Study on the vibration response law of freezing pipe under blasting

In order to ensure that the freezing pipe does not break during blasting and tunneling construction in the freezing bedrock section of the shaft and safety construction of freezing shaft, the vibration response of frozen pipe under explosion is studied.By approximate simplification of explosion stress wave and coordinate transformation; the plural form of stress field and displacement field of the frozen pipe is obtained when the longitudinal wave scatters in the vicinity of the freezing pipe.The numerical simulation of the vibration response of the freezing pipe under different temperatures (-10 ℃, -15 ℃, -20 ℃ and -30 ℃) was carried out by the finite element software ANSYS/LS-DYNA, the vibration response of the freezing pipe to explosion is analyzed by pressure nephogram and velocity nephogram of freezing pipe at different time and curves of stress and velocity of frozen pipe with temperature.The numerical simulation results show that the maximum tensile stress, the maximum compressive stress, the radial vibration velocity and the tangential vibration velocity of the frozen pipe are continuously decreased with the decrease of temperature.The maximum tensile stress of the frozen pipe is greater than the maximum compressive stress, and the radial vibration velocity is greater than the tangential vibration velocity, therefore, the maximum tensile stress and radial vibration velocity of the freezing pipe are taken as the safety control basis for the blasting excavation construction in the freezing bedrock section shaft.The numerical simulation results provide the basis for the design and implementation of blasting scheme and freezing scheme.