Research On No.9 Seam Floor Failure Laws In Xiandewang Mine

Handan Xingtai area is an important base of coal production ,But the safety of coal mining is under some certain restrictions because of the great threat of Ordovician. Many scholars have done a lot of research about safe coal mining and achieved great success. As the water inrush of coal seam floor is a complicated, nonlinear and non equilibrium evolutionary process, it is influenced by many factors, so it is not easy to give an exact description of the process of water inrush progress theoretically.Jizhong Energy Corporation Xiandewang's 9^# seam and the Ordovician interface has an average thickness of 33m, it is a pressure-bearing water low coverage coal seam, and because of seriously threatened by the strong aquifer(Ordovician limestone), the probability of mine water inrush is evidently increasing than coal seam mining. To ensure the safety mining of 9^# coal seam, this article takes Xiandewang 9^# coal seam's 1192 working profile as a researching subject, with field observation data, the author knows the additional stress, principles stress of coal seam mining and sum up the variation regulation of additional stress during the extraction process and get the field observation data of the damage depth of Xiandewang 9^# coal seam floor; then the author did the numerical simulation of vertical stress, plastic deformation, horizontal stress, vertical displacement and support pressure during the whole back pulling progress of the working surface with the use of large numerical simulation software FLAC^3D, and get the imitating damage depth value of coal seam floor by analyze the variation regulation of vertical stress, plastic deformation, horizontal stress, vertical displacement and support pressure; predict the damage depth of Xiandewang 9^# coal seam floor with the use of damage depth predicting model which based on BP neural network.; and finally calculate the theatrical damage depth value of the coal floor with computational method. With the integrated study of filed observation, numerical simulation, BP neural network predict and the theoretical calculation result, the author gets the maximum damage depth of Xiandekuang 9^# coal seam floor, and combined with the field data of coal seam floor damage depth of parts of Han xing area, the author proposes the damage depth empirical formula of Xiandewang 9^# coal seam floor and provides scientific basis for Xiandewang 9^# coal seam's mining under high pressure.