Groundwater Infiltration Reduction Through Grouting of the South River Tunnel, Atlanta, Georgia

摘要

The South River Tunnel is a 14-foot (4.3 m) diameter hard-rock sewer tunnel in Atlanta,rnGeorgia. The geotechnical investigation for the design indicated that up to 2,500 gpm (160 L/s) of groundwaterrnwas likely to flow into the tunnel during construction. Inflow was successfully controlled using pre-excavationrngrouting from the surface, pre-excavation grouting from the tunnel face, and modified contact grouting throughrnthe final cast-in-place concrete lining. The pre-excavation programs used 11,000 bags of Portland cement tornreduce the inflow to 700 gpm (45 L/s) at the end of mining. After modified contact grouting, the final inflowrnwas 18 gpm (1.1 L/s). These grouting programs were critical to meeting both the targeted inflow criterion andrnthe Consent Decree mandated project completion date.