Study On The Dynamic Evolution Characteristics Of Overburden Separation Layer And The Prevention And Control Of Water Damage In The Separation Layer In The Mining Of Extra Thick Coal Seam

Taking Zhaoxian coal mine in Yonglong mining area as the research background,this paper studies the evolution characteristics of overburden separation layer and the prevention and control measures of separation layer water damage in the mining of extra thick coal seam by theoretical analysis,similar simulation,numerical simulation and other research methods,so as to provide reference for the safety prevention and control of Mines under the same or similar conditions and effectively guarantee the safety production of mines.The results are as follows:(1)Based on the case analysis of typical water disaster in the separation layer,the water disaster in the separation layer can be divided into three types:static water inrush type,dynamic water inrush type and dynamic+static water inrush type.(2)According to the transfer rock beam theory and the calculation formula of "two zones"height,the separation layer and "two zones" height of overburden are distinguished,and then the separation layer of water accumulation is determined.(3)The study on the evolution characteristics of overburden separation in single face and multi face mining in super thick coal seam is carried out by means of similar simulation test and numerical simulation.The results show that:the horizontal fracture alternately presents dynamic development and closure from bottom to top;the development height of the horizontal fracture is positively related to the pushing distance of the working face;after the working face advances to a certain distance,the space height of the separation layer is high It does not develop upward,but with the mining of the adjacent working face,the separated layer fracture develops again,and its opening and strike length will further expand.(4)The risk of water inrush from overburden in the first mining area of Zhaoxian coal mine is evaluated:there is a risk of water inrush from overburden in the first mining area of Zhaoxian coal mine.(5)Based on the occurrence conditions(channel conditions,mechanical conditions)of the water disaster in the separated layer,the prevention and control measures such as controlling the mining height and optimizing the mining technology are put forward.