综放开采顶煤破坏的应力驱动原理与破碎程度确定方法研究  

Research on the stress driven principle and fragmentation degree determination method for top-coal failure during fully mechanized caving mining

作　　者：孙志猛 张瑶 李明 张文辉 王兆会[2,3] 孙玉嵩 安君琦 张友源 郭心洋 SUN Zhimeng;ZHANG Yao;LI Ming;ZHANG Wenhui;WANG Zhaohui;SUN Yusong;AN Junqi;ZHANG Youyuan;GUO Xinyang(Honghui No.1 Coal Mine Branch of Gansu Jingmei Energy Co.,Ltd.,Baiyin,Gansu 730918,China;School of Energy and Mining Engineering,China University of Mining and Technology-Beijing,Haidian,Beijing 100083,China;Engineering Research Center of Green and Intelligent Mining for Thick Coal Seam,Ministry of Education,Haidian,Beijing 100083,China)

机构地区：[1]甘肃靖煤能源有限公司红会第一煤矿分公司,甘肃省白银市730918 [2]中国矿业大学(北京)能源与矿业学院,北京市海淀区100083 [3]厚煤层绿色智能开采教育部工程研究中心,北京市海淀区100083

出　　处：《中国煤炭》2025年第4期25-35,共11页China Coal

基　　金：国家重点研发计划资助项目(2022YFC2904002);中央高校基本科研业务费专项资金资助(202411036)。

摘　　要：顶煤破碎效果是影响厚煤层能否选择综放开采的核心要素,为提高顶煤采出率和放煤效率,采用理论分析、室内实验和现场实测手段对顶煤破碎过程与机理进行分析。顶煤在最大主应力加载和最小主应力卸载复合作用下发生破坏,破坏后具备冒放能力,冒放性的优劣取决于顶煤破碎程度;定义顶煤破坏危险性系数k为应力圆的圆心至强度曲线垂直距离同应力圆半径之比,随着最大主应力的加载和最小主应力的卸载,系数k减小,顶煤破坏风险升高,破坏条件为k=1;顶煤破坏危险性系数对最小主应力的敏感度高于最大主应力,单纯加载最大主应力碎煤难度高于卸载最小主应力,两者所需应力增量比为Δσ1/Δσ3=(1+sinφ)/(1-sinφ);顶煤裂隙发育程度同体积塑性应变呈正比,采用后者表征顶煤破碎程度,建立了顶煤体积塑性应变预测模型和顶煤主应力分布确定方法,顶煤体积塑性应变对最小主应力的敏感度高于最大主应力,单纯加载最大主应力增强顶煤冒放性的难度高于卸载最小主应力,最大、最小主应力增量相同,两者引起的体积塑性应变增量比为Δε_(1)/Δε_(3)=(1-sinφ)/(1+sinφ);实验结果表明,卸载最小主应力导致煤体承载能力降低,体积塑性应变和裂隙发育程度升高,同理论分析结果一致,实测顶煤体积塑性应变非线性分布特征同理论结果吻合,表明体积塑性应变预测模型可正确判别顶煤破碎程度。Top-coal fragmentation after crushing is fundamental to the adaptability of longwall top-coal caving to thick coal seams.In order to improve top-coal recovery and caving efficiency,progressive failure process and associated mechanical mechanisms were studied by theoretical analyses,laboratory tests and field measurements.Top coal failed under the influence of composite effects of maximum principal stress loading and minimum principal stress unloading,and caved after failure.However,the caving property was dependent on the failure extent.The ratio of vertical distance between center of the stress circle and the strength line to stress circle radius was defined as potential failure coefficient k of top coal.As the maximum principal stress was loaded and the minimum principal stress was unloaded,the coefficient k decreased and the risk of top coal failure increased,and the failure condition was k=1.The sensitivity of the top coal failure risk coefficient to the minimum principal stress was higher than that to the maximum principal stress,simply loading the maximum principal stress of broken coal was more difficult than unloading the minimum principal stress,and the ratio of maximum and minimum principal stress increments needed to break top coal wasΔσ1/Δσ3=(1+sinφ)/(1-sinφ).Fracture development degree was positive proportional to volumetric plastic strain,so the latter was utilized to denote failure extent of top coal.A prediction model for volumetric plastic strain of top coal and a method for determining the distribution of main stresses in top coal were established,the sensitivity of the plastic strain of the top coal volume to the minimum principal stress was higher than that to the maximum principal stress,the difficulty of enhancing the top coal caving performance by simply loading the maximum principal stress was higher than unloading the minimum principal stress,the maximum and minimum principal stress increments were the same,and the ratio of volumetric plastic strain increments caused by the two was�

关 键 词：顶煤破坏机理 加卸载复合作用 顶煤冒放性 体积塑性应变 

分 类 号：TD324[矿业工程—矿井建设]