Abstract In view of the replacement thickness of red clay cutting bed under ballastless track of Wuhan—Guangzhou high-speed railway,based on results of indoor dynamic test and on-site dynamic response test,the dynamic stability of red clay cutting bed under ballastless track of Wuhan—Guangzhou high-speed railway is preliminary evaluated by methods of critical dynamic stress and dynamic shear strain respectively;and the theory values of minimal replacement thickness of cutting bed are given to meet synchronously two requirements of dynamic strength and dynamic deformation. After considering of 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 corresponding the theory values of minimal replacement thickness are also given. Influences are discussed for water content ratio and confining pressure to replacement thickness of cutting bed,the values of it increase with water ratio increases and reduce with confining pressures increase. The comparitive analysis shows that the dynamic strength condition of roadbed under ballastless track of high-speed railway can be certainly satisfied if the dynamic deformation condition of it 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. The results provide new thought for ensuring replacement thickness of roadbed under ballastless track of high-speed railway.
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Received: 19 July 2010
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