Practical Engineering Behavior of Egyptian Collapsible Soils, Laboratory and In-SituExperimental Study

摘要

In many sites on Egypt desert roads collapsible soils is broadly classified as a problematic soils containing silty fine sand which is style="font-family:Verdana;">cemented with low density and low degree of saturation which is susceptible to a large and sudden reduction in their v style="font-family:Verdana;">olume upon inundation, with or without vibration in its stress. Four sites have been studied for new urban style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">, style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">roads and industry work sits, related to increase in natural water content style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">. style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;"> These soils go through radical rearrangement of their particles, causing sudden changes in the stress-deformation behavior which caus style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">e style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;"> differential settlement of foundation and roads. This chan style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">ge in volume can lead to foundation failures and worth of damages under ground public facilities and infrastructure. In this study, the search program style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">is style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">developed to establish their different behavior under wetting in two phase style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">s: style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;"> field and laboratory work. The obtained results are useful in mapping the trend of the factors affect style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">ed style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;"> in assessing soil collapsibility rate or collapse potentials which style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">are >> style="font-family:;" "=""> style="font-family:Verdana;">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 style="font-family:Verdana;">—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 style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;">d style="font-family:Verdana;"> style="font-family:Verdana;"> style="font-family:Verdana;"> 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.