This paper examines the hydration behaviour of polymer enhanced geosynthetic clay liners (GCLs) under both isothermal conditions and diurnal cyclical temperatures as recorded at a Melbourne landfill site. The diurnal temperature cycles introduced thermal gradients, which induced water movement downwards into the subgrade. It was found that the bulk of the thermal and hydraulic effects occurred within the upper 50 mm of the subgrade layer. Compared to isothermal conditions, diurnal temperature cycling's main effect was to suppress GCL hydration. Thermal gradients induced capillary breaks, and GCL hydration was thus limited to vapour phase hydration from the subgrade, which restricted the gravimetric water content of the GCLs to <30%. The hydration process at the interface was observed to gradually return to isothermal condition hydration levels once the temperature cycle conditions were removed. While the polymer's presence ensures the adsorption of more water, it also renders GCLs more sensitive to the effects of temperature. This study provides insights on the hydration behaviour of uncovered GCLs in field applications and the impact that diurnal temperature cycles can have on GCL hydration in a Mediterranean type climate.

本文研究了在墨尔本垃圾填埋场记录的等温条件和昼夜循环温度下聚合物增强型土工合成粘土衬垫 (GCL) 的水化行为。昼夜温度循环引入了热梯度，导致水向下移动到路基中。发现大部分热力和水力效应发生在路基层的上部 50 毫米内。与等温条件相比，昼夜温度循环的主要作用是抑制 GCL 水合作用。热梯度导致毛细管破裂，因此 GCL 水化仅限于来自路基的气相水化，这将 GCL 的重量含水量限制为 <30%。一旦温度循环条件被移除，界面处的水合过程被观察到逐渐恢复到等温条件水合水平。虽然聚合物的存在确保了更多水的吸附，但它也使 GCL 对温度的影响更加敏感。这项研究提供了对野外应用中未覆盖 GCL 的水合作用的见解，以及昼夜温度循环对地中海型气候中 GCL 水合作用的影响。