Study On Geological Control And Potential Risks Of Deep-seated Karst Water In Chensilou Coal Mine

Chinese shallow coal resources gradually exhausted,the future of mine mainly in the deep.Deep-seated coal mining zones are mainly concentrated in the Carboniferous-Permian.In the Carboniferous-Permian,there are multi-layer carbonate strata,which are rich about groundwater and controlled by many factors such as groundwater recharge,runoff,drainage,distribution and hydrogeochemical characteristics.At the same time,in the process of deep-seated coal mine,the abnormal development of faults changes the original Karst characteristics,so that the Karst hydrodynamic field is very different from the original Karst hydrodynamic field,and to form a unique pattern of circulation.Abundant Karst groundwater will form water inrush accidents under the condition of mine damage of floor.Based on Chensilou coal mine situation and information,about Chensilou Karst water of coal mine geological control and the mode of"thin down-guide"theme,with karst Chensilou coal mine of Taiyuan formation as the research object,combined with the feature of Chensilou coal structure,hydrogeological characteristics,studies reveal hidden Karst development rule of the degree and reveal the hidden Karst geological control;The hydrodynamic field,the law of water level change and the hydrogeochemical field are analyzed to reveal the"drawing-guidance"model.In order to reduce the risk of Karst water inrush,numerical simulation was used to analyze the law of water inrush and evaluate the potential risk.The Taiyuan formation and Majiagou formation are developed in the deep-seated the coal mine,and the Taiyuan Formation mainly develops 11 layers of limestone.Rich Karst water is characterized by unfilled tiny fracture and solution pores,vertical development of Karst hydrogeology,down from the L₁₀ plane distribution law"weak"Naqiang north,difference obvious,in the south of Chensilou anticlinorium Taiyuan formation limestone is under natural fracture zone,pointing to the Chensilou syncline,at the same panel each limestone with synchronous water enrichment regularity of augmentation and reduction,floor grouting engineering to accelerate the Taiyuan formation of Karst water hydraulic connection and deep cycle.Under the dual action of structure and mining,the deep-sedted Karst hydrodynamic field in coal mine has evolved remarkably.The karst characteristics revealed by floor grouting holes indicate that mining activities lead to a large direct drainage of the latent Karst water in the upper rock section of Taiyuan formation,and indirect drainage of the Karst water in the middle and lower sections.Water level observation shows that thin limestone aquifer,the karst water level of Karst systems greatly reduce runoff direction pointing to the mining activities of mining area,the coal mining disturbance and destruction of Taiyuan formation make mine a strong"sink"of groundwater flow field,the Karst water"traceability"pointing to the shallow mining field outcrop area,the karst water circulation in mining activities under the"guidance"to deepen.The hydrogeochemical test results show that mining leads to the deepening of karst water cycle and the increase of mineralization.At the same time,the rock karst system of Taiyuan formation is divided into south wing subsystem,north wing graben subsystem,north wing north subsystem and north wing east system.The water-proof performance and bearing characteristics of deep-seated coal floor are the basic conditions for evaluating water-inrush.The upper section of Taiyuan formation is a typical"extremely soft+extremely hard"lithologic combination.The natural tensile strength of the floor is low and the failure is easy to be tensioned.The three layers of the sand rock segment,clay powder sandstone segment and silt clay rock are all weak water and weak water formation.The uninterruptable test of water resistance coefficient of porous composite coal floor shows that the rock strata under the floor are divided into the main effective water-proof section above the bottom of L₁₀ limestone,and the water-proof section from the bottom of L₁₀ to the top of L₈ as the extension.Under the present condition,the karst-water high pressure zone in the floor consists of the synclinal core of Chensilou and Gaoliuwan in the south wing.FLAC_3D numerical simulation software was used to establish the mechanical model of coal mining under pressure on the working face of coal mining at the level of 2-650m and the comprehensive simulation analysis results showed that the mining failure of the complete floor can cause water inrush,which has potential risks and needs to be prevented by corresponding measures.This thesis has 57 figures,10 tables,74 References.