When longduration seasonal rainstorms happen, diseases are easy to occur to operating tunnels In the paper, the diseases that occurred to a highway tunnel after longduration seasonal rainstorms are investigated, monitored, numerically simulated and analyzed Conclusions drawn are as follows: 1) After longduration rainstorms, interrelated diseases, such as water leakage, floor uplift, mud pumping, central drainage ditch blocking and lining deformation, occur to the tunnel; 2) When the drainage system is blocked, the water pressure on the tunnel lining and the internal force of the tunnel lining increase rapidly, which leads to the damage to the invert and the side wall feet; 3) The following treatment measures are taken: Channels are cut to guide the ground water out so as to eliminate the water leakage disease; the damaged lining is removed section by section, new lining is installed and the invert is reconstructed; the existing central drainage ditch is widened, new sand collection shafts are installed and the drainage system is improved; 4) During the treatment of the tunnel diseases, the deformation of the tunnel structure is small, which demonstrates that the tunnel structure is safe and that the treatment measures taken are reasonable and reliable.