For my Ph.D. I am working on a NSF-NEES funded project called "Levees and Earthquakes: Averting an Impending Disaster". The Principal Investigator is Scott J. Brandenberg, Ph.D, and the Co-Principal Investigators are Jonathan P. Stewart, Ph.D., P.E. from UCLA, Anne Lemnitzer, Ph.D.. from UCI, and George Mylonakis, Ph.D., P.E. from UCLA and the University of Bristol. For more information, please visit the page dedicated to this project.
The Sacramento San Joaquin Delta is the hub of the California water system, supplying fresh water to over 25 million people. The levees circumscribing the water channels in the Delta rest atop peat, an organic soil resulting from the decomposition of plants. With the Delta being located in an area with ground accelerations reaching up to 0.4 g, seismic activity can cause simultaneous levee breaches, drawing saline water into the Delta and consequently halting freshwater delivery for 20 to 30 months. Repair costs and economical loss are estimated in the range of $15 billion or more. To simulate the unique soil-structure (levee) situation, and to better understand the seismic behavior of the liquefiable sandy levees atop the soft peaty materials, four 9m-radius centrifuge tests were performed at UC Davis.
I am currently specializing in the numerical simulations of the tests. The behavior of peat is only partially understood, and to this day no constitutive model has been developed. My Ph.D. thesis focuses on creating a 3D visco-plastic model describe the behavior of peat. This model will first be used to simulate the centrifuge tests and will then serve engineers working in the Delta to better assess the potential of multiple levee failures during a seismic event. We plan to implement our formulations into FLAC, a two-dimensional explicit finite difference program for linear and nonlinear numerical simulations of continuum used in geotechnical engineering