摘要
大倾角大采高工作面煤壁灾变易诱使支架-围岩系统失衡,导致围岩稳定性控制复杂化,故煤壁灾变防控对保障工作面安全生产十分关键,而科学化防控技术的前提是明晰煤壁失稳孕育机制,为此采用数值计算及理论分析法展开研究。研究结果表明:大倾角大采高工作面煤壁承压倾向分区异化,下部区域应力集中程度较中部、上部高,集中区范围由下至上减小,垂向中部应力值较低,应力极值及走向位置与回采距具有正相关性,煤壁揭露前后邻域承压环境会突变,且承压态随煤体破坏演变异化,煤体承压结构会由非连续态经压实过渡为类连续状,而后整体移动至阈值后发生破断结构离散化。煤壁前方塑性区随采动作用不同幅度扩展,其稳定性受制于回采距及速度,低速回采、回采距离增加时煤壁稳定性逐步降低,塑性破裂发育区煤体为支承压力等动载、静载主承体,煤壁失稳是支承压力与扰动区内煤体自身抗压性能动态失衡,由运移、变形等承压行为量变诱发煤体结构质变而破断失稳,承压非对称性及多向耦合造成煤壁失稳分区及范围倾向扩展。
Coal wall instability of large mining height face in steeply dipping is likely to induce the imbalance support-surrounding rock system,leading to the complexity of the stability control of surrounding rock,so the prevention and control of coal wall disaster of large mining height face in steeply dipping is very critical to ensure safe production,the premise of scientific prevention and control technology is to fully understand the instability breeding mechanism of coal wall during the face mining process,so numerical calculations and theoretical analysis are used to carry out the research.The results show that the bearing zones of coal wall of large mining height face in steeply dipping are alienated,the stress concentration in lower part is higher than that in the middle and upper parts,the concentration range decreases from lower to upper,the stress value in the vertical middle of the coal wall is lower,the stress extreme value and strike position are positively correlated with the mining distance,the pressure environment in the neighborhood before and after the coal wall is exposed will change abruptly,and the pressure state will be alienated with the evolution of coal body damage,the bearing structure of the coal body will change from discontinuous state to a quasi-continuous state through compaction,and then move to the threshold as a whole and the fracture occurs,structure discretization.The plastic zone in front of the coal wall expands to different amplitude with the mining action,and its stability is constrained by the mining distance and speed,coal wall stability gradually decreases with the low-speed mining and the increase of the mining distance.The coal body of the plastic fracture development zone is the main bearing body under dynamic and static loads such as abutment pressure,coal wall instability is the dynamic imbalance between abutment pressure and self compressive performance of coal body in disturbance zone,which is broken and unstable due to the qualitative change of coal body structure induced by the quantitative change of pressure bearing behaviors such as migration and deformation,the asymmetry and multi-directional coupling of bearing under the dip angle effect cause the partition and range tendency expansion of coal wall instability.
作者
张浩
伍永平
解盘石
ZHANG Hao;WU Yongping;XIE Panshi(College of Energy Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Key Laboratory of Western Mine Exploitation and Hazard Prevention,Ministry of Education,Xi’an 710054,China)
出处
《中国矿业》
北大核心
2024年第8期107-114,共8页
China Mining Magazine
基金
国家自然科学基金项目资助(编号:52104147,52174126)
陕西省杰出青年科学基金项目资助(编号:2023-JC-JQ-42)
陕西高校青年创新团队项目资助。
关键词
大倾角
大采高
煤壁
塑性区
失稳机理
steeply dipping
large mining height
coal wall
plastic zone
instability mechanism
