The invention relates to an anchor cable structure with a prefabricated inner anchor head for controlling grouting for many times. The anchor cable structure comprises an outer anchoring end and an anchor cable main body, wherein the top end of the anchor cable main body is connected to a frame beam through the outer anchoring end; the anchor cable main body comprises a plurality of unbonded steelstrands, a primary grouting
pipe and a secondary grouting
pipe; the prefabricated inner anchor head is arranged at the bottom end of the anchor cable main body, a 30-50 cm range is reserved at the end, close to the cable anchor main body, of the prefabricated inner anchor head, and is not grouted, a
grout stopping plug is arranged between the prefabricated inner anchor head and the anchor cable main body, and the secondary grouting
pipe stretches into a position which is not grouted in the prefabricated inner anchor head through the
grout stopping plug; after the prefabricated inner anchor head stretches into the bottom of an anchor cable hole,
cement paste is grouted at a normal pressure through the primary grouting pipe, a curtain is formed out of a stainless
steel tube in the prefabricated inner anchor head of an anchoring section, and
cement paste is grouted in a splitting manner to the anchoring section through the secondary grouting pipe to reinforce rock and earth masses aroundthe anchoring section to form a
tree root-shaped expanded anchoring body, so that the anchoring force is improved.