Study On Stability And Reasonable Size Of Gob-side Driving Entry In Large Mining Height

With the reasonable adjustment of coal industrial structure, the large and medium-sized coal mine will continue to maintain growth momentum in coal production, Large mining height mechanized technology has been widely used, from the mine development, roadway layout, and extend the life of the mine, some coal pillars are always kept in distribution rules for supporting the overlying strata to control the surface uneven settlement. With the increasing of mining depth and mining height, coal pillar size not only has a great influence on the stability of surrounding rock of roadway, but also affects the recovery rate of coal resources. Since the1950s, both in china and abroad has carried out experimental research on the technology of roadway protection about coal pillars. At present, the problem of designing the reasonable coal pillar need to be solved in the Large mining height mechanized technology.Width of chain pillars is one of the important parameters of mine development and production safety. Good coal pillar stability will raise the use efficiency of mine tunnel, reduce roadway maintenance costs, promote the normal production of working face and ensure safety management and improve the coal recovery rate. For in terms of chain pillars of mining roadways, the width is larger, the stability of roadway maintenance easier, but it will directly reduce the extraction rate of coal resources. This significant contradictions in large mining height mechanized working face deserves more attention. Therefore, combining mining roadway stability and recovery rate of coal resources in reasonable way, studying and identifying method to determine the size of the chain pillars in large mining height mechanized working face is particularly important.On the basis of referring to previous studies, in this paper, based on remaining narrow coal pillars under the condition of roadway driving along next goaf in San Yuan Wang Zhuang coal mine’s3045large mining height mechanized working face. Firstly, theoretically analysis the surrounding rock roof structure characteristics of roadway driving along goaf and principle of remaining narrow coal pillar and the pillar’s regularity of deformation and failure. Reasonable designed size of coal pillar is given var the calculation through the coal pillar strength formula of experience. Secondly, use the method of numerical simulation, study and analysis the corresponding state of stress distribution and damage of surrounding rock under the condition of remaining different size pillars.Finally, based on the date by observation on-site, adopt the method of numerical analysis, get the lateral abutment pressure distribution of mined-out area and internal stress distribution of coal pillar after digging lane, analysis the influence on the stability of roadway from the surrounding rock stress environment, research the relationship between coal pillar width and its stability, determine the reasonable width of the narrow coal pillar from the perspective of low stress and easy to maintain. Ultimately determine the reasonable width of chain pillars after overall consideration.The research achievements of this paper will provide certain theoretical basis and reference value in other similar conditions about remaining pillars and roadway support design of roadway driving along next goaf in large mining height face.