基于“接触摩擦-梁-接头”模型的矿山法隧道预制拼装二次衬砌分块方法研究

Study on the Partitioning Method for Prefabricated Secondary Lining in Conventional Tunnelling Based on the"Contact Friction-Beam-Joint"Model

为分析矿山法隧道复合式衬砌中预制拼装二次衬砌的分块方式和承载特性,根据荷载与结构模型的分析方法,建立考虑衬砌间相互作用的“接触摩擦-梁-接头”复合式衬砌的计算模型,并考虑围岩对初期支护的法向和切向约束作用,分析矿山法隧道复合式衬砌中初期支护与二次衬砌之间的接触压力以及二次衬砌的内力,并讨论预制拼装二次衬砌的6种分块方案及预制块接头的位置和接头抗弯刚度对二次衬砌内力的影响。研究结果表明:接触刚度对层间接触压力影响较大,最大接触压力均位于隧道衬砌拱脚部位,建议接触刚度系数在接触压力稳定段取值;二次衬砌预制块接头位置对二次衬砌的弯矩影响较大,但对其轴力影响较小;当接头抗弯刚度介于0~100 MN·m·rad^(-1)之间时对衬砌间的接触压力、内力和变形产生的影响最大,建议预制拼装二次衬砌的接头抗弯刚度的取值介于50~400 MN·m·rad^(-1)之间。

In order to analyze the partitioning method and load-bearing characteristics of the prefabricated secondary lining in the composite lining of conventional tunnelling,the"contact friction-beam-joint"composite lining calculation model that takes account of the interaction between linings has been created by using the load-structure model analysis method.With consideration of the normal and tangential constraints on the initial support imposed by the surrounding rock,the contact pressure between the initial support and secondary lining in the composite lining of conventional tunnelling and the internal force of secondary lining have been analyzed.The 6 partitioning methods for prefabricated secondary lining,and the effects of the position of prefabricated block joints and the flexural rigidity of joints on the internal force of secondary lining are also investigated here.As the study results indicate:contact rigidity has major impact on the inter-layer contact pressure,and the maximum contact pressure always occurs at the arch springing of tunnel lining,so it is recommended that the contact rigidity coefficient is selected within the stable range of the contact pressure.The position of prefabricated block joints of secondary lining has major impact on the bending moment of secondary lining but minor impact on its axial force.If the flexural rigidity of joints is in the range of 0~100 MN·m·rad^(-1),the joints impose the greatest impact on the contact pressure,internal force and deformation of the lining,so it is recommended that the flexural rigidity value of the joints of prefabricated secondary lining is kept in the range of 50~400 MN·m·rad^(-1).