COMPARISON OF GYPSIFEROUS SOILS IN SAMARRA AND KARBALA AREAS, IRAQ

J. Yassen, Mohammed; Schanz, Tom; A. Al-Dabbas, Taz; Mou,

	COMPARISON OF GYPSIFEROUS SOILS IN SAMARRA AND KARBALA AREAS, IRAQ
Iraqi Bulletin of Geology and Mining
Article 1, Volume 6, Issue 2, 2010, Pages 115-126
Authors
Mohammed J. Yassen; Tom Schanz; taz A. Al-Dabbas;
Abstract
A proposed engineering gypsiferous soil classification is given using: soil texture, mineralogy, geochemistry, engineering properties, and chemical analyses of soils water-extract. The results reflect that these soils consist of different percentages of sand, silt, clay, and some gravel. Analyses also detected secondary gypsum, quartz, calcite, feldspar and different types of rock fragments and different types of heavy minerals in trace amounts. Clay minerals are dominated by palygorskite. Hydrochemical analyses results of soils water-extract show that the calcium and sulphate ions are most common, followed by sodium, bicarbonate, chloride, magnesium and potassium. Bicarbonate and chloride show high values in Karbala area. Gypsum content ranges from (0.9 – 67.5) % in Samarra area, while in Karbala it ranges from (0.4 – 28.9) %. The physical and engineering properties of the studied soils were determined, such as specific gravity, density, shear strength parameters, unconfined compressive strength, and compression and shear wave velocities, compression index, swelling index, initial void ratio, and collapse potential. Samples, which were allowed to soak water show a sudden drop in unconfined compressive strength and compression and shear values immediately after soaking, then were decreased gradually. The proposed engineering classification of gypsiferous soils includes two classes: “Gypsiferous Soil” and “Highly Gypsiferous Soil”; according to the gypsum content (< 25% and > 25%, respectively), initial void ratio, coefficient of curvature, coefficient of uniformity, collapse potential, compressive strength, cohesion, plasticity index, content of fines, and the T.D.S of the soils water-extract. It is believed that this proposed classification for Iraqi soils can be applied to other locations, therefore, will be useful for other soil scientists and engineers as well, worldwide.

Statistics Article View: 177 PDF Download: 163