Shear Strength of Clay/Clay Shales and Methods of Stability Analysis for Embankment Dams

A historical timeline will be presented that describes significant stability-related failure case histories and how various technologies have been developed for characterizing the shear strength of soils (primarily clays and clay shales), as well as methods for performing stability analyses of embankment dams. The history of soil characterization technology, including shear strength, began in the 1800s but accelerated in the early to mid-1900s through the late 1980s. Each critical milestone in the evolution of soil characterization and stability analysis technology will be identified along with key published references for the audience to review after the webinar. Case histories to be reviewed (briefly) include Fort Peck Dam, MT (abutment clay shale contribution to construction static liquefaction) and the Mt. Polly Tailing Dam, Canada (stability failure resulting from shear strength failure of foundation clays under the impoundment).

Learning objectives attendees will receive from this webinar:

• Learn about the key failure case histories involving stability failures of clayey embankment dams and dam foundations.
• Describe key technical advances in characterizing the properties of clays and clay shales.
• Describe and select appropriate shear strength models for clay and clay shale materials.
• Describe the alternative methods for assessing the stability of embankment slopes and select an appropriate method for an embankment dam stability evaluation.
• Review description and implementation of a Heuristic (Process Flow Diagram) for assessing the stability of an embankment (dam or levee).