1.3　CRTSⅢ Track Structure in Tunnel

CRTSⅢ slab ballastless track structure in tunnel 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 200mm thick（center of straight line section）concrete base，as is shown in Figure 3.

The basic track slab length in tunnel is 5600mm，the structures of the self-compacting concrete structural layer，isolated layer and elastic layer in tunnel are the same as those on bridge，the base width and thickness are the same as those on bridge，its length and direction，limit groove and the setting of transverse expansion joint are the same as those on subgrade.The filling and sealing for expansion joint are the same as those for bridge.The superelevation on curve at tunnel section shall be set on the base.