In-situ experimental study on the relation of drilling cuttings weight to ground pressure and gas pressure

The relation of drilling cuttings weight to ground pressure and gas pressure was investigated by in-situ experiment on the 2124 fully mechanized coal mining face of Sanhui Mine in Chongqing Tianfu Coal Industry Co.,Ltd.The distribution of ground pressure after drilling was obtained as the following: the stress-relief zone width of about 5 m,the location of the plastic zone at 5 to 11 m,the location of the elastic zone at 11 to 20 m,and the location of the original stress zone beyond 20 m.The drilling cuttings weight linearly increased before the peak ground pressure and decreased after it under the premise of drilling in strict accordance with the operating rules.Based on the theoretical analysis of ground pressure and gas pressure on the longwall mining face,a positive relation of drilling cuttings weight to ground pressure and gas pressure was deduced.The drilling cuttings weight positively changed with ground pressure at the fixed gas pressure or with gas pressure at the fixed ground pressure.