Study On Non-probabilistic Analysis Method Of Reliability For Railway Tunnel Lining Structure

The reliability evaluation of tunnel structure is always an important subject in the field of tunnel engineering.At present,the probabilistic reliability theory and the corresponding probabilistic limit state design method have been promoted.However,the research on the application of the non probabilistic reliability evaluation method in the tunnel engineering is still relatively small,and has not formed a complete theory.The main reason is that the reliability index measurement method is not uniform,the interval expansion problem is difficult to control,and the implicit function is difficult to solve.In this paper,based on the interval theory,the non probabilistic reliability analysis method of tunnel lining structure is studied systematically and comprehensively.First of all,starting from the basic theory of interval mathematics,the reasons for the expansion of interval and the commonly used methods are introduced.On this basis,the non probabilistic reliability models are compared and analyzed,and the non probabilistic reliability measurement and calculation method for a given tunnel lining structure is given.Then,according to the limit state equation,the expression of the unified function is given.Then,based on the limit state equation,the expression of the unified function is established,and the non probabilistic reliability analysis model of the lining structure is established based on the perturbation method.Aiming at the problem that there is no explicit expression between lining internal force and surrounding rock and material parameters,a method of correlation factor is proposed to solve the non probabilistic reliability index of implicit function.In addition,in order to eliminate the influence of the moment axial force correlation on the reliability index calculation,the method of parameter combination is proposed.The effectiveness of the method is verified by an engineering example.The non probabilistic reliability index of typical section and the traditional safety factor are compared and analyzed.It is proved that it is more reasonable to use the non probabilistic reliability index to evaluate the safety of tunnel structure.Finally,by analyzing the parameter sensitivity analysis method,the analytical solution and approximate analytical solution of the sensitivity of the non probabilistic reliability index to the limit state function are derived.And an optimization method is proposed to calculate the sensitivity of the reliability index to the implicit function.According to the engineering example,the main sensitive parameters of the typical reliability index of tunnel lining are analyzed,which can be used as reference for the investigation and design of tunnel structure.