The Influence of Compaction Methods on the Compressibility Characteristics of Cohesive Soils

Over the past decades, engineers aimed to enhance the engineering properties of natural soil deposits, by compaction to reduce compressibility, permeability and increase bearing capacity. The most common compaction methods used in the laboratory are the Standard Proctor compaction in which, dynamic compaction is performed to obtain compaction characteristics of soils. However, insitu application of most common shallow compaction methods involve the static compaction which is implemented with the use of compaction rollers. The aim of this study is to investigate the influence of compaction method (dynamically and statically) on the engineering properties of selected soils. In order to meet this objective, an extensive laboratory test program is conducted on two selected soils that have significant variation among their plasticities and composition. Various dynamic compaction efforts are conducted at different moisture contents, which are also simulated using static compression. The compacted specimens are tested for measurement of Electrical Resistivity, Undrained Shear Strength and Compressibility characteristics. Results indicate that static compaction reduces the electrical resistivity, and the undrained shear strength. On the other hand, the compressibility and the swelling potential of the compacted specimens are observed to increase when the static compaction is used. The outcomes of this research indicate that field sampling and testing is required for effective design and control of engineering properties of compacted fills, as the method of compaction is observed to have a significant impact on the engineering behavior of soils. Keywords: Static compaction, Dynamic compaction, Compaction efforts, Electrical resistivity, Undrained shear strength, Compressibility.