Geo Characterization for design and construction of Gulf Intracoastal Waterway - West Closure Complex in New Orleans, Louisiana

摘要

The Gulf Intracoastal Waterway-West Closure Complex (GIWW-WCC), located on the west bank of the Mississippi River in the vicinity of New Orleans, Louisiana was constructed as part of the New Orleans area Hurricane and Storm Damage Risk Reduction System (HSDRRS). Marking a milestone in construction of the world's biggest drainage pumping station and widest sector gate in 2010 at a cost of more than $1 billion, this complex has a 225-foot-wide navigable sector gate and 11 operable pumps with a maximum capacity of 19,140 cubic feet per second. Working in conjunction with the other structural features of the project such as T-wall, I-wall, and newly constructed earthen levees, this complex is capable of reducing the risk associated with a tropical storm event that has a one percent chance of occurring in any given year, or a 100-year storm. The entire project area is located within the Mississippi river deltaic plain, consisting of soft and highly compressible organic clay, fat clay, and peat with interbedded layers of silt, sand, and silty sand formation. Historical geotechnical data indicates that long-term relative subsidence rate in the project area averages about 0.5 ft/century. This presentation will describe the different components of this important HSDRRS and summarize the elaborate field exploration and laboratory testing program conducted to properly characterize the complicated subsurface soil formation at the project site. The procedure used to formulate the soil strength profile used in the design and analyses will be presented. Additionally, results from cone penetrometer tests, static and dynamic pile load tests and their significance in evaluating and selecting the final foundation system for the different components of the HSDRRS will be discussed.