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|Title: ||THE UNSATURATED SHEARSTRENGTH AND SWELLING CHARACTER ISTICS OF EXPANSIVE SOILS OF ARBAMINCH|
|Authors: ||UBA, BANTAYEHU|
|Advisors: ||HADUSH SEGED(PhD)|
|Keywords: ||SHEAR STRENGTH|
|Copyright: ||Jun-2011 |
|Date Added: ||28-Jul-2012 |
|Abstract: ||In Ethiopia, so many researches were done on characterizing expansive soils of several towns but only a single study, done on Addis Ababa expansive soil, exists on the unsaturated shear strength behavior of expansive soils. The present study addresses examining the expansive soils in Arba Minch – a town with a great portion of its terrain covered by the same soil but not considered in previous studies. A laboratory-testing program was planned and carried out on undisturbed soil samples taken from 10 different locations in the town for swelling pressure testing; and among these, one pit was allotted for unsaturated shear strength study.
The laboratory test results revealed that the swelling pressure ranges from 74.53 to 571.29 kPa, Specific Gravity from 2.63 to 2.80, Plasticity Index from 49 to 77%, Shrinkage Index from 81 to 117% and Free Swell from 94.0 to 165.0%. The measured swelling pressures and the geotechnical parameters determined from identification tests are used to assess the validity of already developed expressions by various researchers to the site under study and new models, that relate swelling pressure with index and physical properties, are developed using SPSS16.0 for windows software.
The results from unsaturated shear strength tests performed with a 50kN modified double wall triaxial machine on an undisturbed sample setting matric suction to be 100 kPa, 150 kPa and 200kPa for an effective consolidation pressure of 200kPa have clearly indicated the saturated case to yield smaller shear strength than the unsaturated one. The maximum deviator stress showed to increase from 107.61kPa to 174.35kPa with an increase in matric suction but the shape of the stress-strain diagram remained identical.|
|Appears in:||Thesis - Civil Engineering|
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