Writing
Long-form notes on geotechnical numerical modelling and on building engineering software that can be trusted. The aim is that each article is the best available answer to one narrow question.
What a Mohr circle actually tells you
The Mohr circle turns a stress state into geometry. The angles on it are doubled, the envelope touches it once, and both facts are derived here from scratch.
Soil classification from a grading curve
Reading D10, D30 and D60 off a grading curve is a logarithmic interpolation, not a linear one. A worked USCS classification with every number recomputed.