Browsing by Author "Shamil, Abdulfetah"

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    Investigation in to Some of the Engineering Properties of Soils Found in Worabe Town, Ethiopia
    (Addis Ababa University, 2015-10) Shamil, Abdulfetah; Haile(PhD), Messele
    The main objective of the study is to investigate some of the engineering properties of soil found in Worabe town. To achieve the objective eleven different test pits have been taken and both disturbed and undisturbed samples are collected at a depth of 1.5m and 3m from each test pits. After collecting all samples, the following laboratory tests are conducted; specific gravity, grain size analysis, Atterberg limits, free Swell, unconfined compression strength (UCS) and one dimensional consolidation. According to this study, Worabe town soils are grouped in to four types of soils. Group I (expansive soils), group II (non-expansive soils), group III (marginal soils) and group IV (sandy soils). The grain size analysis test results for group I, group II and group III soils showed that the dominant proportion of soil particles in the research area are clay and silt. For group I soils, the value of clay content ranging from 34.3% – 65.9% and silt fraction ranging from 17.3% - 39.4%. For group II soils, the value of clay content ranging from 37.1% –43.0% and silt fraction ranging from 38.5% - 54.2%. For group III soils, the value of clay content ranging from 36.9% –72.7% and silt fraction ranging from 20.6% - 53.0%. The Atterberg limit test results for group I soils showed that liquid limit ranging from 67.3% – 131.3%, plastic limit ranging from 19.1% – 49.3% and plastic index ranging from 36.0% – 82.0%. For group II soils liquid limit ranging from 54.1% – 70.8%, plastic limit ranging from 24.8% – 43.4% and plastic index ranging from 15% – 34.3%. For group III soils liquid limit ranging from 49.5% – 125.2%, plastic limit ranging from 15.0% – 37.1% and plastic index ranging from 33.7% – 90%. The specific gravity in the study area ranges from 2.65 to 2.85. For group I soils specific gravity ranging from 2.65 to 2.81, for group II soils specific gravity ranging from 2.67 to 2.75, for group III soils specific gravity ranging from 2.68 to 2.85 and for group IV soils specific gravity ranging from 2.65 to 2.77. Investigation into some of the engineering properties of soils found in Worabe Town, Ethiopia 2015 Addis Ababa Institute of Technology Page IX The free swell test results on the samples collected show a value ranging from 30% – 145%.The free swell test results for group I soils showed a value ranging from 103% – 145%, for group II soils a value ranging from 30%-45%, for group III a value ranging from 55%-95% and for group IV a value ranging from 31%-58%. The values of unconfined compressive strength (UCS) in the study area ranging from 89kPa to 188kPa for natural moisture content ranging from 22.6% to 57.5%. The values of unconfined compressive strength (UCS) test for group I soils ranging from 126.2kPa to 178.4kPa and for group III soils a value ranging from 113.4kPa to 144.9kPa. The classification of the soil is done according to American Association of State Highway and Transportation Officials (AASHTO) and Unified Soil Classification System (USCS). According to the AASHTO Classification System, Worabe town soil consists of clay and sandy soils with designation A-7-6, A-7-5 and A-3. Unified Soil Classification System, the soil is mainly categorized as CH, MH, SM, SL and CL. But many areas are covered by highly plastic clay (CH). The result of one-dimensional consolidation tests show that the area under investigation is over consolidated in its natural state and the compression index ranges from 0.359 to 0.622.