Research on Anti-seepage Properties of GCL in Environmental Geotechnical Engineering Problems

To build landfills is a principal means for the cities of our country to dispose garbage. The impervious barrier of cover system and lines system is the key to ensure that the landfills should not be the source of secondary pollution to the surrounding. In recent years, geosynthetic Clay liners (GCLs) are widely used in different kinds of anti-seepage projects and the anti-seepage availabilities of GCLs are regarded as increasingly important by engineers. Anti-seepage effectiveness of GCLs involves at least two aspects, such as Hydraulic conductivity of GCLs under engineering practice conditions, and Absorption ability of bentonite in GCLs in the course of liquid permeation. In this paper, Hydraulic conductivity tests are performed to obtain seepage coefficient of GCLs, taking liquids such as distilled, deioned water and landfill leachate, and solutions with single-species cation as the hydration and permeation liquid. The results Show that cation valence, cation concentration and hydration ionic radius in hydration and permeation liquids have influences on hydraulic conductivity of GCLs. Absorption ability of GCLs in the course of liquid permeation is studied, and its influencing factors are also discussed, including hydration liquid and permeation time. The results Show that GCLs has large absorption ability on the permeation liquids. But the ability is decreasing with increase of permeation volume. And the types of hydration liquids exercise great influence on the variation of GCLs absorption. Analyses are made to combine the conclusion obtained in this Study with practical engineering projects, and proposals of building method of GCLs are advanced, and make suggestion on the future development of this technology.