New developments for geotechnical and hydraulic properties of soils

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New developments for hydraulic properties of soils The general research goal is to improve basic research, testing methods and numerical analyses for groundwater. In the past 6 years, the applicant and his HQP have improved several methods used in groundwater engineering. Their research gave 54 papers in journal and 33 in proceedings, with 86 participations of HQP. The proposed research for the Discovery Grant will study three key basic topics, examine new ideas, propose new solutions, test them, and define new tools for numerical analyses. This research will contribute to the formation of 2 PhD, 4 MSc and 6 undergraduate students, all in groundwater engineering. Topic 1: real soils are too complex to be modelled with all physical details. They are not homogeneous but more or less stratified. There is an old equivalence for saturated hydraulic conductivity parallel to and normal to isotropic layers. However there are no equivalences for unsaturated properties, such as water retention and unsaturated hydraulic conductivity. Thus, there are needs to develop all equivalences between a stratified medium and its equivalent continuum used in analytical solutions and numerical models. Recently, the applicant developed new equivalence equations for the effective porosity to be used for tracer tests in aquifers, and proved them correct with seven field tracer tests, and numerical models. The discovery grant will be used to finish building all equivalence equations for unsaturated properties, two master students (M1, M2) having to improve complex and long tests, helped by 3 undergraduate students. Topic 2: in groundwater papers and reports, there is a systematic confusion between numerical and mathematical convergences. The distinction is made only in recent Computational Fluid Dynamics (CFD) papers and applied mathematics. The proposed research will propose and explain control methods that are needed for groundwater numerical studies. The research will strengthen first findings shown in our recent journal papers. It will involve a master student (M3) and a PhD student (D1). Topic 3: the applicant published a book (2016) on extracting information from grain size distributions and distributions of other parameters. The book is based on a modal decomposition method (MDM), a novel method and line of investigation, developed by the applicant. The Discovery Grant will be used to investigate only one basic problem, that of internal erosion, a hard-to-investigate problem, which is responsible for more than 40% of damage in earth structures (dams, highways, etc.). The proposed research will strengthen initial findings explained in the book. It will involve one master student (M4) and one PhD student (D2), helped by 2 undergraduate students for the tests.