Study On Propagation Law Of Explosion Shock Wave In Underground Space And Its Influence On Adjacent Structures

In view of current research of explosive explosion in air and rock mass,the propagation law of explosion shock wave in underground space and its influence on adjacent structures are comprehensively studied by means of theoretical analysis and numerical simulation in this paper.The following specific contents are investigated:(1)A semi-infinite medium explosion impact model is established.The basic equations and boundary conditions are derived,which are satisfied by the disturbance stress,strain and displacement caused by explosion load.Trial functions of displacement under boundary conditions of displacement is derived through trigonometric function system.The integral-variational equations of the surrounding rock mass are derived by Hamilton time-domain variation principle considering timedomain variation conditions and constraint condition.The steady-state response of discrete vibration equations is obtained by Duhamel integral.The analytical solution of disturbance stress,strain and displacement is obtained by matrix transformation.Numerical examples show that the stress,strain,displacement and velocity excited by explosion load change alternately positive and negative,and the fluctuation amplitude decreases gradually with the increase of proportional distance.With the increase of horizontal proportional distance,the amplitude of surface vertical vibration displacement decreases rapidly,and the amplitude of horizontal vibration displacement increases firstly and then decreases.(2)Taking the explosive enlargement in a mass of soil as an example,the influence of the fluid-solid coupling algorithm,time step,artificial boundary and grid density on the simulation results are analyzed systematically.Based on the ALE algorithm,the air shock wave propagation process in the vertical wall arch cross-section tunnel was simulated considering the shape and blasting height of TNT explosives.The impact waves induced by cylindrical charges are noteworthily directional and form a crossshaped volume in which the portion along the charges' axial direction is more extreme.The wall shape plays an important role in the peak overpressure.Different charging positions will lead to an obvious difference on the peak pressure between the bottom and top of tunnel lining in the near-field,and the peak overpressures at different parts of the same tunnel section are not the same.(3)A fluid-solid model of explosive-air-structure-rock is proposed for typical shield tunnel,and the dynamic response and damage of tunnel were analyzed.The extreme value of the dynamic response in face of blasting face close to the charge increases obviously,and the damage is the largest.The peak value of dynamic response caused by different concrete constitutive models varies greatly.The dynamic response and damage calculated by the KCC model are the largest,while the dynamic response and damage calculated by the HJC model are the smallest.(4)The key factors of blasting vibration are systematically analyzed,and the effects of vibration amplitude,dominant frequency and duration on the damage mechanism of structures are summarized.The correlation between the peak value of particle vibration velocity and blasting vibration failure intensity is established,which can explain the internal mechanism of velocity standard in blasting safety regulations.The propagation and attenuation law of blasting seismic wave,the response characteristics of surrounding rock loose zone and buildings in a municipal blasting excavation project are analyzed.