Landslides articulation in Wadi Hof area southeast of Cairo, Egypt,based on geological and geophysical investigations

摘要

Detailed field geological, geoelectrical, hydrochemical, and microbiological studies were executed in the Wadi Hof area, southeastern Cairo, Egypt to delineate the causes of landslides along the train pathway between the eastern Wadi Hof camp and the western clay quarry. The area under consideration is of a gentle slope from east to west. The Eocene limestone rocks constitute the most common outcrops. Structurally, the investigated area was affected by faulting. Geophysically, 1D Schlumberger Vertical Electrical Soundings in addition to 2D Wenner Electrical Resistivity Tomography (ERT) techniques were performed to characterize the shallow subsurface implications. Eight Vertical Electrical Soundings were measured along with two main profiles-oriented northwest-southeast directions. A Schlumberger configuration with electrode separation starting from electrode separations (AB2)=1.5 m. to AB2=200 m. was applied. Three 2D Electrical Resistivity Tomography profiles crossing the train pathway were constructed in a nearly east-west direction. The 1D inversion is applied using WinSev3.4 software and the 2D-ERT profiles were computed using the RES2DINV computer software. Moreover, hydrochemical and microbiological investigations in the form of water samples analysis were conducted east and west of the train pathway. The hydrochemical and microbiological characteristics of the analyzed water found that the water origin is different on the sides, east and west of the railway tracks. The integrated interpretations indicate that the study area consists of three main rock units; surface marl, calcareous sand, and, finally, clay to sandy clay units. The water originates from the Eocene limestone aquifer east of the train route directed towards the clay quarry west of the train path. Additionally, the landslides apparently result from the swelling of thick clay layers which leads to subsequent railway destruction shortly thereafter.