1.2　Structure of CRTS Ⅱ Slab Ballastless Track on Subgrade

The CRTS Ⅱslab ballastless track on subgrade is composed of four parts，from top to bottom（taking the straight line section as example）：20 cm thick concrete track slab，3 cm thick mortar cushion，30 cm thick concrete bed plate，subgrade bed（composed of surface layer and bottom layer）.Track ultrahigh is realized by subgrade surface layer.The supporting layers of left and right track shall be filled with mineral mixture，and its top surface shall be sealed with C25 concrete at least 15 cm thick.That the supporting layer edge at both sides to berm shall serve as 4％ drainage slope outward and the surface is sealed with asphalt concrete（10 cm）.The structure of ballastless track on subgrade is shown in Figure 2.

The structure of track slab and mortar cushion on subgrade is the same as that on bridge，the supporting layer is constructed with semi-plastic concrete（C15，without reinforcement）.