Abstract：According to the distribution and movement of Xi¢an ground fissure，combining the trend of metro tunnel No.2 in Xi¢an，a geological model has been built，and then the effects of the ground fissure on the metro tunnel have been studied. The experimental results show that the tunnel is in tension and compression states，and behaviors as a cantilever elastic foundation beam under the environment of ground fissure. The tensile parts mainly distribute in the range between 20 and 80 cm away from the fissure in fixed block，and the compressive parts distribute between 20 cm away from the fissure in declined block and 80 cm away from the fissure in fixed block. At the same time，the movement of the ground fissure greatly increases the vertical pressure of surrounding rock at the top of tunnel and reduces the vertical pressure of surrounding rock under the bottom of tunnel in the decline block. Under the environment of ground fissure，the failure mode is mainly circumferential crack；the secondary fissures are controlled by tension-shear areas，and step and y-shaped fissures are mainly induced. Based on the experimental results，the section and position where countermeasures should be taken are put forward when the metro tunnels cross the ground fissure region.
