Geosynthetic clay liners (GCLs) are designed to minimise contaminant migration into subsoils in landfills and other waste containment systems. The so-called mixture theory has typically been chosen as a basis for numerical models describing the complicated behaviour of GCLs subjected to thermo-hydro-mechanical changes. Despite progress in this area in the past decade, some aspects of the response of GCLs have not been captured by these simulations. For example, a typical assumption of these analyses is that the mechanical response to thermal loads of GCLs can be described by linear or non-linear elastic constitutive equations. However, there is evidence that in many instances plastic deformation cannot be avoided. The primary aim of this study is to analyse the hydration and dehydration behaviour of GCLs within a thermo-elasto-plastic framework. First, a thermo-elasto-plastic constitutive model is introduced and numerically implemented. Next, the results of numerical simulations of the performance of GCLs are presented and discussed and the effects of deviations from elastic behaviour are identified. Finally, a parametric study is conducted to identify the influence of key parameters in the constitutive model on the horizontal stress in the GCL’s bentonite during restrained shrinkage driven by thermal dehydration.

中文翻译：

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受热脱水作用的土工合成粘土衬里的热弹塑性分析

土工合成材料粘土衬里（GCL）旨在最大程度地减少污染物迁移到垃圾填埋场和其他废物围护系统中的底土中。通常选择所谓的混合理论作为数值模型的基础，该数值模型描述了受热-水-机械变化影响的GCL的复杂行为。尽管在过去的十年中该领域取得了进展，但这些模拟并未捕获GCL响应的某些方面。例如，这些分析的典型假设是，可以通过线性或非线性弹性本构方程描述GCL对热负荷的机械响应。但是，有证据表明，在许多情况下都无法避免塑性变形。这项研究的主要目的是在热弹塑性框架内分析GCL的水合和脱水行为。首先，引入了热弹塑性本构模型并对其进行了数值实现。接下来，提出并讨论了GCL性能的数值模拟结果，并确定了偏离弹性行为的影响。最后，进行了参数研究，以识别本构模型中关键参数对热脱水驱动的收缩收缩过程中GCL膨润土中水平应力的影响。