(b) the representative critical state strength.

Again, this should ensure a maximum wall displacement of 0.5 per cent wall height, for non-soft and non-loose soils.

When considering the design values of wall friction, <5, and undrained wall adhesion, cw, BS 8002 recommends that the design value be the lesser of the representative value determined by test, or 75 per cent of the design shear strength to be actually mobilised in the soil.

Design tan S = 0.75 x Design tan <j> Design cw = 0.75 x Design cu

BS8002 also provides a design recommendation for unplanned, future excavation in front of the wall. This really only applies to embedded walls and is considered as not less than 0.5 m deep and not less than 10 per cent of the clear height retained. For cantilever walls the clear height is equal to the height of excavation, and for propped walls is equal to the height below the bottom prop. The recommendation provides for unforeseen and accidental events after construction. The code also recommends a minimum design surcharge of 10kN/m2 to be applied to the design of all walls.

During design to both Eurocode 7 and BS 8002, the design values of actions and ground properties are adopted in the analysis and the conformity of a particular limit state is checked for, by ensuring that the magnitude of the restoring moment (or force) is greater than the disturbing moment (or force).

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