FACULTY OF CIVIL ENGINEERING OF ARBA MINCH UNIVERSITY IN PARTIAL FUFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTERS IN GEOTECHNICAL ENGINEERING

Abstract

The town of Dembile is located in Geressie district Southern Ethiopia. Geographically, the study area is situated at latitude of 5°52' 30‘‘ North and longitude of 37°19' 00'' East with the elevation between 1450 and 1470 meter above sea level. The topography of the town almost flat. Therefore, the objective of the research to investigate geotechnical index properties of soils found in Dembile town and through the investigation the aim is to provide maximum information that is useful in the design and construction of the proposed project at a minimum cost. To achieve its objective seven samples from different parts of town were collected and laboratory tests were done on the collected samples. Identifying the soil characteristic is essential to determine the type of test and test procedure that is applied during sampling, sample preparation and testing. For all tests the procedures used for analysis were done using the usual test procedures which is applicable for selected area Atterberg limits were done for different testing procedures on the soil samples to see effect of test manipulation on concretionary bond. The liquid limit tests were carried out on soil specimens mixed for 5 minutes and 30 minutes durations. It was observed from the test results that the mixing durations has significant effect on the values of liquid limits. Accordingly, the soil samples have been sensitive to test procedures. The index property investigation in this study includes; particle size distribution, atterberg limits, compaction, natural moisture content, hydrometer test, shrinkage limit test and specific gravity. The grain size analysis test result showed that the dominant proportion of soil particle in the study area was sand and natural moisture content ranges from 8.45 to 20.72% which have clay content ranging from 3.83 to 36.39% silt fraction 6.67 to 54.35% sand fraction 9.26 to 86.6% and gravel content from 0.00 to 2.9% from the consistency limit test results, liquid limit varies from 24.73to 83.9% plastic limit varies from 9.25 to 44.35% plastic index 10.39 to 42.54% And specific gravity ranges from 2.55 to 2.76%. Compaction tests carried out on samples collected from the study area revealed that the maximum dry density (MMD) varies from 1.35 to 1.97 g/cm³ and the optimum moisture content varies from 10.86 to 31.02%. From the above all tests the dominant was sand fraction.