Anti-hole-collapse drilling tool

The utility model discloses an anti-hole-collapse drilling tool which comprises a tube-shaped drill rod, a hollow hole expanding drill bit and a center drill bit. The hole expanding drill bit is installed at the front end of the drill rod, a first dropping body and a second dropping body are arranged at the front end of the drill rod, the rear portion of the first dropping body is located in the hole expanding drill bit and connected with the hole expanding drill bit in a key mode, the front of the first dropping body extends out of the front end of the hole expanding drill bit and connected with the center drill bit, a stepped hole is formed along the axial lead of the first dropping body, the second dropping body is located in the drill rod, the front end of the second dropping body is located in the stepped hole in the first dropping body and matched with the stepped hole in a sliding mode, a compression spring is arranged in the stepped hole, and the two ends of the compression spring respectively act on the stepped end face of the stepped hole and the front end face of the second dropping body. After the drilling tool is used for drilling a hole in the collapsed rock-soil, a conveying channel can be formed through the drill rod and can not be blocked by second-time collapsed rock-soil.