Dynamical Numerical Investigation into Influence of Vibrating Load on Intersecting Tunnel Structure

Taking as examples of South Gate tunnel project and Metro Line 2 crossing project in Xi’an, this paper analyses the dynamic response of motor vehicle and train loads acting on a tunnel structure .based on finite element model of three-dimensional dynamics. By comprehensive use of load numerical fixation method and analytic formula method, the vibrating load curves of motor vehicle and subway train are calculated. A finite element model of dynamics is established as excitation source. While features of dynamic response and vibration propagation regularity of subway tunnel structure are analysed respectively through three aspects of displacement, velocity and acceleration. The results indicate that: The moving vehicles and trains at South Gate both exert striking impact on subway tunnel structure. The vibration response of vehicles load mainly acts on the arch of subway structure and influences little on side walls. Under either independent effect of vehicle dynamic load or joint action of vehicles and train loads, the acceleration and velocity response of each vibration detecting points are basically consistent. After putting in use, the South Gate Tunnel has exerted certain impact on the safety of existing subway structure, but improbably results in any damages. Therefore, the research results provide certain theoretical support for the safety assessment of dynamic response of Metro Line 2 structure.