Study on Impact of Blasting Excavation on Mechanical Properties of Adjacent Tunnel

In order to solve the instability problems caused by the blasting of the adjacent tunnel surrounding rock,the impact of mechanical properties of the adjacent tunnel blasting during the construction process were studied.We take Hongyan River Nuclear Power Plant water tunnel as support projects,using the finite element software PLAXIS3D blasting for tunnel construction process simulation,and analyse stress,deformation,vibration velocity which are produced by the blasting of tunnel wall rock.The concentration phenomenon of tensile stress would be produced on the middle and upper part of the vertical wall directly adjacent to the tunnel wall,the maximum tensile stress value of surrounding rock also appears in this position,the stress concentration was significantly greater than those which is away from the excavating tunnel.The displacement generated by blasting vibration on the side of towards blasting is to be significantly larger than the side of away from blasting,the vertical displacement is much smaller than the horizontal displacement,and the biggest part is the peak value of co-displacements on the upper part of the vertical wall of towards blasting.The vibration velocity caused by blasting in the horizontal direction is much larger than vertical direction,the lowest rate of vibration lies in the dorsal side.Maximum peak rate took place in the upper side of the vertical wall which is the most dangerous place of vibration.According to the stress,displacement and vibration velocity analysis,the connections between the vertical wall of the side of towards blasting and the arch wire are the most dangerous position in the blasting that should be be focused on monitoring.