【摘要】 坐落于中卫—同心逆冲断裂带中间部位的黄河黑山峡大柳树坝址距F201发震断层垂直距离不足1.5km。在坝址区内,中卫—同心断裂带由数条断层组成,并可进一步分为主干断层、分支断层。这些断层与主干断层F201具有密切关系。统计表明,在青藏高原及其周缘地区,当发生7级以上破坏性地震时,距发震断裂两侧3~5km的范围内都有可能出现断层的分支破裂、次生破裂等错断效应。晚更新世以来沿F201发生过多次地震破裂事件,大柳树坝址处于7级以上地震时的分支破裂发生带内,因此存在工程错断可能。三维有限元数值模拟结果表明,F201发生错动时,坝址地段分支断层F93、F39、F40相对于F201的错动比率处分别达到14.38%、12.00%和9.84%以上。更多还原

【Abstract】 The Daliushu dam site in the Heishanxia Gorge of the Yellow River is located in the middle of Zhongwei-Tongxin overthrust nappe fracture zone,which is 1.5km apart from the seismogenic fault F₂₀₁.In the damsite area,the fracture zone is composed of many faults,and the faults can be divided into main faults and branch faults,which have a close relation with the fault F₂₀₁.The results of statistic indicates that the rupturing effects as branch fracture,secondary fracture will be appeared around the 3-5km area apart from seismogenic fault when the Earthquakes with M_s ≥7.0 happen in the Qinghai-Tibet Plateau and its margins.Since late Pleistocene,the earthquake rupture events have happened along the fault F₂₀₁ time after time,and the Daliushu dam site is located in the branch fracture zone when the earthquakes with M_s ≥7.0 happen,so it is possible for the engineering rupturing.Analysis result of 3D finite element indicates that the dislocation ratio of the fault F₉₃,F₃₉ and F₄₀ to the fault F₂₀₁ arrives at 14.38%,12.0% and 9.8% separately,when the rupturing effects of fault F₂₀₁ happens.更多还原