隧道穿越沟谷浅埋地段的施工方法探讨

Discussion on Construction Method for Tunnel Crossing Shallow Buried Section of Valley

通过总结和比较明挖法、盖挖法及浅埋暗挖法在浅埋地形下的适用性,结合沟谷地形特征和地质情况,提出隧道在穿越沟谷浅埋段时应分区设计施工方案,并对过渡段在施工及支护方面的差异进行分析和对策探讨。结果表明:以超浅埋界限深度和浅埋界限深度作为U、V形沟谷施工方法选取的界限是切实可行的;采用设置变形缝或预留变形量的措施能有效消除结构间刚度差异;桩长渐变是结构基础埋深差异过渡的可行方案。

By summarizing and comparing the applicability of the excavation method, the digging method and the shallow burial method in shallow buried terrain, combined with the terrain features and geological conditions of the valley, it was proposed that zoning design and construction should be applied when the tunnel crosses the shallow buried section of valleys. And the differences in construction and support of the transition section and the countermeasures were analyzed. The results show that it is feasible to set the boundaries for U and V-shaped valleys as the boundaries of ultra-shallow buried depth and shallow buried depth. The use of measures to set the deformation joints or reserve an amount of deformation can effectively eliminate the difference in stiffness between structures; gradient pile length is a feasible solution for structural transition.