Abstract The behaviour of geosynthetic clay liners (GCLs) as part of a physical-environmental system is examined. Consideration is given to: (a) both the physical and hydraulic interactions with the materials, and the chemical interactions with the fluids, above and below the liner, (b) time-dependent changes in the materials, (c) heat generated from the material to be contained, as well as (d) the climatic conditions both during construction and during service. This paper explores some common perceptions about GCL behaviour and then examines the misconceptions that can arise and their implications. It demonstrates how what may first appear obvious is not always as one expects and that more is not always better. It discusses: (i) the pore structure of a GCL, (ii) the dependency of the water retention curve of the GCL on its structure, bentonite particle sizes and applied stress, (iii) the effect of the subgrade pore water chemistry, (iv) the mineralogy of the subgrade, and (v) thermal effects. The desirability of a GCL being reasonably well-hydrated before being permeated is examined. The critical size of needle-punch bundles at which preferential flow can increase hydraulic conductivity by orders of magnitude is illustrated. The dependency of self-healing of holes on the interaction between GCL and subgrade is discussed. Finally, the transmissivity of the geomembrane/GCL interface is shown to be a function of GCL and geomembrane characteristics and to be poorly correlated with GCL hydraulic conductivity.

中文翻译：

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土工合成粘土衬垫：认知和误解

摘要 对作为物理-环境系统一部分的土工合成粘土衬垫 (GCL) 的行为进行了检查。考虑到：(a) 与材料的物理和水力相互作用，以及与衬管上方和下方流体的化学相互作用，(b) 材料随时间的变化，(c) 由内衬产生的热量所包含的材料，以及 (d) 建造和使用期间的气候条件。本文探讨了对 GCL 行为的一些常见看法，然后检查可能出现的误解及其影响。它展示了最初看起来显而易见的东西并不总是如人们所期望的那样，而且并不总是越多越好。它讨论了：（i）GCL 的孔隙结构，（ii）GCL 的保水曲线对其结构的依赖性，膨润土颗粒大小和施加的应力，(iii) 路基孔隙水化学的影响，(iv) 路基的矿物学，以及 (v) 热效应。检查了 GCL 在被渗透之前适当地充分水合的合意性。说明了针刺束的临界尺寸，在该尺寸处优先流动可以将导水率提高几个数量级。讨论了孔洞自愈对协鑫与路基相互作用的依赖性。最后，土工膜/GCL 界面的透水率显示为 GCL 和土工膜特性的函数，与 GCL 导水率的相关性较差。检查了 GCL 在被渗透之前适当地充分水合的合意性。说明了针刺束的临界尺寸，在该尺寸处优先流动可以将导水率提高几个数量级。讨论了孔洞自愈对协鑫与路基相互作用的依赖性。最后，土工膜/GCL 界面的透水率显示为 GCL 和土工膜特性的函数，与 GCL 导水率的相关性较差。检查了 GCL 在被渗透之前适当地充分水合的合意性。说明了针刺束的临界尺寸，在该尺寸处优先流动可以将导水率提高几个数量级。讨论了孔洞自愈对协鑫与路基相互作用的依赖性。最后，土工膜/GCL 界面的透水率显示为 GCL 和土工膜特性的函数，与 GCL 导水率的相关性较差。