为从微观角度探究管片接缝密封垫的防水机制，基于Roth模型建立密封垫接触面的泄漏通道模型，推导出泄露率的计算公式；通过建立宏观密封垫数值模型和微观锥型峰数值模型，完成以粗糙度、张开量、错位量和硬度为4个影响因素，以泄露率和平均正压力为评价指标的正交试验。主要结论如下： 1）泄露率可以作为评价密封垫防水性能的一个重要指标； 2）随着粗糙度的增加，泄露率逐渐增大，尤其是当粗糙度大于0.8 μm时，泄露率几乎呈指数型增长，考虑到降低粗糙度会增加工程造价，建议密封垫粗糙度控制在0.4~0.8 μm； 3）粗糙度直接决定了初始泄漏通道的尺寸，因此，相比于硬度、张开量、错位量3个因素，粗糙度对于泄露率的影响最为显著。

To explore the waterproof mechanism of sealing gaskets of segment joint from a microscopic view, the leakage channel model of the contact surface of sealing gaskets is established based on the Roth model to deduce the calculation formula of the leakage rate. Thereafter, the macroscopic sealing gasket numerical and microscopic conical peak numerical models are established to conduct the orthogonal test using the roughness, opening amount, dislocation amount, and hardness as the influencing factors, and the leakage rate and average positive pressure as the evaluation indexes. The main conclusions are drawn as follows: (1) The leakage rate can be used as an important index to evaluate the waterproof performance of sealing gaskets. (2) The leakage rate gradually increases as the roughness increases, and it increases exponentially when the roughness exceeds 0.8 μm. Hence, based on engineering cost, the recommended roughness of sealing gaskets ranges from 0.4 to 0.8 μm. (3) The roughness directly determines the size of the initial leakage channel; therefore, the influence of roughness on the leakage rate is the most significant compared with the effects of hardness, opening amount, and dislocation amount.