Workshop attendees USACE-DFI Seepage Control Working Group Workshop DFI’s mission is to connect all stakeholders (design engineers, contractors, material and equipment suppliers, owners and researchers) to find common ground on technical issues. In November 2016, DFI members and representatives from the U.S. Army Corps of Engineers (USACE) along with many of its consulting engineering companies met in Sacramento, Calif., for a workshop to discuss technical and management issues related to the specifications for levee cutoff wall projects using trenching and soil mixing techniques. The USACE’s Sacramento District hosted the workshop at the University of California at Davis. Fifty attendees participated in two days of presentations and in-depth discussion on design, quality control and assurance, acceptance criteria, materials, and relative roles and responsibilities of project stakeholders. Other attendees from USACE Districts participated via web conference. The DFI Seepage Control Working Group (SCWG) organized this workshop. SCWG chair and DFI trustee, David Paul of USACE, was the driving force behind DFI establishing this working group. The aims of the workshop were to identify and understand the rationale behind typical specification provisions for cutoff walls that have been found to cause issues during design and construction, and to suggest changes to provisions that are rational and mutually beneficial. The goal of the discussions was to align expectations and understanding among all parties so that future specifications will produce high-quality cutoff wall design and construction with fewer problems during construction. SCWG members spent months preparing workshop presentations reflecting a consensus view of the state of practice of cutoff wall quality assurance and control testing, acceptance criteria, cutoff wall products (constructed wall materials) and long- term performance. The efforts of the many SCWG members who participated are gratefully acknowledged, especially the following topic leaders: Gianfranco Di Cicco of GDConsulting, Gilbert Tallard of Liquid Earth Support, Steve Artman of Geo-Solutions, David Miller, P.E., of ADM Consulting, Dennis Boehm of Hayward Baker, Dr. Michael Arnold of Bauer Foundation, Fabio Santillan of TREVIICOS Corporation, and Stephan Jefferis, Ph.D., FICE, of Environmental Geotechnics. Michael Kynett, P.E., and Khaled Chowdhury, P.E., G.E., of USACE; Richard Millet of AECOM and Prof. Kenichi Soga of the University of California at Berkeley led the USACE efforts in preparing the presentations on design, long-term performance, and roles and responsibilities of design engineers and construction management agencies. The first day of the workshop included presentations, and the second day included discussion in breakout sessions. Topic leaders moderated the active and productive discussions. Candid discussion led to suggestions for changes in the language in the specifications and to further research work to be conducted. DEEP FOUNDATIONS • JAN/FEB 2017 • 23
