Method Study On The Recognition Of Real Delay Time For Millisecond Blasting

The development of the national economy is inseparable from the support of resources,but also the assistance of infrastructure construction.In the construction of urban subway tunnels,shield construction is the mainstream,but the drilling and blasting method also plays an important role.Due to the special nature of the subway tunnel construction environment,the drilling and blasting method faces many challenges.The construction of the new tunnel is shallow,and the existence of the underground pipeline staggered,the bridge pile foundation and the building foundation of the building add a lot of difficulty to the construction of the drilling and blasting method.In actual engineering,the use of millisecond blasting is generally used to control the damage of blasting seismic waves.Therefore,identifying the actual delay time of millisecond blasting and optimizing the design delay time become the main means to control the damage of blasting seismic waves.Based on the theory of adaptive white noise,the integrated integrated empirical mode decomposition,permutation entropy algorithm,and singular value decomposition,the following research work is carried out:(1)The multi-stage blasting vibration signal is constructed based on the measured single-stage blasting vibration signal.By comparing the recognition effect of the actual differential delay time of the multi-stage blasting vibration signal,the empirical integration of empirical mode decomposition(EMD),EMD instantaneous energy method and adaptive white noise is tested.The methods of modal decomposition(CEEMDAN)and CEEMDAN instantaneous energy method are used to identify the delay time of millisecond blasting.(2)Add noise with different signal-to-noise ratios in the multi-stage blasting vibration signal,and test the anti-interference ability of the four identification methods.For the signal with unsatisfactory recognition effect,the entropy detection is performed on the selected natural modal component,and further singular value decomposition processing is performed when the entropy value is greater than 0.5.(3)Introduce the mathematical principle of wavelet transform and several commonly used wavelet basis functions,and compares the effects of wavelet transform,EMD algorithm and CEEMDAN algorithm to identify the measured blasting vibration signals.(4)Taking the Shenzhen Metro Line 6 Science Museum Station Station and the return line tunnel as the engineering background,compare the EMD method,EMD instantaneous energy method,CEEMDAN method and CEEMDAN instantaneous energy method to deal with the recognition effect of the measured blasting vibration signal delay time The permutation entropy algorithm and the singular value decomposition algorithm are applied to the measured blasting vibration data processing.The research work done in this paper is based on the frontier of the discipline.The CEEMDAN theory is used for the first time to identify the delay time of millisecond blasting.It has a high practical value and lays a technical foundation for the system to carry out differential blasting delay time identification research.