考虑多传播介质耦合的地铁上覆建筑环境振动及路径隔振措施研究

The coupling effects among multiple propagation media play a key role in evaluating subway induced over-track building vibrations and their mitigation measures. This project proposes a source-receiver model by taking account of coupling effects among train, track-tunnel, soil-mitigation device, and building. The train is simulated by a 3D multi-body model, the track-tunnel system is modeled by 2.5D FEM approach, the soil-mitigation device system by 2.5D FE-PML approach, and the building by resource to 3D FEM method. The wave propagation mechanism among multiple propagation media is revealed, and the influence of the coupling effects is analyzed. Expanded Polystyrene (EPS) geofoam is chosen as a wave-absorption material, and its static and dynamic material constants are obtained through laboratory tests. EPS geofoam is latter adopted as a replacement of underground soil and a portion of soil surrounding a pile, serving as a propagation mitigation measure. The efficiency of the mitigation measure is assessed and optimized by the proposed source-receiver model as well as in-situ test. A field test is also conducted in Guangzhou for validating the source-receiver model and for assessing the performance of the mitigation measure. Results of this project lay a solid theoretical foundation for the development and design of new over-track building and of new subway underneath existing building.

多传播介质的耦合作用是认识地铁列车运行引起的弹性振动波从地铁波源到上覆建筑物接受点的传递机理、评估与优化路径隔振措施的关键科学问题。本研究以地铁上覆建筑的环境振动问题为研究对象，考虑列车、轨道－道床－隧道体系、地层－隔振装置体系、建筑物等传播介质的耦合作用，融合3D多体动力学、2.5D FE-PML方法、3D FEM方法，建立弹性波从波源传递到接受点的全过程数值模拟方法，揭示弹性波在各种传播介质的传递机理，分析各种耦合作用的影响；开展室内试验确定EPS土工泡沫的物理常数和动力学参数，提出EPS土工泡沫换填垫层土体、桩周局部土体的路径隔振措施，采用数值方法、现场足尺模型试验进行评估与优化；选取典型工程，验证多传播介质耦合作用下的地铁振动波全过程传播数值模拟方法，检验隔振措施的实践效果，为我国下穿地铁建筑物以及地铁上盖建筑物的开发和设计提供十分有价值的理论指导。

通过考虑列车、轨道－道床－隧道体系、地层－隔振装置体系、建筑物等传播介质的耦合作用，建立了2.5D FE-PML二步法研究道路交通引起的振动和2.5D FE-PML子结构法研究道路铁路交通引起的振动，揭示弹性波在各种传播介质的传递机理，并进行了现场试验验证；通过开展动三轴试验和共振桩试验，确定陶粒-砂与橡胶-砂力学混凝物的动力学参数；通过开展足尺屏障试验，分析陶粒、砂、橡胶回填材料的隔振响应，并通过数值模拟试验分析了不同配比的混合物的减振效果；通过开展桩基换填土体隔振措施的足尺试验，分析陶粒、砂、橡胶作为换填材料的隔振效果；针对具体的工程应用项目，提出了桩周局部土体与建筑物基础换填隔振材料的路径隔振措施，并进行了振动试验与深化设计；通过开展现场桩周局部土体换填隔振材料试验，并开展了该措施的减振降噪效果评估。研究成果直接指导工程实际，为我国下穿地铁建筑物以及地铁上盖建筑物的开发和设计提供十分有价值的理论指导。