Application of Pre-Grouting Technique in Yellow River Crossing Tunnel in Eastern Route of South to North Water Transfer Project

The yellow river crossing tunnel runs through limestone at a depth of about 70m below the level of yellow river. Since the river water, phreatic pore water in loose Quaternary deposits and karst/fissure water in limestone communicates with each other, pre-grouting technique has to be employed before drilling and blasting excavation of the tunnel.