Methane and carbon dioxide are of major concern as greenhouse gases; the landfills have the problem of controlling these gases. Al Akaider in Jordan is the second biggest landfill suffers controlling gases as it lacks a cover design system. In this work, the main goal is to investigate the appropriateness of amended expansive clayey soil in Irbid as a cover barrier. The expansive soil is unwanted in construction projects, thus the modification of this expelled soil enables using it as a low cost landfill cover barrier. In this research, the effect of adding nano-clay material (Hydrophilic Nano Bentonite) on the geotechnical characteristics, hydraulic conductivity, and gas transport coefficients of the clayey soil are studied. The soil samples were obtained from Irbid city. Unconfined compressive strength and free swelling tests were performed on soil samples with different percentages of nano-clay added in the range (0.1% to 1.2%) by weight. The results indicated that the addition of nano-clay at low percentages increases the strength of expansive soil up to 315 kPa at 0.6% of nano-clay and the swelling potential decreased dramatically with the addition of nano-clay. The optimal percent of nano-clay was found to be 0.6%. The intrinsic permeability of the amended soil was 6.03×10–15 m2. The average values of fluid transport coefficients were determined at 25 °C. The hydraulic conductivity for water was about 6.5×10–10 m/s. Gas conductivity coefficients for CO2 and CH4 were 5×10–9 m/s and 2.5×10–9 m/s respectively. Gas diffusion coefficients for CO2 and CH4 were 3×10–6 m2/s and 4×10–6 m2/s respectively. The results obtained in this research showed compatibility with standards conducted on geosynthetic clay liner (GCL), consequently the amended Irbid soil investigated, can be used as a cover barrier in Al Akaider landfill. These findings can also be generalized to landfills with similar conditions.

中文翻译：

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亲水性纳米膨润土对粘土土改良用于填埋场覆盖屏障：案例研究

甲烷和二氧化碳作为温室气体受到主要关注；垃圾填埋场存在控制这些气体的问题。约旦的 Al Akaider 是第二大垃圾填埋场，由于缺乏覆盖设计系统，因此无法控制气体。在这项工作中，主要目标是调查 Irbid 改良膨胀粘土作为覆盖屏障的适宜性。膨胀土在建筑项目中是不需要的，因此对这种排出的土壤进行改性使其能够用作低成本的垃圾填埋场覆盖屏障。本研究研究了添加纳米黏土材料（Hydrophilic Nano Bentonite）对黏性土的岩土特性、导水率和气体输运系数的影响。土壤样品取自伊尔比德市。在土壤样品上进行了无侧限抗压强度和自由膨胀试验，其中添加了不同重量百分比的纳米粘土（0.1% 至 1.2%）。结果表明，在纳米粘土含量为0.6%的情况下，少量纳米粘土的加入使膨胀土的强度提高到315 kPa，并且膨胀势随着纳米粘土的加入而显着降低。发现纳米粘土的最佳百分比为 0.6%。改良土的固有渗透率为6.03×10-15 m2。流体传输系数的平均值在 25 °C 下确定。水的导水率约为 6.5×10-10 m/s。CO2 和 CH4 的气体传导系数分别为 5×10-9 m/s 和 2.5×10-9 m/s。CO2 和 CH4 的气体扩散系数分别为 3×10-6 m2/s 和 4×10-6 m2/s。本研究中获得的结果表明与土工合成粘土衬垫 (GCL) 的标准兼容，因此研究的改良 Irbid 土壤可用作 Al Akaider 垃圾填埋场的覆盖屏障。这些发现也可以推广到具有类似条件的垃圾填埋场。