Study on dynamic response of grade-separated railway tunnels under high-speed train induced dynamic load

This paper corrected the commonly used one-dimensional sine excitation force model for train-induced dynamic loads, to adapt to the simulation of high-speed train at the speed of over 350 km/h. The model was further extended to three dimensional simulation. On this basis, taking the grade separated junction of Wumengshan Tunnel of Liupanshui-Zhanyi Railway and the new Meihuashan Tunnel as an example, through numerical analysis, this paper presented an analysis on train induced dynamic load with the grade separated tunnel structure. At the cross point, three different grade separated structure forms, namely, separately built form, half-separately built form and jointly built form, were established in the dynamic simulation. The response law of displacement, acceleration and internal force of the three structure forms under train-induced dynamic load was studied. The analysis results showed that the jointly built structure, where the grade separated framework and connecting walls that connect the upper and the lower tunnels, possessed a higher structure safety reserve. ©, 2015, Science Press. All right reserved.