BRITE Synergy: Seismic Cracking of Embankments and Earth Dams

Purdue University, West Lafayette IN

Investigators

Abstract

The safety of embankments and earth dams relies on an adequate assessment of seismically-induced deformations. When subjected to earthquake loading, embankments and earth dams may settle, deform laterally and longitudinally, and may exhibit cracking in the longitudinal and/or transverse directions. Cracks are considered one of the most hazardous consequences of strong earthquake shaking on earthen dams, as they can lead to piping failure due to increased seepage and internal erosion through the cracks. Observed cracks in earth dams after an earthquake are most often associated with tensile stresses and strains resulting from earthquake-induced permanent deformations. Current methods to estimate earthquake-induced cracking seem inadequate, given the widespread damage observed in thousands of dams after the 2008 Wenchuan earthquake. The research is geared at advancing our understanding of the cracking processes in embankments and earth dams during an earthquake and at providing improved tools for practitioners. This Boosting Research Ideas for Transformative and Equitable Advances in Engineering (BRITE) Synergy project aims at proving the hypothesis that static analyses may provide information on the location and size of cracking caused by earthquakes but challenges the current standard of practice of performing two-dimensional plane strain analyses to estimate transverse cracking on earth embankments and dams. The work will not only benefit geotechnical and dam engineering, but society at large. An important outcome of the work is an updated database of case studies, as well as guidelines and protocols for collection of future information. The research will also benefit other fields such as mining engineering, e.g., tailing dams in seismic areas and will contribute to increasing infrastructure resilience. The objectives of the research will be accomplished through a number of synergistic activities that aggregate disconnected work, verify or validate unproven assumptions and perceptions and new work to reach generalizations such that the overall outcome is more than the sum of its parts. The work will combine existing information in the form of case studies and empirical recommendations, and outcomes from numerical simulations. It will expand and modernize databases, update and improve empirical methods, and perform detailed dynamic three-dimensional numerical analyses of actual dams, namely Lenihan Dam in California and Gatun Dam in the Panama Canal. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.