膏体充填综采台阶煤壁稳定性半凸力学分析  

Semi-convex mechanical analysis on stability of step coal wall in fully mechanized mining with paste filling

作　　者：常庆粮[1] 袁崇亮 王永忠 张彪[1] 周华强[3] CHANG Qingliang;YUAN Chongliang;WANG Yongzhong;ZHANG Biao;ZHOU Huaqiang(School of Mines,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;Yaojie Coal Power Group Co.,Ltd.,Lanzhou,Gansu 730000,China;State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China)

机构地区：[1]中国矿业大学矿业工程学院,江苏徐州221116 [2]窑街煤电集团有限公司,甘肃兰州730000 [3]中国矿业大学煤炭资源与安全开采国家重点实验室,江苏徐州221116

出　　处：《中国矿业大学学报》2022年第1期46-55,共10页Journal of China University of Mining & Technology

基　　金：国家自然科学基金面上项目(52174130)。

摘　　要：通过细长杆失稳理论,建立台阶半凸力学模型,通过凸模柔度来判断与之相适应的临界载荷公式,并通过能量法近似求出模型的长度因数与稳定系数计算公式,进而得到台阶半凸力学模型失稳时所需的临界力、临界应力和纵向弯曲失稳校核判据;采用FLAC^(3D)数值模拟研究顶煤、中煤、底煤高度比分别为1∶1∶1,2∶2∶1两种不同割煤方案时煤壁前方支承压力、水平应力、水平位移以及工作面周围竖直应力分布.研究表明:煤壁发生片帮失稳所需的临界应力与其柔度有关,且煤壁柔度与长度因数呈正相关,长度因数与下台阶高度呈负相关,因此煤壁的柔度越小,煤壁片帮所需的临界应力就越高,抵抗失稳片帮的能力越强,所以可通过增加下台阶高度来提高煤壁抵抗失稳片帮的能力;不同方案割煤时,煤壁的垂直应力均小于片帮临界应力,因此不会发生失稳片帮;煤壁的上台阶高度减小,水平应力相应增加,位移量减小,下台阶的存在约束了上台阶煤体水平变形,使得煤壁前方支承压力变大,煤壁的承载能力增强,煤壁煤体稳定性增加,因此,可通过增加下台阶高度,提高煤壁稳定性.最终确定窑街三矿水平分层膏体充填开采的台阶高度比为1∶1∶1,为研究特厚急倾斜煤层采用短机身、大采高特殊采煤机割煤时所形成的台阶煤壁稳定性问题提供可靠理论支撑.The step semi-convex mechanical model was established by instability theory of slender rod,and the corresponding critical load formula was determined by the flexibility of punch.The formula for calculating the length factor and stability coefficient of the model were approximately obtained by energy method,and then the critical force,critical stress and criterion required of longitudinal bending instability for the instability of the step semi-convex mechanical model were obtained.The abutment pressure,horizontal stress,horizontal displacement in front of coal wall and the distribution of vertical stress around the working face were researched by FLAC^(3D) numerical simulation when the height ratios of top coal,medium coal and bottom coal were 1∶1∶1 and 2∶2∶1,respectively.The results show the critical stress required for spalling instability of coal wall is related to its flexibility,and the flexibility of coal wall is positively correlated with the length factor,and the length factor is negatively correlated with the lower step height.Therefore,the smaller flexibility of coal wall,the higher critical stress required for coal wall spalling,and the stronger the ability to resist instability spalling.Based on this,the ability of coal wall to resist instability spalling can be improved by increasing the height of lower step.The vertical stress of coal wall is less than the critical stress of rib spalling in different schemes of coal cutting,so there will be no instability rib spalling.The height of the upper step of the coal wall decreases,the horizontal stress increases accordingly,and the displacement decreases.The existence of the lower step restricts the horizontal deformation of the upper step,which increasing the support pressure in front of the coal wall,enhancing the bearing capacity,and increasing the stability of the coal wall.Therefore,the stability of coal wall can be improved by increasing the height of lower step.Finally,the step height ratio of horizontal layered with paste filling mining in Y

关 键 词：半凸力学模型 台阶煤壁 能量法 膏体充填 

分 类 号：TD355[矿业工程—矿井建设]