Abstract: Based on the disaster of floor heave in Taoshuya tunnel, the occurrence mechanism and important influencing factors of tunnel floor heave are analyzed by means of the method of field observation and geological prospecting. Furthermore, the calculating theory of floor heave of soft rock tunnel is deduced by using the continuum mechanics. According to the comparison result between predictive values and field monitoring data, it is proved that the deformation of floor heave of the tunnel can be simulated well by the proposed method, which provides a theoretical basis for calculating the floor heave of subsequent tunnels and treatment measures. Besides, the corresponding prevention techniques for floor heave of soft rock tunnels are obtained. It will be helpful for construction of other projects.