Successfully Constructing Deep Shafts Through High-Yield Glacial Outwash Aquifer Overburden, Shale, and Limestone Rock for the Deep Rock Tunnel Connector Project

摘要

Construction of the Deep Rock Tunnel Connector (DRTC) combined sewer overflow (CSO) tunnel more than 60 m (200 ft) below ground in Indianapolis used several shaft construction techniques. Slurry wall construction for two 15 m (50 ft) diameter shafts through approximately 30 m (100 ft) of high yielding aquifer was successful. Conventional Drill & Blast excavation of shale and limestone completed these shafts. Drilled steel casing through overburden and raise-bored rock excavation was employed for nine utility, drop, and ventilation shafts, 2.3-3.6 m (7.5-12 ft) in diameter. This paper describes the shaft construction operations including challenges and solutions thereto.