CONSTRUCTION OF TWO MICROTUNNEL ACCESS SHAFTS USING THE CUTTER SOIL MIX (CSM) METHOD IN THE SAN JOAQUIN DELTA, CALIFORNIA

摘要

The Contra Costa Water District (CCWD) Alternative Intake Project - Victoria Canal Conveyance Pipeline is located within the San Joaquin Delta region of California, west of Stockton and east of Discovery Bay. The project included an approximately 275 m (900 ft) long tunneled segment that crosses the Old River between Byron Tract and Victoria Island. The contract documents specified that the river crossing be made by microtunneling from a jacking shaft on Byron Tract to a receiving shaft on Victoria Island. As is common in the Delta region of California, the river is confined by levees and the river level is significantly higher than the typical elevation of the land to either side of the river.