浅埋偏压、软弱围岩双线隧道大变形施工控制技术

结合浅埋偏压、软弱围岩高枧槽隧道实体工程,介绍了开挖断面大、岩溶发育、地质复杂的隧道产生大变形的情况及分析产生的原因,提出了地表打入钢管桩预加固提高承载力、中台阶钢架间增设纵向托梁与地表钢管桩焊接提高整体受力、设置临时仰拱或横撑、双层拱架支护等措施。通过及时分析围岩和支护变形情况,最终洞内初期支护变形、拱顶下沉、地表开裂等现象得到有效控制。

Great- Deformation-Controlling Construction Techniques for the Dual-Line Tunnel of the Passengers-Oriented Railway in Shallow-Embedded,Biased Weak Surrounding Rock

With the actual project of the Gaojiancao Tunnel in shallow-embedded, biased weak surrounding rock as a practical ex- ample,introduced in the paper is the mergence of great deformation in a geologically complex tunnel, the excavation section of which is large,and the karst of whose stratum is developed,and the formational causes of the deformation are also analyzed, with the technical measures of driving steel tube piles into the ground for pre-reinforcing the bearing capability, providing longitudinal supporting beams between the mid-step steel frames, which are to be welded together with the ground steel tube piles to improve the overall strength, and erecting temporary inverted arches or cross ties and double arch supports, etc. , presented. With all these technical measures adopted, the deformation of the initial supports inside the cave, the settlement of the arch top and the cracking of the ground surface are effectively controlled through the timely analyses of the surrounding rock and the deformation of supports.