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以乌鞘岭公路隧道破碎岩体段为研究对象,基于随机有限元的结构可靠性理论,统计计算试验所得各个随机变量的数字特征及分布类型;建立极限状态方程后,对乌鞘岭隧道破碎岩体段建立随机有限元模型进行结构可靠性计算。结果表明:随机变量直方图拟合曲线均比较光滑,而且抽样数据各个子序列均有数据且无间隙,表明所进行的随机抽样样本量充分;在此基础上,计算此段隧道的初期支护和二次衬砌各个最大应力及锚杆最大轴力的直方图和概率分布曲线,得到的可靠度及失效概率结果说明初期支护和锚杆最大轴力可靠性偏小,而二次衬砌的可靠性较大,本段隧道整体处于安全状态;隧道结构可靠性灵敏度分析得到:不同随机变量对隧道结构不同应力有着不同影响程度,且喷射混凝土厚度对隧道结构内力影响最为显著。
Taking the fractured rock mass section of Wushaoling highway tunnel as the research object, based on the theory of structural reliability of stochastic finite element method, the digital characteristics and distribution types of each random variable obtained from the experiment are statistically calculated. After the limit state equation is established, The stochastic finite element model is established to calculate the structural reliability of rock mass. The results show that the fitting curve of random variables histogram is relatively smooth, and the data of each sub-series of the sampling data are without gaps, which indicates that the sample size of random sampling is sufficient. On this basis, the initial support And the maximum stress of the secondary lining and the maximum axial force of the bolt histogram and probability distribution curve, the reliability and failure probability obtained results show that the reliability of the maximum axial force of the initial support and bolt is small, and the reliability of the secondary lining The tunnels are in a safe state as a whole. The reliability analysis of the tunnel structure shows that different random variables have different influences on the different stresses of the tunnel structure, and the thickness of the shotcrete has the most significant impact on the internal forces of the tunnel structure.