摘要
The coal strength and deformation properties are key factors affecting safe coal mining and highefficiency coalbed methane(CBM)development.In this paper,reconstituted coal samples are chosen to investigate the weakening behavior of gas on coal strength,meanwhile,its effects on coal deformation are quantitatively evaluated.The results indicate that the weakening degree of gas on coal strength is closely related to the confining stress and gas pressure.Compared with non-gas-saturated coals,the maximum weakening ratios of adsorbed gas to coal strength are 10.58%,18.12%,8.55%and 14.65%under the conditions of confining stress CS=3 MPa and gas pressure GP=1 MPa,CS=3 MPa and GP=2 MPa,CS=4 MPa and GP=1 MPa,and CS=4 MPa and GP=2 MPa,respectively.Furthermore,the maximum weakening ratios of free gas to coal strength are 18.27%,36.54%,14.79%and 29.58%,respectively,under above four conditions.The maximum coal bulk strain decreases as particle sizes of coal powders increase,and it has a maximum value of 0.0227 and a minimum value of 0.0191 in particle size ranges of 0.01–0.041 and 0.5–1 mm.Under the same conditions,the coal bulk strain increases with increasing gas pressure,revealing that coal deformation properties can be enhanced by gas.
基金
financial support from the National Natural Science Foundation of China(Nos.51904310and 51874314)
the Fundamental Research Funds for the Central Universities(No.2020YQAQ03)
the Open Funds of Key Laboratory of Safety and High-efficiency Coal Mining
Ministry of Education(Anhui University of Science and Technology)(No.JYBSYS2019204)
the Open Funds of State Key Laboratory Cultivation Base for Gas Geology and Gas Control(Henan Polytechnic University)(No.WS2018B06)。
