Cutter Soil Mixing and Jet Grouting For Herbert Hoover Dike Rehabilitation-Paper

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The Herbert Hoover Dike Rehabilitation project includes 17.6 miles (28.3 km) of seepage cutoff wall across three task orders on the western shores of Lake Okeechobee, Florida. BAUER Foundation Corp. is installing the wall using Cutter Soil Mixing (CSM), with performance requirements for continuity, minimum thickness, strength, and low permeability.<br /><br />Ground conditions include organic soils, interbedded sands and fine-grained soils, and limestone or sandstone layers that can hinder CSM. Rock was predrilled along the full alignment. Where substantial organic deposits occurred, workers also removed and replaced the soil using cased Kelly drilling; elsewhere, continuous flight augers were used to loosen rock without removing soil. The replacement approach prevented organic material from compromising cement hydration and wall strength.<br /><br />CSM panels are installed fresh-in-fresh to form a continuous wall. Quality control combines automated monitoring of installation parameters with slurry testing, wet-grab sampling, core verification, and permeability tests. Results reported for Task Order 3 met the specified strength acceptance criteria. Core strengths were generally lower in areas with organic-soil replacement, likely because cohesive inclusions remained in cores but were broken down during wet-sample preparation.<br /><br />The project also includes six tie-ins to existing cutoff walls and ten connections to concrete structures. CSM was used to connect to existing walls and soil-bentonite cores, with predrilling through existing cutoff material where needed. Jet grouting will connect the new wall to concrete structures; because rock cannot be eroded by jetting, full-depth soil replacement is planned at those locations. Trial columns achieved or exceeded the target diameter, supporting the selected installation parameters.<br /><br />The project demonstrates that CSM can meet demanding seepage-control requirements in challenging ground when paired with appropriate pretreatment, installation monitoring, and verification.

Keywords

Herbert Hoover Dike

rehabilitation

seepage cutoff wall

Cutter Soil Mixing

Lake Okeechobee

organic soils

predrilling

quality control

jet grouting

soil replacement