基于尖点突变理论的围岩稳定性分析

Analysis on Stability of Surrounding Rock Based on Cusp Catastrophe Theory

针对围岩失稳阈值的不确定性,通过有限元软件模拟隧道开挖过程,基于突变理论研究不同开挖步对应掌子面的变形规律,结合二分法使用曲线拟合法分析围岩失稳阈值,预判围岩失稳时机。结果表明:Ⅳ类围岩隧道宜采用台阶法边开挖边支护施工,拱顶沉降为隧道开挖主要风险控制点;突变理论能够动态把握围岩变形,模拟工况台阶法有支护、无支护、全断面法施工围岩变形突变分别发生在开挖70、56、60m位置。

Aimed at the uncertainties of instability threshold of surrounding rock, the process of tunnel excavation was simulated by finite element software, and the deformation rule of corresponding excavation steps was studied based on catastrophe theory. Combined with the dichotomy method, curve fitting method was applied to analyze the instability threshold of surrounding rock and predict the timing of instability. The results show that the IV type of surrounding rock tunnel should be supported by the step method, while the vault settlement is the main point for risk control of tunnel excavation; the catastrophe theory can dynamically control the deformation of surrounding rock, and the deformation spots are located at 70 m, 56 m, 60 m in the case of support, no support and full-face construction according to the simulation.