Site Characterization of Al-Burrulus Clay Formations

Abstract

An extensive subsurface investigation program was executed to characterize the formations in the city of Al-Burrulus site in the north coast of Egypt. The site is situated on the Mediterranean Sea coast with shallow ground water at the area. According to the subsurface ground investigations, thick layers of sands with relative densities varying from very loose to very dense sand underlain by very soft to hard clay and intermixed soils are characteristic of this area. A plethora of high quality laboratory and insitu tests were performed to identify the soil properties. The field tests include the Standard Penetration Test (SPT), Piezocone (CPTu), Seismic Piezocone (SCPT) and Downhole Test (DHT). Additionally, “undisturbed” specimens are extracted from the cohesive soils using Shelby tube samplers, while disturbed samples are obtained from cohesionless soil layers. Several laboratory tests were performed on the extracted specimens for classification purposes (e.g. grain size distribution and Atterberg limits). Tests on “undisturbed” samples are conducted to determine the strength properties (e.g. consolidated undrained triaxial test, unconsolidated undrained triaxial test, and direct shear tests). Site specific correlations are developed between the clay strength obtained from tests performed on high quality Shelby tube specimens and insitu tests. These correlations are beneficial to estimate clay strength in future projects in Al-Burrulus area based on field tests.