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路基面动变形是高铁路基设计的控制标准之一,其影响因素具有一定的不确定性,因此对其进行可靠度研究显得至关重要。利用布氏解公式,得到了列车荷载作用下路基面动变形的确定性计算模型。在确定性计算模型的基础上,引入列车动轴重、基床表层及基床底层弹性模量的变异性,得到了路基面动变形的概率分布。根据《铁路路基极限状态设计暂行规范(试行)》规定的路基面动变形不超过1mm的要求,建立了列车荷载作用下路基面动变形的极限状态方程;通过可靠度指标对参数的敏感性分析,分析了列车动轴重、基床表层及基床底层弹性模量的均值、变异系数等控制因素的影响作用,并以根据目标可靠度指标所确定的变异程度控制范围作为路基设计的控制标准。结果表明,列车荷载作用下路基面动变形服从对数正态分布,且同时受到基床底层弹性模量、动轴重的均值和变异性的显著影响。确定性分析与可靠度分析相结合能够更有利于高铁路基的安全设计。
Subgrade deformation is one of the control standards for high-speed railway embankment design, and its influencing factors have some uncertainties. Therefore, it is very important to study the reliability of subgrade. Using the Brillouin solution, a deterministic calculation model of dynamic deformation of subgrade under train load is obtained. Based on the deterministic calculation model, the variation of the elastic modulus of the moving bed, the surface of the bed bed and the bottom bed of the bed is introduced, and the probability distribution of the moving deformation of the roadbed is obtained. According to the requirements of “Provisional Regulations for Design of Limit State of Railway Subgrade” (for Trial Implementation), the limit state equation of dynamic deformation of subgrade under train load is established according to the requirements that the deformation of subgrade is not more than 1mm. Sensitivity analysis of parameters by reliability index , The effects of control factors such as the moving axle weight of the train, the mean value of the elastic modulus of the bed surface and the bottom bed of the bed, and the coefficient of variation were analyzed. The control range of the variation degree as determined according to the target reliability index was taken as the control standard for the subgrade design . The results show that the dynamic deformation of subgrade under train load obeys lognormal distribution and is affected by both the elastic modulus of bottom bed and the mean and variability of moving axle weight. The combination of deterministic analysis and reliability analysis can be more beneficial to the safety design of high-speed railway embankment.