Laterite Soil Shear Strength Characteristics from the Use of the Standard Proctor and Compression Machine

Abstract

This research investigates the influence of compaction methods on the shear strength characteristics of laterite soil. Comparison was made between static and dynamic methods of compaction in order to ascertain their similarity and a better optional method. The use of compression machine is a probabilistic method under uncertainties that is anticipated to produce similar results compared to the Standard Proctor compaction method due to machine wear and tear. Therefore, this research compares the shear strength of laterite soil compacted using Standard Proctor and that of compression machine. Basic indices and mechanical properties of laterite soil such as specific gravity, Atterberg limits, particle size distribution, compaction and shear strength properties were determined. The effects of moisture content, compactive methods and the rate of stress-strain on the unconfined shear strength were also studied. The maximum deviator stress for the laterite soil compacted at 26.4 % moisture content using standard proctor and compression machine compaction are 459.35 kPa and 219.5 kPa respectively. The results obtained from this study show that the laterite soil samples compacted using the Standard Proctor yielded higher unconfined compressive strength compared to those compacted using compression machine. Therefore, to obtain shear strength of soils for field applications, the use of static compaction technique in laboratory requires careful investigation because it might not produce the required representative results.