【摘要】 2008年5月12日汶川MS8.0级地震后,为了解发震断裂附近地应力分布特征,于2009年10月-12月期间,在龙门山断裂带东北段江油、北川地区3个200m钻孔中开展水压致裂地应力测量工作;本文首先依据研究区域内3个200m钻孔的水压致裂地应力测量结果,分析了汶川8.0级地震发生1年后,龙门山断裂带东北段附近现今地应力状态分布特征;其次,基于龙门山断裂带基础地质、地球物理等研究资料,采用线弹性有限元模拟方法,运用ANSYS有限元模拟软件,模拟得到了地震后研究区内现今地应力状态;再次,综合研究区内地应力测量结果和应力场的三维有限元数值模拟结果,揭示了断裂带附近江油～北川剖面现今应力场的变化规律;文章最后探讨了龙门山断裂带东北段江油和北川地区的地震危险性.更多还原

【Abstract】 After Wenchuan MS 8.0 earthquake occurred on the May 12th 2008,in Sichuan province,China,in an attempt to understand the distribution of the in situ stress near the fault,we made a series of in situ stress measurements in three 200 m-deep boreholes drilled in Beichuan and Jiangyou areas near the northeastern segment of Longmenshan fault belt,in 2009,using the hydraulic fracturing technique.Firstly,according to the in-situ stress results with the method of hydraulic fracturing measurement in three 200 m-deep boreholes in the region,the distribution characterizes of current in-situ stress state near the northern segment of Longmenshan fault was analyzed over one year after Wenchuan MS 8.0 earthquake.Secondly,on basis of foundational geological data of Longmenshan fault,we calculate the present stress state by the method of linear elastic finite element numerical simulation with ANSYS.Thirdly,combined the in situ stress measurements with the simulation results,the variation of the stress state along the profile between Jiangyou and Beichuan is revealed.Finally,seismic risk in Jiangyou and Beichuan areas along the northern segment of Longmenshan fault is discussed.更多还原