Development and application of experimental apparatus of permeability for large coal samples

doi:10.3969/j.issn.1673-9787.2012.06.004

Abstract：A self-developed experimental apparatus of permeability for large coal samples is presented in de- tail. It is compose of a gas source system, a gas pressure testing system, a gas flow testing system, servo-con- trolled loading system, an acoustic emission (AE) system and and experimental apparatus of permeability. The coal sample size is 150 mm x 150 mm x 150 mm (the volume of testing sample is 17 times of a standard coal sample). The followings are main features of this testing equipment : It can carry out permeability experi- ments for large coal samples containing original joints, figures and beddings. During the loading process of a large coal sample, the stress, acoustic emission (AE) and gas pressure correspond well to the permeability flow. The lowest gas flow is in the later stage of elasticity, the increase of gas flow begins in the yield-point, and the maximum of gas flow fell behind the peak strength of a coal sample. It can perform repeated loading by a servo-control system, the operation system is easy, and the gas tightness is also good. This equipment also reflects how the stress impacts on permeability of coal containing gas and the permeability characteristics of coal in front of working face, and the results can provide a scientific basis for gas drainage plan and safety management in the working face.