Characterization of Black Cotton Soil from Index Properties Along Sebeta-Tefki Road Section

Mulachew, Alemayehu (2005) Characterization of Black Cotton Soil from Index Properties Along Sebeta-Tefki Road Section. Masters thesis, Addis Ababa University.

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Abstract

This MSc thesis work is entitled "Characterization of Black Cotton soil from Index Properties in Sebetta area". The study area located at 32km, Southwest of Addis Ababa in the Oromia regional state; covering an area of 126 km2. The main objective of the study is to characterize the black cotton soil of the area from index properties. The index properties define certain physical properties used basically for classification but also for correlation with engineering properties. The methodologies employed to achieve the objective are literature review pertaining to the area, filed data collection on soil and rocks, laboratory testing of soil samples and data analysis and interpretation. The study revealed that the geology of the area is represented by rocks of Tertiary age (65my) namely; basalt, andesite, and ignimbrite, and Quaternary soil units. Four engineering geological rock units and three soil units were mapped. Disturbed and undisturbed soil samples were analysed for index tests, namely, particle size distribution, Atterberg limits, free swell, and shrinkage limits, in the Central Laboratory of Geological survey according to BS 1377: part 2: 1990 standard. Laboratory test results from the present and previous studies have shown that fines are over 90 %. Liquid limit (LL) and plastic limit (PL) values are ranging from 50-110 %, 24-50 % respectively. The free swell varies from 118-140 %, while the shrinkage limit test values range from 15-20 % respectively. The main index properties used for identification and classification of black cotton soil are clay fraction (minus 2 micron), Atterberg limits, free swell, and shrinkage limits. Accordingly, the black cotton soil is potentially active and requires countermeasures.

Item Type: Thesis (Masters)
Subjects: Q Science > QE Geology
Q Science > QK Botany
S Agriculture > S Agriculture (General)
S Agriculture > SB Plant culture
Divisions: Africana
Depositing User: Selom Ghislain
Date Deposited: 19 Jun 2018 13:56
Last Modified: 19 Jun 2018 13:56
URI: http://thesisbank.jhia.ac.ke/id/eprint/4641

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