引水隧洞二衬刚度与施作时机优选及系统构建

二次衬砌结构刚度与施作时机优选是隧洞工程中关键问题之一,对于引水隧洞穿越软弱流变围岩洞段则尤为突出。为研究引水隧洞开挖过程中时空效应耦合作用对二衬优选的影响,基于现场围岩和支护结构实测应力变形数据,采用三维粘弹塑性有限元方法,结合开挖和支护设计实际工况考虑二次衬砌施作距掌子面不同距离和不同二衬刚度(厚度),分析了围岩变形、二衬内力及变形的变化规律。结果表明,二衬刚度对二衬时机的优选影响不大,围岩应力的释放及围岩变形为二衬时机优选的关键因素,最后针对设计和施工人员开发了二衬支护结构优选系统。研究成果和优选系统可为类似隧洞工程施工和设计提供参考依据。

Optimization of Stiffness and Supporting Time of Secondary Lining and Analysis Platform Construction for Diversion Tunnel

Optimization of stiffness and supporting time of secondary lining is one of the key problems in tunnel engineering,especially for the large span passing through the rheological rock.In order to study the space-time coupling effect on secondary lining optimization during large span tunnel excavation,based on the stress and deformation monitoring data of on-site surrounding rock and support structure,3Dvisco-elastoplastic finite element method was adopted to analyze the deformation of surrounding rock and internal force and deformation of secondary lining by combining with the actual conditions of excavation and support design considering different distance between secondary lining and tunnel face and different secondary lining stiffness(thickness).The results show that the rigidity of the second lining has little impact on the optimization of the second lining time,and the stress release and deformation of the surrounding rock are the key factors for the optimization of the second lining time.Finally,the secondary lining optimization system was developed for the designers and constructors.The research results and optimization system can provide reference for similar tunnel construction and design.