为探明初期支护中包裹钢拱架锈蚀对隧道支护体系承载力的影响，考虑锈蚀条件下工字钢与混凝土之间黏结滑移退化关系，将其本构引入ANSYS模拟钢拱架锈蚀状态下隧道支护体系受力变化规律。分析表明： 1）钢拱架锈蚀率小于5%的时候，钢拱架自身、喷射混凝土、初期支护与二次衬砌之间接触压力以及二次衬砌混凝土内力变化较小，受锈蚀率的作用不大。2）钢拱架锈蚀率为5%~55%，支护体系的受力行为及安全性变化很大；当锈蚀率达到55%，工字钢与初期支护混凝土之间的黏结完全失效，钢拱架与初期支护混凝土之间的整体受力功能完全丧失。3）随着钢拱架锈蚀率增加，围岩荷载逐渐向二次衬砌转移，二次衬砌逐渐取代初期支护而成为围岩荷载的主要承担者。
To investigate the corrosion effect of wrapped steel
arch frames in the primary support on the mechanical behaviors of the tunnel
support system, the bondslip degradation relationship
between Ishaped steel and concrete under the corrosion
condition is considered, and its constitutive relationship is introduced into
ANSYS to simulate the force change law of the tunnel support system under the
corrosion condition of steel arch frames. The analytical results show that: (1)
When the corrosion rate of steel arch frame is less than 5%, the internal force
of steel arch frame, sprayed concrete, secondary lining concrete, and the
contact pressure between the primary support and secondary lining change less
and are not affected by the corrosion rate. (2) When the corrosion rate of
steel arch is 5%~55%, the force behavior and safety of the support system
changes greatly. When the corrosion rate reaches 55%, the bond between steel
arch frame and sprayed concrete completely fails and the overall forcebearing function between steel arch frame and primary support
concrete is completely lost. (3) As the corrosion rate of steel arch frame
increases, the surrounding rock load is gradually transferred to the secondary
lining, and the secondary lining gradually replaces the primary support and
becomes the main bearer of the surrounding rock load.
