地铁激励下建筑结构竖向振动的分析模型与基础隔振措施研究

With the problems induced by subway vibrations are more and more prominent, it is particularly important to accurately predict the effects of environmental vibrations on building structures, and design the reasonable vibration controlling measurements. However, the full structures’ numerical modal is still the main way used to analyze the structures’ vertical vibrations induced by subway. This kind of method has some drawbacks such as the complex of modeling process, great amount of computation, and uncertainty of the prediction accuracy. To over these problems, the transferring mechanism of subway-induced vertical vibrations in building structures, and the effectiveness of base-isolation method will be studied by scale model testing in this project firstly. Then a simplified two-stage method will be proposed to predict floorslab’s vertical vibrations induced by subway according to the testing results. Analytical and numerical solutions of the above model will be used to verify the rationality and applicability of the basic assumptions in this method. By the above method, a kind of simplified structures’ vertical vibration analysis model which considered soil-structure interactions, floorslabs’ vertical vibrations and structures’ rotary vibrations will be established. With the above simplified analysis model, the basic principles of subway nearby buildings’ base isolation method will be analyzed, and the design principles about this method will be developed after considering the adverse effects of structures’ vertical vibration modals on the isolation performance.

随着地铁运行诱发的环境振动问题日益突出，准确预测该类环境振动对建筑结构的影响，以及设计合理的振动控制措施就显得尤为重要。目前国内外在分析地铁激励下建筑结构的竖向振动问题时，仍以整体结构的有限元分析模型为主，不仅建模和计算工作量大、需反复调试的设计参数众多，且难以保证预测精度。本项目拟针对上述问题，首先通过框架结构缩尺模型试验，探明竖向高频地铁环境振动在建筑结构中传递机理，验证基础隔振措施的有效性。再根据上述试验结果提出简化预测楼板竖向振动的“两阶段方法”，应用理论解及数值解验证基本假设的合理性与适用条件。以此为基础，在综合考虑土-结相互作用效应、楼板竖向振动效应及上部结构的旋转振动效应等关键因素后，建立地铁激励下建筑结构的竖向振动简化分析模型。并应用该模型分析地铁邻近建筑基础隔振措施的基本原理，在考虑上部结构竖向振型等因素对隔振效率的不利影响后，建立基础隔振措施的设计方法。

地铁环境振动扰民现象日益突出，但目前地铁运行引发邻近建筑物竖向振动的简化分析模型较为缺乏，且基础隔振措施尚不成熟。本项目首先结合缩尺模型试验，建立了地铁邻近建筑的竖向振动简化分析模型，并对其预测精度作了校核。在此基础上，进一步提出了地铁邻近建筑的砂袋垫层减振隔振新措施，通过试验分析了其减、隔振效果及地震作用时上部建筑结构的安全性。最后，研发了一种新型竖向减、隔振支座，并对其动力学性能开展了一系列试验研究。本项目的研究结果表明：（1）提出的局部柱顶竖向振动简化分析模型具有较高预测精度；（2）砂袋垫层对地铁和道路交通环境振动均具有较好的减、隔振效果；（3）砂袋垫层对地震动的减震效果也较为突出，同时具有抗液化性能；（4）研发的新型竖向减、隔振支座具有较高极限抗压强度，且同时具有低刚度和高阻尼特性，其减、隔振性能优于传统厚层橡胶支座。