A Rock Fracturing Method Using High-Pressure Gas Expansion: Case Study on Its Application in Hangzhou-Lin’an Intercity Railway

Table 2

Results of vibration velocity monitoring.

Location	Number of expansion tubes	K1		K2
		Distance (m)	Velocity (cm/s)	Distance (m)	Velocity (cm/s)
Upper bench	8	9.5	1.67	18.5	0.81
Lower bench	5	9.5	1.45	18.5	0.72