非轴对称下隧道锚网喷支护结构的可靠度分析

以圆形隧洞围岩的弹塑性解析解为基础,建立非轴对称情况下锚网喷支护结构的可靠度分析模型。考虑功能函数的高度非线性,采用Monte-Carlo法和Rosenblueth法计算可靠度指标。计算结果表明:锚网喷支护结构的可靠性是围岩、锚杆、钢筋网和喷层共同作用的结果,其可靠指标随围岩地应力、粘聚力、内摩擦角、喷层厚度、喷层混凝土抗压强度、锚杆抗拉强度和锚固力的变异系数的增加而降低。可靠指标随侧压系数的增加而增加,随地应力的增加而迅速降低。

RELIABILITY INDEX ANALYSIS ON ANCHOR-NET-SHOTCRET SUPPORT STRUCTURE OF TUNNEL UNDER NON-SYMMETRICAL CONDITION

Based on the analytical solution of elasticity and plasticity theory of circular tunnel surrounding rocks,the analytical model of reliability index on an anchor-net-shotcrete support structure of a tunnel under a non-symmetrical condition is built.Considered the high non-linearity of functions,the reliability index computation is adopted by the Monte-Carlo and Rosenblueth methods.The calculation results show that the reliability of a support structure is a common action result of surrounding rock,anchor,net and shotcrete.Reliability index decreases with the increase of the variation coefficients of the crustal stress,cohesive force,inner friction angle,thickness of a spraying layer,and the extension strength of an anchor and an anchor-reinforced force.Reliability index increases with the increase of a lateral pressure factor.The reliability index rapidly decreases with the increase of crustal stress.