Study On The Process Of Water Inrush From Sandstone Aquifer In The Roof Of Coal Mine Roadway

Mine water damage is one of the five major disasters in coal mines.The sandstone aquifer is covered by the roof of the return roadway of the Maiduoshan Coal Mine.The distance is 8m-28m.During the excavation process,water inrush accidents occur many times.The reason for the water inrush is due to the roadway.The water guiding channel of the roof communicates with groundwater or surface water,or directly exposes the aquifer and causes water inrush.Therefore,understanding the relationship between roof stability and water inrush in roadway excavation is of great significance for effectively preventing mine water inrush disaster.This paper takes the example of water inrush in the backwater tunnel of Maiduoshan Coal Mine as the engineering background.Through theoretical and numerical simulation methods,the causes of water inrush in the roadway of coal mine roadway are analyzed.The main research results are as follows:(1)Analyze and summarize the water inrush type of coal mine roadway from the nature of water-filled water source,the nature of aquifer,the characteristics of aquifer medium,the location of water inrush and the nature of water inrush,and combine the theoretical research to obtain the roadway for coal mine roadway.The form of destruction of the working face.(2)Based on the limit analysis method,the two-dimensional maneuvering field model is established.At the same time,the limit analysis upper bound theorem is used to derive the ultimate failure equilibrium relation,and the ultimate damage height expression of the maneuvering field of the coal mine roadway is derived,indicating its main influence.The factors include surrounding rock strength parameters,overburden aquifer,roadway excavation height and roadway depth,and the influence of the above influencing factors on the ultimate failure height is obtained:the ultimate failure height is inversely proportional to the surrounding rock strength,and the roadway excavation height and roadway The buried depth is proportional to the height of the ultimate failure when the top plate is occupied by the sandstone aquifer,and the danger of water inrush from the roadway is considered.failure height is obtained:the ultimate failure height is inversely proportional to the surrounding rock strength,and the roadway excavation height and roadway The buried depth is proportional to the height of the ultimate failure when the top plate is occupied by the sandstone aquifer,and the danger of water inrush from the roadway is considered.(3)Based on the example of water inrush in the backwater tunnel of the Maiduoshan coal mine,the numerical simulation of the roadway of the Maiduoshan coal mine was carried out by FLAC3D,and the theoretical value and numerical simulation results were compared and analyzed.The results show that the distribution of the plastic zone obtained by the numerical simulation is consistent with the hypothetical instability sliding failure;the ultimate failure height is similar to the numerical value of the plastic zone,which verifies the rationality of the theoretical calculation.(4)For the expression of the ultimate failure height of the working face of coal mine roadway,it has certain engineering significance:when there is a sandstone aquifer at a certain distance from the roof of the coal roadway,the ultimate damage height expression is used to judge the water inrush in the coal mine roadway.To provide a theoretical basis for explaining the cause of water inrush in the roadway of Maiduoshan Coal Mine.