| Huaibei Linhuan coalmine with complex hydrogeological conditions had happened limestone water accident many times.The No.10 coal seam is generally under the threat by the water inrush of Taiyuan formation limestone aquifer.Therefore,doing some research on hydrogeological conditions,groundwater dynamiccharacteristics,discharge of limestone aquifer and taking some effective prevention and measures for water inrush to achieve safe production of coalmines are of great significance.In this paper,based on the studied of lithology,permeability coefficient,slurry leakage and logging curve of the 1st4thh limestone of Taiyuan formation,the stratum sedimentary characteristics,karst developmental situation and control mechanism were analyzed.In addition,based on the analysis of limestone water chemistry and hydrodynamic characteristics,the dynamic changes of groundwater level were simulated by Visual Modflow software.The results were used to offer a reference for the drainage analysis of limestone water and the floor limestone water prevention of No.10 coal.The following main conclusions are obtained:1.The main limestone karst cracks development of forms are corrosion cracks and solution opening.Also,the development of limestone karst cracks showed a negative correlation with depth.The Taiyuan formation of three and four limestone are well-developed more than one and two and the karst development is bad under the depth of-500m.The development of limestone karst is mainly affected by the limestone mineral composition,geological structure and groundwater runoff.2.Based on the studies of chemistry characteristics of limestone water,the coalmine district can be divided into three hydrogeological subunits,which include East,Northwest and Southwest subunit.Meanwhile,the analysis on limestone water hydrodynamic characteristics and the recharge,runoff and drainage conditions of Taiyuan formation show that the Taiyuan formation is not fully recharged and the alternation cycle is weak.In the vertical direction,it can be divided into strong runoff zone,weak runoff zone,retention zone.3.By the analysis of pumping test and hydrogeological conditions,the conceptual model and mathematical model of Taiyuan formation limestone are established.The hydrogeological parameters are obtained and the dynamic change process of groundwater flow field are simulated,after the identification and verification of model.The simulated results provided an important guides of discharge evaluation of Taiyuan formation limestone water.4.Combined with the experience of water control in Huaibei coalmine,the control method of limestone water are offered,which“Hydrophobic depressurization and limited pressure mining”is mainly with“Local grouting reconstruction and compression mining”as a supplement. |
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