Amplitude-variable tower crane boom and crane carriage matched with same

The utility model discloses an amplitude-variable tower crane boom and a matched crane carriage thereof, the sectional areas of triangular trusses of the first to seventh sections and the ninth section of the boom are the same, the seventh section and the ninth section are respectively provided with a lap joint section, and the sectional area of the triangular truss of the eighth section is increased. The seventh lap joint section and the ninth lap joint section are inserted into the eighth section to be fixed after lap joint, the ninth section can be completely contained in the eighth section, and the ninth section is further fixedly connected with the seventh section when completely contained in the eighth section. When the lap joint section of the seventh section and the ninth section is inserted into the eighth section to be fixed in a lap joint mode, the length of the cargo boom is the longest, and when the ninth section is completely contained in the eighth section, the length of the cargo boom is the s