \(-10\,^{\circ}\)C, and an \"N\"-shaped pattern was observed.