Grant: Discovery Grants Program - Individual

The Cascadia subduction zone along the Pacific coast of North America, is likely to produce a large-magnitude earthquake measuring M=8-9.1. Soil liquefaction is anticipated, triggering loss of stiffness and strength, and this may cause ground failures of settlement or lateral movement. Since the beginning of the 20th century, there have been 95 earthquakes between M=8-8.9 globally and only five earthquakes M=9 or larger. The engineering community's knowledge base of liquefaction was primarily developed using case history data for lower-magnitude earthquakes because they occur more frequently. Few studies have evaluated liquefaction in soils from large-magnitude earthquakes. Yet large-magnitude earthquakes have longer durations of shaking, and this may trigger liquefaction in deposits not typically considered at risk. My research program pairs laboratory testing of soils, numerical simulations, and analyses of case history data to improve engineering design tools. The long-term objective of my research program is to improve current analysis tools to enable the design of safer, more cost-effective infrastructure, and with the goal of mitigating liquefaction hazards produced by long-duration, large-magnitude earthquakes. This five-year research program has three short-term objectives. Objective 1 is to update the stress reduction and magnitude scaling factor relationships in the liquefaction triggering procedures for large-magnitude earthquakes. My research team will use recorded and synthetic ground motion recordings to update the relationships that account for seismic demands as a function of earthquake magnitude. In Objective 2, we will characterize the liquefaction triggering and strain accumulation behavior from irregular, long-duration, large-magnitude earthquakes. We will use laboratory testing to simulate idealized loading from a large-magnitude earthquake, building on the findings from Objective 1. The focus of Objective 3 is the evaluation of the earthquake demands that trigger liquefaction in deep soil deposits. We will use case history data and numerical simulation tools to evaluate the characteristics of earthquake motions that are likely to cause liquefaction deep below the ground surface. The research contributions from this grant will be improvements to current tools for assessing and evaluating liquefaction during long-duration, large-magnitude earthquakes. Training is also a central focus of this research program, preparing the next generation of HQP to be competitive in tomorrow's workforce as academics or practicing engineers. This research will result in the training of 2 PhDs, 4 MASc, and 2 undergraduates. Graduates will develop strong technical and professional skill sets to prepare them to address the complex geotechnical earthquake engineering issues facing society.