Cutoff Wall
The construction and design of flood protection embankment levees within coastal areas have become a focal point for infrastructure management. Due to their proximity to flood plains, the levees are usually constructed over soils with inferior bearing capacity. The foundation soils create issues with long-term settlement, changing the protection height and requiring periodic building back to the design height. DSM is needed for proper long-term load transfer to reduce settlements and maintenance to preserve design height protection.
Also, dam sites with slightly cohesive soils and fine sands in the foundation are typically vulnerable to significant loss of strength by liquefaction during a potentially strong earthquake. DSM has been recommended to remediate a potentially weak foundation and thereby improve the seismic stability of an earth embankment dam. With reinforcement, these applications can become more efficient in time and cost vs. unreinforced.
Raito has decades of successful experience protecting some of the nation’s most challenging levee seepage control, chemical containment, and groundwater cutoff wall projects. Our products have been utilized in numerous U.S. remediation projects, including Sacramento River Levee Flood Protection and Mississippi River Hurricane Flood Wall projects. Cutoff walls exclude groundwater from an excavation to minimize the requirement for dewatering pumping. Typically, the method involves installing a shallow permeability physical cutoff wall or barrier around the perimeter of the excavation to prevent groundwater from entering the working area. Most commonly, the cutoff is vertical and ideally penetrates down to a very low permeability stratum (such as clay or unfractured bedrock) that forms a basal seal for the excavation.
Project Examples:
West Sacramento River
The Sacramento River Flood Control System includes dams, reservoirs, levees, weirs, bypasses, and other features built over the last 150 years. This complex system's approximately 980 mi of levees protects urban and rural areas within the Sacramento River Watershed, which covers 27,100 miles from frequent flooding.
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Hurricane Flood Wall
In 2005, Hurricanes Katrina and Rita made landfall, causing significant damage in southwest Louisiana and the Louisiana-Texas state line. DSM was performed for the WBV Hurricane Protection Project, which included reinforcing flood walls for higher water events in the Westwego to Harvey area.
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