Internal structural architecture of a soft-linkage transfer zone using outcrop and DC resistivity data: Implications for preliminary engineering assessment

Abstract

The current study presents a new integrative approach for detailed structural mapping of a soft-linkage transfer zone using outcrop, boreholes and DCR data in the form of soundings and 2D-electrical resistivity tomography (2D-ERT). As a case study, the present approach is implied for studying the geo-engineering conditions of a highly deformed desert-land entry to reclaim at Cairo-Suez district, Egypt. The approach has led to the spatial understanding of the subsurface heterogeneity and complex structures at a level of accuracy unattainable with traditional surface structural mapping alone. For preliminary geotechnical assessment, some physical and geotechnical properties are characterized by field and laboratory measurements for collected soil samples. Moreover, the inverted DCR data are used to predict the RQD values using a polynomial relationship between RQD and the intrinsic resistivity (ρ). Notably, the calculated and actual values of RQD are, in general, in the same order considering the error factor value, and hence, the derived equation for RQD prediction is satisfactory. Therefore, the proposed approach reduces the uncertainty of the constructed structural model for engineering design. In addition, merging outcrop with DCR data allows us with a limited frame of time to partially mitigate disasters to civilization by better (i) potential location understanding and (ii) remediation plans tuning for a complex structured site.