침목패드 강성에 따른 자갈궤도 거동의 해석적 평가
Analytical evaluation of ballasted track behaviors according to the change of stiffness of Under Sleeper Pad
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초록
자갈궤도에서 침목과 도상은 열차하중을 지지하고 노반에 전달하는 역할을 하는 궤도구성품이다. 자갈로 이루어진 도상은 경제성과 진동 흡수능력 측면에서 장점이 있으나, 불연속 재료의 특성으로 인한 침하 및 열차하중에 의해 접촉면에서 파쇄가 발생할 우려가 있다. 본 연구에서는 PC 침목 바닥면에 침목패드(Under Sleeper Pad, USP) 부착 유무 및 USP 강성에 따른 수직 응력(접촉압력)과 침하 거동을 3차원 수치해석적으로 분석하였다. 해석 결과 USP 설치 및 강성 감소 시 궤도 연직변위가 약간 증가하였으나, 연직응력(접지압) 감소 및 하중분산 효과가 있음을 확인하였다. 따라서, USP 설치 효과로 궤도틀림 발생과 유지보수 업무를 감소시킬 수 있을 것으로 기대된다.
Abstract
A ballasted track consists of steel rails, concrete sleepers over ballast gravel, and subgrade soils. It supports and transfers various type of train loads to the subgrade. The ballast layer made of gravel has advantages in the aspects of economics and vibration absorption, but settlement can occur due to the discontinuous material properties and breakage of gravel at contact plane between sleeper and ballast under train load. In this study, 3-dimensional numerical analyses were performed to investigate the behaviors of vertical stress (contact pressure) and settlement due to applying Under Sleeper Pad(USP) and its stiffness on ballasted track. The results verify that rail vertical displacement increases without significant meaning in case of installation and decrease stiffness of USP, and there is a considerable reduction of vertical stress beneath sleeper. Therefore, it is expected that the track irregularities and maintenance work on ballasted track could be reduced by the installation effects of USP.
참고문헌 (11)
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