# Formation Mechanism and Control Technology of an Excavation Damage Zone in Tunnel-Surrounding Rock
## 3 Blasting and Vibration Tests  
Firstly, the first blasting damage test of the surrounding rock was carried out with nonelectric detonators. The hole arrangement and initiation sequence are shown in Figure 1, and the blasting parameters are shown in Table 2. Because the section passes through an operating highway tunnel, the blasting vibration test points are arranged in the operating highway tunnel and above the excavation face. The specific monitoring points are arranged \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Geotechnical Name** & **Unit Weight \(\gamma\) (kN/m3)** & **Cohesion (kPa)** & **Angle of Internal** & **Basic Bearing Capacity \(\sigma_{0}\)** \\  & & **(kN/m3)** & **(kPa)** & **Friction \(\varphi\) (\({}^{\circ}\))** & **(kPa)** \\ \hline Gravel soil & 21 & & 20 & 100 \\ Mollison & 18.5 & 12 & 7 & 100 \\ Silty clay & 19 & 20 & 15 & 150 \\ Mudstone clamp & 22 & & 35 & 300 \\ Sandstone & 23 & & 45 & 450 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Material property parameters of main stratum types of excavated tunnels. in Figure 2. The \(y\)-direction blasting vibration velocity received by the three-direction velocity sensor is the largest according to the spatial position of the sensor and the explosion source, so these tests focus on the \(y\)-direction vibration velocity. The blasting vibration velocity waveform is shown in Figure 3.  
Then, the blasting test of surrounding rock damage was carried out by using electronic detonators. In order to ensure that the two tests have high contrast, the same hole arrangement of the two tests is ensured, as shown in Figure 4. The hole charge weight and blasting vibration test point arrangements are the same as those for nonelectric detonator blasting. The vibration velocity waveform of the electronic detonators is shown in Figure 5. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Bench**} & \multirow{2}{*}{\begin{tabular}{c} **Name of the** \\ **Boreholes** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Number of** \\ **Holes** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Borehole** \\ **Depth (m)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Single Hole** \\ **Charge (kg)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Detonator** \\ **Segment** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Subsection** \\ **Charge (kg)** \\ \end{tabular} } \\ \hline \multirow{4}{*}{\begin{tabular}{c} The arch part of \\ upper bench \\ \end{tabular} } & Auxiliary hole & 6 & 3 & 1.0 & MS7 & 6.0 \\  & Auxiliary hole & 9 & 3 & 1.0 & MS9 & 9.0 \\  & Auxiliary hole & 15 & 3 & 1.0 & MS11 & 15.0 \\  & Peripheral hole & 28 & 3 & 0.6 & MS15 & 16.8 \\ \hline \multirow{4}{*}{\
\begin{tabular}{c} The lower part \\ of upper bench \\ \end{tabular} } & Cutting hole & 10 & 4.5 & 2.0 & MS1 & 20.0 \\  & Auxiliary hole & 6 & 4 & 1.8 & MS3 & 10.4 \\  & Auxiliary hole & 4 & 4 & 1.6 & MS5 & 6.4 \\  & Auxiliary hole & 12 & 3 & 1.2 & MS7 & 7.2 \\  & Auxiliary hole & 6 & 3 & 1.0 & MS9 & 6.0 \\  & Auxiliary hole & 6 & 3 & 1.0 & MS11 & 6.0 \\  & Peripheral hole & 10 & 3 & 0.6 & MS13 & 6.0 \\ \hline \multirow{4}{*}{
\begin{tabular}{c} Bottom bench \\ \end{tabular} } & Auxiliary hole & 12 & 3 & 1.8 & MS11 & 21.6 \\  & Auxiliary hole & 13 & 3 & 1.8 & MS13 & 23.4 \\  & Auxiliary hole & 14 & 3 & 1.8 & MS15 & 25.2 \\  & Peripheral hole & 6 & 3 & 0.6 & MS17 & 3.6 \\ \hline Total & & 157 & & & & 182.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Details of blasting holes and explosive parameters. Figure 1: The hole arrangement and initiation sequence of nonelectric detonator blasting in the test. Note: The marked MS represents the detonator delay time series. The holes connected by dotted lines are in the same delay sequence and represent simultaneous initiation. Figure 4: The blasting hole arrangement and initiation sequence of tunnel electronic detonators. Figure 3: Vibration waveform of tunnel nonelectric detonator blasting.