Correlation Between Compaction Characterstics And Atterberg Limits Of Fine Grained Soil Found In Addis Ababa

Abstract

Compaction is a way of eliminating air out of the voids of a soil by mechanical means. Compaction is mandatory in different fields of civil engineering such as in highway, airfield, embankments, and dams; to reduce compressibility and permeability of a soil hence increases the shear strength and bearing capacity of a soil. A laboratory tests called standard Proctor and modified proctor tests were advanced to determine the maximum dry density and optimum moisture content of a soil. In this study standard compaction is used. However, in huge projects conducting laboratory tests by using proctor tests consume time, money, a lot of effort or energy and required a large quantity of samples. An effort to make correlation between compaction characteristics and Atterberg limits of fine grained soil found in Addis Ababa which allows us to estimate the compaction parameters of fine grained soils from Atterberg limits is done in this thesis. To develop the correlation, a total 10 test pits have been excavated and a total of 20 disturbed samples (primary data) were collected from different places, 2 samples from each test pits at different depths ranging from 1.00m to 3.00m. And 36 secondary data (laboratory results) were collected from AACRA. After the samples were collected, they were transported to Gondwana engineering laboratory and different laboratory tests (Atterberg limits, grain size analysis, specific gravity and compaction tests) has been conducted. After the tests were conducted, the recorded data was analyzed using descriptive and analytical methods, and then correlation between compaction characteristics and Atterberg limits of fine grained soil using regression analysis has been done. Regression analysis was conducted by using EXCEL and SPSS software. And from the statistical analysis part one can observe that there is a relatively good correlation between OMC and PL and similarly a good correlation is observed between MDD and LL, PL and PI together. The equations found are listed below. 1. OMC = 0.916 * PL - 0.030 * PI - 0.875, R 2 = 0.807 2. MDD = - 0.18* PL - 0.027 * PI + 21.182, R 2 = 0.835