Abstract
The soils used as trackbed in Korea are selected using USCS utilizing basic soil properties such as Grain Size Distribution(GSD), % passing of #200 sieve ($P_{200}$), % passing of #4 sieve ($P_4$), Coefficient of uniformity ($C_u$), and Coefficient of curvature ($C_c$). Degree of compaction of the soils adapted in the code by KR should be evaluated by maximum dry density (${\gamma}_{d-max}$) and deformation modulus $E_{v2}$. The most important influencing factor that is critical to stability and deformation of the compacted soils used as trackbed is stiffness. Thus, it is necessary to construct a correlation between the modulus and the basic soil properties of trackbed soil in order to redefine a new soil classification system adaptable only to railway construction. To construct the relationship, basic soil test data is collected as a database, including GSD, maximum dry unit weight (${\gamma}_{d-max}$), OMC, $P_{200}$, $P_4$, $C_u$, $C_c$, etc.; deformation modulus $E_{v2}$ and $E_{vd}$ are obtained independently by performing a Repeated Plated Bearing Test (RPBT) and Light Weight Deflectometer Test (LWDT) for ten different railway construction sites. A linear regression analysis is performed using SPSS to obtain the relationship between the basic soil properties and the deformation modulus $E_{v2}$ and $E_v$. Based on the constructed relationship and the various obtained mechanical test data, a new soil classification system will be proposed later as a guideline for the design and construction of trackbed foundation in Korea.
국내 궤도 흙노반재료의 선정기준은 기초물성 값(입경, 200번체 통과량($P_{200}$), 4번체 통과량($P_4$), 균등계수($C_u$), 곡률계수($C_c$)등)을 이용하는 통일분류법에 의존하고 있으며, 선정된 궤도노반의 현장 다짐도는 들밀도 시험 및 반복평판재하시험 결과 $E_{v2}$에 의해 파악한다. 그러나 궤도노반의 변형 및 안정성에 미치는 가장 큰 영향요소는 강성(Stiffness)이므로, 노반재료의 분류특성은 기초물성 값 자체 보다는 다짐 후 변형계수를 활용하는 것이 보다 정확하다고 할 수 있다. 본 연구에서는 궤도노반에 사용되는 국내 대표적인 흙 재료의 기초물성과 현장시험에 의한 변형계수($E_{v2}$, $E_{vd}$)와의 상관식을 도출하였다. 이와 같은 상관특성은 성능설계를 위한 국내 고유의 철도궤도용 전용흙분류기준수립을 위한 근거로 사용될 수 있다.
