当前位置: X-MOL 学术Geotext. Geomembr. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Irrigated composite liner designs for fast hydration and prevention of thermal desiccation of geosynthetics clay liners
Geotextiles and Geomembranes ( IF 5.2 ) Pub Date : 2020-12-01 , DOI: 10.1016/j.geotexmem.2020.08.004
Bowei Yu , Abbas El-Zein

Abstract In composite liners made of geomembrane (GMB)-geosynthetics clay liners (GCLs), maintaining bentonite in the GCL in a suitably hydrated state is critical for their performance. Hydration of GCL from subsoil, following industry best practice, is time consuming and conditional on suitable water chemistry in subsoil. In addition, under thermal gradients, dehydration occurs, with moisture migrating downwards to the subsoil, leading to the development of cracks in the bentonite and hence loss of performance. Two novel ideas are proposed in this paper, namely hydration of GCLs by artificial irrigation and hydraulic separation of the liner system from the underlying subsoil. Three new composite liner designs allowing for actively irrigating a geosynthetic clay liner (GCL) through a geocomposite layer were investigated. In two of the three designs, the hydraulic connection between the GCL and the subsoil was broken by placing an additional GMB between them. The new designs were tested in column experiments under 20 kPa overburden pressure and temperatures of up to 78 °C applied to the top of the liner. The performances of the new designs were compared to that of a standard GCL-GMB design where GCL was allowed to hydrate from a well-graded sandy subsoil. Three scenarios for the staging of hydration and thermal load application were investigated. Under active hydration of the composite liners, it took less than 14 days for the GCLs to reach a gravimetric water content ω of 110–130%, compared to 49 days taken to reach ω~95% under hydration from the subsoil. GCLs in the new designs in which the hydraulic connection with the subsoil was broken, remained well-hydrated (ω>100%) after 14 days of heating and no cracks appeared in the bentonite. On the other hand, the GCL in the conventional design experienced severe desiccation under the same conditions. The new designs hence offer a viable solution to the problem of slow hydration and/or thermal desiccation of GCLs.

中文翻译:

用于快速水化和防止土工合成粘土衬垫热干燥的灌溉复合衬垫设计

摘要 在由土工膜 (GMB)-土工合成材料粘土衬垫 (GCL) 制成的复合衬垫中,保持 GCL 中的膨润土处于适当的水合状态对其性能至关重要。根据行业最佳实践,从底土中水合 GCL 是耗时的,并且取决于底土中合适的水化学。此外,在温度梯度下,会发生脱水,水分向下迁移到底土,导致膨润土出现裂缝,从而导致性能下降。本文提出了两个新的想法,即通过人工灌溉使 GCLs 水化和将衬垫系统与下层底土水力分离。研究了三种新的复合衬垫设计,允许通过土工复合材料层积极灌溉土工合成粘土衬垫 (GCL)。在三个设计中的两个中,GCL 和底土之间的液压连接通过在它们之间放置一个额外的 GMB 被打破。新设计在 20 kPa 上覆压力和高达 78 °C 的温度应用于衬管顶部的色谱柱实验中进行了测试。新设计的性能与标准 GCL-GMB 设计的性能进行了比较,其中 GCL 可以从分级良好的沙质底土中水化。研究了水合作用和热负荷应用的三种情况。在复合衬垫的主动水合作用下,GCLs 用不到 14 天的时间达到 110-130% 的重量含水量 ω,而在底土的水合作用下达到 ω~95% 需要 49 天。新设计中的 GCL 与底土的液压连接被破坏,加热 14 天后仍保持良好的水合状态(ω>100%),且膨润土未出现裂纹。另一方面,传统设计中的 GCL 在相同条件下经历了严重的干燥。因此,新设计为 GCL 的缓慢水合和/或热干燥问题提供了可行的解决方案。
更新日期:2020-12-01
down
wechat
bug