Relation between the compaction of soils and certain physical properties including tensile strength.

One of the main objectives of the present work is to investigate the effect of the change in dynamic energy on the compaction of soils. A synthetic soli passing the 3/I6 in. B.S. mesh sieve and containing 7.2% of particles passing the No. 200 B.S. mesh sieve, was chosen. The energy was changed by changing, the height of drop, or the diameter of the striking area, or the weight of the rammer. The film theory advanced to interpret the compaction phenomena has been discussed In the light of the present work, and led to the development of a new theory, which Is capable of Interpreting all the phenomena encountered in the compaction process. A general equation has been derived, and proved dimensionally, to determine the maximum dry density of any type of soil compacted under any dynamic energy, one the mechanical analysis curve and the specific gravity of the soli are known. Consequently, another general equation has been derived for the determination of the optimum moisture content of any type of soil. An Investigation of the effect of compaction under static loads on the tensile strength of cohesive soils is given in the course of this thesis, disturbed samples of Staines London Clay, Blue London Clay and Clayey Brickearth were chosen for such investigation. The compactive efforts used to compact the specimens, were 250, 500, and 750 lb/sq.in. A new and simple device was constructed to measure the tensile strength of specimens having the same shape as the standard cement briquette. The new device can measure a tensile strength as low as 2 lb/sq. in. The Investigations have shown that compaction increases the tensile strength of clays, and that this property can he used as a means of classifying clays used in the construction of earth-work. Furthermore, the compactive effort required to compact a certain clay in the field can he selected. It is hoped that the present work has indicated the significance of the determination of the tensile strength of cohesive soils in some problems in soil mechanics