复杂层状岩层隧道塌方原因分析与加固后信息化施工技术

关口垭隧道右洞Yk73+955～Yk73+925段在施工过程中出现塌方，从层状岩层分布、偏压和雨水侵蚀作用以及前期地质勘测欠准确等方面分析塌方原因，结合工程具体情况，比较分析超前小导管和长大管棚处理方案的优缺点，选择超前小导管预注浆辅以工字钢处理塌方区，在处理段增设监测断面，通过监测隧道的收敛位移和拱顶下沉量以及钢拱架的内力反映隧道围岩的稳定状况，量测结果表明，在一定时间内围岩达到稳定，表明采用超前小导管预注浆方法处理隧道塌方区效果良好。

Cause analysis of complex layered rock tunnel collapse and information construction technology after consolidation

During Guankouya Tunnel construction, collapse of the section YK73+955-YK73+925 of right tunnel arose. Distribution of layered rock, unsymmetrical pressure, continuous rainstorm and cracked surrounding rock, inaccurate results of geological survey were discussed for reason of tunnel collapse. According to engineering geology and construction condition in-situ, ahead ductile grouting method and long and large tube shed method were analyzed; and ahead ductile grouting method was applied to tunnel surrounding rock consolidation successfully. In order to test consolidation effect, observational method of consolidated tunnel collapse zone was constructed; convergence displacement, vault crown settlement and inner forces of steel frame were measured. It is shown from measured results, ahead ductile grouting method is the optimization method for temporary support requirements against potential collapse.