Underground engineering construction in the karst regions of Southwestern China has become a focal point of China’s advancing regional urban development. However, construction activities interfere with the karst groundwater environment, which is characterized by irregular pore distributions and complex, variable flow patterns. This study establishes a numerical model of the karst water system traversed by Line 2 of the Guiyang Rail Transit in China. Incorporating hydrogeological conditions and tunnel engineering parameters, the model simulates the effects of tunnel construction on the karst groundwater system. The flow-field distribution of the karst groundwater system is altered at various stages of tunnel construction. During tunnel excavation, a drainage zone centered around the subway forms in the groundwater system, altering the groundwater flow field and causing fluctuations in the groundwater level. During the lining phase, the tunnel area gradually transforms into a waterproof zone. Although the groundwater level gradually recovers under rainfall recharge, the waterproofing effect of the tunnel drives the formation of a new groundwater flow field within the groundwater system, changing both the groundwater level and the original flow field. This work offers support for the coordinated development of underground engineering and environmental protection in karst areas, facilitating sustainable urbanization.

《地球科学》(ISSN 1000-2383;CN42-1874/P) (原刊名《地球科学——中国地质大学学报》ISSN 1000-2383;CN42-1233/P)，创刊于1957年，是由教育部主管、中国地质大学主办的综合性地学学术理论期刊，月刊，2015年改名为《地球科学》,她以反映中国地质大学教学与科研最新的、高水平的基础地质、应用地质、资源与环境地质及地学工程技术研究成果为主要任务。

Reinjection is critical for the sustainable utilization of geothermal resources. However, in high-temperature reservoirs, it triggers water–rock interactions that cause formation damage and a severe decline in productivity. This study integrates laboratory experiments and numerical simulations to investigate water–rock interactions during geothermal reinjection and proposes optimized reinjection strategies to mitigate reservoir clogging. A site-specific numerical model of the Yangbajing geothermal field was developed to simulate the evolution of water–rock interactions in the geothermal reservoir under reinjection conditions, supported by high-temperature and high-pressure water–rock reaction experiments. The thermodynamic parameters in the TOUGHREACT simulator were calibrated using the experimental data to improve the accuracy and reliability of the model. The results demonstrated that quartz and feldspar were the dominant minerals undergoing dissolution in the production wells, whereas illite and mica were the primary precipitated phases. Conversely, in the injection wells, mica is the main mineral undergoing dissolution, and quartz, feldspar, and illite constitute the major precipitated phases. These mineral dissolution–precipitation dynamics near geothermal wells induce a 10% decrease in reservoir porosity and permeability. Furthermore, sensitivity analyses involving adjustments to key simulation parameters revealed that low-temperature and low-flow reinjection mitigated the extent of mineral dissolution–precipitation during geothermal reinjection, thereby alleviating adverse impacts on reservoir permeability and porosity. The flow rate should be maintained below 14 L/s, and reinjection should be performed at a temperature of 50℃, thereby minimizing adverse impacts on the geothermal reservoir. This study provides a systematic analysis of reinjection-induced site clogging arising from water–rock interactions, and the findings offer valuable insights for optimizing the sustainable exploitation of high-temperature geothermal reservoirs.