电力工程建设场地设计地震动参数的研究

以江苏某电厂为例,采用概率法对其工程场地进行地震危险性分析,确定基岩水平向地震加速度时程,并根据场地土的静、动力性能参数的测试结果,采用等效线性化考虑土的非线性特性的影响,利用一维波动模型进行场地土层地震反应分析和地震动效应分析。文中得到了50年超越概率63%、10%和3%的地表水平向地震动峰值加速度和反应谱,将所得结果与电力工程相关规范作了一些比较,指出了相关规范中的一些不足,提出应对大型电力工程场地的设计地震动参数做专门的研究。

Study on Designing Ground Motion Parameters of Electric Power Engineering Site

Since electric power engineering is a vitally important lifeline engineering, the careful design of ground motion parameters of electric power engineering site have great practical values. To determine ground motion parameter, one of the methods is the statistical empirical method corresponding to code and another is seismic response analysis for soil layers. In this paper, taking a certain electric power engineering site as an example, probability method of seismic hazard analysis considering sites earthquake environment of surrounding area and rock ground motion attenuation is used to determine the bed-rock peak ground motion accelerations and the acceleration response spectrum with different exceedance probabilities in the area. Considering the effect of soil nonlinear dynamic property of soil layer, the site effect and earthquake response of soil layers are also analyzed by one-dimensional equivalent linearization wave motion model. And design ground motion parameters of soil layers for exceedance probability 63%,10% and 3% in fifty years are given. The result is very useful to the design of earthquake engineering of this project. The main conclusions are:(1). Because of the lack of strong earthquake record in the area, the formula of the bedrock ground motion attenuaion relationship in the area is obtained by selecting the seismic intensity attenuation relationship suitable to this area and the rock ground motion attenuation relationship in the west United States. The bedrock peak acceleration exceedance probability 63%, 10% and 3% in fifty years are 0.026 g, 0.063 g and 0.088 g respectively.(2). The seismic waves are either amplified or absorbed while they go through the soil layers, which results in the ground peak acceleration magnified by the covering soil layers. The ground peak acceleration value at the site with exceedance probability 63%, 10% and 3% in fifty years are 0.044 g, 0.083 g and 0.114 g, enlarged to a certain extent. (3). Compared with the values in some codes, the calculated one are more precise. For the electric power engineering site, special attention should be paid to the designing seismic ground motion parameters.