An approach to design of retaining walls with expansive soil backfill

Expansive soil deposits are considered to be problematic to the civil engineering construction. Lateral pressure development of expansive soils based on large scale tests indicate that under KO condition and under KA condition, the lateral pressure exerted by expansive soil is much higher and different from those predicted by normal theories. However, under air dry and compacted states the lateral pressure behaviour is as per conventional theories. The studies based on tests conducted in large scale devices (2 to 4 m wall height) with cohesive non swelling soil (CNS) backing interposed between wall and expansive soil have revealed that the CNS is helpful in reducing the lateral pressure by more than 90%. Based on displacements in relation to self equilibrating boundary concept, the lateral pressure equations developed for saturated expansive soil with and without CNS backing give lateral pressure distributions close to that observed in the experiments. This publication is intended to serve as a reference book in universities and guide to practicing geotechnical engineers for design of retaining structures with expansive soil backfill.