System and method for testing rock fracture under vacuum and extreme-temperature condition

A system for testing rock fracture under a vacuum and extreme-temperature condition, comprising:

• a vacuum extreme-temperature loading structure;
• an overall loading frame structure;
• and
• a mobile cart;
• wherein the vacuum extreme-temperature loading structure comprises a vacuum transparent shield, a vacuum base, and an extreme-temperature loading module;
• a bottom end of the vacuum transparent shield is covered on the vacuum base and is hermetically connected with the vacuum base to form a vacuum structure;
• and the extreme-temperature loading module is provided inside the vacuum structure;
• the overall loading frame structure comprises an overall frame and a loading cylinder;
• a middle of the overall frame is provided with a loading space, and the vacuum extreme-temperature loading structure is located in the loading space;
• a center of a top end of the overall frame is provided with a first loading through hole, and the loading cylinder is located above the first loading through hole to enable a loading rod of the loading cylinder to pass through the first loading through hole to apply a loading force to the extreme-temperature loading module;
• an end of the loading cylinder is fixedly connected with the overall frame;
• the loading cylinder is configured to apply the loading force to a uniaxially compressed rock sample in the vacuum extreme-temperature loading structure;
• and
• the mobile cart is located in the loading space and is slidably connected with the overall frame, and the vacuum base is arranged on the mobile cart;
• the extreme-temperature loading module further comprises:
• a heat conduction cavity;
• a first vacuum liquid nitrogen delivery circulating pipe;
• a second vacuum liquid nitrogen delivery circulating pipe;
• a liquid nitrogen refrigeration circulating pipe;
• a plurality of electromagnetic heating plate;
• a transverse deformation sensor,
• an acoustic emission sensor;
• and
• a temperature sensor;
• wherein the heat conduction cavity has a cubic hollow structure;
• a top of the heat conduction cavity is provided with two liquid nitrogen circulating pipe through holes;
• a first end of the first vacuum liquid nitrogen delivery circulating pipe is connected to an outlet of a liquid nitrogen circulation tank, and a first end of the second vacuum liquid nitrogen delivery circulating pipe is connected to an inlet of the liquid nitrogen circulation tank;
• a first end of the liquid nitrogen refrigeration circulating pipe is connected to a second end of the first vacuum liquid nitrogen delivery circulating pipe;
• the plurality of electromagnetic heating plates are arranged in the heat conduction cavity and closely against an inner side wall of the heat conduction cavity;
• two ends of the transverse deformation sensor are configured to abut against and be fixed to an outer side wall of the heat conduction cavity;
• the acoustic emission sensor is arranged inside the heat conduction cavity;
• the temperature sensor is arranged inside the heat conduction cavity;
• and
• the vacuum base is also provided with two vacuum liquid nitrogen delivery holes and an electromagnetic heating guide hole;
• a second end of the liquid nitrogen refrigeration circulating pipe is configured to passes through one of the two vacuum liquid nitrogen delivery holes and one of the two liquid nitrogen circulating pipe through holes in sequence to enter the heat conduction cavity;
• the second end of the liquid nitrogen refrigeration circulating pipe is arranged at intervals with the plurality of the electromagnetic heating plates closely against the inner side wall of the heat conduction cavity, and then passes through the other of the two liquid nitrogen circulating pipe through holes and the other of the two vacuum liquid nitrogen delivery holes in sequence to be connected to the second end of the second vacuum liquid nitrogen delivery circulating pipe;
• and the plurality of electromagnetic heating plates are connected in series through electromagnetic heating wires and pass through the electromagnetic heating guide hole to be connected to a power supply;
• the overall loading frame structure further comprises a displacement sensor, and the displacement sensor is located at a center of a second end of the loading cylinder.