为研究隧道中衬砌减薄缺陷对结构力学行为特征的影响,以重庆市在建的笔架山隧道为现场原型,对不同围岩级别条件下衬砌减薄引发的结构形变、病害、承载力等特征及合理补强方式进行研究,获得如下结论:不同围岩级别条件下,无论衬砌(拱顶)有无减薄,结构产生病害所对应的荷载基本相同,但结构的变形及破坏模式、病害的先后次序将随着拱顶减薄程度的不同而迥异.围岩条件越差,衬砌减薄带来的病害程度越严重.结构产生病害时所对应的荷载随围岩级别的提高而提高,当空洞回填其影响消失后,拱顶衬砌厚度减薄的多少将成为影响结构承载力提高的直接原因,不同围岩级别条件下衬砌减薄对结构受力分布规律的影响性较小,内表面补强方案应成为衬砌减薄维护加固的首选方案.本文研究结果可为运营隧道维修加固提供参考.%In order to study the influence of the thickness decrease of lining on the characteristics of tunnel structure mechanics behavior, the under-construction Bijia Mountain Tunnel of the Chongqing Municipality was taken as an in-situ prototype. Structure deformations, diseases, bearing capacity and other features caused by thickness decrease of lining under the conditions of different grades of surrounding rock and reinforcing modes were investigaled. Conclusions show as below-.Under the conditions of different grades of surrounding rock,no matter whether the thickness of vault lining is decreased or not,the loads where diseases happen are basically the same,hawever,structure deformations,failure modes and precedence of diseases vary significantly with different degrees of thickness decrease;the poorer the surrounding rock conditions,the severer the diseases caused by decrease of lining thickness;loads corresponding to occurrence of structure diseases rise with heightening of surrounding rock grades;after the influence of cavity backfilling disappears,the magnitude of thickness decrease of vault lining becomes the direct reason of increase of structure bearing capacity;the thickness decrease of lining has small influence on the distribution law of structure stresses under conditions of different grades of surrounding rock; reinforcing the internal surface of lining should be the first alternative to reinforce lining with thickness decreasing. The research results provide guidance for maintaining and reinforcing of tunnels in operation.
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