大规模的城市建设行为导致了众多包括地震在内的地质灾害问题.通过总结城市建设的主要荷载以及城市建设影响场地动力特性的方式,针对未有城市建设因素作用前的均匀土层场地、均布桩基的场地、均布地下空间基础的场地、复合地基改良的场地等共4个工况建立场地地震时程分析模型.结果表明,城市建设改变了场地条件,不同场地对地震波的放大作用各不相同.城市建设因素造成场地刚度提高,土体对波传递能力增强,消耗波动能量的粘、塑性减少.但相应场地上短周期的建筑物危险性增大,城市建设因素使得场地地震反应发生变异.
Large-scale city construction behavior leads to many geological hazards, including earthquake problems. By summarizing the construction loads and the dynamic characteristics of city construction, a total of four site seismic time-history analysis model is established under different conditions as site without city construct factors, site of pile foundation, site of underground special structure and site of compound foundation. The results indicate that city construction has changed site conditions and different sites have different magnify actions to seismic wave. City construction would improve rigidity of sites and the transfer ability of wave through soil in specific areas, and then decrease the viscoplasticity which consume wave energy there. All these factors would increase the risks of short-period buildings, and change the site seismic response.