Full-section bolting and grouting high-pre-tightening supporting device and system for extremely broken soft rock roadway

The utility model discloses a full-section bolting and grouting high pre-tightening supporting device and system for an extremely broken soft rock roadway, which belongs to the field of underground supporting and comprises a composite roadway layer, and the composite roadway layer comprises a shallow grout stopping layer and a terrace which are sequentially constructed on the surface of roadway surrounding rock; a plurality of bolting and grouting high-pre-tightening supporting anchor rods are arranged on the composite roadway layer at equal intervals; the bolting and grouting high pre-tightening support comprises a large-diameter sleeve anchor cable arranged in the composite roadway, the middle section of the large-diameter anchor cable is sleeved with a plastic sleeve, a gap is reserved between the inner hole wall of the plastic sleeve and the outer wall of the large-diameter anchor cable to form a large-diameter anchor cable free section, and threads are arranged on the tail section of the large-diameter a