Retaining wall types, Rankine and Coulomb lateral earth pressure theory, and the overturning, sliding, bearing, and global stability checks every freestanding wall design has to pass.
A retaining wall holds back a semi-fluid soil pressure system, not a static dead load — and how much pressure it actually sees depends on soil properties, moisture, and critically, how far the wall itself is free to move. This module walks through the five wall systems used on real projects (gravity, cantilever, MSE, sheet pile, and soldier pile), then builds up Rankine and Coulomb earth pressure theory from first principles so you understand not just the formulas but why active pressure requires wall movement to develop and why passive resistance requires far more movement than most designers assume.
By the end of this module you should be able to explain why a wall can pass its overturning, sliding, and bearing checks individually and still fail from inadequate drainage or a deep-seated global stability failure — the two failure modes retaining wall investigations find most often, and the reason every earth-pressure formula in this module assumes a drained soil condition that has to be engineered on purpose, not assumed.