Practical Engineering Behavior of Egyptian Collapsible Soils, Laboratory and <i>In-Situ</i> Experimental Study

Abstract

In many sites on Egypt desert roads collapsible soils is broadly classified as a problematic soils contain ing silty fine sand which is cemented with low density and low degree of saturation which is susceptible to a large and sudden reduction in their v olume upon inundation, with or without vibration in its stress. Four sites have been studied for new urban , roads and industry work sits, related to increase in natural water content . These soils go through radical rearrangement of their particles, causing sudden changes in the stress-deformation behavior which caus e differential settlement of foundation and roads. This chan ge in volume can lead to foundation failures and worth of damages under ground public facilities and infrastructure. In this study, the search program is developed to establish their different behavior under wetting in two phase s: field and laboratory work. The obtained results are useful in mapping the trend of the factors affect ed in assessing soil collapsibility rate or collapse potentials which are observed in construction with volume change problems. The major factors observed are the natural structure skeleton of the soil particle and its grain size and mechanism of soil sedimentation. The field collapse potentials value assigned for these tested sites along Alexandria —Cairo desert road indicated that the field measured collapsibility potentials are smaller than those measured on the same extracted undisturbed samples in laboratory by 15%, which can be save d in coast, change in proposed collapsibility improvement method and change in select foundation type. Also, field tests evaluate the collapsibility rate with time and highlight that environmental history and natural soil structure in field are the important factors affected on these soil collapse, and also, knowledgeable by collapsible soils during wetting in these sites studied.