ENGINEERING GEOLOGY AND GEOPHYSICAL INVESTIGATIONS OF ROCK MASSES AT THE FOUNDATION LEVEL OF NEW EL- FAYIUM CITY

Abstract

New El-Fayium City is one of the most modern urban settlements established in 2000 like New Cairo and New Assuit. The proposed site of the study area is located southeast of El-Fayium City, between Latitudes 29°12′ and 29°14′ N and Longitudes 30°52′ and 30°54′ E. The city covers an area of about 1,700 km2 and it is considered as a wadi plain with a gentle relief in the northeastern direction and at the southwestern of the city, the elevation is more than 70 m where Naalun Mountain is located but at the northern part the elevation is less than 40 m. The foundation layers at New El-Fayium City consist mainly of impure calcareous sandy silt, calcareous clayey silt, sandy silt, calcareous silty clay which have high swelling characteristics and calcareous sand conglomerate. In the study area, as a result of inadequate studies of the geological formations and nature of the soil and their impact on buildings, several cases of structural imperfections or cracks in concrete members were observed in the city. It was observed that expansive soils in the study area are considered among the difficult foundation materials and expand upon wetting due to water leakage from agricultural areas. Expansive soils are considered problematic soils for architectural and civil engineers when used as foundation materials or a foundation level to support various types of civil engineering structures. This type of soils may cause minor to major structural damages to pavements and buildings. Clay soils in the study area are mainly containing a considerable amount of montmorillonite (smectite), in addition to kaolinite and illite. Such a mineral (montmorillonite) has high potentiality for swelling or shrinking, due to changes in its moisture content. Moreover, direct and indirect methods are used to evaluate the swelling potentiality of the soils.