PLENARY 4: Keynote Speaker: Dam and Levee Barrier Walls at the Corps of Engineers: Historical Review and Current State of the Practice-PPT Presentation

PPT Presentation

Pdf Summary

The presentation reviews the U.S. Army Corps of Engineers’ use of barrier walls in dams and levees, from early projects to current practice. Case histories show how walls have been used to reduce seepage and failure risk in varied ground conditions.<br /><br />At Mud Mountain Dam, construction demonstrated that barrier walls can extend more than 400 feet deep, while underscoring the importance of quality control and pre-grouting to prevent damage. At Wolf Creek Dam, the original 1970s wall did not cut through all seepage pathways in the karst foundation, making a deeper replacement wall necessary. Lessons included verifying wall integrity carefully, using in-situ permeability testing, and managing construction data effectively.<br /><br />At Herbert Hoover Dike, performance-based specifications supported several construction methods, including trench cutting and remixing, cutter soil mix, clamshell excavation, and hydromill. These methods enabled substantial risk reduction, but self-hardening slurry walls can crack. Northern California levee projects highlighted the challenges of treating long reaches and the value of close collaboration when construction problems arise.<br /><br />Current practice emphasizes identifying needs through risk assessment, designing with performance specifications, and conducting independent design and constructability reviews. Pre-grouting may be needed where voids could cause slurry loss or damage. During construction, owners, designers, and contractors should communicate regularly, use test sections, and maintain accessible data to detect and resolve issues. Risk assessments should continue after construction to confirm that projected risk reductions were achieved. The presentation’s central message is to keep improving methods while prioritizing quality, collaboration, and risk management.

Keywords

U.S. Army Corps of Engineers

barrier walls

dams

levees

seepage control

risk assessment

quality control

pre-grouting

karst foundation

performance specifications