T-shaped blade root groove for small-enthalpy-drop blade of high-parameter steam turbine

The utility model relates to the field of turbine blade roots, in particular to a T-shaped blade root groove used for a low-enthalpy-drop blade of a high-parameter turbine, and aims to solve the problems that a rotor blade root groove in a high-temperature area of a multi-stage low-enthalpy-drop high-parameter turbine unit is easy to generate stress concentration and thermal stress influence is caused by temperature change. According to the scheme, a blade root groove neck, a blade root groove force-bearing surface I, a blade root groove force-unloading surface I and a blade root groove force-unloading surface II are sequentially connected end to end, the width of the blade root groove neck is b1, the height of the blade root groove neck is h1, the length of the blade root force-bearing surface I is b2, the section of the blade root groove force-unloading surface I is a circular arc of Ra, and the section of the blade root groove force-unloading surface II is a circular arc of Rb. The blade root groove force