Research Initiation: Numerical Solution of Hazardous Waste Containment and Consolidation via Artificial Ground Freezing

本研究探讨使用人工地面冻结作为一种 控制和巩固危险废物的手段。 两 土壤固化的三维有限元模拟， 提出了 数字战略利用创新技术， 表示枝晶曲率、有限元网格部署和 数值热量和质量守恒 固化模型为 基于耦合，瞬态热量和质量方程，在两个冻结 解冻阶段。 边界条件解释了界面 能量、动力学和溶质排斥效应。 自适应有限 单元网格连续地跟踪相阵面， 条件直接应用于接口。 自动 重新离散化例程，它不需要用户 在模拟过程中进行干预。 数值模拟将是 与现有的大规模实验数据相比， 包括有无氯化钠的土壤固化 以及含有危险废物（氯仿、苯、甲苯）的土壤 和四氯乙烯）。 人工冻结在我国已经应用了世纪。 土木工程应用。 它能够形成不透水的 屏障、脱水污泥和加固固体已被 演示。 然而，预测或控制物体的位置 对于任意几何形状，冻结屏障作为时间的函数， 未破案件 在耦合传热传质系统中， 与枝晶生长相关的不稳定性， 过冷和成分过冷。 耦合输运 处理土壤固化的系统是不可替代的， 超越一维情形的解析解。 因此，委员会认为， 这项提案研究有很大的希望，如果照亮 控制地面冻结的解决方案。

This research investigates the use of artificial ground freezing as a means of containing and consolidating hazardous waste. A two dimensional finite element simulation of soil solidification is proposed. The numerical strategy utilizes innovative techniques for representing dendrite curvature, finite element grid deployment and numerical heat and mass conservation. The solidification model is based on the coupled, transient heat and mass equations in both frozen and unfrozen phases. Boundary conditions account for the interfacial energy, kinetics and solute rejection effects. The adaptive finite element mesh continually tracks the phase front such that boundary conditions are applied directly on the interface. An automatic rediscretization routine is employed which requires no user intervention during the simulation. The numerical simulations will be compared to existing, large-scale experimental data for situations involving the solidification of soils with and without sodium chloride and soils spiked with hazardous wastes (chloroform, benzene, toluene and tetrachloroethylene). Artificial ground freezing has been in practice for over a century in civil engineering applications. Its ability to form impermeable barriers, dewater sludge, and consolidate solids has been demonstrated. However, predicting or controlling the location of the frozen barrier as a function of time for arbitrary geometries is unsolved. Inherent in the coupled heat and mass transfer system lie instabilities associated with the growth of dendrites due to undercooling and constitutional supercooling. The coupled transport system dealing with solidification of the soil is unamendable to analytical solutions beyond one dimensional situations. Consequently, this proposal research holds great promise if illuminating the solution to the control of ground freezing.