Experimental Validation of an Method for In Situ Estimation of Hydraulic Conductivity of Water Treatment Granular Materials

Domestic wastewater-treatment system is today a widely held technique. In order to evaluate the efficiency of these systems, it is necessary to determinate the in situ hydraulic conductivity of the water-treatment granular materials constituting them. The in situ measurement of the hydraulic conductivity of soils has proven to be imprecise, take a long time. Empirical equations based on the physical properties of soil have been proposed to overcome these difficulties. In this context, the originality of this paper is to propose an in situ method to obtain reliable input parameters for the predictive equations of Chapuis (Can Geotech J 41(5): 787–795, 2004) and Carrier (J Geotech Geoenviron Eng 129(11): 1054–1056, 2003) by using both a penetrometer and a geoendoscope. This method is described in the first part of this paper. Then, the validation of the method based on laboratory tests performed under controlled conditions for three kinds of soils is presented. Hydraulic conductivity obtained when applying the method is compared to that measured by a Darcy permeameter. The difference between these two hydraulic conductivities is less than 25%. Finally, the precision of the results is discussed.