Permeability and Consolidation Characteristics of Soils Producing Irregular-Shaped Compaction Curves

Through many years of study, it has been found that one of the best methods of classifying soils is by strength, and the best and most economical method of obtaining strength is by compaction. By compacting a soil, the shear strength is increased permeability decreased, and future settlement or consolidation decreased. These properties. of\u27 permeability and consolidation are important in the design of any structure whether it is a dam, single or multi-story building, bridge, highway, or lagoon. The engineer must be sure that the consolidation and permeability of the soil are such that the structure will be able to function £or many years to come. In soils engineering, permeability is a soil property which indicates the ease with which the water is able to travel through its interconnecting voids (pores). Permeability plays a vital part in problems related to drainage of highways and agriculture lands, seepage through earthen darns and levees, uplift pressures beneath concrete dams, estimating available ground water storage, and dewatering of excavation sites to permit construction. In all these instances permeability characteristics of the soil have a controlling influence on the effective strength properties of the soil. The determination of the permeability of a soil is therefore a most important aspect of soil testing and analysis. Water movement through soil follows the principles established by Darcy between hydraulic flow and hydraulic gradient. Darcy\u27s basic work consisted of permeability tests on saturated siliceous sand. This study is the fourth in a series of studies carried out at South Dakota State University, under the sponsorship of the National Science Foundation, dealing with soils that produce irregular-shaped compaction curves. Two properties ·of soils that play an important part in both design and construction are consolidation and permeability. Extensive research has been completed on these properties in relation to soils. that produce regular and irregular-shaped compaction curves. The objectives of this study are twofold: (1) First a relationship was sought between permeability and density. (2) Secondly a relationship was sought between consolidation and density. The results obtained should provide information and explain the effects of consolidation and permeability on irregular-shaped compaction curves. This information could then be used to further compaction curve theories to include irregular-shaped compaction curves