Hollow Effect of Ground Vibration Induced by Electronic Detonator in Shallow Tunnel

Table 2

Averages and standard deviations of PPV.

Monitoring distance	X-axis average (cm/s)	X-axis standard deviation	Y-axis average (cm/s)	Y-axis standard deviation	Z-axis average (cm/s)	Z-axis standard deviation
0	0.755	0.183	0.806	0.226	1.143	0.419
−10	1.005	0.301	0.722	0.204	1.025	0.070
+10	0.689	0.140	0.701	0.166	0.785	0.140
−20	0.715	0.315	0.469	0.078	0.873	0.027
+20	0.378	0.038	0.455	0.046	0.470	0.147
−30	0.558	0.038	0.408	0.068	0.642	0.054
+30	0.341	0.040	0.378	0.093	0.471	0.125