【摘要】 本文叙述河北省玉田和天津市宁河烈度异常区的地面脉动测试情况,并指出由功率谱得到的卓越周期与零交法得到的平均周期并不总是一致的,用后者来描述场地的频率特性更为适当。其次,从脉动记录分析中还将看到,水平分量显示出土质条件的区域性差异,垂直分量可反映表层土的局部构造情况。作者用平均周期、最大合矢量振幅及不同方向的频率差值作场地土质条件评定的指标分别对两个测区按地震效应的好坏进行等级划分,结果与实际震害基本相符。更多还原

【Abstract】 This paper describes the measurement of microtremor of ground in abnormal intensity regions of Yutian county,Hebei Province,and Ninghe county,Tianjin City and shows that the prominent period obtained by the power spectrum and the average period obtained by the zero-crossing method are not always consistent.The average period is more suitable for the description of frequency characteristics of sites.In addition,it is found in the analysis of microtremor records that the horizontal component of microtremor shows local difference in soil condition,while the vertical component reflects the local structure of sur-fieial soil layer.The average period,the maximum resultant vector amplitude and the difference of frequency in various directions are used as criterion in the assessment of soil condition at sites Soil of the above two abnormal regions are cfassified by using the criterion according; to the earthquake effect.And the results arc basically consistent with the earthquake damages in the field.更多还原