EXPANSIVE SOILS: TRL'S RESEARCH STRATEGY

This paper describes some aspects of a TRL programme of research on expansive soils. The aim of the research programme was to provide practising engineers with guidance on design and construction of roads built on or with expansive soils. Particular emphasis was placed on the development of improved identification procedures, both in the laboratory and in the field, for expansive soils. A further aspect of work was the development of new techniques whereby the influence of suction on the soil behaviour could be investigated both in the field and the laboratory. The influence of stress, density and moisture content on the swelling characteristics of compacted expansive soils was investigated experimentally using a range of swell test procedures. Recommendations were then made on appropriate test procedures for assessing the swell characteristics of compacted expansive soils. The practical application of the research programme is to provide road engineers with guidance on: laboratory and field identification of expansive soils, laboratory swell testing of expansive soils, assessment of the potential for volume change in the field and the options available for road design. (A)