粤东山区浅埋偏压隧道进洞施工优化研究

Optimization of Shallow-buried Unsymmetrical-loaded Tunnel in Eastern Mountainous Area of Guangdong Province

以粤东山区大潮高速公路浅埋偏压隧道梅岭隧道为背景,开展围岩预加固措施及进洞施工优化研究,并根据实际应用评价优化效果。研究结果表明,在隧址区降雨量充沛和工期紧的特殊条件下,采用“管棚+地表小导管注浆+混凝土反压护拱”的措施能较好地起到围岩超前加固的作用,该加固条件配合“短台阶预留核心土法”进洞施工,施工安全和工期得到了较好的保障。依托工程采用优化方案后,进洞施工总体较为顺利,仅在洞内初期支护上出现轻微裂缝,开展裂缝监测和结构验算后进一步表明,该初支裂缝为浅层的,二次衬砌施工后可确保结构安全。

In this paper,taking the shallow-buried and unsymmetrical-loaded Meiling Tunnel of Dachao Expressway in eastern mountainous area of Guangdong Province as an example,research on optimization of pre-reinforcement measures on rock masses and excavation plan has been carried out,the optimization results have been evaluated.It has shown that,in rainy and tight-scheduled condition,"pipe roof+surface grouting+concrete arch"in accompany with"step excavation with core soil"could strengthen the surrounding rocks,ensure construction safety and conform to the time limit of a project.Structure checking suggests that the minor crack on shoot concrete will be eliminated once the second lining is applied.