Slope Stability Redux 2020-11-21

This is a video I recorded near the middle of the fall term, 2020. One of the video files was too big to transfer to a thumb drive. For that and other reasons, I didn't get around to editing it until now. It's too late for my Surface Processes class this year, but perhaps helpful for years to come. This is a talk at a whiteboard. It goes through the derivation of the Factor of Safety equation for slope stability. There is a discrepancy between the form of the equation I derived in class and the equation given in the Anderson & Anderson (2010) textbook. I believe that my version is right, and the A&A version is wrong, because they neglected to consider the flow of water in the subsurface, the orientation of equipotential lines perpendicular to the flow direction and, therefore, the ground surface, and the implications for the determination of the pore pressure at the failure (or potential failure) plane. I cover the determination of pore pressure in the static- and flowing-water cases, the derivation of the Factor of Safety with the pore pressure due to flowing water, and the steady-state slope hydrology of a small, steep catchment.