사면의 기하학적 증폭특성을 고려한 지진시 산사태 예측기술개발 Ⅰ: 지진시 서울지역 산사면의 기하학적 증폭 특성 분석

초록

Research on seismic mountain slope stability hazard map is widely being pursued in order to reduce the hazard induced by earthquakes. The hazard maps use the Newmark sliding block analysis, which in turn uses the peak ground acceleration estimated from theseismic design code. The seismic coefficients are developed to represent the amplification characteristics of horizontally layered soilprofiles. However, it is not appropriate to apply such coefficients considering that typical mountain slopes in Korea have inclined bedrockparallel to the slope surface, and the soil layer thinly covers the slope. In this study, a series of nonlinear dynamic analyses areperformed to derive the amplification factors of mountain slopes in Seoul. The amplification factors are calculated from the normaland shear stresses acting on the failure surface, from which the equivalent acceleration time history is derived. The calculated amplificationfactors are shown to be approximately 30% lower than the seismic coefficients of horizontally layered soil profiles. It is thereforeconcluded that use of the seismic coefficients given in the seismic code will result in very conservative estimate of the groundmotion, and that use of the recommended factors are more realistic. The factors derived in this paper are used to develop slope hazardmaps in the companion paper.

키워드