大瑞铁路老红坡隧道穿越接触带单侧涌泥处理技术

大瑞铁路老红坡隧道穿越可溶岩与非可溶岩接触带施工单侧发生涌泥大变形地质灾害。通过分析变形开裂及地质成因，正洞内采用迂回导坑方案探明涌泥体范围，采用洞内扩挖工作洞室，在隧道单侧轮廓外施作超前水平注浆+高压水平旋喷桩加固及超前水平长大管棚的方案进行处理，并对该段支护及衬砌结构调整加强。依据现场工况，采用三台阶法分部、分段拆换作业，在钢架拱脚增设临时仰拱或临时横撑控制收敛变形，及时施作格栅钢架模筑衬砌，变形稳定后再施作永久二次衬砌。该技术在大瑞铁路老红坡隧道单侧突泥涌水地质灾害处治施工实践中得到了成功应用，取得了良好效果。

Treatment Technology for Mud Gushing from One Side of Laohongpo Tunnel Crossing Contact Zone of Dali Ruili Railway

The mud gushing and large deformation occurred to Laohongpo tunnel of Dali Ruili railway when crossing contact zone between soluble rock and non soluble rock. According, the deformation, cracking and geological causes are analyzed, the mud gushing scope in main tunnel is explored by using bypass heading, the working chamber in tunnel is enlarged, treatment method of advanced horizontal grouting + high pressure horizontal jet grouting pile and advanced horizontal large pipe roof is adopted, and the support and lining structure are adjusted and strengthened. According to the site working conditions, the three bench method is adopted to separate and replace the steel frame in sections. The temporary invert or temporary cross brace is added at the arch foot of the steel frame to control the convergence deformation. The grid steel frame formwork lining is constructed in time, and the permanent secondary lining is constructed after the deformation becomes stable. The technology mentioned has been successfully applied to the construction practice in Laohongpo tunnel of Dali Ruili railway, and good results have been achieved.