深埋地下结构地震反应分析的局部反应加速度法

LOCAL RESPONSE ACCELERATION METHOD FOR SEISMIC ANALYSIS OF DEEP BURIED UNDERGROUND STRUCTURES

  • 摘要: 城市地下结构逐渐呈现埋深更大化、断面复杂化、空间立体化等特点,中国现行《城市轨道交通结构抗震设计规范》(GB 50909−2014)推荐采用的反应位移法和反应加速度法在计算大埋深或复杂断面地下结构的动力反应方面存在一定的局限性。在广义反应位移法和传统反应加速度法的基础上,该文提出一种适用于深埋地下结构地震反应分析的局部反应加速度法,该方法只需确定局部区域自由场加速度和土层剪力;结合某深埋圆形断面的隧道结构,以整体动力时程分析方法为基准,分析了不同模型高度和结构刚度工况下局部反应加速度法的计算效果。结果表明:该文提出的局部反应加速度法是一种操作简便的实用分析方法,并且当模型高度取为地下结构高度的5倍时,可以获得较为准确的结构反应。

     

    Abstract: The urban underground structures gradually show the characteristics of larger buried depth, of complicated section and of stereoscopic space. The response displacement method (RDM) and response acceleration method (RAM) recommended by Code for Seismic Design of Urban Rail Transit Structures (GB 50909−2014) have some limitations in the seismic analysis of underground structures with large buried depth or complicated sections. Based on the generalized response displacement method (GRDM) and traditional RAM, this paper proposes the local response acceleration method (LRAM) for the seismic analysis of deep buried underground structures, and this method only needs to determine the acceleration and soil shear stress of the local free field. In combination with a tunnel structure with circle cross section, the validity of the proposed method with different heights of the model and different stiffness of the structure is verified by comparing with the results of the dynamic time history analysis method. The analysis results show that the proposed method is a practical analysis method with a simple operation. When the height of the model is 5 times that of the underground structure, a more accurate structural response can be obtained.

     

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