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Probabilistic Failure-time Analysis of Soil Slope under Rainfall Infiltration by Numerical Analysis

수치해석에 의한 강우 침투 시 사면 파괴시간의 확률론적 해석

  • Cho, Sung-Eun (Dept. of Civil, Safety, and Environmental Engrg. & Construction Engrg. Research Institute, Hankyong National Univ.)
  • 조성은 (한경대학교 토목안전환경공학과)
  • Received : 2019.09.16
  • Accepted : 2019.12.06
  • Published : 2019.12.31

Abstract

In this study, a stochastic analysis procedure based on numerical analysis was proposed to evaluate a kind of intensity-duration rainfall threshold for the initiation of slope failure due to rainfall infiltration. Fragility curves were generated as a function of rainfall intensity-duration from the results of probabilistic slope stability analysis by MCS considering the uncertainty of the soil shear strength, reflecting the results of infiltration analysis of rainfall over time. In the probabilistic analysis, slope stability analyses combined with the infiltration analysis of rainfall were performed to calculate the limit state function. Using the derived fragility curves, a chart showing the relationship between rainfall intensity and slope failure-time was developed. It is based on a probabilistic analysis considering the uncertainty of the soil properties. The proposed probabilistic failure distribution analysis could be beneficial for analyzing the time-dependent failure process of soil slopes due to rainfall infiltration, and for predicting when the slope failure should occur.

본 연구에서는 강우의 침투에 따른 토사사면의 파괴에 대한 강우강도-지속시간의 강우기준을 평가하기 위하여 수치해석에 의한 파괴시간의 확률론적 해석 절차를 제안하였다. 취약도 곡선은 시간에 따른 강우의 침투해석 결과를 반영하며 지반의 역학적 특성의 불확실성을 고려한 MCS에 의한 확률론적 사면 안정해석의 결과로부터 강우강도-지속기간의 함수로 생성하였다. 확률론적 해석에서 한계상태함수를 계산하기 위하여 강우의 침투해석과 연동된 사면 안정해석을 수행하였다. 생성된 사면의 취약도 곡선들을 기반으로 확률론적 사면 파괴분포 분석을 수행하여 지반의 불확실성을 고려한 사면 파괴 유발 강우기준을 평가하였다. 제안된 사면 파괴분포 분석법은 강우의 침투로 인한 사면 파괴의 과정을 분석하고 사면 파괴가 발생할 수 있는 시간을 예측하는데 유용하게 사용될 수 있다.

Keywords

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