Research On Anti-Seepage Availability Of Geosynthetic Clay Liners And Related Mechanism Analysis

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. Meanwhile, increasing needs and requests of laboratory test and mechanism analysis are being asked. Anti-seepage effectiveness of GCLs involves at least three aspects followed: l)Hydraulic conductivity of GCLs under engineering practice conditions, 2)Absorption ability of bentonite in GCLs in the course of liquid permeation and 3)GCL internal shear strength while used in anti-seepage system. The above aspects are so important that they could directly affect the factor of safety and effectiveness of anti-seepage project. In this dissertation, a series of research work including about the laboratory tests of GCLs and the mechanism analysis of test results, is conducted and several valuable conclusions are obtained:1) A geosynthetic hydraulic conductivity device is designed and manufactured to measure hydraulic conductivity of GCLs under constant normal stress or horizontal strain conditions. Hydraulic conductivity of GCLs is measured for different hydrated and permeated liquids using the device.2) Free swelling tests and hydration swelling tests of GCLs and bentonite are performed in order to research the swelling characteristics of GCLs and its influencing factors, including normal stress, loading-hydration sequence and hydration liquid. The results show that the above factors have influences on GCLs swelling characteristics. Similar influencing laws can be obtained in the two types of tests.3) Hydraulic conductivity tests are performed to obtain hydraulic conductivity 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.