Anchor hole reaming construction method capable of preventing hole collapse

The invention relates to an anchor hole reaming construction method capable of preventing hole collapse, and belongs to the technical field of anchoring. The free section adopts a common drill bit to carry out pipe-following construction and screw-in, the common drill bit is withdrawn when the free section reaches the joint position of the free section and the anchoring section, a rotary spraying drill bit is arranged below the free section, high-pressure cement paste is injected from a rotary spraying drill rod to the rotary spraying drill bit, the high-pressure cement paste is sprayed out from a drill bit guniting opening to cut the soil body of the anchoring section, the drill bit is rotated while the high-pressure cement paste is sprayed, and drilling is not carried out temporarily; drilling is conducted till the expanded part is gradually filled with cement grout in the expanded hole, drilling is strictly prohibited before the expanded part is filled with the grout, and drilling is started to be conducte