沿空留巷不均衡承载特征探讨与应用分析

Investigation and application analysis of unbalanced bearing characteristics of gob-side entry retaining

考虑到沿空留巷围岩应力环境和结构特点,阐述了沿空留巷不均衡承载特征,将沿空留巷基本顶简化为巷旁支护体及实煤体帮共同承载的力学模型,定义实煤体帮承载与巷旁支护体承载比值为沿空留巷不均衡承载系数,得到了不均衡承载系数的计算公式,并分析了不均衡承载系数的影响因素及其变化规律。研究结果表明:实煤体弹性模量和直接顶损伤变量与不均衡承载系数呈正相关;巷旁支护体弹性模量、直接顶弹性模量、巷道宽度、巷旁支护体宽度和实煤体帮支护强度与不均衡承载系数呈负相关。在此基础上,依据沿空留巷不均衡承载系数的变化规律,设计了柳家庄煤矿4211回风平巷沿空留巷围岩控制方案,并通过数值计算和现场矿压监测的方法,验证了高水材料巷旁充填沿空留巷围岩不均衡承载特征。研究成果已成功应用于大采高沿空留巷。

Considering the characteristics of the surrounding rock structure and the stress field for gob-side entry retaining, the unbalanced bearing characteristics of gob-side entry retaining is presented, and the main roof structure is simplified as a mechanical model composed of roadside support body and the roadside coal body. The unbalanced bearing coefficient is proposed, which is defined as the ratio of solid coal body bearing and roadside support body beating, and then an expression is derived for calculating the unbalanced bearing coefficient. The main factors influencing the change law of the unbalanced bearing coefficient are analyzed. The results show that the unbalanced bearing coefficient is positively correlated with solid coal elastic modulus and the immediate roof damage variable, and negatively correlated with the roadside support body elastic modulus, the immediate roof elastic modulus, the roadway width and the roadside support body width. Based on the change law of the unbalanced bearing coefficient for gob-side entry retaining, the control countermeasures are determined against surrounding rocks around gob-side entry retaining of 4211 air-return gate in Liujiazhuang Colliery. The unbalanced bearing characteristics of gob-side entry retaining with high-water materials as roadside backfill is demonstrated by the methods of FLAC^3D numerical simulation and the field monitoring. The research results have been applied to the gob-side entry retaining of large mining height successfully.