Mine pressure behavior law of large mining height fully mechanized caving face in near shallow seam under multi-layer thick and hard roof
In view of the strong mine pressure problems such as large shrinkage of large period weighting support column,high stress concentration coefficient of coal pillar and poor stability under the condition of near-shallow buried multi-layer thick and hard roof in Yushen mining area,numerical calculation,microseismic and coal body stress monitoring were used to study the fracture movement of overburden rock and the weighting law of working face.The results show that:Firstly,in the fracture movement of overburden rock,the large vertical separation space and bottom-up sequential alternate collapse of multi-layer thick and hard roof create the space-time basis of high and low level combined fracture of roof,which is the key inducement of large period weighting enhancement;at the same time,the spatial and temporal evolution of coal pillar stress is controlled by the fracture and collapse of multi-layer thick and hard roof.Secondly,in terms of mine pressure behavior,the average shrinkage of support column can reach 945mm under the large cycle,the continuous distance is 12.10 m,and it can be composed of 2～5 consecutive strong weightings;the stress concentration factor of roadway coal pillar reaches 1.80～2.30,and the influence range is 126 m in front of the working face to 471.3 m in the rear,which has obvious characteristics of high strength,large range and long rising period.Aiming at the prevention and control of strong mine pressure under this condition,the technical ideas of"weakening lower roof,optimizing fracture structure"and"weakening upper roof,changing fracture sequence"were put forward,respectively,and favorable application results were obtained.
Yushen mining areanear shallow buried coal seamthick and hard roofstrong mine pressure preventionmicroseismic monitoring
NETL
NSTL
万方数据
