The UK soil classification systems

The basic UK soil classification system is based on and very similar to USCS. Details can be found in Dumbleton (1981). 

The Highways Agency in the United Kingdom has developed another classification system of materials for highway earthworks. This system, apart from soil materials, also includes stabilised soils or any combination of materials (Highways Agency 2009a). 

The proposed Highways Agency classification system also provides information for typical use of materials and property requirements, together with acceptability limits and compaction requirements. 

The soil materials, as well as the stabilised soil materials or any other material or combination of materials for highway earthworks, are grouped into nine general categories denoted by numbers from 1 to 9. Each number corresponds to the following general category  

The first level of subclassification is notified by a letter from A to S, and the second level of subclassification, where needed, is notified by a number from 1 to 5. For example, class 6F2 refers to a selected granular fill material, coarse grading, for capping. 

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In this book, the AASHTO, the ASTM, the European and the UK soil classification systems will be presented in brief. 

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