The island abutment remains in the protective coat stress concentration, the unsuitable width of island abutment would form stress concentration belt and it occurs the coal and outburst.

• 摘要保护层采空区留有煤柱会引起应力集中，留有煤柱的宽度不适将会形成应力集中带，以致发生强度较大的煤与瓦斯突出。