Novel hollow grouting anchor cable capable of firstly expanding and then reducing and capable of absorbing energy and preventing impact and using method of novel hollow grouting anchor cable

The invention provides a first-diameter-expanding and second-diameter-reducing type energy-absorbing and anti-scour novel hollow grouting anchor cable and a using method thereof, and relates to the field of underground engineering safety supporting. The invention discloses a first-diameter-expanding and second-diameter-reducing type energy-absorbing and anti-impact novel hollow grouting anchor cable which comprises a novel hollow grouting anchor cable body, a diameter expanding sleeve, a diameter expanding lock, a pressure bearing tray, an anchor cable lock and a diameter reducing device. The reducing device comprises a reducing outer sleeve, a reducing sleeve, a reducing sleeve baffle and a reducing opening; the anchor cable lockset, the expanding lockset, the expanding sleeve, the pressure-bearing tray, the reducing outer sleeve, the reducing sleeve, the reducing sleeve baffle and the reducing opening are coaxially sleeved at the tail end of the novel hollow grouting anchor cable in sequence; the left end a