In this lab we will experimentally investigate the properties of different soil materials under conditions that may lead to slope failure. Your goal is to design the most stable slope for each of the following conditions.
Dry soil at varying angles
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Wet soil at varying angles. You get to choose how much moisture to add.
Increasing amounts of "rain" at a fixed slope.
Repeat with a different mix, depth, or area of materials.
For each failure of the slope, record your observations about the conditions under which the slope failed (angle, moisture content of the soil, whether water was soaking into or running over the surface), the pattern of failure (rotational landslide, translational slide, debris flow, alluvial erosion), and the quantity of material that failed (did the whole slope give way, or just a small section?).
How well do the mini-landslides observed in the lab compare to the real landslides we talked about in lecture and those you can find by browsing Google Earth? For reference: a map of the landslides observed in Sonoma County. The USGS has maps for all Bay Area counties as a part of their landslide site: http://landslides.usgs.gov/.
Also think about how landslides are relevant to human society. The news lately is proof that they are relevant, but how can communities deal with the danger of landslides? How do landslides affect the potential for archeological discoveries? How do humans (or other biology) affect landslides?
West Washmawapta Debris Flow
Here's a debris flow that I set off when I stepped on a bit of saturated till at the base of the West Washmawapta Glacier in Canada.
Slope Stability Lab Movies
We tried a variety of conditions. I only took pictures of some experiments.