Risk Assessment Of Water Inrush From Floor With Fault In The Western Area Of The Xingcun Coalmine

This paper presents a risk assessment of coalmining-induced groundwater inrushfrom the floor with faults in the Xingcun Coalmine．Based on an extensive collectionof data, such as drilling data，geophysical prospecting，hydrogeological conditions ofthe Ordovician limestone aquifers， theoretical analysis， numerical simulation andmulti-source information fusion technology are adopted to evaluate the risk ofunderground water inrush from the floor due to mining Coal Seam No.3．The mainresults are as follows：（1） When Coal Seam No.3is mined in the western area of the XingcunCoalmine, the aquifers of sandstone and Limestone No.3are the direct groundwatersource．However，their hydrogeological condition is simple because of poor waterrecharge and static reserves， which will have little possibility to influence the coalmine safety．Some parts of the coalmine are influenced by the Ordovician limestonewith a large water pressure and a large density of fault， which should be indeedfocused on because of it’s easily cause of groundwater inrush accidents from thefloor．（2）Based on the analysis of the main factors affecting groundwater inrush fromthe floor with faults in the Xingcun Coalmine，including fault structure，conductivityof aquifer，the water pressure of floor aquifer，aquiclude and mine pressures，thispaper simulates the influences of floor with faults，integrate floor without fault，flooraquifuge lithological properties of different combinations and cutting heights on thefloor damage degree by using the code FLAC3D．The combination of the theoreticalanalysis and numerical simulation is more intuitive to accurately describe theinfluencing factors in groundwater inrush process．（3）The following indexes for groundwater inrush risk evaluation are selectedcombined with the actual situation of the Xingcun Coalmine: fault density， faultintersections and endpoints，the index for fault scale，pressure of aquifer，effectivethickness of aquifuge，depth of Seam No.3mining，and cutting height of coal seam．The weight of evaluation index is calculated by using the entropy weight coefficientmethod, principal component analysis， analytic hierarchy process． A model ofgroundwater inrush from fault in floor is constructed by using multi-sourceinformation fusion technology for the composition and superposition of evaluationindexes． （4）The commonly used Otsu method in the image segmentation，maximumentropy value in information theory and natural classification are introduced toestablish the threshold groundwater inrush risk zoning from fault in floor．Accordingto the three kinds of groundwater inrush risk zoning，the optimal model of the entropyweight method was chosen by combining with the specific characteristics ofgroundwater inrush of the Xingcun Coalmine in this paper．Comparisons among themethod used in this paper with the traditional method show that the entropy weightmethod proposed in this paper is more suitable for the risk assessment of groundwaterinrush from floor with faults．...