In this study, the train loading spectrum transmitted to the ground is evaluated using an analytical model to analyze and estimate the ground vibrations due to trains running on railway tracks. Using this loading spectrum as input,the ground vibration analysis is performed and the results are compared with the on-site experimental results and environmental standards.
To evaluate the train transit loadings acting on the ground, the trains are modeled as 2-dof moving mass system for each axle and the railway track as 2-layer continuous support model. The train loads are separated into 2 component i.e. quasi-static and roughness component. The load transmitted to the ground is evaluated using these components and then the equivalent plane strain load is calculated for the purpose of the ground vibration analysis. The quasistatic load effect is found to be the dominant component at low frequencies, whereas the rail roughness effect predominates at high frequencies in train loading spectrum.
The ground vibration analysis is performed using finite and infinite elements to model the near and far fields of the soil medium respectively. In this analysis KIESSI, which is the soil-structure interaction analysis program made in KAIST, was used.
열차하중에 의한 철도연변에서의 지반진동을 분석/예측하기 위해 노반구간에서의 열차하중의 산정 및 이에 의한 지반진동의 전파에 대하여 연구하였다. 노반구간에서의 열차하중 산정을 위해 차량을 2질량모형으로, 궤도를 2중보 연속지지모형으로 나타내고 열차하중을 이동축중 하중과 조도성분하중으로 나누어 하중을 산정하였으며, 진동의 지반전파해석을 위해 등가의 평면하중을 산정하였다. 또한, 2차원 지반진동 전파해석을 수행하여 계측결과와 비교하였으며 Octave band해석을 통해 환경진동 기준과 비교하였다.