At present,mining method is widely used in tunnel construction.The influence of blasting vibration on surrounding rock and supporting structure in tunnel and its disaster control are always hot issues.In order to study the propagation law of blasting vibration inside a tunnel,the vibration signals of simultaneous detonation and detonation at three benches were monitored on site based on the engineering background of a tunnel with soft surrounding rock.The nonlinear regression of Sadovski formula and Fourier transform method were used to analyze and study the test data.The results show that for the same section of the tunnel,the vault has the characteristics of large vibration velocity,high vibration frequency and slow attenuation rate.When 100 ms delay blasting is used between the three steps,the blasting energy can be discretely distributed in time and space,and the vibration superposition effect can be significantly weakened.A single hole blasting test was set in the middle of the cut area,and the single hole vibration waveform was obtained by setting the delay between the test hole and the entire blast as 100 ms.Based on the principle of linear superposition,the delay time was optimized by investigating vibration waveforms synthesized by cut blasting.The results show that when the delay time between holes is 4~7 ms,the peak vibration velocity caused by cut blasting decreases sharply,and the effect of interference is obvious.After the delay time exceeds 7 ms,the peak vibration velocity has no significant difference.