Long-term performance of geosynthetic barrier systems for groundwater protection

土工合成屏障系统用于大多数垃圾填埋场（占加拿大固体废物的68%），受污染的液体泻湖和许多采矿应用(例如。堆浸垫、尾矿储存设施；使用280,000,000平方米/年土工膜)，必须尽量减少污染流体向地表水或地下水的损失。从历史上看，该系统通常涉及单个复合衬垫，其中1.5毫米厚（塑料）土工膜衬垫焊接在1厘米厚的土工合成粘土衬垫上（以减少通过土工膜孔的泄漏），过去的研究主要集中在这种情况下。现在人们知道，单管道只适用于低风险项目，而在两个复合管道之间铺设土工复合管道的双系统通常用于大型垃圾填埋场或其他高风险应用。这些系统通常被期望限制污染物逸出(即。在某些资源回收应用中具有几十年的使用寿命，在大型垃圾填埋场具有几百年的使用寿命，在某些矿山废物中具有几千年的使用寿命。目前，人们对化学相互作用或施加载荷对复合衬垫泄漏的影响以及双复合衬垫系统的使用寿命几乎一无所知。这项研究代表了一个全新的研究领域，将是有史以来第一次研究这些问题。该研究利用了最近的研究突破，采用了一种新的研究策略，考虑了双层复合衬垫屏障系统中所有组分之间的相互作用，包括老化对次级排水层（土工复合排水）流动的影响。在新技术和正在开发的设备方面，它是独特的，新颖的和创新的，用于检查这些关键系统的性能随时间的变化，如果它们发生故障，则无法修复或更换。这项工作预计将导致关键衬底设计和施工的范式转变，这可能会导致土工膜和通常使用的排水层的彻底改变。它将对人类健康和环境产生深远的影响，提供：(i)对控制单和双复合衬垫系统长期性能的过程的新的基本科学见解；（ii）基于科学的使用寿命估计；（iii）为堆填区和采矿应用设计屏障系统提供新的指导方针；（iv）为21世纪提供环境保护的法规提供科学依据。这项研究将使加拿大的设计顾问、监管机构、制造商、土工合成材料安装商、设施所有者/运营商、原住民和普通公众受益，他们都将能够更加依赖这些屏障系统，并提高加拿大在环境可持续发展方面的国际竞争力和声誉。本研究将培养博士8人，硕士2人，本科生5人

Geosynthetic barrier systems are used in most landfills (taking 68% of Canadian solid waste), contaminated fluid lagoons, and many mining applications (eg. heap leach pads, tailings storage facilities; using 280,000,000 m2/yr of geomembrane) where loss of contaminated fluid to surface or ground water must be minimized. Historically, this system has often involved a single composite liner with welded panels of a 1.5mm thick (plastic) geomembrane liner over a 1 cm thick geosynthetic clay liner (to reduce leakage through holes in the geomembrane) and past research has focused on this case. It is now known that a single liner is only suitable for low risk projects and a double system with a geocomposite drain between two composite liners is routinely being used for large landfills or other higher risk applications. These systems are typically expected to limit contaminant escape (ie. have a service-life of) from many decades in some resource recovery applications, to centuries for large landfills, to millennia for some mine waste. At present, virtually nothing is known about the effect of chemical interaction or applied loads on leakage through composite liners or the service-life of double composite liner systems. This research represents a completely new area of investigation and will be the first to ever examine these issues. The research capitalizes on recent research breakthroughs and adopts a new research strategy for considering the interactions between all components of a double composite liner barrier system including the effects of aging on flow in a secondary drainage layer (geocomposite drain). It is unique, novel & innovative in terms of the new techniques & equipment being developed to examine the time-dependent change in the performance of these critical systems which cannot be repaired or replaced if they fail. This work is expected to result in a paradigm shift in the design and construction of critical bottom liners that will likely result in complete change in the geomembranes and drainage layers typically used. It will have a profound impact on human health and the environment by providing: (i) new fundamental scientific insights into the processes controlling long-term performance of single and double composite liner systems; (ii) science-based estimates of service-life; (iii) new guidelines for the design of barrier systems for landfills and mining applications, & (iv) a scientific basis for 21st Century regulations to provide environmental protection. The research will benefit Canadian design consultants, regulators, manufacturers, geosynthetics installers, facility owners/operators, First Nations, and the general public who will all be able to place greater reliance on these barrier systems and enhance Canada's international competitiveness and reputation for environmentally sustainable development. The research will educate 8 PhD, 2 MASc & 5 undergraduate students.**