Engineering Evaluation of Bearing Strata at Selected Regions in Missan Governorate/South of Iraq

Abstract

19 boreholes extending to 20 m depth for each were drilled in seven selectedregions at Missan Governorate/ south of Iraq in order to study somegeotechnical properties of their soils. The results of standard penetration test andparticle size analysis are used to classify the Quaternary deposits extendingvertically to the consistency and compactness. These layers are; stiff brownsilty clay and clayey silt (CL,CH &ML), medium stiff brown and gray siltyclay and clayey silt with little sand (CL,CH & ML), stiff gray silty clay andclayey silt with sand (CL &ML), very stiff gray silty clay and clayey silt(CL,CH &ML), medium dense gray silty sand (SM), hard brown clay-silt-sandmixture, silty clay and clayey silt (CL & ML) and dense and very dense graysilty sand (SM). The bearing capacity of the first layer is suitable to holdshallow foundations of different light buildings in the study area. For heavystructures, piles of different types must be extended to depths that vary between14-17 m which represent the depth of 6th and 7th layers of high bearing capacity.Plasticity chart shows that most samples are classified as inorganic clays ofmedium and high plasticity. Most soils are considered to have very high degreeof compressibility and high degree of expansion which must be taken inconsideration at construction of shallow foundations. The depth of groundwaterin study area is shallow, varies between 1-2.5 m, which affects the strength ofsoil and change the capacity of bearing strata.