Abstract

The coupled THMC model, interface for pressure solution analysis under coupled conditions, IPSACC, that was proposed by the authors and can describe the long-term evolution in rock permeability due to mineral reactions (i.e., pressure solution and free-face dissolution/precipitation) within rock fractures, was upgraded in the present study by incorporating the processes of fracture initiation/propagation. The remarkable characteristic of the proposed model is its ability to simulate the generation of fractures and the mineral reactions within the generated fractures as well as the subsequent changes in permeability. The proposed model was applied to predictions of the long-term changes in the permeability of rock located near high-level radioactive waste within a geological repository. The predicted results revealed that fractures were generated near the disposal cavity and that the permeability of the damaged zone increased significantly more than that of the intact rock during the excavation, while the permeability in almost the entire damaged zone decreased by about one order of magnitude due to pressure solution at the contacting asperities within the rock fractures after setting virtual radioactive waste into the disposal cavity. Overall, it was clarified that the proposed model is capable of calculating the permeability evolution of rock through fracture generation and subsequent sealing due to mineral reactions at the actual field scale. Thus, the potential for using the proposed model to examine the long-term performance of natural barriers for delaying the transport of radionuclides has been shown.

中文翻译：

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岩石热导率-水力-力学-化学耦合模型通过裂隙的产生和随后的封闭作用进行岩石渗透性演化

摘要

耦合的THMC模型，耦合条件下压力溶液分析的接口，IPSACC是由作者提出的，可以描述岩石裂缝中矿物反应（即压力溶液和自由面溶解/沉淀）引起的岩石渗透性的长期演变，在本研究中通过结合骨折的开始/传播。所提出模型的显着特征是它能够模拟裂缝的产生和所产生的裂缝内的矿物反应以及随后的渗透率变化的能力。所提出的模型用于预测位于地质处置库内高放射性废物附近的岩石渗透率的长期变化。预测结果表明，在开挖孔洞附近产生了裂缝，在开挖过程中，受损区域的渗透率显着高于完整岩石，而几乎整个受损区域的渗透率却下降了约一个数量级。将虚拟放射性废物置入处置腔后，在岩石裂缝内的接触凹凸处施加压力溶液。总体而言，已澄清的是，所提出的模型能够计算岩石的渗透率演变，该过程通过裂缝的产生以及随后在实际油田范围内由于矿物反应而引起的封闭作用。因此，已显示出使用所提出的模型检查天然屏障对延迟放射性核素传输的长期性能的潜力。