Improving metastable loess ground

Loess soils cover approximately 10% of the world's landmass. Loess is an aeolian quaternary deposit of predominately silt size, which forms open metastable structures through various bonding agents. These agents include water, clay and carbonate and upon loading usually in combination of water, collapse occurs. This collapse can be up to 30% by volume and as a result present a major geotechnical challenge. It is essential therefore, that a full appreciation of what loess is and how it fundamentally behaves is made before any treatment strategies can be economically and effectively employed. Various models have been produced and these will enable a fundamental study of the treatment process to be made. There are a wide variety of improvement techniques that have been used to improve loess ground and include various compaction, inundation and chemical treatments. Other more exotic methods have been suggested, however, their cost or environmental consequences have restricted their practical use. The choices made when faced with loess ground are illustrated with a case history.