Temporary top sealing structure for sunken underground square

The utility model discloses a temporary top sealing structure for a sunken underground square, which is arranged at the top of an exit of the underground square, supporting members of the underground square are arranged around the exit of the underground square, and each supporting member comprises a main body structure column, a main body structure beam and a main body structure plate for supporting the underground square, a supporting column is arranged at the exit position of the underground square, a top sealing component is arranged on the upper portion of the supporting column and comprises a heightening column and a top sealing plate, the heightening column is arranged above the supporting column, and the top face of the heightening column is flush with the top face of the main body structure column; a capping structural beam is arranged between the upper part of the heightening column and the main body structural beam; the top sealing structural beams, the heightening columns and the main body structu