SUNNYDALE CSO TUNNEL-DEALING WITH URBAN INFRASTRUCTURE

摘要

During heavy storms, flooding can impact hundreds of residents in the VisitacionrnValley neighborhood of southern San Francisco, California. This flooding, a mixturernof storm and sewer water, can occasionally overwhelm the existing 1910-era sewagernsystem. The new 1.2-km (4,000-ft) long Sunnydale Auxiliary sewer tunnel, rangingrnfrom 2.4 to 3.7 m (8 to 12 ft) in diameter, will help minimize the flooding problems.rnThis tunnel, excavated by earth pressure balance machine (EPBM), will cross beneathrncongested existing infrastructure and pass through a wide variety of ground conditions,rnincluding soft ground and highly variable Franciscan Formation bedrock. This paper willrnoutline the planning and design process in selecting a construction approach.