Long-term dynamic stability evaluation of cutting bed under ballastless track of Wuhan—Guangzhou high-speed railway

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.