Yiming Dai , Lili Zhang , Yaowen Zhang , Yunsheng Yao , Renlong Wang
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The fluid-solid coupling theory was applied to calculate the dynamic spatial changes in pore pressure and Coulomb stress in the faults and surrounding rocks during reservoir impoundment. The findings indicated that the added head pore water pressure at the bottom of the reservoir had a maximum impact range of approximately −2800 m on the surrounding rock, whereas the Xiannvshan and Jiuwanxi faults had a maximum diffusion range of approximately −4300 m. Rock permeability also played a significant role in the water storage process. During the 1 56 m water impoundment stage, owing to rapid water storage activity, stress could not be transmitted to both sides in a timely manner, resulting in the formation of an extreme stress change zone at −4000 m inside the fault. This may have been the reason for the frequent earthquakes during this stage. The 17 5 m cycle water storage stage also exhibited a significant degree of seismicity, potentially attributable to the long-term infiltration of reservoir water and accumulation of stress in the previous stage. The stress in the study area at the four stages are in a process of accumulation-release-accumulation-release.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"889 ","pages":"Article 230482"},"PeriodicalIF":2.7000,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Analysis of stress field in the head area of the Three Gorges Reservoir based on coupled fluid-solid theory\",\"authors\":\"Yiming Dai , Lili Zhang , Yaowen Zhang , Yunsheng Yao , Renlong Wang\",\"doi\":\"10.1016/j.tecto.2024.230482\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The Three Gorges Reservoir, one of the largest water conservation system in the world, has been of keen interest to scientists globally since its impoundment. After construction of the dam, there has been a significant increase in seismic activity in the head area of the reservoir. It is generally accepted that earthquakes in this region are predominantly caused by the Jiuwanxi and Xiannvshan faults. This study focused on the stress changes occurring in the research area. A three-dimensional finite element model of the reservoir area was constructed using the geological structure and digital ground elevation data of the reservoir area. The fluid-solid coupling theory was applied to calculate the dynamic spatial changes in pore pressure and Coulomb stress in the faults and surrounding rocks during reservoir impoundment. The findings indicated that the added head pore water pressure at the bottom of the reservoir had a maximum impact range of approximately −2800 m on the surrounding rock, whereas the Xiannvshan and Jiuwanxi faults had a maximum diffusion range of approximately −4300 m. Rock permeability also played a significant role in the water storage process. 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引用次数: 0
摘要
三峡水库是世界上最大的水利系统之一,自蓄水以来一直受到全球科学家的密切关注。大坝建成后,库首地区的地震活动明显增加。一般认为,该地区的地震主要是由九畹溪断层和仙女山断层引起的。本研究的重点是研究该地区发生的应力变化。利用库区的地质构造和数字地面高程数据,构建了库区的三维有限元模型。应用流固耦合理论计算了水库蓄水过程中断层和围岩中孔隙压力和库仑应力的动态空间变化。研究结果表明,水库底部增加的水头孔隙水压力对围岩的最大影响范围约为-2800 m,而仙女山断层和九畹溪断层的最大扩散范围约为-4300 m。在 1 56 m 的蓄水阶段,由于蓄水活动迅速,应力不能及时向两侧传递,导致断层内-4000 m 处形成极应力变化带。这可能是这一阶段频繁发生地震的原因。17 5 米循环蓄水阶段也出现了明显的地震,这可能是由于水库水的长期渗透和前一阶段应力的积累。研究区四个阶段的应力处于积累-释放-积累-释放的过程中。
Analysis of stress field in the head area of the Three Gorges Reservoir based on coupled fluid-solid theory
The Three Gorges Reservoir, one of the largest water conservation system in the world, has been of keen interest to scientists globally since its impoundment. After construction of the dam, there has been a significant increase in seismic activity in the head area of the reservoir. It is generally accepted that earthquakes in this region are predominantly caused by the Jiuwanxi and Xiannvshan faults. This study focused on the stress changes occurring in the research area. A three-dimensional finite element model of the reservoir area was constructed using the geological structure and digital ground elevation data of the reservoir area. The fluid-solid coupling theory was applied to calculate the dynamic spatial changes in pore pressure and Coulomb stress in the faults and surrounding rocks during reservoir impoundment. The findings indicated that the added head pore water pressure at the bottom of the reservoir had a maximum impact range of approximately −2800 m on the surrounding rock, whereas the Xiannvshan and Jiuwanxi faults had a maximum diffusion range of approximately −4300 m. Rock permeability also played a significant role in the water storage process. During the 1 56 m water impoundment stage, owing to rapid water storage activity, stress could not be transmitted to both sides in a timely manner, resulting in the formation of an extreme stress change zone at −4000 m inside the fault. This may have been the reason for the frequent earthquakes during this stage. The 17 5 m cycle water storage stage also exhibited a significant degree of seismicity, potentially attributable to the long-term infiltration of reservoir water and accumulation of stress in the previous stage. The stress in the study area at the four stages are in a process of accumulation-release-accumulation-release.
期刊介绍:
The prime focus of Tectonophysics will be high-impact original research and reviews in the fields of kinematics, structure, composition, and dynamics of the solid arth at all scales. Tectonophysics particularly encourages submission of papers based on the integration of a multitude of geophysical, geological, geochemical, geodynamic, and geotectonic methods