1.1 The Structure of Slab Type Turnout Area on Subgrade
The structure of slab type turnout area on subgrade includes，from top to bottom，turnout parts，prefabricated turnout plate，self-compacting concrete base（packing layer），concrete cushion（foundation treatment）and so on，and shear bar shall be set between turnout slab and base，as is shown in Figure 1.
Figure 1 Sketch Map of Cross Section for Slab Type Ballastless Track Structure in Turnout Area on Subgrade
1.1.1 Concrete cushion
Concrete cushion is paved on subgrade surface layer，designed as plain concrete structure，its thickness is 12cm and concrete grade is C25.
1.1.2 Self-compacting concrete base：
The design thickness of self-compacting concrete base is 18cm，reinforced concrete structure，concrete grade is C40，and the concrete is of strong flowability，gap passing ability and stability.At the middle one layer of HRB335 rebar shall be set inside，with longitudinal rebar diameter 25mm and transverse rebar diameter 12mm.
1.1.3 Prefabricated turnout slab
The design thickness of turnout slab is 24cm，concrete grade is C55，non-stressed reinforced concrete structure，inner rebar is double layered and two-way structure，transverse rebar is common rebar，longitudinal rebar and bearing rebar are epoxy coating insulating rebar，and four groups of gantry rebar shall be applied under every turnout slab on subgrade section（to be extended far below self compacting concrete）.The rail bearing platform is free of bumping shoulder，the rail bearing platform spacing is 600mm，and precracking shall be set between rail bearing platform.The length，width and casing pipe hole position of every turnout slab is different from each other（every turnout slab is of an unique serial number），the turnout with different number requires different quantity of turnout slabs（eg.The turnout numbered 18 requires 27 turnout slabs，and the turnout numbered 42 requires 57 turnout slabs）.Turnout slab shall be prefabrication produced in factory，generally it weight shall be restricted as l0 t，and width shall not be longer than 3.2m.The turnout slabs shall not be connected longitudinally with each other and the expansion joint of certain width shall be reserved，the joint shall be filled with asphalt before turnout pavement.The basic structure and serial number of turnout slab is shown in Figure 2.
Figure 2 Example of Turnout Slab Structure
1.1.4 Turnout parts
The turnout parts are mainly composed of frog rail，wing rail，switch rail，frog components，spacer block and fasteners.The turnout parts shall be preassembled by the manufacturer before ex-factory，and then transported to construction site for fine adjustment.