Laboratory permeability and single ring infiltration tests for the testing of waterproofing barriers of landfill tanks.

Diego Barbero; Andrea Maroni; Sandra Peyrot

Abstract

Hydraulic conductivity is a fundamental hydrogeological parameter for the testing of waterproofing barriers of landfill tanks. These barriers are aimed at guaranteeing the isolation of the waste and preventing the infiltration of the percolate in the subsoil.Geotechnical features of mineral barriers must be preliminarily established through geotechnical laboratory tests in order to verify their suitability for their application.The main mineral barriers correspond to the bottom waterproofing of the landfill tanks where the normative standards of specifications generally require values of hydraulic conductivity of 1.00 x 10-7 cm/s and to the cover of waterproofing barriers (top and slopes of the tanks) where the normative standards of specifications generally require values of hydraulic conductivity less than 1.00 x 10-6 cm/s.We report on the results of several permeability tests carried out both in situ with single-ring infiltrometric tests and in the laboratory with falling head permeameter apparatus, in order to evaluate the different results of vertical hydraulic conductivity found. These results are important in the design phase of a landfill tanks with the aim of predicting the infiltration of leakage in the subsoil with consequent pollution of both soil and aquifer. The aim of this paper is therefore to propose to freelance geologists some operational suggestions when ones have to attest the validity of clayey material for the waterproofing of the landfill.In these cases, two different situations can occur: i) the evaluation of the clayey soil for the waterproofing of the tank to receive waste, whose geotechnical proprieties have been examined with laboratory tests; ii) the evaluation of the quality of the clayey soil after the waterproofing of the landfill tanks with in situ and laboratory tests.

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