下穿铁路隧道爆破施工动力响应研究

Study on Dynamic Response of undercrossing Railway Tunnel in Blasting Construction

针对新建公路隧道爆破施工下穿既有铁路隧道时,引起既有铁路隧道动力响应问题。运用有限元数值软件模拟分析了下穿公路隧道与既有铁路隧道中心位置不同时,既有铁路隧道的动力响应规律。研究结果表明:爆破施工至铁路隧道正下方中心时,既有铁路隧道底部最大振动速度为5.97 cm/s,小于规范允许值6.00 cm/s,数值模拟结果符合现场振动监测数据值;对既有铁路隧道的变形影响,从公路隧道开挖至近侧、中心、远侧、贯通,四个阶段最大变形值为4.86 mm,未超过规范允许值10.00 mm。

Blasting construction of new highway tunnel incurred dynamic response of existing undercrossing railway tunnel.When the central positions of the undercrossing highway and railway tunnels were different,the law of this dynamic response was analyzed with finite element numerical simulation software.The result shows that,when the blasting construction goes to the center right below the existing railway tunnel,the maximum vibration speed at the tunnel bottom is 5.97 cm/s and less than the allowable value of 6.00 cm/s in the standard,and the result of numerical simulation is consistent with the field vibration monitoring data;for the effects on the deformation of existing railway tunnel,the maximum deformation value in 4 stages when the highway tunnel is excavated to the near side,the center,the distant side and breakthrough,is 4.86 mm and not more than the allowable value of 10.00 mm.