Tadese, Samuel(PhD)Fikadu, Aklilu2018-06-132023-11-112018-06-132023-11-112015-11http://etd.aau.edu.et/handle/12345678/626Under the action of heavy loads, greater than the swelling pressure, the soil undergoes consolidation. The rate of consolidation depends on the applied load, coefficient of permeability, thickness, and compressibility of the soil. The objective of this thesis is, therefore, mainly intended to investigate the relationship between swelling & consolidation behavior of expansive soils of Galan Town using one-dimensional consolidation theory of Terzaghi. To attain the purpose of this research, representative disturbed & undisturbed samples of expansive soil were collected from different locations of Galan town & a series of swellconsolidation tests were carried out in the laboratory. According to the test result obtained from Index property tests, the expansive soil of Galan Town, according to USCS is classified as Inorganic Clays soil of high plasticity, CH, & A-7-5 according AASHTO soil classification. The value of compression index Cc obtained from expansive soils of Galan Town, ranges from 0.24-0.34 & the value of coefficient of consolidation Cv ranges from 0.32-0.42 m2/year, while initial dry density & initial moisture content range of 1.17- 1.37 g/cm3 & 30.6-50.1% respectively during the sample collection In the course of this research, it has been found that swelling potential of expansive soils decrease with increase in initial moisture content for constant dry density. On the other had the percent swell & swelling pressure increase with increasing initial dry density increases. Maximum swelling pressure is obtained from the samples prepared with optimum moisture content & maximum dry density. The value of compression index Cc of sample with high swelling potential (high degree of disturbance) is greater as compared to samples with low swelling potential. Increase in moisture content decreases the amount & rate of both swell and consolidation. Therefore, the consolidation characteristic of expansive soil is not inherent property of the soil mass because, swelling is also additional factor that can influence consolidation characteristics expansive soil.enGeotechnical EngineeringThesis