摘要
白鹤滩水电站作为全球第二大已建水电站,其库区地震活动受水库蓄水影响显著。采用数值模拟方法,建立基于区域地质构造特征的三维地质模型,并运用FLAC^(3D)软件进行渗流—应力耦合数值模拟,系统分析了库水位从高程640 m上升至825 m过程中的应力应变响应。结果表明:蓄水过程中穿越库区的则木河断裂和小江断裂带周边出现明显的应力集中现象;剪应变增量与水位变化呈现正相关关系,其高值区(>4.97×10^(-4))空间分布与实际地震密集区高度一致。从机理上看,库水荷载与渗透作用的共同影响降低了断层面的有效应力,同时增强了剪切应力。这种应力状态的改变促进了断层活化,进而诱发地震活动。
Baihetan Hydropower Station,the world\s second-largest operational hydropower station,exhibits significant reservoir-induced seismicity in its reservoir area.In this study,a 3D geological model was established based on regional tectonic features by using numerical simulation methods.Stress-strain responses during the reservoir water level rise from an elevation of 640 m to 825 m were systematically analyzed through coupled seepage-stress simulations performed with FLAC^(3D) software.The results reveal that distinct stress concentration phenomena occur in the area around the Zemuhe Fault and Xiaojiang Fault Zone traversing the reservoir area during the impoundment process.The shear strain increment demonstrated a positive correlation with water level,and the spatial distribution of high-value areas(>4.97×10^(-4))closely aligned with actual seismic activity clusters.Mechanistically,the combined effects of reservoir water loading and seepage reduced effective stress on fault planes while increasing shear stress.This altered stress state promotes fault reactivation,thereby triggering seismic activity.
作者
姚运生
杨俊杰
袁丽
陈俊华
张丽芬
YAO Yunsheng;YANG Junjie;YUAN Li;CHEN Junhua;ZHANG Lifen(Institute of Disaster Prevention,Sanhe 065201,China;Hebei Key Laboratory of Earthquake Disaster Prevention and Risk Assessment,Sanhe 065201,China;Wuhan Institute of Technology,Wuhan 430205,China;Institute of Seismology,China Earthquake Administratio n,Wuhan 430071,China)
出处
《防灾科技学院学报》
2025年第4期13-26,共14页
Journal of Institute of Disaster Prevention
基金
国家自然科学基金(42174177)。
关键词
白鹤滩水库
水库诱发地震
数值模拟
有效应力
断层活化
Baihetan Reservoir
reservoir-induced earthquakes
numerical simulation
effective stress
fault activation
