Comparison of Theoretical and Laboratory Permeability for Coarse-Grained Soil

The permeability of soil is an essential parameter in estimating the quantity of seepage under foundation of hydraulic structures, which in turn affect the stability of structures. Empirical correlations such as Hazen, Kozeny-Carman, Breyer, Slitcher, Terzaghi, USBR, Alyamani and Sen are function of grain sizes, porosity/void ratio, coefficient of uniformity (C-u), coefficient of curvature (C-c) and viscosity of pore fluids. These correlations are quite effective for preliminary assessment of permeability during prefeasibility stage. However, at the designing stage, actual measurement of permeability is very important for structural integrity. The measurement of permeability is carried out by in situ tests for assessment of foundation of hydraulic structures and also for investigation of canals in cutting. The assessment of permeability of borrow area soils for construction of embankment is determined by laboratory methods. Depending upon the size of the soil particles, gradation, interaction among the soil particles, etc. constant head and falling head laboratory tests are more popular for coarse-grained and fine-grained soil, respectively. In the present study, attempt has been made to correlate permeability values evaluated through these correlations and also through constant head laboratory test. The samples were packed in permeability mould at 95% relative density. For comparison, four different types of soils from different sources have been selected. The values of laboratory permeability and theoretical permeability obtained through correlations are compared and have been discussed in the present paper. The results are also compared with Odong Odong (J Am Sci 3(3), 2007, [1]) and same indicate close resemblance in terms of applicability of correlation for assessment of permeability of different types of sands.