Geotechnical Properties of Soils in Abu Al-Khasib City, Southern Iraq

Abstract

To investigate some geotechnical characteristics of the soils in a chosen area of Abu Al-Khasib city, Basrah Governorate, southern Iraq, nine boreholes that range in depth from 10 to 32 meters were drilled. Based on the results of standard penetration tests and particle size analysis the Quaternary deposits, which extend vertically to a depth of 32 meters, are divided into 8 layers with varying bearing capacities depending on their consistency and compactness. These layers are Medium stiff brown lean clay, soft and very soft gray lean clay, medium stiff gray lean clay, stiff gray lean clay, medium denes gray silty sand, denes gray silty sand , hard gray clay-silt-sand mixture and very dense gray silty sand. The first layer's bearing capacity is 140 kN/m2, so it is considered as moderately adequate to support the isolated, strip,or raft shallow foundations of various light buildings in the study region, and soil improvement techniques, especially mechanical methods, are required. Different types of deep foundations such as piles and well foundations for heavy constructions must be extended to depths of 27 and 30 meters, which represents the 7th and 8th layers of high bearing capacity (640-760, 1100 kN/m2 respectively) in the study area. Inorganic clays with low plasticity are the most common classification for samples. The soils of the study area are considered highly compressible soils and have medium expansion degree which must be taken into account when constructing shallow foundations to minimize damage to buildings. The percentages of sulphates, total dissolved salts, organic content, and gypsum content are minimal and considered ineffective, whereas the percentages of carbonates and chlorides are high and affect the safety of shallow foundations. In the study site, the groundwater is around 0.5 m deep.