分岔隧道过渡段爆破对中隔墙振动响应的数值分析

Numerical Analysis of Vibration Response of Mid-partition by Blasting in Transition Section of Branching-out Tunnel

针对包湾村分岔隧道爆破施工过程进行三维有限元仿真分析,研究中隔墙及中夹岩的振动响应规律.结果表明:沿中隔墙截面方向,各爆源处中隔墙迎爆侧振速与背爆侧振速差值与中隔墙厚度成正比;竖向振速作为主导振速,且同一竖截面上部和下部振速略大于中部振速;单侧隧道未开挖段中隔墙振速较开挖段中隔墙振速会放大1.3倍;大断面向连拱段的过渡施工对中隔墙的影响更大;过渡段爆源处中隔墙竖向最大振速与厚度呈负指数关系,分析得到了分岔隧道连拱段爆破时左右线的危险区域.

Three-dimensional finite element simulation analysis was carried out for the blasting construction process of Baowan Village branchine-out Tunnel,and the vibration response law of mid-partition wall and mid-adjacent rock was studied.The results show that along the cross-section direction of the mid-partition wall,the difference between the vibration velocity of the front side and the back side of the mid-partition wall at each explosion source is proportional to the thickness of the mid-partition wall.The vertical vibration velocity is the dominant vibration velocity,and the upper and lower vibration velocities of the same vertical section are slightly larger than the middle vibration velocity.The vibration velocity of the mid-partition wall in the trenchless section of the unilateral tunnel will be 1.3 times larger than that in the excavated section.The transition construction from large fault to multi-arch section has a greater impact on the mid-partition wall.There is a negative exponential relationship between the vertical maximum vibration velocity and the thickness of the mid-partition wall at the explosion source of the transition section,and the dangerous areas of the left and right lines during the explosion of the multi-arch section of the branching-out tunnel are obtained by analysis.