地铁—建筑物合建结构中钢弹簧浮置板轨道基频优选影响因素

The Influencing Factors of Natural Frequency Optimization for Steel-Spring Floating Slab Track in the Metro-Building Integrated Structure

结合2个合建工程实例,通过结构的模态分析和钢弹簧支反力的特征分析,研究地铁—建筑物合建结构中钢弹簧浮置板轨道基频优选的影响因素。结果表明：对于不同的地铁—建筑物合建结构,当其竖向自由振动频率在20~80 Hz范围内时,累积的参振质量比例均较高,达50%以上,而在与钢弹簧浮置板轨道基频相近的4~10 Hz竖向自由振动频率范围内,参振质量比例的分布情况却差异较大,这与合建结构的型式和刚度等因素有关;在其他参数不变的情况下,随着钢弹簧浮置板厚度的增加,钢弹簧浮置板的固有频率在向低频移动的同时,虽提高了轨道结构对中高频振动的减振效率,但在钢弹簧浮置板固有频率附近被放大的能量也将随之增加,进而会加大合建结构的低频受迫振动响应。因此对于地铁-建筑物合建结构工程,在选取钢弹簧浮置板轨道基频时,需要综合考虑合建结构型式、结构刚度以及钢弹簧支反力的时域与频域特性。

Combined with two examples of the integrated structures,the influencing factors of natural frequency optimization for steel-spring floating slab track in the metro-building integrated structure were researched through modal analysis of the integrated structures and the characteristics analysis of the support reaction force of steel spring.The results show： as for different metro-building integrated structures,when the natural frequencies of their vertical free vibration are within 20~80 Hz,their accumulated quality ratio of free vibration occupies a high proportion,more than 50%.However,when the natural frequencies of their vertical free vibration are within 4~10 Hz which are close to the natural frequency of steel-spring floating slab track,the distribution of their quality ratio of vertical free vibration remains great difference,which has something to do with the type and the stiffness of the integrated structure.Under the condition that other parameters are invariable,with the thickness of steel-spring floating slab increasing,the natural frequency of steel-spring floating slab track moves to the lower frequency.At the same time, its efficiency to decrease vibration of middle and high frequency is improved,but the amplified vibration energy near the natural frequency of steel-spring floating slab track will also increase and further worsen the low-frequency forced-vibration response of the integrated structure.Thus,as for metro-building integrated structural engineering,in the process to select the natural frequency of steel-spring floating slab track,the type,the structural rigidity and the characteristics in time and frequency domains of counter-force spectrums of steel spring must be taken into account.