既有公路山岭隧道扩建技术及数值模拟研究

依托芜合高速公路试刀山隧道改扩建工程,介绍了改扩建施工方案。通过建立有限元模型模拟开挖过程,分析隧道改扩建过程中围岩的变形,扩挖完成后的拱顶沉降、周边位移的特征,初支的应力变化规律。结果表明,隧道扩挖完成后最大竖向位移12.7mm,初期支护最大弯矩116.2kN·m,中隔撑的最大弯矩为119.2kN·m;采用加中隔撑的扩挖方案可保证施工安全。隧道扩挖施工后隧道开挖量较大的一侧围岩产生的竖向位移大,初期支护弯矩、轴力、剪力均表现出不对称性,扩挖过程中应及时支护、加强监控量测。

CONSTRUCTION TECHNOLOGY AND FINITE ELEMENT ANALYSIS ON MOUNTAIN HIGHWAY TUNNEL EXPANSION

In this paper,based on expansion of Shidaoshan tunnel of Wuhe Expressway,the expansion construction technology was presented.Numerical simulation was adopted to study the rock deformation,crown settlement and stress of primary support during expansion process.After expansion,the maximum vertical displacement was 12.7mm,the maximum moment of the primary support was 116.2kN · m,the maximum moment of the middle pillared was 119.2kN · m.The results indicated that the expansion method of setting middle pillared can guarantee safety.The vertical displacement of surrounding rock is larger when the amount of tunnel excavation is large.Timely support,intense monitoring and measurement are necessary in the process of expanding excavation.