Downloads & Free Reading Options - Results

Influence of soil suction, clay microstructure, and applied external loading upon the swelling behavior was undertaken to further the understanding of expansive soils. For the soil tested, the microstructure produced by kneading compaction did not change the particle orientation to any significant degree. Evaluation of the microstructure was performed with both X-ray diffraction and scanning electron microscopy techniques. The microstructure is perhaps best described by multi-grain or packet arrangements. A higher degree of packet dispersion occurred at molding water contents wet of optimum; however, it did not approach any high degree of preferred particle orientation. A swell test was developed using the Bishop Oedometer in which both soil suction and external loading could be controlled and measured. Using the axis of translation technique with a high air entry ceramic stone soil suctions of 5.1 kg/sq cm were measured. Results indicate that below a certain value of soil suction the swell will be accelerated with a further decrease in suction. As the applied loading is increased it will limit this acceleration and the soil suction-swell relationship becomes more linear with decreasing suctions.