大丽铁路碎裂玄武岩夹凝灰岩型隧道特征及施工对策

Characteristics of Fractured Tuff in Basalt Tunnel of Dali-Lijiang and Its Construction Countermeasures

研究目的:玄武岩夹凝灰岩型隧道工程条件具不确定性,现有勘察手段难以查明凝灰岩确切分布位置,给隧道施工带来较大困难,有必要研究该类围岩特性及隧道施工对策。研究方法:通过研究隧道开挖揭示的凝灰岩的物理性能及其与玄武岩的各种组合关系,结合超前地质预报,分析各种工况的支护体系。研究结果:针对玄武岩夹凝灰岩的结构特性,提出了玄武岩与凝灰岩不同组合关系的各类围岩级别下7种工况的支护体系和衬砌结构。研究结论:工程实践表明,碎裂玄武岩与凝灰岩不同组合情况的工程措施合理,根据施工信息反馈及时动态调整,效果良好。

Research purposes： There exists uncertainty in the engineering conditions of tunnel with basalt intercalated with the tuff. Adopting the current prospecting method is hard to make clear the exact distribution position of the tuff. This brings the greater difficulty to tunnel construction, so it is necessary to do the research on the characteristics of this kind of surrounding rock and the countermeasures for tunnel construction.Research methods ： By means of researching the physical properties of tuff and all kind of basalt combination relation to the tunnel excavation, and in combination with the geological predicting ahead of the working face, the various support systems for construction are analyzed. Research results：According to the structural characteristics of the tuff in fractured basalt, seven support systems for construction and tunnel lining structure of different combination relations to basalt and tuff under all kinds of surrounding rock class are presented.Research conclusions：The construction practice indicates that the construction measures for the different combination states of the fractured basalt and tuff are reasonable, and the effect of the timely dynamic adjustment based on the construction information feedback is favorable.