Abstract: The water level difference between dry season and flood season in Yangtze River basin amounts to over ten meters, which exerts an unneglectable impact on the stability of cross-river tunnel. Studying the stability performance of cross-river tunnel during subway train operation under water level fluctuation is an urgent task. In this paper, a cross-river tunnel model is built using the discrete element method. Microparameters of the tunnel are first calibrated based on triaxial test. A two-dimensional subway train load is adopted to execute dynamic load on the tunnel. Particle acceleration, radial and hoop stresses of the tunnel lining are considered as parameters to analyze the dynamic characteristics of the tunnel lining segments under different water levels. Results show that the tensile and compressive stresses of the lining segments under flood level are four times larger than those under normal water level, and are still smaller than the tensile strength. The average value of particle vibration acceleration reflecting the influence of subway train load on the lining under normal water level is 150 times larger than that under flood level. Therefore, during train operation, the inspection and maintenance of lining segments should be strengthened no matter in dry or flood season.

Key words: discrete element method, cross-river tunnel, subway train load, water level, acceleration, stress