Impact of High Concentration Solutions on Hydraulic Properties of Geosynthetic Clay Liner Materials

Materials

Qiang Xue¹  Qian Zhang² 

[1] State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China;

关键词: geosynthetic clay liner materials;    high concentration chemical solutions;    chemical attack effect;    hydraulic conductivity;    hydration swelling;   

DOI  :  10.3390/ma5112326

来源: mdpi

【 摘 要 】

This study focuses on the impact of landfill high concentration solutions erosion on geosynthetic clay liner (GCL) materials permeability. The permeation tests on the GCL, submerged using different kinds of solutions with different concentrations, were carried out systematically by taking these chemical solutions as permeant liquids. Based on seasonal variations of ion concentrations in Chenjiachong landfill leachate (Wuhan Province), CaCl₂, MgCl₂, NaCl, and KCl were selected as chemical attack solutions to carry out experimental investigations under three concentrations (50mM, 100mM, 200mM) and soak times (5, 10, and 20 days). The variation law of the GCL hydraulic conductivity under different operating conditions was analyzed. The relationship between GCL hydraulic conductivity, chemical solutions categories, concentrations, and soak times were further discussed. The GCL hydraulic conductivity, when soaked and permeated with high concentration chemical solutions, increases several times or exceeds two orders of magnitude, as compared with the permeation test under normal conditions that used water as the permeant liquid. This reveals that GCL is very susceptible to chemical attack. For four chemical solutions, the chemical attack effect on GCL hydraulic conductivity is CaCl₂ > MgCl₂ > KCl > NaCl. The impact of soak times on GCL hydraulic conductivity is the cooperative contribution of the liner chemical attack reaction and hydration swelling. A longer soak time results in a more advantageous hydration swelling effect. The chemical attack reaction restrains the hydration swelling of the GCL. Moreover, the GCL hydraulic conductivity exponentially decreases with the increased amplitude of thickness.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.