深埋隧道TBM卡机机理及控制措施研究

TBM jamming mechanism and control measures in deep buried tunnels

当前TBM在中国应用越来越广泛,然而TBM在深埋软弱岩石隧洞中施工时,很容易发生护盾被卡事故,造成严重后果,因此对其卡机机理及控制措施研究很有必要。首先,基于Hoek-Brown准则圆形隧道围岩流变变形研究成果,考虑管片衬砌支护和掌子面效应,提出了护盾区域围岩变形计算模型;其次,根据上述变形计算模型和围岩、护盾变形协调条件,建立了停机和连续掘进两种工况下卡机状态判断模型,两种模型均考虑了围岩流变效应;再次,在卡机机理研究成果基础上,进行了卡机控制措施的研究。推导了临界预留变形计算公式;同时提出了预留变形和超前支护相结合时临界超前支护强度的计算模型;最后,将卡机判据和临界预留变形量及超前支护强度理论在工程算例中进行了应用。

TBM is widely used in China at present. However, when it is driven in deep buried weak rock tunnels, shield is probably jammed and serious consequences may occur, so it is necessary to study shield jamming mechanism and control measures. Firstly, according to the research results of rheological deformation of the surrounding rock of circular tunnels based on the Hoek-Brown criterion and taking segment lining and tunnel face effects into account, a model for calculating the deformation of the surrounding rock in shield area is established. Secondly, the relevant models for judging jamming state during downtime and continuous excavating conditions are proposed based on the above deformation model and coordinating conditions between the surrounding rock and the shield. Moreover, the rheological effects are taken into consideration in two judged models. Thirdly, control measures for jamming are studied based on the research results of jamming mechanism. The formulae for calculating the critical over-excavation amount are deduced; meanwhile, the models for calculating the critical forepoling strength are also deduced when the over-excavation and forepoling measures are used together. Finally, the above proposed models are applied in an engineering example.