Aiming at the blasting demolition project of a 120 m high reinforced concrete exhaust tower,the finite element software ANSYS/LS-DYNA was used to simulate the collapse process by a separate common node model.Compared with the video data,the movement state of the structural support part,the fracture part,and the top position of the instability failure process were analyzed.The results show that the cylinder structure with a large slenderness ratio was prone to fracture due to its large self-weight inertia and section mutation in the structure shape,and the interaction between impact failure and accelerated fall appeared in the process of sitting down.It was found that the blasting cut was formed at 0.2 s,and the stress concentration first appeared was at the top angle of the cut.After tipping at a certain angle,the back part was pulled and the stress concentration was transferred to the bottom angle of the cut.Furthermore,the initial stress redistribution time was at about 4.5 s,and there was a crack at 75 m of the structure at 9 s.Meanwhile,the cylinder was separated,the lower cylinder was slowly overturned around the plastic hinge,and the upper cylinder fell freely.The recorded video showed that the crack appeared at the position of the structure at about 70 m with a sudden mutation of the cross section at 8.5 s.The simulated collapse length was 104 m,the vibration velocity of cylinder collapse reached the maximum,the maximum velocity of the upper cylinder was 49 m/s,and the maximum velocity of the lower cylinder was 29 m/s.Besides,the simulated collapse time was about 12 s and the actual collapse time was 11.8 s,these two times were very close.