穿越岩土交界面竖井结构水平地震响应分析

ANALYSIS OF THE INFLUENCE OF ROCK-SOIL INTERFACE SITE ON THE HORIZONTAL SEISMIC RESPONSE OF UNDERGROUND SHAFT

  • 摘要: 已有震害经验表明地下结构面临严重的地震威胁,国内外学者对地下结构的地震响应开展了大量研究,铅直型竖井结构由于在功能上连通地表和地下空间,在设计建造过程中不可避免面临穿越岩土交界面的问题,针对岩土交界面对竖井的地震响应的影响研究相对缺乏,且穿越岩土交界面地层环境的竖井结构动力响应尚未明确,因此,该文主要开展岩土交界位置及岩土相对刚度对竖井结构的地震响应影响研究。基于有限元分析软件ABAQUS建立了岩土交界面场地与竖井结构的三维土-结构相互作用模型,采用等效线性化的动力时程分析方法,对水平地震动作用下的竖井结构内力变化及变形情况进行研究分析。结果表明:地震作用下竖井结构在岩土交界面位置处产生的内力突变,且位置越深所产生的轴力和弯矩越大,同时相应位置处应变和直径变形率较大;当岩土相对刚度较大时,竖井在岩土交界面处所产生的内力及变形均大于岩土相对刚度较小工况。在实际的工程设计中应对竖井结构穿越岩土交界面予以足够的重视。

     

    Abstract: In recent years, earthquake damage cases have shown that underground structures are subjected to the threaten of earthquake motion. Scholars have carried out a lot of research on the seismic response of underground structures. Because vertical shafts are functionally connected to the surface and underground space, it is inevitable to face the problem of crossing the rock-soil interface, and there is a relative lack of research on the influence of the rock-soil interface on the seismic response of the shaft. The dynamic response of the shaft structure passing through the rock-soil interface stratum environment is unclear. Therefore, this paper mainly studies the influence of the position of the rock-soil interface and the relative stiffness between rock and soil on the seismic response of the shaft. Based on the finite element analysis software ABAQUS, a three-dimensional soil-structure interaction model between the site of rock-soil interface and shaft is established. The dynamic time-history analysis method of equivalent linearization is used to study and analyze the internal force change and deformation of shaft under horizontal ground motion. The results show that the sudden change of the internal force happened at the rock-soil interface, and greater axial force and bending moment at deeper position lead to larger strain and diameter deformation rate. When the relative stiffness of rock and soil is larger, the internal force and deformation of the shaft at the rock-soil interface are larger than those with smaller relative stiffness. In the engineering design, enough attention should be paid to the shaft structure crossing the rock-soil interface.

     

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