京沈客专朝阳隧道下穿既有锦赤铁路桥梁施工安全性数值分析

A Numerical Analysis of Construction Safety of Chaoyang Tunnel under Existing Railway Bridge on Beijing-Shenyang High Speed Railway

结合新建京沈客运专线朝阳隧道下穿既有锦赤铁路霍家特大桥的工程实例,利用有限元数值模拟软件分析新建隧道矿山法开挖对既有桥梁变形和位移的影响,计算分析结果表明:隧道下穿4号和5号桥墩施工过程中,土体及桥墩结构发生较大的变形。通过采取隔离防护、注浆堵水、超前支护等一系列措施后,隧道各开挖步骤产生的位移均小于5 mm的预警值,说明施工中所采取的工程措施是可行的,为实际施工提供理论依据和经验借鉴。

Based on the engineering project of the Chaoyang tunnel on the newly-built Beijing-Shenyang dedicated passenger line passing under the existing Huojia extra-long bridge on Jinzhou-Chifeng Railway,the influence of excavation with new tunnel mining method on the deformation and displacement of the existing bridge is analyzed by finite element numerical simulation software. The results of calculation and analysis show that during the construction of the tunnel passing under No.4 and No.5 piers,the soil and the pier structure are greatly deformed. By taking a series of measures such as isolation protection,grouting and water shutoff,and advanced support,the displacements caused subsequently following tunnel excavation step are less than 5 mm of the early warning value. This indicates that the engineering measures taken in the construction are feasible and could provide theoretical basis and experience for practical construction.