Abstract：Based on in-situ measurements carried out by the authors at Jinjiayan railway tunnel，a simulated vertical dynamic load of passing trains is put forward. 2D finite element method is adopted to analyze the dynamic responses of tunnels and their surrounding masses to the traffic vibration. In the analyses various structure types，various curvatures，various stiffnesses of the invert and various types of connection of the invert with side wall are considered. The stresses of invert and stress distribution of the surrounding masses under the invert are obtained，and the effect of the structure type of invert on vibration responses is assessed. As a result，a rational structure type of railway tunnel under dynamic vibration load is put forward. The effective measures and rational structure for the railway tunnel bed under dynamic vibration load are that (1) the tunnel invert with the larger ratio of rise to span is recommended，(2) the filling on invert is as thick as possible，(3) a entire rigid structure should consist of invert，filling and road bed with help of concrete of the same strength，(4) the water stocked under the invert must be drained away to avoid rock-soil liquefaction under long-term vibration，and (5) grouting and bolting should be employed to reinforce the surrounding rock masses under invert.
