管片衬砌可靠度分析实用方法研究

由于盾构隧道管片衬砌结构形式的特殊性,可靠度分析中仅采用截面承载力极限状态方程作为功能函数不够全面,故文中提出管片可靠度分析应采用双功能函数,即增选管片裂缝宽度控制方程作为第二功能函数.考虑到随机变量的非正态分布和功能函数的高度非线性,常规一次二阶矩法精度较低,提出采用映射变换和二次二阶矩相结合的方法进行管片衬砌可靠度分析.实例表明：双功能函数相互补充,可保证结构的安全可靠,映射变换和二次二阶矩结合分析法清晰简便,能较好地解决功能函数高度非线性、随机变量非正态分布等问题.

Study on Utility Method of Reliability Analysis for Segment Lining

Due to the particularity of structure style of segment lining for shield tunnel,it is not comprehensive just to take sectional bearing limit state formula as conventional performance function in reliability analysis,so this paper proposed that the reliability analysis for segment lining should adopts double performance functions：the control formula of segment crack width is supplemented as the other performance function.Considering the non-normal distribution of random variable and non-linearity of performance function,the accuracy of first order second moment method is very low,and a synthesized method which combines reflection transformation with second order second moment method is put forward to study reliability of segment lining.Examples show that the double performance functions reinforced each other,which may ensure safety and reliability of structure.The analysis method can solve the problem of non-normal distribution of random variable and non-linearity of performance function,which is rational choice of reliability analysis of segment lining.