Hydraulic ring geological crack measuring device

The utility model discloses a hydraulic ring geological crack measuring device, which belongs to the technical field of measuring devices and comprises a base, supports are sleeved at two ends of the base, a bearing seat is fixed in the base, a vertical rod is fixed in the bearing seat, a bump is fixed at the top end of the vertical rod, a bottom support is fixed at the bottom end of the vertical rod, and a connecting block is rotatably connected in the bottom support. A first limiting bolt is arranged on one side of the connecting block, a screw hole matched with the first limiting bolt is formed in the bottom support, a transverse rod is fixed to the bottom end of the connecting block, scales are arranged on the transverse rod, the transverse rod is sleeved with two sliding sleeves, second limiting bolts are arranged on the two sliding sleeves, and the bottom ends of the two second limiting bolts abut against the top end of the transverse rod. Shells are integrally formed at the bottom ends of the two slidi