寒区隧道衬砌结构设计方法

在寒区冬冻夏融周期变化的环境下,冻害问题常影响到隧道结构及运营安全。为提高寒区隧道设计水平,节约工程建设成本,同时保证隧道安全正常运营,本文提出了新的寒区隧道衬砌结构设计思路:在提出寒区隧道衬砌设计流程的基础上,给出了不同冻土段衬砌结构选型的建议:冻岩隧道可采用三层复合式衬砌结构,工程冻土段隧道可采用柔性支护体系的复合式衬砌;系统总结了多年冻土段和工程冻土段的冻胀力控制措施;从结构设计角度,分析了铺设保温层的必要性取决于:冻胀力的量值和衬砌结构的耐久性;最后将提出的寒区隧道衬砌结构设计方法应用于实际工程,定量评估了姜路岭隧道围岩冻胀力控制措施的效果,且目前隧道现场科研监测未测到冻胀力;根据本文研究成果,优化了白茫雪山1号隧道衬砌结构的设计,考虑到保温层铺设成本较高且延缓了施工速度,调整了衬砌保温结构设计,减少保温层铺设长度3 810 m。

Design Method of Tunnel Lining Structure in Cold Region

Tunnel structure and their operation safety is usually affected by frost damage problem caused by cyclic freezing and thawing in cold region.To improve the designing level of cold region tunnel lining structure,and save the cost of engineering construction,meanwhile,ensure tunnels to operate normally and safely,a new idea of cold region tunnel lining structure design was proposed.On the basis of given cold regions tunnel lining design process,suggestions of selection of the lining structure for different classifications of frozen soil were proposed:three-layers composite lining structure could be adopted in frozen rock tunnel,and flexible composite supporting system could be adopted in engineering caused frozen section tunnel;The controlling measures of frost heave force in permafrost region and engineering caused frozen section were summarized systematically;from the view of structure design,the value of frost heave force and the durability of lining structure decided the necessity of insulation layer.Finally,the method of tunnel lining structure design was applied in practical engineering,and the effect of heave force controlling measures was quantitatively evaluated in Jiangluling Tunnel,monitoring showed that there was no heave force in it;The lining structure design of Baimang snow mountain tunnel # 1 was optimized by the method proposed in this paper,and in consideration of the high construction cost and slow speed of insulation layer construction,the lining insulation structure design was adjusted,insulation layer laying length was reduced by 3810m in detail.