Evaluation Of Main Mining Geological Conditions And Prediction Of Gully Burst Water Risk In Shaliang Field

Shaliang Minefield is located in the northwestern part of the Miaohagu mining area which belongs to the Jurassic coalfield in the northern of Shaanxi province.The coal seam is buried shallow and the bedrock is thin.When the area with thin bedrock thickness is subjected to different degrees of weathering,weak roof bedrock will appear in local areas.All of these have certain influence on the driving of mine roadway and the safe mining of coal seam.The faults are relatively developed in the minefield,and the 2-2 coal seam and 5-2 coal seam in the local area of the channel are shallower.There is a risk of water bursting in the channel after the coal seam mining is finished.In this paper,shaliang minefield is taken as the research area to carry out the research on the prediction and evaluation of structural complexity,classification of coal seam roof and prediction of gully water burst risk.Through the study and analysis of the geological conditions of shaliang minefield,geophysical exploration and drilling to reveal the fault situation,the three main control factors for the analysis and evaluation of the structural complexity of shaliang minefield are as follows:fractal dimension value,strength index and density.According to the combined results of the AHP and the entropy method,the main control factors are assigned weight values,and the thematic maps are superimposed by ArcGIS,and the structural complexity of the Shaliang minefield is predicted and evaluated,and the range of the minefield The degree of complexity is divided into 4 grade areas,including complex structure area,more complex structure area,medium structure area,and simple structure area.The middle and western part of shaliang well field is a complex structural area.The middle part is a complex structural area.The area to the north of The DF2 fault is a medium structural area.The area south of the DF2 fault and between the DF2 fault and the DF3 fault are simple structural areas.Through the statistical analysis of the drilling data of the 5-2 coal seam in Shaliang Minefield,the direct roof and basic roof rock structure types of the 5-2 coal seam are classified.Among them,the direct roof rock structure types within the mine field are divided into non-direct roof and there are four types of fine sandstone,medium sandstone and mudstone.The basic top rock layer structure types are divided into three types:fine sandstone,medium sandstone and coarse sandstone.Using theoretical calculations and comprehensive analysis methods,combined with drilling statistics in the study area,the relationship between the direct roof and basic roof lithology of the 5-2 coal seam,the relationship between rock formation and rock strength,the initial step distance and the initial pressure equivalent and base load ratio The relationship among parameters such as,caving ratio,rock strata strength,mining height,etc.,has determined and used the prediction model of the direct roof initial stepping distance and the old roof initial pressure equivalent,and the direct roof type and basic The top type is predicted by partition.Combining the results of flood flow prediction in the channel in the study area,based on the superimposed analysis of the water breach classification standards and the prediction results of the channel fracture safety zoning,the channel water burst risk evaluation standard was formulated,and the risk was divided into:safety zone,According to this classification standard,the channel water burst amount during the flood period of the trading ditch channel is predicted,and the channel cracking safety is combined with the five levels of low risk,small risk,medium risk,and strong risk.Based on the predictive results,we finally get the regional prediction maps of water burst risk in different sections of the Maimaigou channel during the mining process in the 2-2coal and 5-2coal storage areas.In the mining process of 2-2 coal,the degree of water bursting danger within its occurrence range is moderate.In the mining process of 5-2 coal,the north of DF2 fault in the gully area is mainly relatively safe section,while the south of DF2 fault is mainly dangerous section.