New method to measure the effective porosity of clays

The effective porosity is a required parameter for the mass flow rate calculations in groundwater hydrogeology. It is also a useful parameter in geotechnical engineering. In this paper, a methodology based on the tracer analysis technique is proposed to measure the effective porosity of clays. A test apparatus was developed and operational conditions were optimized to measure the effective porosity in the laboratory. Then the effective porosity of three clays under different chemical environments was measured. The measured effective porosity values showed that there is no unique effective porosity value for a given clay when tested under different chemical environments. The ratio of effective to total porosity values for silty and low plastic clays decreased while those for high plastic clay increased with the increase in degree of contamination.