Cantilever main beam for supporting heavy-load anchor rod

A main body of the cantilever main beam is of a box-shaped structure extending front and back, a pin row extending front and back is fixed to the bottom face of the middle-rear portion of the box-shaped structure, and a left guide rail and a right guide rail extending front and back are arranged at the lower positions of the left side face and the right side face of the middle-rear portion of the box-shaped structure respectively. The left guide rail and the right guide rail are located on the left outer side and the right outer side of the middle rear portion of the box-shaped structure respectively, an inner cavity of the box-shaped structure is divided into an upper cavity and a lower cavity, a plurality of partition plates are welded in the lower cavity front and back at intervals, and the four edges of the partition plates are fixedly connected with the upper plate face, the lower plate face, the left plate face and the right plate face of the lower cavity in a one-to-one mode. The height of the front po