Bearing characteristics of coal pillars based on modified limit equilibrium theory  

作　　者：Wang Xiangyu Bai Jianbiao Wang Ruofan Sheng Wenlong 

机构地区：[1]School of Mines, Key Laboratory of Deep Coal Resource Mining, Ministry of Education of China, China University of Mining & Technology [2]State Key Laboratory of Coal Resources and Mine Safety, China University of Mining & Technology

出　　处：《International Journal of Mining Science and Technology》2015年第6期943-947,共5页矿业科学技术学报（英文版）

基　　金：supported by the National Programs for Fundamental Research and Development (No. 2013CB227900);the National Natural Science Foundation of China (Nos. 51204166, 51174195 and 51474209);the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)

摘　　要：There are two states for the coal-mass on the goal-side which is in stress equilibrium： the state of limit equilibrium （the bearing stress in the coal-mass equals its ultimate bearing stress） and the state of non- ultimate equilibrium （the bearing stress in the coal-mass is less than its ultimate bearing stress）. To ana- lyze the bearing characteristics of a coal pillar in the state of limit equilibrium and guide the design of pillar width, we established a mechanical analytical model of the non-ultimate equilibrium zone in the coal-mass on the goal-side combined with the limit equilibrium theory as well as adopting the methods of theory analysis and mechanical analysis based on the assumption of a state of non-ultimate equilibrium. The width correction coeffident of the limit equilibrium zone has been given. The influence of mining depth, stress concentration coefficient of the surrounding rock, the non-limit strength of the coal-mass and stability of the coal rock interface has been studied. On this basis, we have confirmed that when the width ofa longwall mining face roadway protection coal pillar is between 11.6 m and 13.16 m in No. 4 coal seam of Xinrui coal mine in Lvliang in Shanxi province the elastic core region in the coal pillar can be assured and the roadway will be located in the area of lower stress which is outside the peak stress. So the revised width of the limit eauilibrium zone is more oractical.There are two states for the coal-mass on the goaf-side which is in stress equilibrium: the state of limit equilibrium(the bearing stress in the coal-mass equals its ultimate bearing stress) and the state of nonultimate equilibrium(the bearing stress in the coal-mass is less than its ultimate bearing stress). To analyze the bearing characteristics of a coal pillar in the state of limit equilibrium and guide the design of pillar width, we established a mechanical analytical model of the non-ultimate equilibrium zone in the coal-mass on the goaf-side combined with the limit equilibrium theory as well as adopting the methods of theory analysis and mechanical analysis based on the assumption of a state of non-ultimate equilibrium. The width correction coefficient of the limit equilibrium zone has been given. The influence of mining depth, stress concentration coefficient of the surrounding rock, the non-limit strength of the coal-mass and stability of the coal rock interface has been studied. On this basis, we have confirmed that when the width of a longwall mining face roadway protection coal pillar is between 11.6 m and 13.16 m in No. 4 coal seam of Xinrui coal mine in Lvliang in Shanxi province the elastic core region in the coal pillar can be assured and the roadway will be located in the area of lower stress which is outside the peak stress. So the revised width of the limit equilibrium zone is more practical.

关 键 词：Coal bearingZone of non-ultimate equilibriumWidth correction coefficient of plastic zoneWidth of roadway protection pillar 

分 类 号：TD822.3[矿业工程—煤矿开采]