基于累积变形演化状态控制的高速铁路基床结构设计计算方法

实现长期循环荷载作用下基床结构累积变形有效控制是建造高速铁路的技术难点之一.基于高速铁路无砟与有砟轨道路基承受列车动荷载特征,提出和完善了用于基床结构设计的荷载作用模式;根据循环荷载作用下土工填料累积变形演化状态的分类及阈值判别准则,结合室内单元结构填土模型试验,获得了级配碎石基床填料变形状态演化的阈值参数.以设计荷载条件和填料设计参数为基础,针对无砟与有砟轨道对基床变形状态控制的不同要求,采用结构分析原理,构建了基于累积变形演化状态控制的高速铁路基床结构设计计算方法,确定了无砟与有砟轨道基床结构累积变形分别满足快速稳定和缓慢稳定的状态控制要求,以地基系数K30值表征的关键参数指标.研究成果为实现高速铁路基床结构由构造设计向状态控制定值分析转变奠定了基础.

Computational methods of high-speed railway subgrade structure design based on cumulative deformation evolution state control

It is one of the technical difficulties to reach the effective control over cumulative deformation of subgrade structure under the function of long-term cyclic loading. Considering the features of train-induced dynamic load born by high-speed ballastless and ballast tracks, load mode for subgrade structure design has been proposed and completed. In accordance with the classification of evolution state of geotechnical-filling cumulative deformation under the function of cyclic loading and threshold criterion as well as the integration with indoor modular construction filling model test, threshold parameters of deformation evolution of grading gravel subgrade filling have been obtained. Based on design load conditions and filling design parameters and considering different requirements of ballastless and ballast tracks for subgrade deformation state control, principle of structural analysis has been adopted, so as to establish computational methods of high-speed railway subgrade structure based on cumulative deformation evolution control, which has confirmed that cumulative deformation of ballastless and ballast tracks subgrade structure could satisfy the control requirements of fast ＆ steady state and slow ＆ steady state respectively as well as key parameter index represented by coefficient of subgrade reaction K30 value. The research outcomes will lay a solid foundation for the transition of high-speed railway subgrade structure from structure design to deterministic analysis of state control.