A Simple Field Method to Qualify the State of Saturation in Capillary Barriers
Burnotte, F
Department of Civil Engineering, Collège de Sherbrooke, Sherbrooke, Canada

Cabra, lA
Department of Civil Engineering, Université de Sherbrooke, Sherbrooke, Canada

Lefebvre, G
Department of Civil Engineering, Université de Sherbrooke, Sherbrooke, Canada

(Received 30 December 1899; accepted 30 December 1899)

Abstract
A simple and straightforward field method to rapidly qualify the state of saturation of moisture retaining layers (MRL) is proposed and the details of its calibration and operation, described. The technique is based on the simple fact that if gas samples cannot be taken from a stainless tube that is inserted to the desired depth within the MRL, the air filled voids at that depth are not interconnected and the material can be qualified, for all practical purposes, as saturated. In this case, the threshold degree of saturation beyond which gas flux substantially decreases (approximately 85%), has been attained. In several sites covered with deinking by-products (DBP), an industrial residue that can be used as alternative construction material for landfills and acid-producing mine sites covers, it has been often impossible to collect gas samples below approximately 20 cm from the surface of the DBP layer. The question was thus to know if this is a reliable indicator that the threshold degree of saturation has or not been attained and that the layer is performing its role of gas barrier. In order to answer this question, a calibration was performed in the laboratory and in the field. The calibration consisted mainly on attempting to extract gas from samples compacted at different degrees of saturation. The results show that the threshold degree of saturation for DBP is attained at approximately 83%.

Keywords:
acid rock drainage, capillary barriers, landfill gas extraction, moisture retaining layer, rock

Paper ID: GTJ12112
DOI: 10.1520/GTJ12112

ASTM International is a member of CrossRef.
Author Burnotte, F Affiliation Department of Civil Engineering, Collège de Sherbrooke, Sherbrooke, Canada Author Cabra, lA Affiliation Department of Civil Engineering, Université de Sherbrooke, Sherbrooke, Canada Author Lefebvre, G Affiliation Department of Civil Engineering, Université de Sherbrooke, Sherbrooke, Canada Author Burnotte F, Cabral AR, Lefebvre G Title A Simple Field Method to Qualify the State of Saturation in Capillary Barriers Symposium , Committee on