Analysis on Deep Hole Grouting Consolidation for Tunnels in Water-rich Sandy Gravel Stratum

It has been proved that EPB shield tunneling for Chengdu metro in water-rich sand gravel stratum is feasible. Yet delayed settlements above the tunnel occurs occasionally after shield driving which directly affects the safety of pipe lines, buildings and people above the metro, even causes big accidents. By analyzing the mechanism of delayed settlements of EBP shield driving through water-rich sand gravel stratum in Chengdu city, the technique of deep hole grouting consolidation at fixed points was proposed, which can effectively reduce the risks induced by delayed settlements.