铁路膨胀岩隧道初期支护稳定性分析及设计优化

Stability Analysis and Design Optimization for Preliminary Support of Railway Swelling Rock Tunnel

通过对国内外学者研究成果的归纳总结,结合隧道工程特点,提出一种膨胀岩综合分级标准。以玉(溪)蒙(自)铁路秀山隧道为工程背景,采用ANSYS软件分析中、强膨胀级别下膨胀力对初期支护的影响规律。结果表明:原设计中等膨胀工况膨胀范围为4 m时最小加固范围为6 m,强膨胀工况加固范围太大,常规注浆工艺较难实现;隧道断面优化后中等膨胀工况膨胀范围为4 m时最小加固范围为2 m,强膨胀工况膨胀范围为3 m时最小加固范围为4 m;随膨胀级别升高,初期支护仰拱底鼓和边墙收敛量增加;优化后由于加固范围减小,初期支护变形量增大。

Through summarizing the domestic and foreign scholars＇ research results and combining with the characteristics of tunnel engineering, a comprehensive classification standard for swelling rock was presented. The influence law of swelling force on preliminary support under medium and strong swelling level was analyzed by taking the Xiushan tunnel of Yuxi-Mengzi railway as the engineering background and using ANSYS software. The results show that minimum reinforcement range is 6 m in medium swelling condition where swelling range is 4 m and reinforcement range is too large for strong swelling condition in the original design for implementation of conventional grouting technology. The minimum reinforcement range is 2 m in medium swelling condition where swelling range is 4 m and the minimum reinforcement range is 4 m in strong swelling condition where swelling range is 3 m after tunnel section optimization. The invert floor heave and sidewall convergence of preliminary support increase with swelling level increasing, and the preliminary support deformation increases due to the reinforcement range decreasing after optimization.