| 龙门山断裂带中段及邻区构造变形特征及应力场演化的数值模拟研究 |
| |
| 引用本文： | 付平,张新辉,尹健民,韩晓玉,周春华.龙门山断裂带中段及邻区构造变形特征及应力场演化的数值模拟研究[J].地震研究,2020(1):28-36,I0002. |
| |
| 作者姓名： | 付平 张新辉 尹健民 韩晓玉 周春华 |
| |
| 作者单位： | 长江科学院水利部岩土力学与工程重点实验室 |
| |
| 基金项目： | 国家重点研发计划项目(2016YFC0401803);国家自然科学基金项目(51879014)联合资助。 |
| |
| 摘 要： | 根据龙门山断裂带中段及邻区的主要构造特征,同时考虑地壳速度结构和构造运动的深浅部差异,建立该地区的二维接触有限元模型,数值模拟了长期构造过程中断裂带位移和应力的时间演化过程。结果显示:①汶川—茂县断裂、映秀—北川断裂、灌县—安县断裂的逆冲速率与实际观测结果基本一致,映秀—北川断裂逆冲性质最强,巴颜喀拉块体和断裂带区域呈水平缩短与增厚抬升趋势,四川盆地保持相对稳定;②断裂带附近岩体大小主应力比随深度增加而减小,总体上与实际测试结果相符,且主应力轴方向和倾角与利用震源机制解反演得到的构造应力场特征亦较为接近;③龙门山断裂带中段区域构造应力场呈低态稳定—应力累积—临界稳定的阶段式演化过程,与该区所处的应力累积—地震发生—应力再累积的地震活动特征相呼应。此外,仅根据地表调查和震前GPS观测所揭示的断裂活动速率评价活动断裂区的地震危险程度具有一定局限性,需结合其深部动力学过程和区域应力状态进行综合分析。
|
| 关 键 词： | 龙门山断裂带 构造运动 变形速率 应力场 有限元模拟 |
Numerical Simulation of the Tectonic Deformation Features and Stress Fields Evolution of the Middle Segment of Longmenshan Fault Zone and Its Adjacent Areas |
| |
| FU Ping,ZHANG Xinhui,YIN Jianmin,HAN Xiaoyu,ZHOU Chunhua.Numerical Simulation of the Tectonic Deformation Features and Stress Fields Evolution of the Middle Segment of Longmenshan Fault Zone and Its Adjacent Areas[J].Journal of Seismological Research,2020(1):28-36,I0002. |
| |
| Authors: | FU Ping ZHANG Xinhui YIN Jianmin HAN Xiaoyu ZHOU Chunhua |
| |
| Institution: | (Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry of Water Resources,Changjiang River Scientific Research Institute,Wuhan 430010,Hubei,China) |
| |
| Abstract: | Based on the regional tectonic characteristics of the middle segment of Longmenshan fault zone and its adjacent areas,a two-dimensional contact finite element model is established to simulate the evolution of displacement and stress fields during long term tectonic movement.The differences of wave velocity and tectonic movement rate between the deep and shallow crust are taken into consideration.The numerical results indicate that the:①Thrust fault slip rates of Wenchuan-Maoxian,Yingxiu-Beichuan and Guanxian-Anxian fault are basically consistent with the observed data,and Yingxiu-Beichuan fault has more stronger thrust property.The Bay an Har block and the fault zone experience overall uplift and shortening,while the Sichuan basin remains relatively stable.②The ratios of maximum and minimum principal stress near faults decrease as the depth increases,and broadly conform with the in-situ stress measurements.Furthermore,the simulated principal stress directions and inclination are close to that inversed by focal mechanism solutions.③The tectonic stress field of Longmenshan fault zone presents a staged evolution of low state stability-stress accumulation-critical state stability,which is correspond with the seismic activity feature of stress accumulation-earthquake occurrence-stress reaccumulation.In addition,we suggest that seismic risk assessment needs the comprehensive analyses of the deep geodynamic process and regional stress states,for the slip rates of the active faults obtained from near-surface survey and GPS observations are much limited. |
| |
| Keywords: | Longmenshan fault zone tectonic movement deformation rate crustal stress finite element modeling |
| 本文献已被 CNKI 维普 等数据库收录！ |
|
