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

含有硫酸盐矿物硬石膏的粘土岩石在与水接触时会膨胀。粘土-硫酸盐岩的膨胀是隧道和地热钻探中的一个威胁。例如，在施陶芬，地面隆起率超过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使专家能够测试和优化对策。然而，我们对膨胀过程中发生的过程的了解是有限的。有矛盾的概念膨胀模型，和公认的数学膨胀规律量化粘土硫酸盐岩的膨胀是缺乏的。虽然各种数值模型的膨胀模拟已经提出到目前为止，所有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，本研究计划有两个主要目标：（1）完善我们目前对膨胀的理解，特别是涉及的耦合THMC过程;（2）提高我们全面模拟膨胀过程的能力。随后用实地观察来挑战模型。为此，研究中心Staufen提供了非常全面的热力学、水力学、化学和机械数据。不同的模型将通过观测数据进行验证或拒绝，还将通过不确定性研究进行评估。该项目最终将使用模型在研究现场的修复策略的优化，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普遍可用，并为他人使用。因此，我们将采用开源软件并发布开发的代码;我们将举办一个研讨会和研讨会，交流膨胀粘土硫酸盐岩领域的知识和建模经验。拟议的项目遵循我们以前的研究，将机械过程添加和耦合到我们已经开发的水力化学方法，同时仍然保持3D地质和工程环境的水文地质和地球化学复杂性。该项目将从我们以前的项目中受益匪浅，因为现场特定的处理数据（三维地质模型，观测数据和边界条件的时间序列，水力和地球化学流体和岩石特性）已经在手。

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.