Hollow Exploration and Backfill Grouting for Inclined Shaft Liner in Quicksand Layer

Water leakage with sand of inclined shaft wall in quicksand layer can lead to hollow development behind lining. The distribution of hollows and water-enriched regions behind the inclined shaft lining in quicksand layer was gained by the ground penetrating radar （GPR） and drilling. In order to ensure the stability of the wellbore, the backfill grouting technique is used to deal with the hollows and water-enriched area. The backfill grouting uses double pipe grouting technique, and the grouting materials include single liquid cement slurry and C-S slurry. The phenomenon of water inflow with sand was eliminated dramatically after the backfill grouting, and the results of grout pressure test indicate a good result for backfill grouting.