Fractured rock mass multi-section self-expansion anchor rod and method for calculating drawing force of anchor rod

The invention provides a fractured rock mass multi-section self-expansion anchor rod and an anchor rod drawing force calculation method. The fractured rock mass multi-section self-expansion anchor rod comprises an anchoring structure, a sleeve, an expansion assembly and a movable extrusion assembly. The anchoring structure is used for making contact with the hole wall of the fractured rock mass. The sleeve is arranged on the periphery of the anchoring structure in a sleeving mode and is in sliding connection with the anchoring structure, and the sleeve is arranged in the vertical direction; a plurality of avoiding notches are formed in the sleeve, and the avoiding notches are arranged around the central axis of the sleeve at intervals; the number of the expansion assemblies is multiple, the expansion assemblies and the avoiding notches are arranged in a one-to-one correspondence mode, the expansion assemblies are arranged on the anchoring structure, and the expansion assemblies are arranged in the correspondi