Nowadays, the mechanism of borehole strain precursor anomaly at Fengjie station is not clear. In this paper, combined with other observation data and historical background information, the reliability and physical significance of the anomaly were compared and analyzed, and the precursory anomaly mechanism was further analyzed by finite element simulation method. The results showed that the trend change of borehole strain at Fengjie station, which is consistent with other nearby observation data, is a record of changes in regional stress field. Fengjie station is located in the eastern margin of Sichuan depression of Yangtze platform. Numerical simulation results showed that the substrate of Yangtze platform is hard and has good stress transmission. The lithology at the edge of Yangtze platform is relatively soft, easy to deform under stress, and sensitive to the stress at the other end of the platform. Therefore, the abnormal trend change of borehole strain at Fengjie station is the result of stress transfer in regional stress field.
龚丽文,陈丽娟,郭卫英,陈涛,唐小勇.奉节钻孔应变前兆异常机理分析——区域应力场应力传递的结果[J].地震工程学报,2021,43(5):1087-1094,1102. GONG Liwen, CHEN Lijuan, GUO Weiying, CHEN Tao, TANG Xiaoyong. Mechanism of borehole strain precursor anomaly at Fengjie station: results from stress transfer in regional stress field[J]. China Earthquake Engineering Journal,2021,43(5):1087-1094,1102.复制