The importance of desiccation cracks in water migration inside expansive ground

Highly plastic clays are generally regarded as very impermeable materials. However, it is well known that desiccation cracks, inherent fissuring, increase the in-situ apparent permeability inside active zone. The paper presents long-term measurements of matric suction and moisture sensors installed under a mat foundation, on shaft bored piles, at free field in expansive marls area Nicosia, Cyprus. data reveal ease with which rainwater percolates ground due to presence shrinkage especially adjacent foundation elements. Several episodes full saturation conditions recorded close its perimeter during course hydrological year after significant rainfall events, even dry season. Moreover, rapid migration along gap forming between soil pile season can lead brief incidents down least 1.5m depth. Back-analysis wetting experiments using finite element method indicates equivalent saturated hydraulic conductivity highly marl near surface 3 4 orders magnitude larger than one measured intact samples laboratory.