Design Considerations and Evaluation Process for a New Tunnel and Ocean Outfall Project
Abstract
The Joint Water Pollution Control Plant, operated by the Sanitation Districts of Los Angeles County, treats wastewater generated by over three million people. A new tunnel and ocean outfall is being considered to meet future hydraulic demands and provide long-term redundancy for the Districts’ existing tunnels, portions of which were constructed as early as the 1930s.
The detailed process used to evaluate the feasibility of various tunnel and outfall locations is described. Challenges include a geologic profile with mixed face and squeezing ground conditions; high water pressures; active fault crossings; gassy and contaminated ground conditions; and liquefaction, slope stability, and lateral spreading concerns in the area of the riser and diffusers.
2009
Rapid Excavation and Tunneling Conference (RETC) Proceedings
Steve Dubnewych
Jacobs Associates
Michael Torsiello
Jacobs Associates
Jon Kaneshiro
Parsons Corporation
David Haug
Sanitation Districts of Los Angeles County
