Subsurface Geological-Geotechnical 3D Modeling to Evaluate the Geohazard of the Alluvial Soils in Tanta Region, Egypt. GIS Approach

Abstract

Geological and geotechnical information from 159 borehole in-situ- and lab-based measured plasticity, unconfinedcompression, and consolidation parameters for alluvial clays have been analysed. For this analysis, 3D models was prepared usingVOXLER 3 software package. The prime objective was to spatially model the geotechnical variability and to derive the loadingfactors along with recognition of the distinctive geotechnical patterns. Results have been presented for the alluvial soils of Tantaregion, Egypt with the principal geotechnical hazards in the main eight districts were identified. Plasticity charts indicated that thesoils are inorganic cohesive highly plastic clays. Geotechnical parameters showed wide ranges evidenced by their large standarddeviations. Al-Mahata and Quhafa areas are characterized by high plasticity soils. Quahafa and beneath Al-Galaa street areasshowed the largest unconfined compression strength. Largest over-consolidation ratio and compression index values wererecorded in Al-Mahata and Al-Emary areas, respectively. High natural water content areas match well with those where watertable is closer to the ground surface in Quhafa and Al-Emary areas. The results of the employed approach can help to establishgeohazard zonation 3D maps with construction favorability for safe urban expansions.