Research On Vibration Rule Of High-storey Structure Under Tunnel Blasting And Reduction Technology Optimization

The harmful effects of blasting vibration generated by blasting excavation of subway tunnels are likely to cause damage to surrounding buildings.Especially when the tunnel is worn down the building at a close distance,the vibration disturbance of the building is greater.Therefore,in the construction of subway tunnels,real-time monitoring or safety reinforcement should be carried out on the buildings underneath,and the construction design parameters should be changed if necessary.Usually,when monitoring buildings,the focus is on the vibration of the surface,ignoring the monitoring and treatment of different floors inside the building.This paper takes the 33-story concrete structure high-rise building under the entrance and exit of Xizhen Station of Qingdao Metro Line 1 as the engineering background,and arranges the measuring points on different floors in Building 2 of Tibet Road Community.The TC-4850 blasting vibration monitor is used to monitor different floors.The vibration effect is studied to study the vibration response of subway tunnel blasting to high-rise buildings.The regression analysis is carried out on the field measured data,and the variation law of the peak value of the blasting vibration velocity with the floor is analyzed from the horizontal radial direction,the horizontal tangential direction and the vertical direction.Then,based on the actual parameters of the site,the numerical simulation model is established by using the original ratio of ANSYS/LS-DYNA to determine the material parameters and boundary conditions,and simulate the whole process of blasting.The vibration stress cloud diagram and vibration velocity variation curves of different buildings on different floors are studied,and the vibration response law of tunnel blasting excavation under high-rise buildings is summarized.At last,according to the vibration propagation rules summarized by the field measured data and numerical analysis results,a multi-stage wedge-shaped blasting vibration reduction optimization scheme,which includes multi-stage wedge-shaped blasting,sub-shot blasting and out-hole delay,is proposed for the vibration reduction requirement from the aspects of explosive consumption and cutting mode,and the feasibility of the scheme is verified by field monitoring.This paper can provide a theoretical basis for the blasting and excavation construction of urban underground tunnels with large surrounding rock grades.