Transient water transport in expansive soils under coupled hydraulic, mechanical and thermal boundary conditions: Experimental and numerical study

耦合水力、机械和热边界条件下膨胀土中的瞬态水传输：实验和数值研究

• 批准号: 229210044
• 负责人: Professor Dr.-Ing. Tom Schanz, Ph.D. (†)
• 金额: --
• 依托单位: Lehrstuhl für Bodenmechanik, Grundbau u Umweltgeotechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/229210044?language=en
• 关键词: Transient; water; transport; expansive; soils

Coupled thermal and moisture flows and their consequences on soil behavior are involved in a variety of geotechnical problems such as buried high voltage power cable technology, geothermal energy production from shallow or deep boreholes or oil and gas production. Moreover, thermal and hydraulic aspects are of great importance in the conceptual design of repositories for spent nuclear fuel and medium level nuclear waste. On the other hand, as a consequence of climate change, thermal desiccation of natural soils is expected worldwide and even in areas of central and northern Europe. The typical soils involved in the above mentioned situations often are of expansive nature. However, the experimental study of the coupled thermo-hydro-mechanical (THM) behavior of expansive materials possesses serious difficulties, and it is not a habitual practice in geotechnical laboratories. For this reason, there is a lack of conventional laboratory techniques for THM characterization of expansive soil behavior, and if any experimental procedures are available they usually address soil investigation only under saturated conditions. Experimental data regarding unsaturated THM-material characterization are limited, especially in case of expansive clays. Hence the major aim of the proposed here investigation is to contribute in filling the gap by means of designing an experimental procedure to generate temperature, suction and water content profiles within the expansive soil under thermal and hydraulic gradients. Although experimental work plays an important role in studying the THM processes in soils it may not be self-sufficient because the laboratory tests especially for expansive materials are usually highly time consuming and costly. Therefore, in this project we propose to develop and implement theoretical and numerical modeling concepts for prediction of soil behavior during a particular THM-experiment as well as continuously in a period significantly extending the laboratory test duration. In order to make this study complete the further objectives addressed here are the calibration of the numerical model and the employed material laws via back analysis and the validation of the results by means of model sensitivity analysis.

耦合的热和水分流动及其对土壤行为的后果涉及各种岩土工程问题，如埋地高压电力电缆技术，从浅或深钻孔或石油和天然气生产的地热能生产。此外，热和水力方面在乏核燃料和中等放射性核废物处置库的概念设计中非常重要。另一方面，由于气候变化，预计全世界，甚至中欧和北方地区的天然土壤都将热干燥。上述情况中涉及的典型土壤通常具有膨胀性。然而，膨胀材料的热-水-力耦合特性的试验研究存在严重困难，在岩土实验室中尚不常用。由于这个原因，有一个缺乏常规的实验室技术THM表征膨胀土的行为，如果有任何实验程序，他们通常只解决饱和条件下的土壤调查。关于非饱和THM材料特性的实验数据是有限的，特别是在膨胀性粘土的情况下。因此，建议在这里调查的主要目的是有助于填充差距通过设计一个实验程序，以产生温度，吸力和水分含量的档案内的膨胀土的温度和水力梯度。虽然实验工作在研究土壤中THM过程中起着重要的作用，但由于实验室试验特别是膨胀材料的实验室试验通常非常耗时且昂贵，因此可能无法自给自足。因此，在这个项目中，我们建议开发和实施理论和数值模拟的概念，在一个特定的THM-实验，以及在一段时间内持续显着延长实验室测试时间的土壤行为的预测。为了使这项研究完成进一步的目标，这里解决的是数值模型的校准和所采用的材料的法律，通过反分析和验证的结果，通过模型的敏感性分析。