木寨岭隧道大变形控制技术

Large Deformation Control Techniques for the Muzhailing Tunnel

对于隧道大变形控制,需综合考虑加固围岩、大刚度支护、适度应力释放、合理工法以及强化建设管理等手段,多措并举。文章以木寨岭特长隧道施工大变形控制为工程实例,总结和分析斜井及正洞施工中不同程度的大变形段落支护结构调整及变形控制理念。结果表明:(1)对于一般大变形段,适当提高隧道支护结构强度和刚度即可有效抑制变形和支护破坏;(2)对于中等大变形段,可进一步提高支护结构强度和刚度,或者辅以径向注浆、加长加密锚杆、局部增设套拱等措施,变形也能得到基本控制;(3)对于严重—极严重变形段,必须采取超前应力释放、长短锚固体系加固围岩、分层施作大刚度支护等综合措施才能有效控制变形,保证施工及结构长期安全稳定。

In light of large tunnel deformation control,it′s necessary to consider reinforcement of surrounding rock,large stiffness support,moderate stress release,reasonable construction method and enhanced construction management and so on.Taking the large deformation control during construction of the Muzhailing extra-long tunnel as an example,an analysis and summarization on support structure adjustment process and deformation control concept during the construction of sections with varying degrees of large deformation in inclined shaft and main tunnel were conducted,with the results showing that:(1)for the general large deformation,appropriate improvement of strength and stiffness of support structure can effectively inhibit deformation and support damage;(2)for the medium large deformation,further improvement of strength and stiffness of support structure are to be taken,or radial grouting,lengthened and more dense anchor bolt and local addition of cover arch are to be adopted to basically control deformation;(3)for the severe to extremely severe deformations,comprehensive measures like advance stress release,long and short anchoring system to strengthen surrounding rock and application of multi-layer large-stiffness support,etc.must be adopted to effectively control deformation and ensure construction safety and long-term stability of the structure.