지중구조물의 지진해석을 위한 응답변위법의 보수성에 대한 고찰

The seismic deformation method (SDM) is a standard analysis tool of deciding seismic design force in the earthquake resistance design for underground structures. However, the force can vary significantly depending on how to evaluate the soil stiffness and free-field input. This paper addresses the diversity through numerical analyses for a couple of typical underground structures with three different soil conditions. The numerical results compared with those from an accurate dynamic soil-structure interaction (SSI) analysis showed that the peak earthquake force by the SDM can be more than three times of reference reponse by the SSI. Thus we recommend evaluating the soil spring by FE analysis and free-field input responses by a dynamic site response analysis based on reduced shear modulus.