a confining pressure loading assembly comprising a core cavity for accommodating a core sample of a rock and a liquid outlet being in communication with the core cavity, the confining pressure loading assembly being configured to apply pressures to the core sample located in the core cavity in three directions perpendicular to each other;

a drill bit for inserting into the core cavity to drill the core sample;

a drill rod connected to the drill bit;

a drilling fluid circulation assembly, comprising a drilling fluid inlet, a drilling fluid outlet and a mud pump connected therebetween, wherein the drilling fluid outlet is in fluid communication with the drill bit through the drill rod, the drilling fluid inlet is in fluid communication with the liquid outlet, and the mud pump, the drilling fluid outlet, the drill rod, the drill bit, the core cavity, the liquid outlet, the drilling fluid inlet and the mud pump are in fluid communication in sequence to form a mud circulation channel;

a rotary impact assembly, comprising a hydraulic rotary motor and a hydraulic swing motor connected to the drill rod, respectively, wherein the hydraulic rotary motor is capable of applying a torque in a first direction to the drill rod, the hydraulic swing motor is capable of alternately applying an instantaneous torque in the first direction and an instantaneous torque in a second direction to the drill rod, and the first direction and the second direction are clockwise or counterclockwise and opposite to each other; and

an axial impact assembly, comprising a first hydraulic cylinder and a servo linear actuator connected to a piston rod of the first hydraulic cylinder and to the drill rod, wherein the first hydraulic cylinder is capable of applying a thrusting force in a third direction to the drill rod, the servo linear actuator is capable of alternately applying a thrusting force in the third direction and a tensile force in a fourth direction to the drill rod, and the third direction is opposite to the fourth direction.