Compressibility characteristics of soils: Fid-Bau Portal

Compressibility characteristics of soils

Sridharan, A. / Gurtug, Yesim

Abstract. Compressibility characteristics of soils forms one of the important soil parameters required in design considerations. Compression index, Cc, which is the slope of the linear portion of void ratio, e vs. logaritham of effective pressure p(log p) relationship, is extensively used for settlement determination. The e–log p is most often assumed to be linear at higher pressure range and hence Cc is taken as a constant. Both published experimental results as well as results obtained in this investigation reveal that the e vs. log p could be curved, concave upwards or concave downwards depending upon the soil plasticity characteristics and initial water content. Thus, assuming Cc to be constant may not be valid for many cases. In this paper, an alternate procedure is given to characterise the compressibility of a soil. Experimental results show that the deformation expressed as a percent of thickness of the soil, (strain) vs. effective pressure could be treated as a rectangular hyperbola and the behaviour could be characterised by two parameters, ‘a’ and ‘b’. Characterising the compressibility behaviour with effective pressure by two parameters is better than a single parameter, Cc.