Feng Du, Zhenhua Li, Songtao Li, Xiaolei Li, Guodong Li, Xuan Fan, Hao Ren, Zhengzheng Cao
School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo, 454000, Henan, China.
Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Jiaozuo, 454000, Henan, China.
Sci Rep. 2024 Jun 6;14(1):13045. doi: 10.1038/s41598-024-63814-1.
When conducting retreat mining in segmented coal pillars, the dynamic evolution of stress and overlying strata structure is more complex than conventional working faces due to the influence of adjacent working faces. Understanding and mastering the dynamic evolution patterns of overlying strata structure after retreat mining in segmented coal pillar working faces is essential for guiding the safe recovery of coal pillar resources under similar conditions. Through statistical analysis of the types of residual coal and the mining techniques, the current research status of residual coal mining system in China has been summarized. Based on the safety recovery technology system for multi-type residual coal pillar resources at Zhaogu No.2 Mine, this paper focuses on narrow coal pillar working faces in sections with fully mined-out areas on both sides. By using research methods such as on-site measurement, theoretical analysis, numerical simulation, and engineering experiments, starting from the stress state analysis and evolution law of coal seam mining, the dynamic evolution law of the overlying rock structure of sectional coal pillars has been mastered. On this basis, a stress arch mechanical model of the mining area is constructed, and the working resistance of the support is calculated and determined, ensuring the safe recovery of the working face. The research results show that before the backfilling of the sectional coal pillar working face, the working face is affected by the overlapping mining of the goaf on both sides, presenting a "bimodal" stress distribution pattern, with a stress concentration coefficient between 1.78 and 3.2. After the extraction of segmented coal pillars, stress arches consisting of high-stress zones form along both the strike and dip of the working face. The structural support provided by stress arches undergoes a dynamic evolution process of "formation-development-elevation-stabilization" as the working face advances. Following the instability and rupture of the lower basic roof hinge structure, the stress-bearing structure shifts to the higher basic roof, continuing to provide support for the surrounding rock stress in the mining space of the working face. A stress arch mechanical model for the dip and strike of the mining area is constructed , and the shape characteristics of the overlying rock stress arch in the coal pillar working face is mastered. Based on the stress distribution law and stress arch evolution characteristics of the surrounding rock of the coal pillar working face, the maximum working resistance of the support in the working face is theoretically calculated to be 9153.48kN. Compared with the measured mine pressure data, the selected support effectively ensures the safety production of the working face.
在分段煤柱进行后退式开采时，由于受相邻工作面的影响，应力及上覆岩层结构的动态演化比传统工作面更为复杂。了解和掌握分段煤柱工作面后退式开采后上覆岩层结构的动态演化规律，对于指导类似条件下煤柱资源的安全回收至关重要。通过对残留煤类型及开采技术的统计分析，总结了我国残留煤开采系统的研究现状。基于赵固二矿多类型残留煤柱资源安全回收技术体系，本文重点研究两侧采空区的窄煤柱工作面。采用现场实测、理论分析、数值模拟及工程试验等研究方法，从煤层开采的应力状态分析及演化规律入手，掌握了分段煤柱上覆岩层结构的动态演化规律。在此基础上，构建了采区应力拱力学模型，计算并确定了支架工作阻力，确保了工作面的安全回采。研究结果表明，在分段煤柱工作面充填前，工作面受两侧采空区重叠开采影响，呈现“双峰”应力分布模式，应力集中系数在1.78至3.2之间。分段煤柱回采后，沿工作面走向和倾向形成由高应力区组成的应力拱。随着工作面推进，应力拱提供的结构支撑经历“形成—发展—升高—稳定”的动态演化过程。下部基本顶铰接结构失稳破裂后，承载结构转移到上部基本顶，继续为工作面采空区围岩应力提供支撑。构建了采区倾向和走向的应力拱力学模型，掌握了煤柱工作面覆岩应力拱的形态特征。基于煤柱工作面围岩应力分布规律及应力拱演化特征，理论计算出工作面支架最大工作阻力为9153.48kN。与实测矿压数据对比，所选支架有效保障了工作面的安全生产。
