地铁浮置式轨道引起地表振动响应解析预测模型研究

摘要

在土层振动传递固有特性的基础上，提出一种针对地铁浮置式轨道型式引起的地表振动响应的解析预测模型。本模型将地铁环境振动的预测问题转化为计算浮置式轨道作用于基底的频域力群和求解土层振动频响函数的问题，然后通过系统合理简化将两部分进行频域叠加运算得出地表振动响应。采用本模型预测了北京地铁4号线浮置板区间地表振动响应，并与实测数据进行对比分析，结果表明：浮置板区间模型预测和地表实测加速度振动主频均为8～10 Hz，且频域幅值相当，变化趋势相符；实测 Z 振级54．0 dB，预测 Z 振级56．1 dB，预测结果较准确。本频域快速预测模型具有预测速度快、预测精度高、可进行频域预测等特点，是现有环评预测方法的有效补充。%Based on the vibration transmission characteristics in soil,an analytical prediction model of ground vibration response induced by metro floating-type track was presented.With the model,the calculation of ground vibration response was divided into two parts including calculating force in frequency domain on the base of floating-type track and solving soil vibration frequency response functions.Then,the method of superposition in frequency domain was adopted to calculate the ground vibration response induced by metro.The model is used to predict the ground vibration response at the floating slab track sections of Beijing Metro Line 4,and the in-site measurements were also done to validate the calculated vibration response.Comparison of the two results showed that the main vibration frequencies of the prediction results and measurement ones are both around 8~10 Hz and they have the close vibration amplitudes in frequency domain;the Z vibration level is 54.0dB for the measurement and 56.1dB for the prediction;the analytical prediction model has features of fast speed,high accuracy in frequency domain,the model can effectively be used to predict ground vibrations induced by metro,it's an effective supplement to the existing environmental assessment prediction methods.