大柳树高土石坝工程场地抗震安全性研究

黄河黑山峡河段一级开发大柳树高土石坝，坝址距F201发震活断层仅1．5km，且位于断层上盘。坝址区地震动参数值高，建筑物场地类别上属于危险地段。工程建成后，存在水库诱发地震引起次级断层位错而导致建筑物破坏的工程抗断风险；存在大范围松动岩体浸水后在外加地震力作用下的边坡失稳、坝体开裂、隧洞错断等变形破坏的风险。即使采取多种重大工程措施，花费巨大资金进行处理，以防止此变形破坏，也很难保证工程的安全可靠。因此，根据国家强制性标准，应采取安全避让方针，不宜选此坝址为高坝坝址。

Seismic Safety Study on High Earth-rockfill Dam Region for Daliushu Hydropower Project

The Daliushu hydropower project is an earth-rockfill dam with one-stage development on the Heishanxia reach of Yellow River. The dam site is only 1.5 km away from the causality active fault (F_(201)), and it is located on the hanging wall of the fault. The dynamic earthquake parameters are high in the damsite region and the structural areas belong to the category of dangerous zone. Upon completion of the project, there exist not only breaking-resistance risk resulting secondary fault displacement from induced earthquakes to cause damages in the structures, but also deformed failure risks (unstable slope, cracked dam, faulted tunnel etc.) under additional seismic force within a large range of immersed loose rock mass. It is very difficult to guarantee the safety of project even if some important engineering measures are to be adopted, and late treatment is done with a great amount of cost to avoid such deformation damage. So, on the basis of the national mandatory standard, it is not suitable to select this site for the construction of high dam.