Swelling and collapse behavior of expansive marl and its implications in foundation engineering

Expansive soils increase their volume upon wetting, but under high vertical stresses may exhibit collapse, with the latter aspect being rather overlooked in foundation engineering. Oedometer swelling/collapse tests on expansive Pliocene marls of various calcium carbonate content and plasticity index sampled from Nicosia, Cyprus, indicate that, unlike free swelling strain, pressure is insensitive to initial degree saturation. Consequently, significant collapse strains wetting are not unlikely occur practical situations. The paper discusses implications this behavior case shallow foundations proposes methods analysis. Under certain conditions, design based settlement calculations that use as input fully saturated soil properties be unconservative supported structures exposed severe risk damage. For mat foundations, stepwise distributions equivalent modulus subgrade reaction across a function average bearing proposed results coupled finite element simulations. These allow prediction peak bending moments produced at end wet dry seasons due ground shrinkage, respectively, for climatic conditions Cyprus.