An Overview of State-of-the-art Hydraulic Conductivity Measurements in Coarse Grained Materials

Abstract: Embankment dams are made from soil materials of varying sizes and widely used all over the world.When constructing these, knowing the hydraulic conductivity (K) of the soil materials is a keyparameter in order to construct safe embankment dams. A knowledge gap regarding K measurementsin coarse grained soils has been identified. This thesis aims to provide a theoretical overview ofpresent day state-of-the-art methods for measuring hydraulic conductivity and the controllingcharacteristics for K. Coarse grained soils refers to a soil with the coarsest grain fraction being > 20mm and/or have a K > 10-4m/s.   It was found that the fixed wall permeameter is the most suitable laboratory method. In the field, itis possible to estimate K using tracer methods, these however show more potential for leakagepathway detection. Common for all K measurement methods are the controlling characteristics of K,grain size distribution, pore geometry, degree of compaction, particle movement and flow regime.These need to be considered when testing to produce useful measurements. If the relationshipbetween flow velocity and hydraulic head is non-linear, Darcy's law is not valid for calculating K.