吕梁山特长隧道土质浅埋偏压段支护结构受力有限元模拟分析

Finite Element Simulation Analysis of Force of Supporting Structure of Soil Shallow Bias Section of Lüliang Mountain Extra-long Tunnel

目前复合式衬砌隧道的设计参数仍以工程类比法为主,虽然现行公路隧道设计规范对各级围岩的支护结构设计参数有着明确的取值范围,但由于工程地质和水文地质情况千差万别,这种依据规范取值的局限性是非常明显的。隧道进、出口段特别是存在偏压、浅埋、强风化、岩堆等特殊地质情况时,隧道规范并没有具体要求。设计人员往往采用工程类比法,借鉴以往成功案例,采用支护参数,存在安全系数不足或参数过于保守的情况。采用Midas GTS NX有限元分析软件对工程类比法拟定的支护参数进行验算,为隧道支护参数的合理选取提供参考。

At present, the engineering analogy method is mainly used for designing parameters of composite lining tunnel. Although the current highway tunnel design norm has a clear range of design parameters of supporting structure of all levels of surrounding rock, it has obvious limitations, because the engineering geology and hydrogeology are very different. There are no specific requirements for special geological conditions such as bias, shallow burial, strong weathering and rock pile in the entrance and exit section of the tunnel, so designers often adopt engineering analogy method, and use supporting parameters referring to previous successful cases,which have insufficient safety factor or too conservative parameters. This paper used the Midas GTS NX finite element analysis software to check and calculate the supporting parameters drawn up by engineering analogy method, and it provides reference for reasonable selection of tunnel supporting parameters.