Abstract
This study focuses on the impeding behavior to movement of water through various punctures of geomembrane-supported GCL (GS-GCL) specimens. Permeability tests were conducted for the specimens with lacerations or different diameter perforations in tap water under air pressures varying up to 294kPa overburden. For a sample disk having a 5-cm laceration in length, it was observed that the bentonite layer of the lacerated part began to absorb water rapidly and then drainage decreased quickly and established self-healing, although the specimen showed an appreciable amount of drainage for immediately very short time after the overburden pressure was increased. Specimens with perforations of 1cm in diameter or less were completely filled with swollen bentonite gel giving a hydraulic conductivity of <1×10-10cm/s. The sample disk having a perforation of 2.5cm diameter also obtained a hydraulic conductivity of <1×10-10cm/s, but filling the perforation with the swollen bentonite gel required for a longer time. Results appear that self-healing function of punctured GS-GCL will seal a perforation of diameter not exceeding 2.5cm. It has been found out that plastic deformation and extrusion of the swollen bentonite gel layer, to fill and seal the perforation with its own gel, is a function of time and overburden pressure.
