寒区隧道冻胀力模型试验及围岩注浆效果研究

为了研究寒区隧道衬砌背后积水位置不同时结构的受力变化规律和破坏形式,进行冻胀力的室内模型试验。模型试验采用不同水囊大小和分布位置来模拟衬砌背后积水情况,通过模型试验箱外界环境整体降温和隧道底部局部降温的方式,模拟隧道外界的低温环境。试验结果表明:衬砌背后冻胀力在拱顶处较小,在边墙和拱脚处较大;在相同的冻胀压力作用下,拱顶处更容易破坏。最后采用数值计算,对比分析围岩注浆前后3种试验工况下隧道衬砌结构的可靠度。结果表明:仅靠提高衬砌结构的厚度和强度来预防或消除衬砌结构冻害的方法是不可取的,在富水区的寒区隧道采用围岩注浆加固具有较好的效果。

Frost-heaving Force Model Tests of Tunnel in Cold Region and Study on Grouting Effect on Surrounding Rock

In order to study the force variation law and the failure mode of tunnel lining in cold regionwhere the ponding positions behind the lining are different, indoor model tests on frost-heaving force arecarried out. The ponding behind the lining issimulated with different water bag sizes anddistribution positions, and the low temperatureenvironment of tunnel is simulated with overallcooling of the external environment of the model test box and the local cooling at the bottom of the tunnel. Test results show that the frost-heaving forcebehind the lining is smaller in tunnel vault but greater in side wall and arch foot; the tunnel vault underthe same frost-heaving force is likely to be destroyed. Finally, the reliabilities of the tunnel lining underthree test conditions are compared and analyzed with numerical calculation. The results show thatincreasing the thickness and strength of the lining to prevent or eliminate frost damage of the lining is notapplicable, while, the grouting reinforcement of surrounding rock proves effective for tunnels in coldregion.