Self-healing of circular and slit defects in GCLs upon hydration from silty sand under applied stress

摘要

The self-healing of a GCL with artificial defects (circular holes and rectangular slits, both with and without the carrier geotextile preserved below the holes) upon hydration on a Godfrey silty sand (GSS) subgrade with w(fdn) = 5, 10 and 16% under 2-100 kPa is examined. Circular holes with the carrier geotextile missing below holes with diameters up to 25.4 mm self-healed on the w(fdn) = 5% and 10% GSS but not on 16% GSS, while none self-healed when carrier geotextile was preserved below the holes. When DI water was introduced to the surface under 100 kPa, circular holes with diameter up to 38.1 mm self-healed. Neither the single 15 mm-wide slit nor double 15 mm-wide parallel slits with 20 mm-wide strip of undamaged GCL between them resting on w(fdn) = 10% GSS under 20 kPa fully self-healed. The introduction of simulated synthetic landfill leachate (SSL) to the GCL surface under 70 kPa did not result in self-healing. Post-hydration k tests found that GCL without a carrier geotextile below a hole up to 25.4 mm in diameter would not have a significant adverse effect on the hydraulic conductivity compared with an intact GCL provided the permeant was tap water rather than SSL.