摘要
为了研究预裂切顶对空区矸体垮落的影响,以柠条塔煤矿厚煤层切顶成巷为工程背景,进行了现场工程试验.根据矸体垮落特征,建立了以基本顶结构断裂步距、顶板岩层垮落滞后性、矸体尺寸、碎石帮充填率及矸体碎胀稳定性为判析参量的表征体系,探究了空区矸体垮落对切顶效果的响应规律,认为提高切顶强度有利于增大来压步距、提高碎石帮充填率、减小矸体稳定距离;增强切顶效果可减小采空区顶板与巷道顶板间的层内黏聚力,加快顶板垮落速度和减小矸块尺寸;增加切顶高度可增大来压步距、提高碎石帮充填率、减小垮落滞后空间和稳定距离.研究结果表明:单孔装药量由1.2kg增加至1.6kg后,平均来压步距增大了约3m,碎石帮充填率增加了约5%,空区矸体稳定距离减小了约20m;当装药量继续增大至2.8kg后,来压步距再次增加了约30%,碎石帮充填率增加了约4%,空区矸体稳定距离减小了约9m.此外,采空区矸体垮落具有明显的切顶高度效应,当切顶高度由7.5m增加至设计高度9.0m后,平均来压步距增加了约2.3m,碎石帮充填率增加了约3.35%,空区矸体稳定距离减小了约23%,但继续增加切顶高度,各参量变化不再明显.
Directional roof fracturing is one of the key techniques of gob-side entry retaining formed by roof fracturing and pressure release.To study the influence of roof fracturing on caving and distribution of the gangues,field tests were conducted in the S1201 mining panel of Ningtiaota coal mine.Based on the caving characteristics of the gangues,the caving step lengthof the main roof,the caving speed of the gob roof,the maximal diagonal size of the gangue body,the filling ratio of the gangue rib and the bulking stability of the gangues ware chosen as key characteristic parameters to explore caving and distribution laws of the gangues under different fracturing conditions.It was found that the variations of roof fracturing played a significant role in caving and distribution of the gangues in the gob area.Enhancing fracturing effects could help increase caving step length of the main roof,improve filling ratio of the gangue rib and reduce unstable range of the retained entry.The gangue size decreased and the caving speed accelerated with enhancement of roof fracturing.The fracturing height had a positive relation with the periodic weighting step and filling ratio of the gangue rib.The results indicate that as the charging amount increased from 1.2 kg to 1.6 kg,the average roof weighting step increased by appropriately 3 m,the filling ratio of the gangue rib increased by 5% and the distance of the gangues to be stabilized decreased by 20 m.As the charging amount continued to increase to 2.8 kg,the average roof weighting step increased by 30%,the filling ratio of the gangue rib increased by 4% and the distance of the gangues to be stabilized decreased by 9 m.In addition,the roof fracturing height also had remarkable effects on gangue caving.As the fracturing height increased from 7.5 mto 9.0 m（design height）,the average roof weighting step increased by 2.3 m,the filling ratio of the gangue rib increased by 3.35%and the distance of the gangues to be stabilized decreased by appropriately 23%.However,as the fracturing
作者
高玉兵
何满潮
杨军
马新根
GAO Yubing;HE Manchao;YANG Jun;MA Xingen(State Key Laboratory for Geomechanics ＆ Deep Underground Engineering, China University of Mining ＆ Technology （Beijing）, Beijing 100083,China;School of Mechanics and Civil Engineering, China University of Mining ＆ Technology （Beijing） Beijing 100083, China)
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2018年第1期21-31,47,共12页
Journal of China University of Mining & Technology
基金
国家自然科学基金资助项目(51674265
51574248)
关键词
无煤柱开采
切顶成巷
矸体垮落
预裂切顶
pillarless mining
gob-side entry retaining formed by roof fracturing
gangue caving
directional roof fracturing
