Collaborative Research: Experimental and Computational Investigation of Consolidation-Induced Contaminant Transport for High Water Content Geo-Materials

本项目的目标是推进国家的最先进的方面，我们的理解的机制和意义的固结诱导污染物迁移的高含水量的岩土材料。固结与污染物运移耦合现象在岩土工程和环境地质工程中广泛存在。这些应用包括受污染的高含水量地质材料（例如，在非原位工程蓄水池中对尾矿、疏浚物、污泥和泥浆进行处理，对受污染的高含水量地质材料进行机械脱水，通过注入颗粒零价铁（ZVI）泥浆和土壤混合对受氯化溶剂污染的源区进行原位修复，以及对水下受污染沉积物进行原位覆盖。最近的研究表明，固结引起的污染物迁移是一种有效的迁移机制，可能对给定系统的污染物迁移行为产生持久的影响。然而，很少有人知道这种机制的实际应用的一般意义。目前对固结引起的污染物迁移的理解局限于：（1）较高的化学浓度和多种类污染物的影响，例如通常发生在现场;（2）通过胶体颗粒促进迁移的重要性，这可能是具有高度吸附污染物的天然细粒材料的重要机制;（3）测试实际的地质材料，如尾矿或疏浚沉积物;（4）没有进行恒定应变率或离心加载条件下的工作。 拟议的研究将包括一个基本的实验和计算调查的固结引起的污染物传输的几种材料和条件的机制，然后评估这些研究结果的意义相关的岩土工程和地质环境应用。研究计划有六项任务：（1）材料采购和表征;（2）材料性能测试;（3）固结诱导迁移测试;（4）开发和验证计算模型;（5）计算模拟;（6）项目合作和成果传播。拟议的研究既有内在的科学价值，在基本评估这种传输机制和相关参数，以及提高我们的能力，预测污染物从高含水量的地质材料在巩固方面的实际影响。因此，更好地了解固结引起的污染物迁移的机制和意义，从而提高设计者和监管机构的能力，以保护公众健康和环境免受污染物的影响。这项研究的结果有可能改变目前被污染的高含水量地质材料的特性，处理，脱水和/或处置的方式。

The goal of this project is to advance the state-of-the art with respect to our understanding of the mechanisms and significance of consolidation-induced contaminant transport for high water content geo-materials. The phenomenon of coupled consolidation and contaminant transport occurs for a variety of practical applications in geotechnical and geoenvironmental engineering. Such applications include confined disposal of contaminated high water content geo-materials (e.g., tailings, dredgings, sludges, and slurries) in ex situ engineered impoundments, mechanical dewatering of contaminated high water content geo-materials, in situ remediation of source zones contaminated with chlorinated solvents via injection of granular zero valent iron (ZVI) slurry and soil mixing, and in situ capping of subaqueous contaminated sediments. Research has demonstrated only very recently that consolidation-induced transport of contaminants is a valid transport mechanism that may have lasting effects on the contaminant migration behavior for a given system. However, little is known about the general significance of this mechanism for practical applications. Current understanding of consolidation-induced contaminant transport is limited with respect to: (1) the effects of higher chemical concentrations and multispecies contaminants, such that typically occur in field sites; (2) the importance of facilitated transport via colloidal particles, which is likely to be an important mechanism for natural fine-grained materials with highly sorbed contaminants; (3) testing of realistic geo-materials, such as mine tailings or dredged sediments; and (4) absence of work conducted for constant rate-of-strain or centrifuge loading conditions. The proposed research will consist of a fundamental experimental and computational investigation of the mechanism of consolidation-induced contaminant transport for several materials and conditions, and then assess the significance of these findings for relevant geotechnical and geoenvironmental applications. The research plan has six tasks: (1) material procurement and characterization; (2) material property testing; (3) consolidation-induced transport testing; (4) development and validation of computational models; (5) computational simulations; and (6) project collaboration and dissemination of results. The proposed research has both intrinsic scientific merit in terms of a fundamental assessment of this transport mechanism and associated parameters as well as practical implications in terms of improving our ability to predict contaminant outflows from high water content geo-materials during consolidation. As a result, a better understanding of the mechanism and significance of consolidation-induced contaminant transport will be achieved, thereby enhancing the ability of designers and regulators to protect the public health and the environment from the effects of contaminants. Results from this research have the potential to transform the way contaminated high water content geo-materials are currently characterized, handled, dewatered and/or disposed.