基岩地震动相位特性对土层地震反应影响分析

Influence of phase properties of bedrock ground motion on soil earthquake response

以上海地区某实际工程为例,采用一维等效线性化方法,计算了不同随机相位特性的人工合成基岩地震动时程输入下的土层地表地震反应。计算结果表明：计算得到的地表加速度峰值和反应谱值相对极差较大,故地震动相位特征对土层地震反应的影响不可忽略;相应的地表峰值和反应谱值变异系数在5%~8%范围附近振荡变化,故离散度并没有随着基岩反应谱值的增大或者周期的增大而有规律的增大或减小。进一步,采用统计学方法计算给出了土层地震反应所需不同随机相位基岩时程的样本容量。

Taking an actual project in shanghai as the example,using one-dimensional equivalent linearization method,the calculation of soil earthquake response under the synthetic bedrock ground motion time history inputs with different random phase properties have been processed. The calculation results show that,the relative ranges of peak ground acceleration and response spectrum values calculated under the synthetic bedrock ground motion time history input with different random phase properties is relatively large. So the effect of phase properties of ground motion on soil earthquake response is not negligible; the variation coefficient of the results of peak ground acceleration and response spectrum values oscillating change in the range of 5% ~ 8% near. So the discrete degree does not change regularly with the increase of the bedrock response spectrum values or the increase of period. Further,the sample size of bedrock ground motion time history with different random phase for soil earthquake response is given by statistical method.