The Study On The Rules Of Overlying Strata Movement And Surrounding Rock Control Of Gob-side Entry Under Close-distance Thin Coal Seam Group Repeatedly Mining

In the process of protective seam mining, seam will be affected by repeatedly mining. Compared with single coal mining, when the affected seam mining,it has special regularity about overlying strata movement and surrounding rock control of gob-side entry. Multi-research methods, such as the computer numerical simulation, similar material simulation and the field practice was synthetically used in this article that based on 66110 work face of Xinzhuangzi Coal, the overlying strata movement and surrounding rock control of gob-side entry in the case of close-distance thin coal seam group repeatedly mining were studied. Through the research, the article not only got the rules of stress distribution, coal deformation, overlying strata movement and "two belts" growth altitude about the seam that was affected by repeating mining, but got the rules of surrounding rock movement of gob-side entry when it was arranged in the seam being affected, and reasonable surrounding rock control methods was put forward on the basis of them. Researches showed, in the early mining stage the upper discharging pressure boundary angle of overlying strata of the seam being affected by repeating mining was 25°larger and the lower boundary angle was 24°smaller than single seam, and in the late mining stage discharging pressure boundary angles of these two ways tend to be the same. overlying strata displacement curve form basin after single seam mining and the curve was bowl after the affected seam mining, the bolting support system and filling process could keep gob-side entry retaining of 66110 work face steady and meet the requirements of gob-side entry retaining under repeating mining.It has the guiding significance of coal mining and gob-side entry retaining in similar conditions.