Great work Nick.
Expansive soils are an issue in my neck of the woods.
Pyrite is another issue.
A very informative article. The burden for for residential durability, as far as footing construction, should rest with the engineer.
Here we have heavy clay soils, as well as montmorillonite. Engineers here have mitigated the problem by requiring an overexcavation beneath footing grade. Usually 2’ for residences. The building pad, or footprint of the footings, is excavated 2’ below footing grade and replaced with a compacted structural fill (semi-impervious). The thought being moisture swings and potential for expansion or consolidation will be less at depth.
If the engineer designs properly, and the contractor constructs in accordance with the approved soils report, the residence should perform. However the homeowner is informed of conditions, such as irrigating against the house or not properly managing storm water, may result in differential settlement or soil expansion. This is good advice for any geographical area.
I await the article on diatomaceous earth construction.