隧道工程可靠性基本要素统计分析与建议

Statistical analysis and suggestions on basic elements in reliability of tunnel engineering

通过收集与整理203篇隧道工程科研论文和工程案例,对隧道围岩力学参数、荷载参数和支护构件参数的变异系数和概率分布类型以及功能函数设计表达式进行统计分析,结合各行业隧道设计规范的发展现状,从计算变量与功能函数层面指出了当前隧道工程可靠性分析中存在的不足之处,并提出了具体的对策建议.结果表明:支护构件参数的变异性整体小于围岩力学参数和围岩荷载参数、稳定性条件差的围岩变异性大于稳定性条件好的围岩、支护构件几何参数变异性高于材料参数变异性;整理出4种隧道结构可靠性分析功能函数设计表达式,荷载-结构模式下的功能函数主要为结构强度准则,地层结构模式条件下的功能函数则兼有强度准则与变形准则;得出隧道力学参数变异系数的参考值区间及建议概率分布类型,可指导因地勘工作无法进行或者不够全面的条件下隧道工程可靠性分析中的参数取值.

With the collection of 203 papers on tunnel engineering and some engineering cases,the statistical analysis is conducted on the variable coefficient,probability distribution type and design of performance function of the tunnel surrounding rock mechanical parameters,load parameters,and support member parameters.Combined with the development of tunnel design specifications in various industries,the shortcomings in current reliability analysis of tunnel engineering are illustrated from the perspectives of computational variables and performance functions,specific countermeasures are proposed.The results show that:the variability of the parameters of the supporting member is weaker than that of the surrounding rock mechanical parameters and the surrounding rock load parameters,the surrounding rock variability under poor stability condition is greater than that under good stability condition,and the variation of the supporting member geometric parameters is greater than that of supporting member material parameters.The design functions are deducted from the reliability analysis of four types of tunnel structures.In the load-structure mode,the strength functions mainly follow the structural strength criterion.In the stratum-structure mode,both the strength criterion and the deformation criterion are followed.The reference value interval and the proposed probability distribution type of the variable coefficient of the tunnel mechanical parameters are obtained,which can guide the determination of parameter values in the reliability analysis of the tunnel engineering when the parameter values are hard to determine due to the failure of the geological exploration work or poor conditions.