Authors: J. Hawley & D. Young w/ client - J. Nonnweiler, Sacramento Regional County Sanitation District
Proceedings - Rapid Excavation and Tunneling Conference 2003; Pgs: 179-190; United States
Abstract
The Sacramento Regional County Sanitation District has implemented a billion-dollar interceptor system master plan, including the 31 km (19 mile) long Lower Northwest Interceptor (LNWI). For the two LNWI Sacramento River crossings, pipejack/microtunnel drives in excess of 300 meters (1,000 ft) from 30 meter (100 ft) deep shafts in mixed soil conditions below the water table were considered, as were 600 meter (2,000 ft) tunnel drives utilizing pressurized-face tunnel boring machines. Operation and maintenance concerns, predicted flood scour, and levee concerns are discussed. A risk assessment process was used to select both profile and construction method. Construction began in mid 2004.
