Analysis Of Influence Of Shallow Tunnel Blasting Construction On Adjacent Buildings

It is inevitable to pass through the city buildings when the tunnel is built by drilling and blasting in city,and the effect of blast-induced vibration on the buildings is paid more and more attention.To ensure the safety of buildings during tunnel construction,it is essential to investigate the generation and propagation mechanism,attenuation law and dynamic response characteristics of buildings in the process of tunnel blasting construction and the corresponding control measures of blasting vibration are put forward to minimize blasting vibration damage.To investigate the effect of blast-induced vibration from the tunnel on the adjacent buildings,field tests and numerical simulations method were adopted to study the vibration characteristics of the existing buildings,for the Hudong Road tunnel project as a case study.The following conclusions are drawn:(1)This paper based on the least square method,the field monitoring data of blasting vibration are analyzed by regression analysis.It is show that the vertical vibration velocity of each part of the building is more regular,the vertical vibration velocity of the building measured point caused by blasting is larger than its horizontal and longitudinal vibration velocity,the vertical vibration velocity has elevation amplification effect along the floor,and the horizontal and radial elevation amplification effect is not obvious.The main frequency of vertical vibration is mainly between 25～35Hz,which is closer to the natural frequency of structure than that of horizontal and longitudinal vibration.(2)Based on ANSYS/LS-DYNA finite element software,an elastic-plastic model is established to analyze the structure comprehensively.It is show that the velocity of measuring points and the main frequency are different as the height of the measuring point in the building increases,and the effect of building elevation amplification is more obvious than the field monitoring data.It is also show that the higher the surrounding rock grade the stronger vibration response of the building.(3)As the blasting vibration waves propagates upward inside the building,part of the strain energy is converted into kinetic energy,and the shear stress of the building column decreases gradually as the height of the measuring point in the building increases,and the vibration velocity accords with the elevation amplification effect.Meanwhile,the shear stress of the floor slab is smaller than that of the column,which decreases first and then increases along the length direction of the floor slab.(4)Using the grey correlation theory to sort the influencing factors of blasting vibration.Based on the order of factors’ importance,the corresponding control measures of blasting vibration are put forward to reduce the damage of blasting vibration.