软弱围岩隧道台阶法施工喷射混凝土早期强度控制研究

Tunnel Stepping Construction Methods-Shotcrete Early Strength Control

为合理地控制隧道开挖后引起的围岩变形不超过预留变形量,对隧道初期支护早期刚度有一定要求。而初期支护结构早期刚度的增长取决于喷射混凝土早期强度的增长,因此需要合理地设计喷射混凝土早期强度。依托浩吉铁路崤山隧道工程,采用MIDAS有限元分析软件,通过模拟初支结构不同的刚度增长趋势,找出围岩变形接近预留变形量时初支结构的刚度增长规律,然后换算得出喷射混凝土早期强度的增长指标,为施工现场合理配制混凝土提供方法和依据。

In order to reasonably control the deformation of surrounding rock caused by tunnel excavation within the deformation thresholds,there are certain requirements on the early stiffness of the initial tunnel support structure.The increase of the early stiffness of the initial support structure depends on the increase of the early strength of shotcrete,so it is necessary to design the early strength of shotcrete reasonably.By leveraging the Gushan tunnel project of Haolebaoji-Ji'an Raiway railway,Midas finite element analysis software is used to simulate the different stiffness growth trend of the primary support structure,find out the stiffness growth rule when the surrounding rock deformation is close to the limit,and then the results are converted to get the growth index of the early strength of shotcrete,so as to provide a method and basis for the reasonable preparation of concrete at the construction site.