| The family of compaction curves has been found and used in construction quality control as the one-point method for many years. The objective of this study is to investigate soil compaction theory for fine-grained soils, especially the fundamental aspects related to the family of compaction curves, and its influence on their engineering behaviors.; Studies of the characteristics of the complete compaction curve allowed a promising equation for describing the compaction curve for fine-grained soils to be proposed. The equation has four parameters which physically define the boundary conditions, shape and size of the compaction curve. The relationships between the compaction parameters and the physical properties of a given soil are studied. The equation can easily be used to predict a family of compaction curves for the same soil for varying compactive efforts. In order to explain the origin of the family of compaction curves, the evolution of particle size distribution for residual soils due to weathering is analyzed using uniform fragmentation theory. The profiles of unconfined compression strength along the complete compaction curves are presented. It is found that the matric suction value at the compaction sensitivity threshold is equal to compactive stress applied during the test, which is important for understanding the compaction mechanism and determining the effective compaction region and the water content where the maximum compressive strength occurs.; The deformation behavior of the compacted fine-grained soils is another focus of this research. A new testing procedure using undisturbed compacted samples is developed that combines compaction, one-dimensional compression and wetting collapse testing in one apparatus. A series of soil deformation behaviors are summarized with variation in water content, compactive efforts, and wetting-flooding sequences. A continuous model to describe the one-dimensional compression curve over the complete stress range is proposed. Based on the equation and the concept of the family of compression curves, a new method is proposed to estimate the settlement of a thick compacted layer. |
