Estimating the geotechnical parameters from CSEM monitoring data at the city of 15th May, Egypt

Abstract

The present work provides a technical procedure to estimate the geomechanical and geoelectrical parameters as key information of the dynamic state and stability of the massive structure. It involves the application of Control Source Electromagnetic "CSEM" approach developed by IGF UB RAS to image the ranked deformation levels in the massive structure. The Wide Profile System of Observation had been used to monitor the three component electromagnetic field along predefined measuring lines at Quarter 27 in the City of 15th of May, Helwan, Egypt. Four cycles of observation had been carried out in 2008, 2010, 2011, and 2012. The acquired data set had been subjected to analytical processing procedure to estimate the changes in the geotechnical parameters over time of observation. Interpreting the measured data concluded that the general dynamic state at the area is getting worse over the time, this is reflected in the crack's densities and positions, also on the changes in the lateral distribution of the geoelectric heterogeneity as indicator for water saturation. This is clearly evinced at profiles 2 and 5. Profile 7 represents a deformation case of instability close to destruction level, so that, it is recommended to annually monitor the massive structure beneath it.