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Correction Factors for Modulus Calculation Equation used in Light Weight Deflectometer Considering Track Foundation

궤도노반 강성차이를 고려한 동평판재하시험(LWDT) 동탄성계수 산정공식 수정계수

  • Choi, Chan Yong (Korea Railroad Research Institute) ;
  • Lee, Jin Wook (Korea Railroad Research Institute) ;
  • Lim, Yuijn (Department of Civil, Environmental and Railroad Engineering, Paichai University) ;
  • Cho, Hojin (Department of Civil, Environmental and Railroad Engineering, Paichai University)
  • Received : 2014.12.08
  • Accepted : 2015.01.19
  • Published : 2015.02.28

Abstract

LWDT was developed for use as an alternative technique to measure the stiffness of trackbed soils. In this study, numerical and theoretical analyses of LWDT's acting mechanism were performed. The effectiveness of the adapted elastic formula used for calculation of the dynamic modulus, Evd, was investigated theoretically and also numerically by running ABAQUS analysis. The minimum thickness of the upper layer is proposed based on the analysis. Correction factors for the formula of elastic modulus are also proposed in this study. In the future, following field test results and laboratory mechanical tests such as the resonant column test, a guideline for the use of LWDT as a standard test protocol in track construction sites, as a measuring tool for the degree of compaction and/or stiffness and dynamic modulus, will be proposed based on this analysis.

동평판재하시험기(LWDT)는 궤도노반 등의 다짐강성 측정을 위하여 개발된 시험기이며 낙하추를 자유낙하시킬 때 가속도계를 이용하여 다짐표면의 처짐량을 측정, 반무한 탄성체로 가정된 노반의 동탄성계수를 결정한다. 본 연구에서는 LWDT시험기의 구성과 구동 메커니즘 및 동탄성계수 추출공식의 유효성을 상세히 분석하였다. 특히, 2층구조 노반 위에서 LWDT 시험시 상부층의 강성평가 유효깊이를 유한요소해석으로부터 결정하였다. 또한, LWDT 시험시 노반의 강성 차이를 고려하여 사용할 수 있는 동탄성계수 추출공식 수정계수를 제시하였다.

Keywords

References

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Cited by

  1. Construction of Correlation between Basic Soil Properties and Deformation Modulus of Trackbed Soils Based on Laboratory and Field Mechanical Tests vol.19, pp.2, 2016, https://doi.org/10.7782/JKSR.2016.19.2.204