Abstract
Compaction curves of soils are essential for establishing practical and reliable criteria for an effective control of field compaction. This paper deals with the development of a practical method of assessing laboratory compaction curves of fine-grained soils. It is found that for a given fine-grained soil compacted at a particular compaction energy, the relationships between water content (w) and degree of saturation (S) are represented by power function, which are w=AdSBd and w=AwSBw for the dry and the wet sides of optimum, respectively (where Ad, Aw, Bd and Bw are constant). The Bd and Bw values and optimum degree of saturation (ODS) are mainly dependent upon soil type irrespective of compaction energy. The Ad and Aw values decrease with the logarithm of compaction energy and the decrease rates are practically the same for any compacted fine-grained soil. This leads to a simple and rational method to assess the compaction curve wherein the compaction energy varies over a wide range using a one point test (a single test). Assuming that fine-grained soils compacted under standard Proctor energy behave in agreement with Ohio's curves, the modified Ohio's curves for the other three compaction energy levels (296.3, 1346.6 and 2693.3 kJ/m3) are developed based on the proposed method. These curves can be used to assess the entire compaction curves at the required compaction energy based on a single set data of dry unit weight and water content.
