Installation of a Cutoff Wall Along the Mississippi River

Video Transcription

Video Summary

The speaker described a major deep cut-off wall project on the Mississippi River in East St. Louis, designed by the Army Corps of Engineers to protect about 250,000 people and $4.5 billion in assets. The 4,400-foot wall was installed up to 142 feet deep through sands, silts, clays, debris, and hard limestone, using a self-hardening slurry wall system with strict quality control and permeability/strength requirements. Construction involved slurry mixing, grab and cutter excavation, continuous monitoring, and verticality checks to ensure continuity. Midway through the job, two large utility gaps were encountered, and the team developed a combined solution using partial slurry wall closures and angled jet grouting columns, verified by 3D modeling and pump tests. The project faced challenges including COVID, weather shutdowns, difficult rock, and pervious gravel layers, but exceeded performance targets and received a 2023 Outstanding Project Award.

Keywords

Mississippi River

deep cutoff wall

slurry wall system

jet grouting

Army Corps of Engineers

utility gaps