Similar to other geological structures, bedding slip is thought to be determined by the in-situ rock stress and the rock properties. Under the acknowledged regular pattern of in-situ rock stress, a three-seam 3-D model by FLAC3D was established to recover the formation of bedding slip in this paper, in which model of Mohr-Coulomb (MC) and strain hardening & softening (SS) were taken as a comparison, variation of geologic factors, such as dip angle, strength, thickness and depth of rock stratum, were done. It was verified that bedding slip formed by the application of horizontal in-situ stress and the difference of rock strength. Localization band in coal-seam were found by SS model, which produced a stress concentration, lower coal strength, more fissures for the gas aggregation and storage and these are thought to be the key factors for the happening of coal and gas outburst. It was testified by simulation that localization is determined by the in-situ horizontal stress and the rock strength. The conclusion is significant and encouraging to the prediction and prevention of outburst in BS coal seam.
As one of the most important geological structures, bedding slip produced by in-situ stress on different scales and connected closely with the soft stratum in crust (Zhang, 1984). Therefore, it often formed in coal measure strata since coal-seam is right a typical soft stratum. Bedding slip (BS) in coal-seam, which may be termed as bedding fault sometimes, has been studied by scientists for its strong proneness to coal & gas outburst and many encouraging suggestions were achieved. With simple elastic model and Coulomb- Navier rule, the mechanical formation of BS was studied by Hubbert & Rubey (1959) and other geologists (Chen, 1986), of which no detail structure of BS discussed, especially for those formed in depth.