运营公路隧道衬砌正常使用极限状态模糊随机可靠度分析

该文基于运营公路隧道衬砌正常使用极限状态的特征,针对钢筋混凝土偏心受压构件的最大裂缝宽度极限状态开展了研究。建立了考虑衬砌结构抗力模糊性及荷载效应随机性的正常使用极限状态下模糊随机可靠度分析方法,并对某海底隧道海域Ⅲ级（Ⅳ类）围岩下衬砌结构最大裂缝宽度的可靠度进行了计算。计算结果表明：（1）在考虑结构安全重要性系数、结构的使用环境及荷载条件等因素前提下,模糊失效准则的边界应根据规范规定的允许裂缝宽度值确定;（2）某海底隧道海域Ⅳ类围岩下左洞某断面衬砌拱顶处出现最大宽度裂缝时的失效概率pf=0.194,小于50%,可以满足使用要求;（3）某海底隧道海域Ⅳ类围岩下左洞某断面衬砌拱腰处出现最大宽度裂缝时的失效概率pf=0.322,小于50%,可以满足使用要求。

Fuzzy stochastic reliability analysis of serviceability limit state for linings of operating highway tunnels

According to the serviceability limit state features of operating highway tunnel linings, the limit states for maximum crack width of reinforced concrete eccentric compression members are studied and a fuzzy stochastic reliability analysis method for the serviceability limit state of linings is established. In the proposed method, the resistance fuzziness and the load effect randomness are considered. The reliability of maximum crack width for the linings of a level Ⅲ(class Ⅳ) subsea tunnel is calculated. The conclusions show that: （1）The bounds of the fuzzy failure criterion should be confirmed by the crack width values in the specifications, which consider the importance coefficient of structure safety, the environment around the structure and the load conditions, etc. (2) For the maximum width the crack occurs in the vault of lining from the left hole section in class IV. Surrounding rocks in some sea area around a subsea tunnel, if the failure probability equals to 0.194 (pf=0.194) and is less than 50%, the serviceability requirements can be meet; (3) When the maximum width of the crack occurs at the haunch of lining from the left hole section in class Ⅳ surrounding rocks in some sea area around a subsea tunnel, if the failure probability equals to 0.322 (pf=0.322) and is less than 50%, the serviceability requirements can be meet.