A novel large-scale three-dimensional apparatus to study mechanisms of coal and gas outburst

Abstract

Coal and gas outburst disasters affect safe production from coal mines. There has been limited progress in understanding and predicting these outbursts in the past years. Therefore, a novel large scale three-dimensional simulation experimental apparatus to study mechanisms of coal and gas outburst was developed. The experimental apparatus has dimensions of 1.5 m × 0.8 m × 0.8 m and can achieve a gas seal of 6 MPa. Its hydraulic sub-system can perform axial (3000 t) and horizontal symmetric (2000 t) loading. The outburst port can be initiated actively and instantaneously, similar to the sudden excitation of an outburst. The apparatus realizes the roadway network simulation of various fluid migration routes, resistance characteristics, and ventilation facilities. Simultaneously, 90 test channels and a sampling frequency of up to 4 Ms/s can be used to monitor the time–space distribution law of multiple parameters in the apparatus and realize the real-time observation of the experimental phenomena. The experimental apparatus can be used to simulate the entire process of the coal and gas outburst, including accumulation, motivation, development, and termination stages as well as systematically study the features and mechanisms of the outburst. A complete simulation experiment of an outburst under a high geo-stress was performed. The distribution and variation of the gas pressure and geo-stress before, during, and after the outburst were analyzed. The distribution of the outburst-pulverized coal and gas concentration rule was obtained, which shows the characteristics of the extrusion type. This experiment validates the capability and reliability of the newly developed coal and gas outburst simulation apparatus.