摘要
随着城市地下空间的利用和开发,地面交通荷载引起地下浅埋结构振动,对地下结构中活动人群舒适度产生较大影响,使之日益成为土木工程界的热点问题。当前解决此类问题的主要措施是在地下结构顶部设置隔振橡胶支座。针对此类橡胶支座,根据橡胶支座实际构造建立振动力学模型,进而采用有限元计算的方法建立了振动力学模型和支座实体模型,对比分析交通荷载频率1~30 Hz范围内隔振支座的隔振效果。分析结果表明建立的振动力学模型与实体模型振动响应和隔振效果较为一致,隔振支座具有较好的隔振效果;在此基础上,利用振动力学模型,根据实际工程条件,建立某路基隔振支座群有限元分析模型,采用交通随机荷载作为输入荷载形式,提取路面顶层、支座顶部、支座底部竖向加速度时域响应曲线并对其进行时频变换分析,采用Z振级及其降幅系数分别作为地下结构舒适度和支座隔振效果评价指标对支座群排布水平净距进行优化分析,经过隔振支座群后,振动信号的Z振级大幅降低,降幅系数达到70%以上,远远低于规范规定下限值65 dB,且认为在此工程中1.5 m为合适的支座水平净距。
With the rapid development and utilization of urban underground space,the influence of traffic load on the vibration of shallow-buried structure and human body amenity became more significant,which attracted the attention of researchers and engineers. Rubber isolation bearing rested on the top of underground structure was considered to be the main solution for these problems currently. In this paper,a simplified mechanic and a solid model were established according to the real structure of rubber bearing. The vibration isolation performances of the above two model under traffic load between 1 Hz to 30 Hz frequencies were analyzed by Abaqus software. the analysis results show that the vibration response and isolation effect of the simplified model has good consistence with that of solid model and the rubber bearing. On the basis of which,isolation analysis of a practical project under random traffic load was carried out by employing a group of bearing structures. The time-history curves of vertical acceleration response of several feature points,including the pavement surface and the outline of bearing structure,was extracted and then transferred into frequency domain by using FFT method. The degree of Z direction vibration and its decreasing amplitude were also adopted as the evaluation indexes of human body amenity for optimization analysis. The analysis results indicated that the group of vibration bearings can dramatically reduce the degree of Z direction vibration by more than 70 percent,which was far less than the lower limit value 65 dB in design codes. The optimized clear distance between adjacent bearings was finally taken as 1. 5 m.
出处
《公路工程》
北大核心
2017年第6期158-164,共7页
Highway Engineering
基金
天津市科技支撑重点项目(14ZCZDGX00001)
中国民航大学机场工程科研基地项目(14JCGCKYJD)
关键词
道路工程
振动力学
力学模型
隔振分析
road engineering
mechanics of vibration
mechanics model
vibration isolation analysis
