Research On The Vibration Effect And Vibration Reduction Measures Of Tunnel Excavation Blasting In The Environment Near The Oil Pipeline

The problem of tunnel blasting and excavation near buried oil pipelines,because of its special protection object,must ensure the safe operation of oil pipelines and ensure the progress of tunnel construction,so it is of great significance for studying the law of blasting vibration and effective vibration reduction measures in such complex environments.The Yongxing No.1 tunnel of the Guiyang-Nanning high-speed railway section is adjacent to the buried oil pipeline,and the geological conditions are complex and the safe operation of the pipeline is considered,and the difficulty of blasting and excavation is high and the risk is high.Based on waveform superposition theory and finite element analysis theory,this paper uses numerical analysis and numerical simulation methods to analyze the safety of oil pipelines under the action of blasting seismic waves,and compares numerical simulations and field tests of various vibration reduction measures to obtain the optimal vibration reduction method and provide a theoretical basis for safe and efficient construction.The main research contents and results are as follows:Firstly,using MATLAB software to analyze the collected blast vibration data and the Hilbert-Huang(HHT)transformation method,the frequency domain characteristics and energy characteristics of the blast vibration signal were studied to select the optimal delay time,and the common results of the two were considered as the optimal delay time period: 28～32ms.Secondly,using ANSYS/LS-DYNA finite element software,the optimal delay time period is accurately taken,and the combined vibration speeds of28 ms,30ms and 32 ms are compared by numerical simulation methods,and the optimal delay time is selected: 30 ms,and the delay time is used as the subsequent study time difference.Based on the above analysis and based on the blasting vibration velocity,the vibration velocity around the pipeline is studied,and the point most prone to destruction is located at the steel pipe particle of the explosion-facing surface,and the change law of the vibration peak under different internal pressures is selected at the point,and the stress analysis is analyzed.The blasting vibration data are analyzed and a nonlinear prediction model and a BP neural network prediction model are established to obtain the K and αvalues under this geological condition,and the comparison of the two shows that the BP neural network prediction model is more suitable for vibration prediction of tunnel excavation.Finally,the vibration damping effect of three kinds of delay time and three kinds of spaced charging materials was studied by numerical simulation and field test,and the reliability of modeling was proved to be proved by field test pairs and the numerical simulation results were obtained,and the optimal vibration reduction measure was the use of soil spacing materials for charging under 30 ms delay time.Guidance can be provided for similar operating conditions.