1.2　CRTSⅢ Track Structure on Subgrade

CRTSⅢ slab ballastless track structure on subgrade is mainly composed of，from top to bottom（taking straight line as an example），200mm thick two-way prestressed track slab，90mm thick self-compacting concrete structural layer，isolated layer and elastic layer on base surface，and 300mm thick（center of straight line section）concrete base，as is shown in Figure 2.

The structures of the track slab，self-compacting concrete structural layer，isolated layer and elastic layer on subgrade are the same as those on bridge，the base width is 3100mm，its length and direction correspond to 3 or 4 pieces of track slab and the unit structure is formed thereby，2 limit grooves shall be set in the base under every track slab，and both ends of unit base shall be set with 20mm transverse expansion joint，the filling，sealing for the expansion joints are the same as those for bridge.The dowel steel shall be set at the expansion joint for subgrade base unit，the dowel steel shall be unbounded sheath type or coated round steel bar type，the dowel steel and the expansion joint shall be fixed by rebar binding.The superelevation on curve at subgrade section shall be set on surface layer of subgrade bed.

Figure 2　Sketch Map for Structure of CRTSⅢ Slab Ballastless Track on Subgrade（Straight Line Section，Unit：mm）