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

PPT Presentation

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The Herbert Hoover Dike Rehabilitation project involved installing 17.6 miles (28.3 km) of seepage cutoff wall across three USACE task orders, plus connections to existing cutoff walls and concrete structures. Ground conditions included Florida limestone and cemented sands, with strengths ranging from moderate penetration resistance to refusal.<br /><br />The main cutoff wall was built using Cutter Soil Mixing (CSM), with predrilling and, in some areas, partial soil replacement to address challenging ground conditions such as interbedded rock. The performance-based requirements included a continuous, homogeneous wall 24 inches thick, specified overlap, low permeability, and minimum compressive strength. Quality assurance included slurry testing, wet-grab samples, panel installation records, and verification borings with core inspection and in-situ permeability testing.<br /><br />CSM was also used to connect the new wall to existing cutoff walls beneath structures and to soil-bentonite cores. Probing confirmed the locations of existing walls, and installation overcut them and adjacent soil-bentonite where required. Jet grouting provided connections at 10 existing concrete structures. The approach evolved from planned soil replacement and single-fluid jetting to converting as much of the connection area as possible to CSM, with jet-grouting stages including pre-jetting, jetting, and remixing. Quality control monitored grout properties, backflow, sample strength, and installation parameters.<br /><br />The project demonstrated that predrilling and partial soil replacement can enable CSM in difficult ground while meeting stringent cutoff-wall requirements. CSM also facilitated tie-ins to existing seepage barriers, and jet grouting was successfully used for concrete-structure connections.

Keywords

Herbert Hoover Dike

rehabilitation

seepage cutoff wall

cutter soil mixing

CSM

jet grouting

Florida limestone

soil replacement

quality assurance

permeability control