Study On The Pressure Law Of Fully Mechanized Mining Plane Under Large-scale Irregular Magmatic Rock Erosion Conditions

Based on high hardness of magmatic rock,working face roof leakage and slowness of advance under the condition of the fully mechanized coal face which has been eroded by a wide range of irregular magmatic erosion,in this paper,Ⅱ3714W mining face of Huaibei Shuanglong mining company as an engineering background,the regularity of rock pressure and stress distribution in the fully mechanized mining face under large-scale irregular magmatic rock erosion conditions are analyzed by means of theoretical analysis,physical similarity simulation and numerical simulation.(1)Through theoretical and physical simulation analysis,it can be seen that the structural characteristics of the overlying strata in the stope under the condition of magmatic rock erosion are summarized,and the structural stability of the roof of the working face is analyzed.After the fracture of the first fine sandstone layer,the rock mass can form a triangle arch structure,and the fractured basic roof block continues to support the upper stratum;By establishing the structural mechanics model of "support-surrounding rock" under different erosion conditions,the load of the support under different erosion conditions was calculated.(2)Through the study of similitude simulation,the first fine sandstone layer of the roof covering on the working face is an obvious overburden sub-key layer,which plays a main control role in the local overburden strata activity on the stope.The caving height of overlying strata under the influence of initial pressure is obviously higher than that in the process of periodic pressure.However,under the three roof conditions of non-erosion,partial erosion and severe erosion of coal seam,the basic roof caving form of the roof on the stope is also completely different,and the "masonry beam" structure formed by overlying strata also changed during normal mining.(3)Through numerical simulation research,because the overburden load directly on the direct roof of the underlying hard magmatic rock,under the condition of partial erosion of coal seam,the peak value of supporting pressure in front of coal wall of working face is larger than that of non-erosion and severe erosion.At the same time,a stress release zone is formed behind the goaf on the working face,and the tensile stress value of the goaf is larger under partial erosion condition;Under the condition of partial erosion of coal seam,the maximum value of direct roof subsidence is obviouslylarger than the other two conditions,and it is mainly concentrated in the central area along the goaf strike.(4)In the erosion section of magmatic rock,the method of combining coal machine with blasting is adopted to break the rock,so the blasting technology,blasting parameters and safety technical measures are put forward.And the advance degree of mining in working face before and after adopting measures is compared and analyzed.Figure [54] Table [9] Reference [70]...