(Sponsor: RGC-CERG; PI: Prof. LM Zhang; PhD student: Mr. D.S. Chang)

Security of critical infrastructures is of great concern to society. The subject of this project is breaching of dams and levees that pose increasing risks to the public. The breaching of levees in New Orleans in 2005 during Hurricane Katrina alone caused damage of US$100-200 billion and a regional death count of 1599. Past disasters showed that consequences of dam or levee failures are directly related to the time available to evacuate people at risk. It is therefore important to understand the process of dam or levee breaching, and study robust designs with which a catastrophic breach can be avoided or delayed. The principal objectives of this project are to investigate the entire breaching process of embankment dams or levees by internal soil erosion and to study key elements for achieving a robust design against breaching. The study will be performed by (1) examination of records of approximately 500 breaches ; (2) conducting laboratory tests to determine soil erosion parameters for use in the analysis and design of dams, levees, and slopes; (3) establishing probability-based criteria for determining internal erosion considering various uncertainties; and (4) developing a numerical procedure to simulate the process of breaching due to internal erosion.