Bad ground is deemed to be natural or made-up ground between the base of the excavation and the binder course level that contains any of the following:
Class E Unacceptable materials, as specified in A1.5.
Materials that are loose or friable in their natural state and are not self-supporting at an exposed face.
An excessive amount of rocks or boulders, loose random rubble, penning, setts or cobbles etc, at any depth where their removal during excavation could cause loosening of the ground adjacent to the excavation.
Materials that are saturated, regardless of whether free or running water is present.