South Australia & NT Chapter

Revetment Walls for Unsaturated Clay

Richard Herraman & John Woodburn & Dr William Kaggwa & Chris Ward

Most of you will have built a retaining wall in a stiff clay. You excavate the clay, often to a steep slope, and it stays there while you build the wall and backfill. During this time you’re thinkinghellip; “Why am I building a wall to retain this clay?” You comfort yourself with the thought that, if the clay gets wet, say from a leaking water pipe, it would weaken and collapse if not for your retaining wall. But would it? The answer to this question is worth a lot of money if you are building an underpass.

The Department for Transport, Energy and Infrastructure has funded a project looking for cheaper walls for its future underpasses. The project team has worked out how to maintain the stability of a near vertical excavation of moderate height in unsaturated clay in Adelaide. You only need to cover the surface with a facing with some drainage, that is, a revetment wall. This is significantly cheaper than a retaining wall.

Come along and find out how to design a revetment wall for an unsaturated clay in Adelaide. We’ve also worked out the field and laboratory testing needed to provide soil parameters for the design and we’ve come up with some ideas for cheaper construction.

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