An X-ray imaging facility to improve geosynthetic landfill liner materials

用于改进土工合成垃圾填埋场衬垫材料的 X 射线成像设备

• 批准号: 440485-2013
• 负责人: Take, WilliamAndrew
• 金额: $ 7.12万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments - Category 1 (<$150,000)
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=508884
• 关键词: ray; imaging; facility; improve; geosynthetic

The purpose of a landfill liner is to act as a hydraulic barrier between leachate produced in a landfill and our groundwater drinking water supply. A composite landfill liner typically consists of two barrier layers - the first a thin (e.g. 1.5 mm thick) high density polyethylene (HDPE) geomembrane (GM), and the second a 10 mm thick geosynthetic clay liner (GCL). This second layer is needed because the top GM layer will realistically always contain accidental punctures created during the construction process. A GCL consists of a layer of exceptionally low permeability clay (bentonite) that is bonded to one or more geosynthetics (e.g., sandwiched between two geotextiles using needle-punched fibres, or stitch bonding, or to a geomembrane using an adhesive). Because the GCL contains clay, it will shrink and swell with the loss and uptake of moisture. On the negative side, this means that if the GCL dries out, it will shrink and perhaps even crack. A cracked landfill liner is obviously not an effective barrier to either landfill gas (e.g. methane) or fluid. On the positive side, the potential for this clay to experience large amounts of swelling can create a situation where these cracks can be swollen shut resulting in the barrier self-healing and regaining its excellent hydraulic properties. However, this swelling is only possible in certain circumstances depending on the chemistry of the fluid that tries to resaturate the barrier (i.e. it will self-heal if permeated with water, but some components of landfill leachate or pore fluid from chemically complex foundation soils may supress this ability). Fundamental research is therefore needed to understand the complex mechanisms of cracking and self-healing in these materials. However, because the bentonite clay inside the GCL is fabric encased, these cracks are hidden from view and can only be seen using X-rays. The purpose of this grant is to seek funding for an X-ray imaging facility so that a team of 5 MSc. students and 4 Ph.D. students can to perform non-destructive testing (NDT) on GCL liner (and other) materials to quantify the risk of GCL damage under a wide range of field exposure conditions and aid in the on-going collaboration with a Canadian GCL manufacturer to develop new more damage-resistant GCL products.

垃圾填埋场的目的是充当垃圾填埋场和我们的地下水饮用水供应的渗滤液之间的液压屏障。复合垃圾填埋场通常由两个屏障层组成 - 第一个层层是薄（例如1.5 mm厚）高密度聚乙烯（HDPE）地质膜（GM），第二个厚度为10毫米厚的地球合成粘土衬里（GCL）。需要第二层，因为顶部的GM层实际上将始终包含在施工过程中产生的意外穿刺。 GCL由一层异常低的渗透性粘土（膨润土）组成，该粘土（膨润土）粘合到一种或多种地质合成材料（例如，使用针键式纤维或针迹粘合或使用胶粘剂夹在两个土工织物之间，或使用针迹粘合夹在两个土工上的杂物之间）。由于GCL含有粘土，因此随着水分的损失和吸收，它会收缩和膨胀。在负面方面，这意味着，如果GCL干燥，它将收缩甚至会破裂。破裂的垃圾填埋衬里显然不是垃圾填埋气（例如甲烷）或液体的有效障碍。从积极的一面来看，这种粘土有大量肿胀的潜力可能会造成一种情况，使这些裂缝可能膨胀，从而导致屏障自我修复并重新获得其出色的液压特性。但是，只有在某些情况下，这种肿胀才有可能取决于试图使障碍物变为障碍的液体的化学反应（即，如果用水渗透，它会自我灌溉，但是垃圾填埋场浸出液的某些成分或化学复杂地基的孔隙液可能会自我替代此能力）。因此，需要基础研究来了解这些材料中破裂和自我修复的复杂机制。但是，由于GCL内部的膨润土粘土被包裹着织物，因此这些裂缝被隐藏在视图上，只能使用X射线看到。这笔赠款的目的是为X射线成像设施寻求资金，以便由5 MSC组成的团队。学生和4博士学位学生可以在GCL衬里（和其他）材料上执行非破坏性测试（NDT），以量化在广泛的现场曝光条件下造成GCL损害的风险，并有助于与加拿大GCL制造商进行持续的合作以开发新的。更多耐损害的GCL产品。