Strata Behavior Patterns Of Fully-Mechanized Coal Mining With Super-longwall And Large Mining Height

In this paper,according to the existing conditions of 121304 working face in kouzidong coal mine,it studies the movement characteristics of overlying strata and the law of rock pressure appearance on the overlength and overlength working face of kouzidong mine through numerical simulation,theoretical analysis and field practice,and puts forward the measures for controlling the surrounding rock during the pressure period through the analysis of the adaptability of the hydraulic support.The 121304 working face of kouzidong mine is a "cutter type" design.It is a common working face with long 250m in the early stage.After the working face is completed,the working face becomes a super long working face with a length of 340m.In this paper,the rule of overlying rock failure,the subsidence of the roof,the maximum vertical displacement and the change of stress on the top of the gob area of the 121304 "knives" working face of kouzidong mine are analyzed in detail,and the characteristics of overlying rock movement in the overlength overlength working face are revealed,and the shadow of the overlying area above the goaf is obtained by the change of the length of the face.Ring.By using the "three band" theory,the height and influence factors of the "two bands" of the overlong working face are analyzed in detail,and the periodic pressure step distance of the old roof of the 121304 working face of kouzidong mine is obtained by using the theory of key layer.Through the field practice,it is found that the hydraulic support of the large mining height overlength working face is greatly forced by the overlying rock,and some of the support has been in a large working resistance state.With the increase of the length of the working face,the pressure step of the working face is shorter,the pressure strength becomes larger,the working resistance of the support increases obviously,and the large overlength working face is high.The deformation speed of roadway is large,the influence range of supporting pressure is large,and the influence range of supporting pressure is greater for the two sides,and the deformation speed of the two sides of roadway is faster.According to the specific condition of the overlying strata in the 121304 working face,the working resistance of the hydraulic support is obtained.According to the study of the surrounding rock system of the stope support,the influence factors of the surrounding rock system are obtained,and the improvement opinions on the hydraulic support are put forward according to the factors affecting the stability of the hydraulic support under the overlength working face of the large mining height.Suggestions on surrounding rock control during the period of pressure.The results of this study can provide reference for safety mining and support selection for large and super long working face of kilometer deep well,and provide technical guidance for safe mining of super long working face in kouzidong coal mine.