为探究隧道穿越第三系半成岩富水段时引发的涌水突泥、冒顶等地质灾害机制，依托云南临清高速公路王家寨隧道，通过室内力学试验和模糊层次分析法，对第三系半成岩力学特性、作用机制及涌水突泥灾害风险进行分析。研究表明： 1）王家寨隧道第三系半成岩遇水软化特性明显，随着含水率增加其黏聚力先增后减，内摩擦角不断减小，含水率为18%时黏聚力与内摩擦角分别为12.53 kPa和7.35°，围岩逐渐失稳。2）软弱的第三系半成岩、高地下水量及隧道开挖扰动为王家寨隧道第三系半成岩富水段发生涌水突泥灾害的主要影响因素。3）王家寨隧道第三系半成岩段可按工程地质条件、水文地质条件划分为A、B、C、D 4段，各段涌水突泥灾害风险由大到小排序为B段=C段>A段>D段，其中评估的A段涌泥量与实际涌泥量较为吻合。

To investigate the mechanisms of water and mud inrush and roof collapse when tunneling through water-rich tertiary semi-diagenetic strata, a case study is conducted on Wangjiazhai tunnel of the Linze-Qingshui highway in Yunnan, China, and the mechanical properties, action mechanisms, and water inrush risk of tertiary semi-diagenetic strata are examined through indoor mechanical tests and fuzzy analytic hierarchy process. The results reveal the following: (1) The tertiary semi-diagenetic strata in the Wangjiazhai tunnel significantly soften upon water exposure, with cohesion initially increasing and then decreasing as water content rises, while the internal friction angle continuously decreases. At 18% water content, cohesion and internal friction angle are 12.53 kPa and 7.53°, respectively, indicating rock mass destabilization. (2) Weak tertiary semi-diagenetic strata, high groundwater level, and tunnel excavation disturbance are the primary factors influencing water and mud inrush disasters in the Wangjiazhai tunnel. (3) The tertiary semi-diagenetic strata section of the tunnel can be divided into four parts (A, B, C, and D) based on engineering geological and hydrogeological conditions, with disaster risks ranked as B=C>A>D. The estimated mud inrush volume in section A closely matches the actual disaster situation.