Geosentetik kil örtülerin su tutma ve uzun dönem hidrolik iletkenlik davranışının değerlendirilmesi

The experimental study was conducted to determine the water uptake and hydraulic conductivity behaviors of eight needle-punched GCLs. The GCLs were denoted as low performance (LP), medium performance (MP) and high performance (HP) depending on the bentonite liquid limits. Hydration performance of GCLs and its effects on the water uptake and the hydraulic conductivity were investigated by simulating cover applications in the laboratory. For this purpose, GCLs were hydrated over compacted sand and zeolite subsoils which were placed in flexible wall permeameters with two different methods (i.e. control sample method, CSM, and single large sample method, SLSM). The effects of hydration method, hydration duration, water contents of the subsoil, type of GCL and bentonite mass per unit area (MPUA) of GCL were the parameters investigated in this study. The suction characteristics of the subsoils and GCLs were determined as well. Hydraulic conductivity tests were conducted on the hydrated GCLs to determine the influence of hydration on the hydraulic conductivity. Since the swelling ability of bentonite influences the hydraulic performance of GCLs, the changes in the swell indices of bentonites after hydration were also investigated. Finally, the swelling performance of GCLs was linked to the cation exchange that took place between subsoil and GCL. This was quantified with cation analysis conducted on either subsoils or GCLs. Significant findings were obtained throughout the study some of which have been published in outstanding journals so far.