Experimental Study on Gas Migration Law in Gob Area of Fully Mechanized Caving Coal Face

JIANG Zhong’an; JIANG Jianglin; WANG Hongsheng; DU Cuifeng; LUO Junfeng

Abstract：In this paper the similar criterion numbers for simulating the gas migration law in the gob area of the fully mechanized caving face were derived by using the similarity criterion and the Darcy’s Law of porous media seepage. By taking the gob area of 2306 working face in Zhangcun Coal Mine as the background, a similar model for the gob area in the fully mechanized caving face was established, and with this model, the experimental study was carried out on the laws of air flow and gas migration in the gob area and the change of the gas concentration at the upper corner angle of the working face with U, U+L or U+I ventilation pattern at different air speed. Results showed that the ventilation patterns would determine the space variation law of the air flow and gas migration in the gob area;the air speed would determine their fluctuation degree and influence scope;the change of gas concentration at the upper corner angle of the working face was subject to the influence of the ventilation pattern and air speed, U+I ventilation pattern was most conducive to lower the gas concentration at the upper corner angle, the lower air speed in the working face would cause gas accumulation, the higher gas concentration fluctuated significantly, and when the air speed was in the range of 1. 5-2. 5 m/s, the gas concentration at the upper corner angle can be under better control.