The Study And Application Of Loading Methods On The Numerical Simulation Of Blasting Loads

This thesis taking the blasting construction of the QiPanShan tunnel as background, took the in-situ measured vibration velocity as input load, and used the finite element software to make a numerical simulation for the blasting vibration of tunnel. discussed the suitable loading method, calculation models and calculation method and calculation condition for reliable calculated result, compared the vibration velocity characters of rock in different input load, researched the Surrounding rock stress characteristics and the loosen scope of rock caused by the blasting excavation of the tunnel In addition, the scope of loosen circle of rock was monitored in the QiPanShan tunnel blasting construction site, and compared with the numerical simulation results. The main research content and research results of the paper are as follows:A regression analysis for in-situ measured blasting vibration speed was made, and blasting vibration decay laws formula in the adjacent area of QiPanShan tunnel was got.Theoretical analysis and experimental methods were used to study three kinds of loading methods for blasting vibration, and the achievements showed that it is closer to the engineering practice by using measured vibration velocity as the input load.The whole section blasting vibration waveform was taken as input load in simulation, and the biggest vibrating speed, vibration period and peaks and troughs got was relatively close to the field test values, In addition, a stress analysis was made for the elements in vaults, arched feet and arched bottom, and the analysis results show the broken of rock in these three parts is due to surrounding rock reaching tensile strength limit. A linear function fitting was got according to the relationship between the maximum tensile stress and the maximum vibration velocity. The critical vibration velocity of the surrounding rock-mass got in QiPanShan tunnel was 32～45 cm/s, while the loosen scope of rock was 0.8～1.5m.The scope of loosen rock was measured in the blasting construction site of QiPanShan tunnel, which was about 0.9～1.6m and were basically the same with numerical simulation results. The numerical calculation loading methods obtained in this paper has very good guiding value for research of underground engineering related problems and blasting numerical calculation.