Safety Distance of Shotcrete Subjected to Blasting Vibration in Large-Span High-Speed Railway Tunnels

Table 6

Minimum safety distances of shotcretes subjected to blasting vibration using two different criteria (unit: m).

Rock mass class	Q (kg)	Bond failure criterion			Chinese safety standard
		0.5–3 d	3–7 d	7–28 d	0–3 d	3–7 d	7–28 d
III	120	5.27–9.24	4.83–5.27	4.83–4.97	7.95–8.61	5.50–6.37	4.35–4.71
IV	100	5.02–8.89	4.56–5.02	4.56–4.71	7.48–8.10	5.18–5.99	4.10–4.43
V	80	2.92–5.52	2.49–2.92	2.49–2.67	6.95–7.52	4.81–5.56	3.80–4.12