Study On The Mining Activation Mechanism And The Rational Design Of Waterproof Coal Pillar Of F_6-6 Fault In Kongzhuang Mine

For coal mining,water inrush is one of the main constraints,and the main form of water damage is fault water inrush.The existence of fault destroys the integrity of the aquifers,reduces the distance between the coal seam and the aquifer,and greatly increases the possibility of water inrush in the mine.At the same time,the possibility of the fault zone itself becoming a water inrush channel is greatly increased by the phenomenon of fault activation under the mining condition.The water inrush after fault activation seriously threatens the safe mining of coal resources.F6-6 fault is the large normal faults in Kongzhuang mine.Because of its large drop,long extension and the uncertainty of the properties of transmitting and containing water,it restricts the safe mining of the mine if it is activating in the process of the mining.Therefore,the study on the mechanism of F_6-6-6 fault activation and the design of waterproof coal pillar is of great significance to ensure the subsequent safety mining of the Kongzhuang mine.The paper is based on the collection of data from the exploration and production stages of the Kongzhuang mine.Based on the comprehensive analysis method of theoretical analysis,numerical simulation,experimental research and data analysis,the paper studies the activation mechanism of fault mining and the design of waterproof coal pillar.The following research results have been obtained.?1?On the basis of the analysis results of fault elements and engineering geological conditions,it is considered that the the properties of transmitting and containing water of F_6-6 fault are poor combined with the situation of transient electromagnetic exploration and field practice.?2?Based on the guidance of mine pressure and rock formation control theory,the distribution law of supporting stress in mining seam floor is summarized.And a mechanical model of fault activation under mining is established.At the same time,the necessary condition for fault activation is analyzed.It is considered that the necessary condition of fault activation under mining is that the cohesive coefficient of the rock in the fault is less than or equal to the critical value C_max.?3?Using FLAC3D numerical simulation software to analyze the influencing factors of fault activation.The results show that the possibility of activation in the shallow area of fault coal seam intersection line in F_6-6 fault is greater than that in the deep area.It is proved that the propelling distance of working face is the main influencing factor of fault activation by using variance analysis and grey correlation analysis.?4?Based on the discussion of the theoretical design formula for the fault waterproof pillar,the fault floor water inrush formula combined with width of water flowing fractured zone is selected.Finally,the optimum waterproof coal pillar width for the 7th coal of F6-6 fault is respectively 64.82m,67.33m,58.69m,and 61.42m on the 19,20,21,and 22 exploration lines.And the optimum waterproof coal pillar width for the 8th coal is respectively 68.42 m,73.13m,65.67m and 70.46m.