超大采高综放工作面板裂化片帮特征及合理护帮控制

Investigation on coal face slabbed spalling features and reasonable control at the longwall face with super large cutting height and longwall top coal caving method

针对榆神矿区超大采高综采工作面煤壁板裂化片帮问题,基于金鸡滩煤矿超大采高综放工作面开采技术条件,采用理论分析与工程实践相结合的方法,分析了超大采高工作面煤壁板裂化片帮特征,研究了适宜的护帮板结构形式和合理护帮控制措施。发现板裂化片帮具有多种特征:板状板裂化、“洋葱皮状”板裂化、弹射型板裂化(俗称“炸帮”)和护帮板动载扰动下板裂化片帮,提出并求解了整体式和分体式护帮板承载能力曲线,将护帮板承载能力曲线作为护帮板承载性能评价指标,分别分析和对比了2种结构形式护帮板运动特性及其与煤壁结构耦合关系,从力学特性和运动学特性角度得出整体式护帮板具有承载性能优、灵活性好和结构耦合适应性强等优点,建议在满足护帮高度要求的前提下,优先选用整体式二级护帮板结构。结合工业性生产实践,对煤壁板裂化片帮特征及危害进行分析,提出并讨论了相应的煤壁板裂化片帮防治措施。分析和借鉴同一盘区相邻8.2 m超大采高一次采全厚工作面分体式三级护帮板应用情况及其对煤壁维护效果,结合7.0 m超大采高综放工作面支架-围岩结构耦合关系,认为7.0 m超大采高综放工作面宜采用整体式二级护帮板。生产实践表明:整体式二级护帮板能有效维护超大采高综放工作面煤壁稳定,便于自动化控制和工作面高效开采。

Based on the mining conditions of the longwall face with super large cutting height and longwall top coal caving(LTCC)method at the Jinjitan Coal Mine,China,this paper aimed at solving the problems caused by slabbed spalling at the longwall face with super large cutting height.The feature and mechanism of slabbed failure and spalling at the longwall face with super large cutting height were elaborated and the appropriate structural form of the face sprag and reasonable spalling control measures of coal face were studied through combining the research methods of theoretical analysis and engineering practice.It was found that the slabbed spalling has many characteristics,such as slab-like spalling,onionskin-like spalling,ejection-type spalling and spalling caused by the disturbance of face sprags of hydraulic roof supports.Bearing capacity curves of both the integral-type sprag and the split-type sprag were proposed and calculated,which could also be used as an evaluation index of bearing capacity of the face sprag.The kinetic characteristics and the structural coupling relationships of the coal face and two types of structural forms of sprags were analyzed individually.It is concluded that the integral-type sprag has the advantages of strong bearing capacity,excellent flexibility and high adaptability of structural coupling,which was analyzed from the perspective of mechanical properties and kinematic properties.It is suggested that the integral-type sprag with two plates should be selected in priority under the premise of the required protective height of coal face is satisfied.According to the site observation,the features and damage of slabbed spalling of the coal face were investigated,and the corresponding controlling measures were put forward.The application and the maintenance effect of the split-type sprag with three plates used at the adjacent longwall face with 8.2 m super-large cutting height were analyzed.Combined with the structural coupling relationship between the hydraulic roof supports and surrounding rock at the longwall top coal caving face with 7.0 m super-large cutting height,it is concluded that it is more suitable to adopt the integrated-type sprag with two plates at the longwall top coal caving face with 7.0 m super-high mining height.Production practice shows that the integral-type sprag with two plates could effectively maintain the stability of the longwall coal face with super large cutting height and LTCC,and it could make contribution to automation control and high-efficient mine production.