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.
highway tunneltertiary semi-diagenetic rockwater and mud inrush mechanismrisk assessmentfuzzy analytic hierarchy process
NETL
NSTL
万方数据
