Study On Surrounding Rock Control Technology Of Dynamic Pressure Coal Roadway On Isolated Land Fully Mechanized Caving Face

Based on the N1206 driving face of Yuwu Coal Mine,the complicated engineering problems are solved by on-the-spot investigation,literature review,numerical simulation and on-the-spot experiment.The practical problems of dynamic pressure roadway in fully mechanized caving face are solved under the condition of isolated island.The surrounding rock control technology of dynamic pressure coal roadway under fully mechanized caving face in isolated land is studied.This paper summarizes the relevant conclusions,puts forward the effective means and method of maintenance of dynamic pressure roadway under the condition of the fully mechanized caving face one the isolated land,and finally applies the control technology of dynamic pressure coal roadway on the fully mechanized caving face on the isolated land to the field practice,and obtains the following main results:(1)The stress distribution characteristics of the surrounding rock under the condition of isolated island are studied.It is found that the stress concentration in the roadway is larger than that in the solid coal side of the roadway.It is easy to produce flaps,and the displacement of roof is large here.(2)During working face mining in isolated island state,there exists stress concentration in the opening and cutting eye of roadway solid coal side.The stress concentration area always moves along with the advance of working face.The stress concentration range is within the advance distance of working face 21 m and during working face mining.Strengthen the maintenance of the roadway adjacent to the coal side of the roadway and prevent the occurrence of safety accidents.(3)The theory of equal-strength beam support is used to calculate the supporting parameters,which is mainly suitable for the case where the roof is non-uniform load.It is calculated that the maximum bending normal stress is produced at 0.577L(L is the width of roadway)distance from the solid coal side of the roadway,and the effective length of anchor rod at different positions of the roadway is calculated by the formula.(4)Using numerical simulation,the supporting scheme is simulated and studied.By comparing the stress,displacement and plastic zone of three different schemes,the reasonable original surrounding rock support scheme is determined by taking the field conditions into account.The bolt with diameter of 2200mm,length of 2400mm,length of 2200mm,length of 2000mm and 1800mm are selected.There are 7 anchors at the top row,the row spacing is 830 ×900mm,the row spacing is 850 ×900mm.Anchor cables are arranged along the heading direction from 2-3-2,the diameter of anchor cables is 22mm,the spacing is 900mm,the length is 8300mm.(5)The results show that the displacement of the roof is 150.65mm,the displacement of the bottom plate is 30.57mm,and the displacement of the left side of the roadway is 450.68mm.When the roadway is not supported,the displacement of the roof is 150.65mm,and the displacement of the left side of the roadway is 450.68mm.The displacement of right side of roadway is 120.23 mm.After the supporting method is adopted,the actual displacement of roof is 17 mm,the actual displacement of bottom plate is 6 mm,the actual displacement of left side of roadway is 13 mm,and the actual displacement of right side of roadway is 8.5 mm.It can be seen from the supporting effect that the supporting mode is reasonable,which is suitable for controlling the surrounding rock of the coal roadway under dynamic pressure of the isolated land fully mechanized caving face,and suitable for popularizing and using.