基于Burgers蠕变模型的圆形隧道内力分析方法对比研究

以高黎贡山TBM施工的特定段圆形隧道为工程对象,基于围岩蠕变的Burgers模型,提出了隧道衬砌内力计算的地层结构分析法和荷载结构分析法,对比研究两种分析方法的异同点和特点,得出以下结论:(1)地层结构分析法能模拟地层自重应力及其重分布、隧道开挖和支护效应,并能通过蠕变的非线性迭代获得隧道衬砌内力结果,在隧道开挖后围岩蠕变的整个过程中,模拟精度较高,但计算耗时稍长;(2)荷载结构分析法不能考虑地层自重应力以及隧道开挖支护效应,建模相对简单,计算耗时短,但计算前需准备等效节点荷载,对蠕变早期的模拟精度相对较差,对蠕变中后期的模拟结果与地层结构分析法较为一致;(3)综合考虑各种因素,建议围岩蠕变下的隧道衬砌内力分析优先选用地层结构分析法。

Comparative Study on Internal Force Analysis Methods of Circular Tunnel based on Burgers Creep Model

In view of the circular tunnel of Gaoligong Mountain constructed with TBM,stratum structure analysis method and load structure analysis method are conducted to calculate the internal force of tunnel lining based on the Burgers model of rock creep. Based on the similarities and differences of the two methods,conclusions are as follows:( 1) the stratum structure analysis method can simulate geostatic stress of the formation and its redistribution,effect of tunnel excavation and support,the internal force of tunnel lining can be obtained by nonlinear iteration of creep,the simulation accuracy is higher in the whole process of rock creep after tunnel excavation,but the calculation time is slightly longer;( 2) the load structure analysis method fails to take into account of the geostatic stress of the formation and the effect of tunnel excavation and support,the modeling is relatively simple and the computation time is short,but the equivalent nodal load needs to be prepared before calculation,the simulation precision is relatively low in the early stage of creep,and the simulation results in the mid-late stages of creep are consistent with that of the stratum structure analysis method;( 3) based on various factors,the stratum structure analysis method is prioritized for the analysis of internal force of tunnel lining subject to rock creep.