Abstract The desiccation and subsequent hydraulic conductivity of both a standard (GCL_A) and polymer-enhanced (GCL_B) Na-bentonite GCL hydrated from a well-graded sandy subsoil under 20 kPa, then subjected to a thermal gradient, and finally rehydrated and permeated with distilled water or 0.325 mol/L Na+ synthetic brine are reported. With moderate temperature of 40 °C applied to the top of the liner, GCL_B experienced less cracking than GCL_A, but this advantage disappeared when temperatures increased. Both desiccated specimens of GCL_A and B showed significant self-healing when permeated with distilled water and their hydraulic conductivities quickly reduced to around 10−11 m/s at 20 kPa upon rehydration. However, when GCL_B desiccated specimens were permeated with the synthetic brine, their hydraulic conductivities were found to be one to two orders of magnitude higher than corresponding values obtained with distilled water. On the other hand, GCL_A (with no polymer treatment) maintained its hydraulic conductivities at the same level obtained with distilled water. It is concluded that caution should be exercised in using polymer-bentonite in applications in which GCLs are subjected to significant thermal gradients unless there is data to show they are resistant to thermal effects.

中文翻译：

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添加聚合物对受热梯度影响的土工合成粘土衬垫干燥和愈合的影响

摘要 标准 (GCL_A) 和聚合物增强 (GCL_B) Na-膨润土 GCL 在 20 kPa 下从分级良好的砂质底土中水化，然后经受热梯度，最后再水化并渗透报告了蒸馏水或 0.325 mol/L Na+ 合成盐水。将 40 °C 的中等温度应用于衬管顶部，GCL_B 的裂纹比 GCL_A 少，但当温度升高时，这种优势消失了。GCL_A 和 B 的干燥样品在用蒸馏水渗透时都表现出显着的自愈性，并且在 20 kPa 下再水化时，它们的水力传导率迅速降低到 10-11 m/s 左右。然而，当 GCL_B 干燥样品被合成盐水渗透时，发现它们的水力传导率比用蒸馏水获得的相应值高一到两个数量级。另一方面，GCL_A（未经聚合物处理）将其水力传导率保持在与蒸馏水相同的水平。得出的结论是，在 GCL 经受显着热梯度的应用中使用聚合物-膨润土时应谨慎行事，除非有数据表明它们能抵抗热效应。