Long-term hydraulic conductivity of bentonite-polymer geosynthetic clay liners

IF 4.7 1区工程技术 Q1 ENGINEERING, GEOLOGICAL

Geotextiles and Geomembranes Pub Date : 2024-04-30 DOI:10.1016/j.geotexmem.2024.04.006

Hanrui Zhao, Dong Li, Kuo Tian

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Abstract

Hydraulic conductivity tests were conducted on six bentonite-polymer (B–P) geosynthetic clay liners (GCLs) to investigate the effect of the slow cation exchange process and polymer elution on the long-term hydraulic conductivity of B–P GCLs. Tests were conducted up to 1458 days and as many as 443 pore volumes of flows (PVFs). Three B–P GCLs consist of linear polymer whereas the other three have crosslinked polymer. One sodium geosynthetic clay liner (Na–B GCL) was used as a control. Hydraulic conductivities (K₆₇₆₆) of B–P GCLs (5.4 × 10⁻¹² m/s to 3.7 × 10⁻¹¹ m/s) per ASTM D6766 were approximately 2-3 orders of magnitude lower than that of Na–B GCL (2.3 × 10⁻⁹ m/s to 3.5 × 10⁻⁹ m/s). Tests were continued after hydraulic and chemical equilibrium to investigate the long-term hydraulic conductivity of GCLs. Hydraulic conductivities of GCLs had an increasing trend after hydraulic and chemical equilibrium. The ratio of K_L/K₆₇₆₆ for B–P GCLs was 3.5–14.7, whereas ratio of K_L/K₆₇₆₆ for Na–B GCLs was 1.0–1.7. Total organic carbon (TOC) tests results confirmed that polymer elution occurred during the entire permeation process. The higher ratio of K_L/K₆₇₆₆ for B–P GCLs was attributed to the effect of polymer elution.

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膨润土-聚合物土工合成粘土衬里的长期导水性

对六种膨润土-聚合物（B-P）土工合成粘土衬里（GCL）进行了水力传导性测试，以研究缓慢的阳离子交换过程和聚合物洗脱对 B-P GCL 长期水力传导性的影响。测试时间长达 1458 天，测试孔隙流量（PVF）多达 443 个。三种 B-P GCL 由线性聚合物组成，而另外三种则由交联聚合物组成。一种钠土工合成粘土衬垫（Na-B GCL）用作对照。根据 ASTM D6766 标准，B-P GCL 的水导率（K6766）（5.4 × 10-12 m/s 至 3.7 × 10-11 m/s）比 Na-B GCL 的水导率（2.3 × 10-9 m/s 至 3.5 × 10-9 m/s）低约 2-3 个数量级。在水力和化学平衡后继续进行试验，以研究 GCL 的长期水力传导性。水力和化学平衡后，GCL 的水导率呈上升趋势。B-P 型 GCL 的 KL/K6766 比率为 3.5-14.7，而 Na-B 型 GCL 的 KL/K6766 比率为 1.0-1.7。总有机碳（TOC）测试结果证实，聚合物洗脱发生在整个渗透过程中。B-P GCL 的 KL/K6766 比率较高是由于聚合物洗脱的影响。

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来源期刊

Geotextiles and Geomembranes 地学-地球科学综合

CiteScore

9.50

自引率

21.20%

发文量

111

审稿时长

59 days

期刊介绍： The range of products and their applications has expanded rapidly over the last decade with geotextiles and geomembranes being specified world wide. This rapid growth is paralleled by a virtual explosion of technology. Current reference books and even manufacturers' sponsored publications tend to date very quickly and the need for a vehicle to bring together and discuss the growing body of technology now available has become evident. Geotextiles and Geomembranes fills this need and provides a forum for the dissemination of information amongst research workers, designers, users and manufacturers. By providing a growing fund of information the journal increases general awareness, prompts further research and assists in the establishment of international codes and regulations.