Abstract
Introduction
1.1. The Working Party
The Working Party was convened in late 1985 by the Engineering Group of the Geological Society. The Treasurer of the Working Party, and also at that time Chairman of the Engineering Group, was Dr Roy Taylor of Durham University, who sadly died in the Autumn of 1987 when the Working Party was preparing for the public discussion of its first draft. This took place at the Geological Society, London on 8 March 1988. Dr Taylor was replaced on the Committee by Mr John Charman and it is due to his hard work that the financial and technical work continued. A particular debt of gratitude is owed to both members.
Tropical residual soils differ from transported soils which are principally derived from coastal, alluvial, wind blown or glacial processes. In the tropics, residual soils probably form the largest group with which the engineer has to deal. Being formed in situ these soils have particular characteristics which distinguish them from material deposited from a fluid medium such as wind or water.
Much has been written on the various tropical residual soils, in pedological, geological, geographical and engineering literature. However, from the engineering point of view, there is considerable confusion as to what defines a residual soil, how it is formed and what its properties are. It is reasonable to conclude that there is at present a considerable gap between scientific and engineering knowledge. Many engineers mistakenly call all red tropical residual soils ‘laterite’, whereas the original scientific