Study On Fracture Distribution Characteristics Of Coal Mining Collapse In Loess Hilly Area

In recent years,with the development of social economy,the demand for coal resources has increased year by year.A large number of coal mining has severely damaged the mine environment.On the one hand,resources in the eastern part of China are gradually depleted,and the westward advancement of coal has made the environment of the coal-to-land complex in the western Loess Plateau worse.On the other hand,unreasonable underground mining in these areas caused frequent cracks in the ground,which further increased the pressure of sustainable land use.To explore the fractal characteristics of ground fissures,to serve the protection of land in mining areas and ecological restoration is urgently needed.Based on literature review,mining basic data collection and field investigation,combined with the geological environment and ecological environment in the study area,the paper studies the fractal characteristics of coal mining ground fissures in the well mining area of Pingshuo Mining Area.The paper selects the surface cracks caused by the mining of wells as the research object,uses the linear density and length statistics to analyze the time dimension of the ground fissures,and uses the box-counting dimension method to analyze the spatial fields of the ground fissures.The main conclusions of the paper are:1.The feasibility of multi-source data acquisition for ground fissure disaster investigation was verified through Google image data and drone ground fissure information collection,which provided technical support for rapid disaster recovery in the future.This method is helpful for future restoration work.2.Based on the analysis of the density of ground fissures from 2013 to 2017,it is found that the linear density of ground fissures in the whole area is in the range of4-819(m/m~2).According to the distribution of ground fissures,it is divided into five ranges:4-237,237-298,298-349,349-436,436-819(m/m~2).In general,the linear density values of each range are relatively stable,indicating that there are consistency or similar characteristics in development characteristics or activity patterns.Ground fissures show a high linear density of 349-436m/m2 in development,and 4-237(m/m~2)have the lowest linear density,while those in the median density range.Comparison is average and the ratio is the lowest.3.Based on the statistics of the spatial distribution and box-counting dimension of ground fissures,we can see that the distribution structure,length and complexity of ground fissures are different,but there is a common feature,that is self-similarity.And as time changes,the distribution of structure starts from simple to complex.The distribution structure of 2013-2015 is simple,and the corresponding fractal dimensions are 1.16,1.13,and 1.08,while the ground fissure structure from 2014 to2015 is more complex.Their corresponding fractal dimensions are 1.19 and 1.35,respectively;The spatial distribution of ground fissures is approximately 1.08-1.35.