黄河黑山峡大柳树坝址区最大潜在地震变形及地震应力模拟预测

Potential Earthquake Deformation and Stress Simulation of Daliushu Dam-site in Heishan Gorge of Yellow River

在分析黄河黑山峡大柳树坝址处的中卫活动断裂带潜在地震危险性及地质、地球物理条件基础上,采用三维有限元方法模拟计算了该断裂带内F201断层发生6.5级、7.0级和7.5级地震时大柳树坝址区的潜在地震变形及地震应力。结果表明,F201断层发生中强以上地震(MS≥6.5)时,其南侧至少3 km范围内的地震变形及地震应力将超出地壳岩石的破裂变形极限,大柳树坝址的地震应变量值更是大于10-4,地震应力也将达到几兆帕,存在工程上尚难以处理的地震抗断问题。

On the base of analysing earthquake risk, geological and geophysical conditions for Zhongwei active fault zone where Daliusu dam-site located, the potential earthquake deformation and stress near the dam in the condition of earthquake with Ms6.5, Ms7.0 and Ms7.5 on the fault F201 in the fault zone are simulated using 3D finite element method. The calculation results shows that if an earthquake of Ms≥6.5 occurres on the fault F201, the ground earthquake deformation and stress would exceed the cracking limit of crust rock at least in the range of 3 km at south of the fault, the earthquake strain of Daliushu dam-site would be over 10.4 and the stress would be several megapascal （MPa）, which will lead to the anti-rupture problem hard to solve in engineering project yet.