Device for weakening hard rock through alternate cooling and heating circulation

The utility model discloses a device for weakening hard rock through alternate cooling and heating circulation, which comprises a main frame mounted at the center of a cutter head of a shield tunneling machine, and a drilling mechanism and a hard rock weakening mechanism through cooling and heating circulation are arranged on the main frame; the cold and hot circulation weakening hard rock mechanism comprises a cold flow device, a hot flow device and an injection device used for injecting cold fluid or hot fluid into the drill hole, the flowing direction of the fluid serves as the downstream direction, and the downstream end of the cold flow device and the downstream end of the hot flow device are both connected with the injection device. When a hard rock stratum is encountered in shield construction, the cold flow and hot flow jetting device can be installed in the center of a cutter head of a shield tunneling machine, and rock mass strength and cutting resistance of hard rock are weakened by alternately jet