Research On Entry Floor Failure Mechanism And Entry Support In Jiangjiahe Coal Mine

Research on the failure mechanism and support in the surrounding rock of rectangular roadway is one of the important subjects in the construction and production of coal mine.In this paper,based on the engineering background of ZF204 transporting crossheading in Jiangjiahe coal mine,the mechanism of the floor heave and the support scheme are researched by field measurement,physical simulation,numerical simulation and theoretical calculation.The main conclusions are as follows:Through physical simulation,it can be concluded that the damage of the ZF204 transporting crossheading,the main the wall of roadway settlement began to help the foot destruction,the floor by the help of coal pillar pressure uplift.the wall of roadway damage caused by rock limit equilibrium arch increases,and the original supporting roof side effect is reduced,rib spalling in coal mine,serious damage occurs,the broken coal,the floor of the waist failure,roof separation and failure occurs,the roof subsidence,appear net phenomenon.The mechanical model of the roadway floor failure is established,and the ultimate bearing capacity of the two ribs is calculated by taking into account the floor weight and the weight of the floor slab under the condition,and the variation curves of the ultimate bearing capacity and the cohesive force and the inner friction angle of the roadway floor are drawn.the internal friction angle is constant,the ultimate bearing capacity of two ribs floor and cohesion into a linear relationship,the greater the angle of internal friction and cohesion force,the greater slope roadway bearing corresponding limit,and cohesive force when the friction angle is small,the ultimate bearing capacity is small,the ultimate bearing capacity with reduce the internal friction angle,just began to decrease faster,then slow down,tends to be stable.Based on the analysis of the floor failure range,it is concluded that the hbd of the bottom of the rock mass and the maximum failure depth of the floor are hd max and the linear relationship between the maximum failure depth of the floor and the width of the L of the limit equilibrium zone of the coal seam is φ.If l1max +l2max,W0 is the excavation width of roadway floor in a "W" failure;if lmax+l2max≥W0,The failure of roadway floor has a significant influence on the two ribs and roof,calculate the floor damage maximum roof damage caused by the "limit equilibrium circle" theory.The limit equilibrium zone of supporting conditions,the transport capacity along the tank bottom limit is 23.42MPa,maximum failure depth of floor is 3.57m,the failure depth of the two ribs of the feet of 1.67m,the floor failure caused by roadside failure depth is 1.52m,the roof natural arch height is 3.24m,the limit equilibrium arch height is 5.45m.Selecting combine support with cable anchor and bottom anchor.