【摘要】 采用动力Winkler地基模型,推导解析方法对沉箱加桩复合基础的地震响应。首先,考虑复合基础与土的相互作用以及沉箱部分和群桩部分的连接,分析复合基础在简谐S波作用下的运动响应;然后,对基础和上部结构系统建立"基础–柱–质点"简化模型,并应用Fourier变换实现地震响应的频域求解;第三,应用DRM两阶段时程有限元方法对采用沉箱加桩复合基础的土–基础–结构系统地震响应进行计算,与本文简化方法对比,验证本文方法的正确性。最后,通过算例研究加桩对增强基础和结构抗震能力的效果,并得出加桩抗震的主要机制在于消除了沉箱基础的类共振现象。更多还原

【Abstract】 Seismic response of a new type of foundation,the composite caisson-piles foundation,is studied through a simplified analytical method.The focus is the contribution of the piles beneath the caisson in increasing the earthquake resistance of the foundation-superstructure system.Firstly,considering the interaction between the soil and foundation with dynamic Winkler model,the equation of kinematic response of the composite foundation under S-wave is derived.Secondly,a simplified model for the seismic response of the foundation-column-lumped mass system in frequency domain is built;and with Fourier transformation this method is applied to transient seismic problems.Thirdly,with an example of soil-foundation-superstructure seismic behavior,this proposed method is validated by comparison against 3D dynamic FEM modeling,in which domain reduction method(DRM) is utilized.Lastly,the significance and mechanism of adding piles in improving the earthquake resistance of the foundation and superstructure are analyzed through examples in different soil conditions.Discovery in this study is that adding piles under the caisson is an efficient way to increase the seismic resistant capability of the soil-foundation-superstructure system;and the main mechanism is the elimination of the pseudo-resonance.更多还原