结合现行水利及相关行业抗震设计规范,讨论了新版区划图的主要改进之处,阐述了地震动参数在水利工程抗震设防中的意义与作用。应用新版区划图确定场地地震动参数方法:(1)从图上查得Ⅱ类场地条件下的基本地震动参数,地震概率水准为50 a超越概率10%;(2)根据场地土层等效剪切波速(或岩石剪切波速)及场地覆盖层厚度值,确定场地类别;(3)根据场地类别提出调整后的场地地震动参数(其中地震动峰值加速度不完全等同于设计地震加速度);(4)根据Ⅱ类场地地震动峰值加速度提出对应的地震烈度(不完全等同于设计烈度);(5)根据工程抗震设计需要提供其他概率水准的场地地震动参数。工程实例表明,新版区划图对水工建筑物提出了更高的抗震要求,可操作性更强,得到的场地地震动参数更为安全、科学与合理。
Combining with codes for seismic design of water conservancy and relevant industries, the major improvements about the new edition zoning map has been discussed, and the meanings and functions of these seisnlic ground motion parameters in the seismic fortifi- cation have been elaborated. The method of determining seismic ground motion parameters is as the following: (1)To get the basis ground motion parameters from the map on the condition of site classification II, the probability of exceedance is 10 percent in 50 years. (2)To determine the site classification according to its soil layer equivalent cutting wave speed ( or rock cutting wave speed) and ground cover layer thickness. (3)To put forward the modified seisnfic ground motion parameters according to its site classification ( the seismic peak ground acceleration is not completely equal to the design earthquake). (4)To provide the coiTespomling seismic intensity according to the seismic peak ground acceleration (is not completely equal to the design intensity). (5)To give the seismic ground mo- tion parameterson the other probability levels on the basis of engineering seismic design needs. The engineering practice shows that the new edition zoning mapputs forward higher seismic requirements on hydraulic structures, has stronger operability, and the results are more safe, scientific and reasonable.