Coupled thermo-hydro-mechanical-chemical (THMC) processes in swelling clay-sulfate rocks

膨胀粘土-硫酸盐岩石中的热-水-机械-化学耦合 (THMC) 过程

• 批准号: 258019622
• 负责人: Professor Dr. Christoph Butscher
• 金额: --
• 依托单位: Institut für Geotechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/258019622?language=en
• 关键词: Coupled; thermo; hydro; mechanical; chemical

Clay rocks containing the sulfate mineral anhydrite swell when getting in contact with water. The swelling of clay-sulfate rocks is a threat in tunneling and geothermal drilling. In Staufen, for example, swelling ground with uplift rates exceeding 1 cm/month resulted in more than 250 seriously damaged houses after the installation of geothermal heat pumps. Numerical models that simulate the swelling allow experts to test and optimize countermeasures. However, our knowledge about the processes taking place during swelling is limited. There are contradicting conceptual swelling models, and an accepted mathematical swelling law to quantify the swelling of clay-sulfate rocks is lacking. Although various numerical models for swelling simulations have been proposed so far, all existing approaches have limitations. To overcome them, enhanced numerical models must consider the coupling of thermal, hydraulic, mechanical and chemical (THMC) processes and, at the same time, must be able to include the complexity of the geological setting as well as the impact of engineering activities, such as drilling, tunneling and groundwater pumping. The planned research has therefore two main goals: (1) to complete our present understanding of the swelling, and in particular of the involved coupled THMC processes; and (2) to improve our ability to simulate the swelling processes comprehensively.The project wants to reach these goals by implementing and comparing different contradicting conceptual and mathematical models into coupled numerical codes; and subsequently challenging the models with field observations. For this purpose, the study site Staufen provides very comprehensive thermal, hydraulic, chemical and mechanical data. The different models will be validated or rejected by observation data, and they will also be evaluated by an uncertainty study. The project will finally use the models for the optimization of remediation strategies at the study site to show their applicability.An additional goal of the project is to make the developed modeling tools commonly available and usable for others. Therefore, we will employ an open-source software and publish developed codes; and we will host a symposium and workshop to exchange knowledge and modeling experience in the area of swelling clay-sulfate rocks.The proposed project follows up our previous research, adding and coupling mechanical processes to our already developed hydraulic-chemical approach, while still maintaining the hydrogeological and geochemical complexity of the 3D geological and engineered setting. The project will strongly benefit from our previous project, because site specific processed data (3D geological model, time series of observation data and boundary conditions, hydraulic and geochemical fluid and rock properties) are already at hand.

含有硫酸盐矿物硬石膏的粘土岩与水接触时会膨胀。硫酸盐粘土岩石的膨胀是隧道和地热钻井的一大威胁。例如，在Staufen，地面隆起速度超过1厘米/月，在安装地热热泵后，造成250多所房屋严重受损。模拟膨胀的数值模型允许专家测试和优化对策。然而，我们对肿胀过程的了解是有限的。目前存在着相互矛盾的概念膨胀模型，也缺乏一个公认的数学膨胀规律来量化粘土-硫酸盐岩石的膨胀。虽然目前已经提出了各种膨胀模拟的数值模型，但现有的方法都有局限性。为了克服这些问题，增强的数值模型必须考虑热、水力、机械和化学（THMC）过程的耦合，同时，必须能够包括地质环境的复杂性以及工程活动的影响，如钻井、隧道和地下水抽水。因此，计划中的研究有两个主要目标：(1)完成我们目前对肿胀的理解，特别是所涉及的耦合THMC过程；(2)提高综合模拟膨胀过程的能力。该项目希望通过将不同的相互矛盾的概念和数学模型实现和比较成耦合的数字代码来实现这些目标；然后用实地观察挑战这些模型。为此，研究地点Staufen提供了非常全面的热、水力、化学和机械数据。不同的模型将通过观测数据验证或拒绝，它们也将通过不确定性研究进行评估。本项目最后将利用模型对研究场地的修复策略进行优化，以显示其适用性。该项目的另一个目标是使开发的建模工具对其他人普遍可用和可用。因此，我们将采用开源软件，发布开发的代码；我们将举办研讨会和研讨会，交流膨胀粘土-硫酸盐岩领域的知识和建模经验。该项目延续了我们之前的研究，将机械过程添加到我们已经开发的水力化学方法中，同时仍然保持了三维地质和工程环境的水文地质和地球化学复杂性。该项目将极大地受益于我们之前的项目，因为现场特定的处理数据（三维地质模型，时间序列观测数据和边界条件，水力和地球化学流体和岩石性质）已经掌握。