Study On Retaining Water-proof Coal Pillar Of F₉ Fault In Changheng Coal Mine

Structural distribution factors further complicate the engineering geological conditions of coal seam mining to a certain extent.The risk degree of coal seam mining under special structural conditions of adjacent faults is higher than that without faults,and its inherent risk attribute leads to the occurrence of coal seam water inrush disaster in the actual coal mining process.The fault waterproof coal pillar has the dual function of bearing the load of the overburden and blocking the hydraulic penetration of the water-bearing rock.Reasonable retention of waterproof coal pillar is the key to avoid the occurrence of water inrush accident at the fault.Scientific research on it is of great significance to reduce coal waste,improve the recovery rate of resources and ensure the safety of mine production.Thesis to Chang heng coal mining area 2 F₉ fault as the research background,the related literature at home and abroad of retrieval,and on the field investigation,clear foundation engineering research,the integrated use of theoretical analysis,numerical simulation and field measurement,the method of combining the 4#coal seam in the mining area 4201 face adjacent to the F₉ fault this mining coal pillar are studied,The main conclusions are as follows:(1)the top and bottom of 4201 working face are mainly mudstone and sandstone,with a high degree of rock integrity and less fracture development.However,the coal strength of the working face is weak,and the fracture development is greatly affected by the mining of the working face.(2)The fault distribution is not"planar"in the mechanical model,but"zonal"in a certain width range.The rock mass inside the fault is mixed and relatively broken,and the phenomenon of fragmentation and swelling and mud occurs after flooding,and the water resistance is weak.F₉fault is a kind of fault without water and weak water conductivity.(3)through the establishment of engineering geological model,considering the direction of coal seam and the compound effect along the direction of coal floor,actual fault coal pillars for the field engineering geological theory,and uses FLAC^3D to simulate,and different coal pillar width were analyzed and coal pillar mining under the influence of fault the evolution characteristics of stress,displacement and plastic area,The minimum width of fault coal pillar in 4201working face is determined to be 31.45m.(4)The in-situ monitoring of the internal stress change of the fault coal pillar and the displacement and deformation characteristics of the roadway during the mining process shows that the stress characteristics are consistent with the theoretical analysis,the displacement and deformation amount is small,and the size of the coal pillar is reasonable.Figure[50]table[18]reference[53]...