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Analysis of Shear Modulus(G)-Shear Strain(γ)-Degree of Saturation(S) Characteristics of Compacted Subgrade Soil used as Railway Trackbed

다짐된 궤도 흙노반 재료의 전단탄성계수(G)-전단변형률(γ)-포화도(S) 관계특성 분석

  • Choi, Chan Yong (Korea Railroad Research Institute) ;
  • Lee, Seong Hyeok (Korea Railroad Research Institute) ;
  • Lim, Yu Jin (Department of Civil, Environmental and Railroad Engineering Paichai University) ;
  • Kim, Dae Sung (Department of Civil, Environmental and Railroad Engineering Paichai University) ;
  • Park, Jae Beom (Department of Civil, Environmental and Railroad Engineering Paichai University)
  • Received : 2014.12.17
  • Accepted : 2015.02.17
  • Published : 2015.04.30

Abstract

It is important to evaluate the stiffness characteristics of compacted subgrade soil under track that is loaded dynamically. Using a mid-size Resonant Column test apparatus, normalized shear modulus and shear modulus variation with changing of confining pressure were investigated with change of degree of saturation (DOS). From an analysis of the test results, it was verified that the maximum shear modulus decreased with increases of DOS. However, normalized shear modulus increased with increases of DOS. Using the test results, a relation of G~${\gamma}$~DOS can be constructed and characterized. In the future, by performing tests with soils used as trackbed broadly in the field, a prediction model for DOS~G~${\gamma}$ can be proposed.

본 연구에서는 국내 철도 궤도하부 다져진 흙노반의 강성 평가를 위하여 Stokoe 방식의 고정단-자유단 중형 공진주 시험기(D=10cm, L=20cm)를 이용, 구속압 및 전단변형률 증가시 포화도(S)변화에 따른 전단탄성계수의 분포변화를 조사, 분석하였다. 분석결과 포화도가 증가할수록 최대전단탄성계수는 감소하고 정규화 전단탄성계수는 증가하는 경향을 보였다. 분석결과를 바탕으로 포화도(S)~전단탄성계수(S)~전단변형률(${\gamma}$) 사이의 고유한 감소 관계특성을 관찰할 수 있었다. 이러한 특성수립 가능성을 기반으로 향후 광범위한 추가시험을 통하여 예측모델을 수립하고 소정의 모델계수 값들을 획득할 수 있을 것이다.

Keywords

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