Dry Barriers for Waste Containment

9800255克雷格复合帽由土工膜和压实的粘土层组成，通常用于封闭垃圾填埋场和隔离受污染的土壤和废物，因为它们在最大限度地减少渗漏方面非常有效。然而，复合帽很贵。因此，人们对成本更低、同样有效的替代盖子产生了兴趣，这些盖子几乎完全由土质材料建造。这项拟议的研究的目的是调查影响一种新的替代土帽行为的基本因素，这种新的土帽被称为“干屏障”，这是一种特殊类型的土盖，利用气流来清除侵入的水。这种设计允许使用更薄的层，同时仍然防止渗漏，即使在最紧张的时期，如积雪融化和冬季大雨。因此，需要更薄的层，并且盖子的成本更低。设计干式屏障需要了解“就地蒸发”过程和多孔介质中充满水蒸气的空气流动。此外，还需要开发用于设计的模型。本研究通过实验工作和计算机模型的开发来解决这些问题。将进行实验，以表征土壤类型、水分含量、气流速度和气流湿度对“就地蒸发过程”的影响。模型将在实验工作的基础上开发，并通过大规模实验室测试和现场实验进行验证。这项研究的结果将证明使用干式护栏的好处，并为其设计提供分析工具和数据。***

9800255 Craig Composite caps consisting of a geomembrane and compacted clay layer are often used for closure of landfills and for isolation of contaminated soil and waste because they are very effective at minimizing percolation. However, composite caps are expensive. As a result, interest has developed in less costly and equally effective alternative caps constructed almost entirely with earthen materials. The objective of the proposed study is to investigate fundamental factors affecting the behavior of a new alternative earthen cap called a "dry barrier," a special type of earthen cover where airflow is used to remove intruding water. This design permits the use of thinner layers while still preventing percolation, even during the most stressful periods, such as snowmelt and heavy winter rainfalls. As a result, thinner layers are required and the cost of the cap is lower. Designing dry barriers requires an understanding of the "in situ evaporation" process and flow of air laden with water vapor in porous media. Moreover, models need to be developed for use in design. This study addresses these issues through experimental work and development of computer models. Experiments will be conducted to characterize the "in situ evaporation process" as a function of soil type, water content, air stream velocity, and humidity of the air stream. Models will be developed based on the experimental work and verified using large-scale laboratory tests and a field experiment. Results of this study will demonstrate the benefits of using dry barriers and provide analytical tools and data for their design. ***