Investigation on Engineering Characteristics of Soils. A Case Study in Wolkite University Compound, Ethiopia

摘要

Investigation of the ground conditions is used for the economical design of the sub- structural elements. It is also necessary to obtained sufficient information on type, characteristics and distributions of a soil and rock underlying at a site of proposed structures for feasibility and economic studies for the proposed project. Thus the purpose of this article was to investigate engineering properties of the soils Wolkite University. To achieve the objective samples from different parts of the compound were collected and laboratory tests were done on the collected samples. The grain size analysis test result showed that the dominant proportion of soil particle in the research area is clay, which have clay content ranging from 5.4 -40 5%, silt faction 17.6 - 60.7%, sand fraction 14.5 - 54.6% and gravel content from 0.0 - 24.8%. The result of Atterberg Limit test on the soil in the research area showed a liquid limit ranging from 29 - 73%, plastic limit ranging from 21 - 35% and plastic index from 13 - 34%. The specific sravity ranges from 2.40 to 2.70. Free swell test conducted on the samples collected shows range from 18 - 50%. From the compaction test results the maximum dry density (MDD) of wolkite University soil ranges from 1.20 to 1.62 g/cm~3 and the optimum moisture content ranges 17.5 to 36.5 percent. According to the Unified Soil Classification System, the soil is categorized as silt and silty sand. Finally one-dimensional consolidation test was done and it shows that the area under investigation is over consolidated in its natural state, have compression index ranging from 0.33-0.40, recompression index ranging from 0.017-0.066, and coefficient of permeability ranging from 10~(-7) to 10~(-9) cm/sec.