Research advances in formation mechanism of ground crack due to coal mining subsidence in China

The ground cracks due to coal mining subsidence seriously threaten the stability of geotechnical engineering and land ecology safety in mining area,herein the study of formation mechanism of ground crack is conducive to the coordinated development of resource and environment. Here we mainly classified the ground cracks regarding to forma- tion mechanism into three categories,and reviewed their research advances,then analyzed the impact factors and re- search methods of ground cracks,and discussed the key issues for the related researches. Finally,we explored the fu- ture opportunities of formation mechanism for ground crack and the challenges they would face,including:① The pro- gress of rock failure and soil deformation,especially the stress and strain mechanism of the interface between bedrock and unconsolidated layers;② The formation mechanism of multi-cycle of dynamic ground crack;③ Construction of mechanical model considering multiple factors;④ comprehensive application of multi-technical means;⑤ Formation mechanism of ground crack due to deep coal mining,high-intensive coal mining in western ecological fragile region and new coal mining technology,etc.