超大埋深高地应力软岩隧道衬砌设计研究

Study on lining design of super-large buried deep high-stress soft rock tunnel

围岩初始地应力场是隧道工程稳定与支护结构设计所需要的基本因素之一,在超大埋深高地应力软岩隧道衬砌设计过程中,如何合理确定围岩压力并进行衬砌针对性设计参数是工程师关注的重要问题。以某铁路超大埋深高地应力软岩隧道为研究对象,从理论推导和数值模拟两个方面出发对围岩压力进行研究,即基于卡斯特耐尔拓展公式理论推导确定围岩压力和基于ANSYS有限元分析软件进行三维地应力场模拟,研究了不同地应力水平和预留变形量组合下的围岩压力,并对三维地应力场模拟结果进行分析探讨;通过上述方法确定围岩压力后,建立有限元分析模型对高地应力软岩隧道衬砌参数(以Ⅳ级围岩为例)进行设计,检算衬砌参数可靠性并形成成果,可以为类似工程提供参考。

The initial geostress field of surrounding rock is one of the basic factors required for the stability and support structure design of tunnel engineering.How to reasonably determine the surrounding rock pressure and design the lining parameters are important issues that engineers pay attention to in the lining design of super-large buried deep high-stress soft rock tunnel.In this paper,a railway tunnel with super-large buried depth and high geostress in soft rock is taken as the research object,and the surrounding rock pressure is studied from theoretical derivation and numerical simulation—Kastner expansion formula and the three-dimensional geostress field simulation based on the ANSYS finite element analysis software.The surrounding rock pressure under different combination of geostress level and reserved deformation is studied,and the simulation result of three-dimensional geostress field are analyzed and discussed.After the surrounding rock pressure is determined by the above method,the finite element analysis model is established to design the lining parameters of the tunnel in high stress soft rock(taking Class IV surrounding rock as an example),and the reliability of the lining parameters is checked and the result are formed,which can provide reference for similar projects.