Variation of permeability with porous media: An overview

Abstract

 Permeability is an important engineering  property of soils and its knowledge is essential in number  of water resource and geotechnical engineering problems  such as seepage and design of filters in hydraulic  structures, water and sewage treatment plants and settlement of structures. Enormous work has been done to  understand the effect of various factors affecting  permeability and numerous relations have been given from  time to time to relate permeability with these factors and  parameters. In this present work, variation of permeability  with change in shape and size of porous media is presented.  First of all the material is separated into five different  shapes by visual examination. Five well defined shapes  were chosen for the present study. The shapes were  classified on the basis of elongation ratio, flatness ratio,  sphericity and shape factor. The shape parameters for these  well examined shapes were calculated. The “three  dimensions of the particle that are necessary for  determination of shape parameters are the longest  dimension (dl), intermediate dimension (di), and shortest  dimension” (ds). These “three dimensions along with the  volume of circumscribing sphere, corresponding to the  longest dimension of the particle were used to calculate”  the shape parameters that are necessary to quantify the  shape. After the sorting of the shape, they were sieved  through a set of IS recommended sieves into different  sizes. Sizes passing through a particular size and retained  on adjacent lower sized sieve were given the name of the  sieve through which they passed. Sieve analysis is  necessary not only for sorting of the material but also for  the calculation of gradation parameters whose effect on  permeability will be studied.