基于模型试验与FEM的TBM圆形隧道压力拱成拱规律

Formation law of pressure arch of circular TBM tunnel based on model test and FEM

不同于软土盾构隧道,TBM隧道多用于岩体条件下隧道的挖掘,传统土力学方法不适用于TBM隧道的荷载计算。在岩石隧道中,荷载的产生与压力拱的形成息息相关,通过对TBM圆形岩石隧道的压力拱分析来确定荷载大小及围岩开挖影响区。通过对围岩开挖后应力变化的理论分析与简化,得到便于使用、结果直观的岩石隧道压力拱范围的判别方法。随后采用大型模型试验,对隧道开挖的塌方情况以及洞周应力变化情况分析,以验证该方法的合理性。最后,将该方法用于TBM圆形岩石隧道中,与各规范计算结果进行对比分析,并对不同埋深下TBM圆形隧道的压力拱区域进行分析,得到盾构隧道压力拱成拱情况以及其对衬砌受力情况的分析结果,以指导工程。

Being different from the shield tunnel in soft soil,TBM tunnel is mostly used in rock tunnel. Therefore,the traditional load calculation method in soil mechanical does not apply to TBM tunnel. In the rock tunnel,the load is closely related to pressure arch,the load and excavation influence area can be determined through the analysis of pressure arch of circular TBM tunnel. In this paper,a visual and handy method for distinguishing the scope of pressure arch was obtained by analyzing and simplifying the stress changes of surrounding rock theoretically. Then a large scale model test was conducted to analyze the collapse and variation of stresses caused by the excavation,which can verify the rationality of the method mentioned above. Finally,the method was used in circular TBM tunnel and compared with results calculated by the different codes. The pressure arch of circular TBM tunnel in different depth was analyzed then the mechanism and the impact on lining of pressure arch were got to guide the engineering.