November 8, 2022

Mosul Dam was built on a complex foundation including soluble gypsum material.  Without continuously maintained grouting, the project is susceptible to seepage and piping through the foundation.  Although subsurface exploration programs were conducted during the original design and to support limited studies undertaken prior to 2016, the extent of solutioning of the foundation was not adequately understood to allow for meaningful understanding of the project’s risk of failure.  Data was especially limited on the subsurface conditions outside the centerline of the dam. From 2017-2019, the US Army Corps of Engineers led investigations to further define subsurface conditions along the dam axis as well as downstream and at the abutments.  Subsurface information obtained from a variety of available technologies to better define the geologic conditions at the project.  Instrumentation and monitoring at the project was vastly upgraded and helped guide subsurface investigations.  Subsurface exploration along with emergency grouting and instrumentation data were used to guide the foundation grouting program and verify its satisfactory implementation.  A Site Information models was developed and used to aid in compilation of data sets and communication of results.  This presentation summarizes the results of the subsurface investigations, extent of deteriorated foundation conditions, and their relationships to project potential failure modes as well as the challenges on site and the conclusion of the work performed.

The webinar will be presented by Dr. Hlepas.  She was the deputy lead engineer at Mosul Dam from 2016-2019 and is currently the lead of the US Army Corps of Engineers (USACE) Geotechnical, Geology, and Materials Community of Practice.  She has 15 years of experience working as a geotechnical engineering on a variety of large civil works modification projects including dams, levees, and confined disposal facilities.  She has focused much of her career on advancing the state-of-practice in project performance monitoring and evaluation, has taught multiple courses and workshops, and has authored numerous papers on instrumentation, project risk, and subsurface investigations.  Dr. Hlepas is also the chairperson the US Society of Dams (USSD) Monitoring of Dams and Their Foundations Committee as well as a member of multiple professional organizations.  She has a master’s degree in civil engineering from Columbia University in New York, a doctorate degree in civil engineering from the University of Illinois at Chicago and is a licensed Professional Engineer in the state of Illinois.  

The webinar will be held online December 9th from 12-1:00 PM Eastern.  An invitation will/has been sent to all the Diplomates of the Academy.