近轨建筑地下室结构柱车致低频振动减振设计

Metro-induced low frequency vibration reduction design of basement structural column of near rail buildings

为了降低车致低频振动,依托实际工程,开展地下室结构柱减振设计研究。基于车辆-轨道耦合动力学理论,考虑短波随机不平顺引起的轮轨中高频振动、土体分层特性、人工黏弹性边界等非线性因素,建立近轨高层建筑车致低频振动预测模型。通过现场地表振动衰减规律测试与车致地下室振动特性测试,验证振动预测模型的有效性。研究地下室非永久柱优化布置,以及非永久柱中嵌入碟形弹簧支座、橡胶支座、粉煤灰支座等4种减振方案对车致低频振动的抑制效果。结果表明:对结构柱进行优化设计可不同程度降低车致低频振动;减少地下室非永久柱可降低地下室整体结构刚度以减少传至高层建筑的振动;采用碟形弹簧支座主要衰减地下室隔板频率63~125 Hz区段振动,高层建筑最大Z振级最多衰减7.3 dB;通过橡胶支座衰减地下室隔板频率40~125 Hz区段振动,高层建筑最大Z振级最多衰减7.6 dB;而采用粉煤灰支座主要衰减地下室隔板频率40~125 Hz区段振动,高层建筑最大Z振级最多衰减5.4 dB;针对该实际工程,结构柱内嵌橡胶支座效果最佳。

In order to suppress the metro-induced low frequency vibration,the vibration reduction design of the basement structural column was presented based on the actual engineering background.Based on the vehicle-track coupling dynamics theory,a metro-induced low-frequency vibration prediction model for near-track high-rise buildings was established by considering nonlinear factors such as medium-high frequency vibration of wheel-rail caused by short-wave random irregularity,layered characteristics of soil,and artificial viscoelastic boundary.Ground vibration attenuation law test and the metro-induced basement vibration characteristic test were carried out to verify the effectiveness of the proposed vibration prediction model.The suppression effects of four vibration reduction schemes,i.e.,optimal arrangement of non-permanent columns in basement,embedded disc spring vibration isolation bearing,rubber vibration isolation bearing,and fly ash bearing in non-permanent columns,on metro-induced low-frequency vibration were studied.The results show that the optimization design of the structural column can suppress the metro-induced low-frequency vibration in different degrees.Reducing the non-permanent columns in the basement can reduce the overall structural stiffness of the basement,and therefore reduce the vibration transmitted to the high-rise building.The setting of disc spring isolation bearing mainly attenuates the vibration within the 63-125Hz frequency section of the basement partition,and the maximum z-vibration level of the high-rise building attenuates by 7.3dB at most.The setting of rubber vibration isolation bearing mainly attenuates the vibration of the basement partition in 40-125Hz frequency section,and the maximum z-vibration level of the high-rise building attenuates by up to 7.6dB.The setting of fly ash bearing mainly attenuates the vibration of the 40-125Hz frequency section of the basement partition,and the maximum z-vibration level of the high-rise building is attenuated by 5.4dB.For this practical project,the effect of structural column embedded rubber bearing is the best.