A Numerical Investigation of Transitional Behavior in Intermediate Soils 

Min Hou, MSc Student at the University of Alberta, presents her talk "A Numerical Investigation of Transitional Behavior in Intermediate Soils".
Abstract: Failures of tailings dams and natural slopes have the potential to result in detrimental human fatalities and economic and environmental consequences, which could be attributed to a lack of knowledge of the transitional behavior in certain geomaterials. In contrast to the conventional critical state soil mechanics (CSSM), soils demonstrating transitional behavior exhibit a non-unique normal compression line (NCL) or critical state line (CSL) even at significant strains, and the mechanical response is state-dependent. This type of special soil is termed intermediate or transitional soil. The prevalence of intermediate soils in natural or engineered earthworks adds more uncertainties, particularly under high-stress conditions, and hence challenges the traditional geotechnical design. This study developed a set of discrete element models to replicate a 1D compression test on loess, particularly focusing on the transitional mechanism under extremely high-stress conditions (58,000 kPa) for the first time. The parametric investigation shows that the microscopic factors influencing transitional behavior are sample initial void ratio, average particle size, contact model type (linear or hertz), particle size distribution (PSD), and friction coefficient. In the end, two innovative indices, normalized bandwidth and ∆e ratio, are proposed to quantify the magnitude of transitional behavior and characterize soil type by linking the microscopic friction coefficient and macroscopic constant volume friction angle.
Speaker Bio: Min Hou is an MSc student in Geotechnical Engineering at the University of Alberta, supervised by Drs. F. Albert Liu and Chao Kang. She is interested in advanced geotechnical numerical modeling of silts, cemented sands, and geotextiles. Being an active member of the Geotechnical Society of Edmonton (GSE) and Canadian Geotechnical Society (CGS), she is passionate about unique soils and sites.