为预防富水断层带隧道突涌灾害，需要确定隧道突水临界安全厚度。采用数值模拟和工程验证的方法，建立考虑围岩力学和渗流参数、隧道参数和断层带参数的数值模型，并在标准工况基础上进行各因素的多水平数值试验，分析各因素对临界安全厚度的影响规律，基于多元线性回归分析建立多因素预测公式，通过6个工程实例对公式进行验证。研究结果表明： 断层带围岩参数（泊松比、渗透系数和孔隙比）及普通围岩泊松比对临界安全厚度影响较小，水压、埋深、断层带厚度、隧道洞径、断层带围岩弹性模量、普通围岩参数（弹性模量和孔隙比）与临界安全厚度正相关，断层带走向及倾角、普通围岩参数（重度、内摩擦角、黏聚力和孔隙比）和断层带围岩参数（重度、内摩擦角和黏聚力）与临界安全厚度负相关；预测公式与数值模拟结果相差较小，预测公式计算结果与工程实际较符合，具有一定的工程参考价值。

To prevent tunnel in waterrich fault zone from water and mud inrush disaster, the critical safety thickness of tunnel should be determined. A model considering the mechanics and seepage parameters of surrounding rock, tunnel and fault zone parameters is established using the methods of numerical simulation and engineering verification. The multilevel numerical tests of various factors in standard working conditions are performed to analyze the influence of various factors on the critical safety thickness. Multivariate linear regression analysis is used to establish a multifactor prediction formula, and the formula is verified through six engineering examples. The research results show the following. (1) The surrounding rock parameters of waterrich fault zone such as Poisson′s ratio, permeability coefficient, and void ratio and the Poisson′s ratio of ordinary surrounding rock have little inference on the critical safe thickness. (2) The factors such as water pressure, buried depth, thickness of fault zone, tunnel diameter, elastic modulus of the surrounding rock of the fault zone, and ordinary surrounding rock parameters (elastic modulus and void ratio) are positively related to the critical safety thickness of water inrush, whereas the strike and dip of the fault zone, ordinary surrounding rock parameters (severity, internal friction angle, cohesion, and porosity ratio), and the surrounding rock parameters of the fault zone (severity, internal friction angle, and cohesion) are negatively related to the critical safety thickness. (3) The calculation results of prediction formula are more consistent with the results of numerical simulation and the actual project, indicating its effectiveness and guidance value to the project.