考虑初期支护作用的引水隧洞衬砌结构配筋计算

Reinforcement Optimization of Diversion Tunnel Lining Structure Considering the Effect of Initial Support

我国水工高压隧洞设计规范中并未考虑围岩和初期支护的承载作用,往往使得最终的配筋量偏大,造成了不必要的浪费,并增加了施工难度。为此,结合某水电站引水隧洞,利用数值分析方法,模拟了隧洞施工全过程和初期支护的作用效果,分析了施加初期支护和不施加初期支护情况下的围岩稳定性,根据数值计算成果进行了衬砌结构配筋,并开展了裂缝开展宽度的复核。结果表明,初期支护可以明显提高围岩自身承载能力,可相应减小衬砌结构配筋量。

The design specification for hydraulic high-pressure tunnel in China do not consider the bearing effect of surrounding rock and initial support,which often makes the final reinforcement amount too large,causing unnecessary waste and increasing construction difficulty.For this reason,combined with the diversion tunnel of a hydropower station,the numerical analysis method is used to simulate the whole process of tunnel construction and the effect of initial support,and the stability of surrounding rock under the conditions of initial support and no initial support are analyzed respectively.Based on the results of numerical calculation,the reinforcement of lining structure is carried out.The crack development width is also reviewed.The results show that the initial support can significantly improve the bearing capacity of the surrounding rock itself,and can correspondingly reduce the reinforcement of lining structure.