轨道交通振动对建筑物影响程度的预测方法

Prediction Method of the Vibration Influence on Buildings Induced by Rail Transit

既有的现场实测与数值模拟相结合预测方法,采用振动响应传递比描述室内外两点之间的振动变换,实现在不同频段上定量预测轨道交通振动对建筑物内人和精密仪器的影响。为将该方法用于预测建筑结构的振动响应,需要将1/3倍频程指标转化为速度峰值指标。指标转换方法是:利用能量守恒原理将1/3倍频程频域内的速度有效值转化为时域内的速度有效值;采用峰值因数将速度有效值转化为速度峰值,并建议在预测对普通建筑物、重点文物建筑的影响时峰值因数分别取4和5,在现场实测峰值因数样本大于9时,给出的指标转换方法不再适用。分析指标转换时的误差水平和使用条件可知,采用的指标转换方法是可行的。

In the existing prediction method of combining the site measurement and the numerical simulation, the vibration response transfer ratio is used to describe the vibration difference between both outdoor and indoor point. In this way, the quantitative prediction on the vibration influence over human beings as well as sensitive instruments in buildings can be realized in different frequencies. In order to apply this method to predict the vibration response of the building structure, root-mean-square （rms） velocity in one-third octave frequency domain should be transferred to peak particle velocity （PPV）. Firstly, rms velocity in one-third octave frequency domain is changed by energy conversation principle to rms velocity in time domain which then will be later changed to PPV by crest factor. When predicting for common buildings and important historic buildings, the crest factor values are suggested to be 4 and 5 respectively. If the crest factors are larger than 9 in the measurement, the method mentioned above is no longer applicable. By analyzing the errors and application conditions, this method of transferring the vibration indexes is feasible.