Testing device for entire process of borehole deformation-crack evolution of coal mass and evaluation method thereof

A testing device for entire process of borehole deformation-crack evolution of coal mass, comprising a loading mechanism and a monitoring mechanism;

• wherein the loading mechanism comprises an outer frame, a bearing plate, a loading cylinder, a spacer block, and a coal specimen;
• the outer frame comprises a first support plate, a second support plate, and a plurality of support rods;
• the first support plate and the second support plate are arranged in parallel, and four corner positions of the first support plate are correspondingly connected to four corner positions of the second support plate through the plurality of support rods;
• the first support plate is set at one end of each support rod, and the second support plate is set at a middle position of each support rod;
• an other end of each support rod is fixedly connected to the bearing plate, and the coal specimen is set between the bearing plate and the second support plate;
• a center position of the bearing plate is provided with a through hole, the coal specimen is provided with a borehole corresponding to the through hole, the coal specimen is in contact with the spacer block except for a side connected to the bearing plate and a side opposite to the side connected to the bearing plate, the loading cylinder is arranged on the spacer block, and the spacer block is provided with a hole arranged along a diagonal line of the spacer block;
• the monitoring mechanism comprises an industrial camera, an acoustic emission detector, and an information acquisition unit;
• the industrial camera is placed in front of the bearing plate and opposite to the through hole;
• the acoustic emission detector is placed in the hole opened in the spacer block and arranged on a surface of the coal specimen;
• the information acquisition unit is configured to monitor and obtain status information of the borehole, and is set as a borehole deformation monitoring sensor;
• the borehole deformation monitoring sensor comprises a water bag, a conduit, and a flow monitor;
• the water bag is placed inside the borehole of the coal specimen, and the flow monitor is connected to the water bag through the conduit.