中文摘要：

基于室内疲劳动力试验所获得的临界动应力、疲劳动剪应变门槛及现场动响应测试成果，采用临界动应力法和动剪应变法，评价武广（武汉－广州）高速铁路无碴轨道红黏土路堑基床的长期动力稳定性，给出同时满足动强度和动变形条件的最小基床换填厚度理论值。综合考虑铁路路基构造要求、实测路基动响应影响深度、红黏土特殊工程性质、安全储备等因素，给出便于工程应用的红黏土基床最小换填厚度建议值，探讨含水比、围压对红黏土基床换填厚度的影响规律。研究结果表明：换填厚度随含水比的增大而增大，随嗣压的增大而减小：若路基满足动变形条件，则动强度条件就自动满足；动变形是高铁无碴轨道路基长期动力稳定的控制因素；动剪应变法是一种优于临界动应力法的高铁无碴轨道路基长期动力稳定性评价方法。

英文摘要：

Based on field dynamic response testing results and the critical dynamic stress and fatigue dynamic shear strain threshold obtained from fatigue test indoor, the long-term dynamic stability of red clay cutting bed under ballastless track of Wuhan-Guangzhou high-speed railway was preliminary evaluated by methods of critical dynamic stress and dynamic shear strain respectively, and the theory values of minimal replacement thickness to meet synchronously two requirements of dynamic strength and dynamic deformation were given. After considering railway bed structure request, actual cutting bed dynamic response influencing depth, special engineering properties of red clay and safety storage and so on, the suggestion values applied conveniently in engineering were also given. Influences for water content ratio and confining pressure on replacement thickness of cutting bed were discussed. The results show that the dynamic shear strain threshold increases with the increase of water ratio and reduces with the increase of confining pressures. Dynamic strength condition of roadbed can be certainly satisfied if the dynamic deformation condition can be done; dynamic deformation is the controlling factor of ballastless track roadbed of high-speed railway. The method of dynamic shear strain is superior to the way of critical dynamic stress.