The geological environment of underground engineering is complex and full of various uncertainties, and ensuring the reliability of tunnel surrounding rock rating results is crucial for projects. In this study, we first analyze the interrelationships and indicator weights of international mainstream rating methods of tunnel surrounding rock, and summarize the applicability of each method. Next, based on dialectical materialism, we propose that the uncertainties can be divided into multiple levels. Then we analyze the probability distribution law of rating indicators such as rock strength and rock integrity, introduce and use the theory of system reliability analysis, and build functions for the surrounding rocks of different classes. Finally we calculate the reliability probability of surrounding rock rating using Monte Carlo method. The study results indicate that, in view of the uncertainty of surrounding rock rating, the proposed approach fully considers the information of each rating method, and also the data dispersion of local fractured zones, weak interlayers and other tunnel face surrounding rock. Moreover, based on the parameters summary, the proposed approach is proved to be applicable to the current rock mass, and thus makes it possible to evaluate the reliability probability of the tunnel surrounding rock rating. This study helps site personnel to assess surrounding rock rating results more conveniently and accurately, and provides precise guidance for reasonably determining the construction method transition interval and optimizing support parameters.

地下工程地质环境复杂，充满各种不确定性，保证隧道围岩评级结果的可靠性对于工程至关重要。本研究首先分析了国际主流隧道围岩评级方法的相互关系和指标权重，总结了各方法的适用性。接下来，基于辩证唯物主义，我们提出不确定性可以分为多个层次。然后分析了岩石强度、岩石完整性等评级指标的概率分布规律，引入并运用系统可靠度分析理论，针对不同类别的围岩建立了函数。最后利用蒙特卡罗方法计算了围岩评级的可靠概率。研究结果表明，针对围岩评级的不确定性，该方法充分考虑了各评级方法的信息，同时也考虑了局部破碎带、软弱夹层等隧道掌子面围岩的数据分散性。此外，基于参数总结，证明该方法适用于当前岩体，从而使评估隧道围岩等级的可靠概率成为可能。该研究有助于现场人员更加方便、准确地评估围岩评级结果，为合理确定工法过渡区间、优化支护参数提供精准指导。