Construction of Correlation between Basic Soil Properties and Deformation Modulus of Trackbed Soils Based on Laboratory and Field Mechanical Tests

최근 국내 철도는 고속화와 통과톤수(MGT)의 증가에 의해 보다 높은 수준의 궤도 안정성과 내구성을 확보하기 위하여 엄밀 하면서도 새로운 궤도노반 분류기준의 재정립이 요구되고 있다. 현재 해외 철도 선진국은 대부분 자국 내 철도 궤도 노반전용 의 흙재료 분류기준을 제정하여 사용하고 있다. 일본의 경우 철도총합기술연구소(RTRI)에서 2007년에 간행한 ‘철도구조물등 설 계표준 동해설[1]’을 통하여 성토구간 흙쌓기용 재료분류기준을 새롭게 제시한 바 있다. 독일 또한 자체의 독자적 흙분류기준을 제정하여 사용하고 있다[2]. 이는 독일이 위치한 고유의 지형학적 토질분류 특성을 반영하도록 한 것이며, 매우 엄밀한 노반전 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 (P200), % passing of #4 sieve (P4), Coefficient of uniformity (Cu), and Coefficient of curvature (Cc). Degree of compaction of the soils adapted in the code by KR should be evaluated by maximum dry density (γd-max) and deformation modulus Ev2. 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 (γd-max), OMC, P200, P4, Cu, Cc, etc.; deformation modulus Ev2 and Evd 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 Ev2 and Ev. 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.