基于实测频响函数列的地铁环境振动响应预测方法

PREDICTION METHOD FOR METRO ENVIRONMENTAL VIBRATIONS BASED ON MEASURED FREQUENCY RESPONSE FUNCTIONS

针对地铁环境振动预测评价体系的施工设计阶段的预测,提出了一种通过隧道内脉冲激励实测地表系列频响函数的预测方法。将地铁环境振动预测问题转化为两部分:构建高精度车轨耦合解析模型求解作用于基底的频率力;隧道内进行脉冲激励实测隧道-土层系统的地表频响函数列。将两部分在频域内进行叠加运算求得地铁列车引起的环境振动响应,并形成科学的预测流程通过MATLAB程序实现。在18m埋深的隧道内部进行锤击实测地表频响函数带入预测流程进行地表振动响应预测,选取15号线类似条件地点的地表加速度实测数据进行对比验证,结果表明:预测结果和现场实测时域峰值均为0.02m/s2,振动主频均为30Hz^80Hz,1/3倍频程及Z振级也非常相近,预测精度及频谱特性良好。

For the prediction of metro environmental vibrations in its construction design stage, a prediction method based on a measured ground frequency response function is presented. The problem of ground vibration prediction is transferred into two parts: a coupled train-track model is used to calculate the forces on the base; pulse tests in a tunnel are used to measure frequency response functions of a tunnel-soil system. Superposition technique in a frequency domain of two parts is used to calculate ground vibration responses. A standard prediction procedure is presented and programmed by MATLAB. Frequency response functions are measured by pulse tests in an 18 m depth tunnel to predict ground vibration responses. Comparative verification is done using the measurement data at Beijing Metro Line 15. The results show that: the peaks of responses are both around 0.02m/s2; main vibration frequencies are both at 30Hz^80Hz; one-third octave spectrums and Z vibration levels are similar. It is implied that the prediction method has good accuracy and spectral distribution property.