Using a Hydraulic Conductivity Apparatus for Determination of the Permeability of Low Permeable Soils on the Example of Clay from Kleszczow

Abstract

The paper presents results of the laboratory tests of the permeability coefficient of clay carried out in the originally constructed apparatus. This device is intended to test the permeability of low permeable soils. To verify the instrument and the reliability of the obtained results, tests on clay samples originating from Kleszczow Rift Valley were performed. In order to better identify the soil sample, its basic physical parameters and grain-size distribution curve were presented. The permeability tests were performed on three undisturbed samples of the same soil at four different pressure gradients. The diameter and the height of the sample were d = 40 mm, h = 30 mm, respectively. The hydraulic conductivity was determined based on the constant head tests results. During tests the penetrating liquid was distilled water. The full permeability test of a single sample was relatively short and lasted from 10 to 12 days. For tested clay the void ratio was equal to 0.53, and the permeability coefficient varied between 4.7· 10-10 to 6.2· 10-10 [m/s] in function of the hydraulic gradient. The values of the permeability coefficient obtained in this work correspond well with results presented in the literature. This shows that the constructed device proved itself for determining the permeability coefficient of clays. Thus, the constructed apparatus and the applied test method are good and simple tool for testing the permeability of low permeable soils.