Safety Threshold Determination for Blasting Vibration of the Lining in Existing Tunnels under Adjacent Tunnel Blasting

<div>The PPV distribution of the existing tunnel lining under different surrounding rock grades. (a) Grade III rock mass. (b) Grade IV rock mass. (c) Grade V rock mass.</div>

Advances in Civil Engineering

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Figure 4

Figure 4: Safety Threshold Determination for Blasting Vibration of the Lining in Existing Tunnels under Adjacent Tunnel Blasting 