Overlying Rock Fissure Development And Porosity Distribution In Shallow Buried

The Shendong mining area in my country is rich in mineral resources.The vigorous development of mineral resources in recent years has exacerbated the environmental and safety issues in the area.One of the important links to solve this problem is to master the development law and distribution characteristics of mining overburden cracks in this area.This paper takes the 22202 working face of Holuowan Mine of Shendong Tianlong Company as the research background,through collating and analyzing the measured data of ore pressure,using similar simulation experiments,numerical simulation experiments and other methods to develop the development law and distribution characteristics of overburden cracks in shallow coal seams.Research.First,the thesis carried out an experimental study on the 22202 face of Holuo Bay Mine through a similar simulation experiment.Based on the mining subsidence law,the development height of the three belts in the shallow coal seam working face is predicted.By observing the crack morphology of the overburden rock in shallow coal seam,the general distribution characteristics of the crack morphology of the overburden rock are obtained.Secondly,after processing the image of the fracture network,the fractal dimension is used to study the morphological parameters of the fracture network,and the general law of the evolution of the morphological parameters of the fracture network is obtained:(1)the formation,expansion,and The distribution is very complicated,but it has fractal characteristics.The fractal dimension can be used to describe the distribution characteristics of mining fracture network in two-dimensional space.(2)The fracture networks of mining rocks in the "three belts" and vertical fractured areas have different fractal dimension features.The fractal dimension values ??of the collapse zone and the separation fracture zone are higher than the fractal dimension values ??of the fracture zone.The fractal dimension ofthe fissure zone spans larger,but overall it is also greater than the fractal dimension value of the fissure zone.(3)The relationship between fractal dimension and mining progress can be divided into three stages: dimension raising stage,dimension reducing stage,and stable dimension changing stage.Finally,the UDEC numerical simulation shows that under the condition of two-dimensional discrete element numerical simulation,the distribution of mining fractures in the overlying rock layer still has good fractal characteristics,and the fractal dimension can also well represent the spatial distribution density of mining fractures and Evolutionary processes such as the generation,expansion,connectivity,and closure of mining fractures.The study on the development law of overburden cracks in shallow coal seams can provide a certain theoretical basis for the safe production of mining face and the prediction of the damage to mining overburden,and it also provides important protection for the mining area's land and buildings and green mining.The reference value is of great significance to the promotion of sustainable economic development in the Holo Bay mining area.