Geotechnical engineering evaluation of soil utilizing 2D multichannel analysis of surface waves (MASW) technique in New Akhmim city, Sohag, Upper Egypt

Abstract

New Akhmim is one of the recent cities in Sohag Governorate which was proposed by Egyptian New Urban Communities Authority (ENUCA) to build new communities overcoming the overpopulation problems. The main objectives of this research are delineating the shallow subsurface structures and lithology of the foundation layers and evaluating their geotechnical characteristics. For calculating shear-wave velocity (VS) in the studied site, sixteen MASW sections were carried out using Geometric strata visor-NZ 48 channels with vertical geophones of 4.5 Hz and inter-geophone spacing of 3 m. The recorded data were analyzed using the SurfSeis software to evaluate the degree of soil compaction or rock consolidation and foundation stability based on seismic wave velocity and density.The proposed site contains two engineering subsurface layers; the first one is the upper most layer and consists of intercalations of unconsolidated material (gravels and sands) of different shear wave velocities. The second layer (compacted shale) is more compact with higher velocity (bedrock). Elastic moduli and geotechnical parameters of the first and the second layers in the eastern part is more competent than the western part. The degree of competence of the second layer is higher than that of the first one, therefore it is considered as more qualified for engineering purpose and constructions design. Precautions should be taken into consideration for the geotechnical engineering problems e.g. swelling or contraction possibly resulting from the second shale layer.