充填墙提升煤柱性能机理与数值模拟研究

Mechanism and numerical simulation of filling walls improving performance of coal pillar

在对条带煤柱破坏失稳过程和规律分析的基础上,研究了充填墙加固煤柱以提升其性能机理,对低强度膏体和高强度矸石混凝土充填墙提升煤柱性能进行了模拟及分析。结果表明:充填墙加固作用主要体现在对煤柱侧向约束和分担煤柱承载载荷上,充填墙自身强度和对煤柱的侧向约束须满足一定条件才能保证煤柱性能提升效果;充填墙主要限制了煤柱塑性破坏区煤体横向变形并使其承载能力增加而宽度减小;充填墙分担煤柱承载载荷,煤柱整体支承压力都有所降低;高强度矸石混凝土充填墙提升煤柱性能效果优于低强度膏体充填墙,相同宽度下可以分担更多煤柱承载载荷、更有效地限制煤柱横向变形并提供足够的侧向约束力;在模拟地质采矿条件下当矸石混凝土充填墙宽度3 m时为最佳,煤柱性能得到显著提升,又不至过大增加成本,煤柱整体应力分布趋于平缓、均匀,横向变形较小,3 m宽矸石混凝土充填墙可等效7.93 m宽煤柱,煤柱尺寸可减小15.86 m,煤炭采出率可提高17.62%。

Based on the analysis of failure process and law of strip coal pillar, the mechanism of filling walls reinforcing strip coal pillar and improving its performance was studied, and the reinforcing effects of filling walls with low-strength paste and high-strength gangue concrete were simulated and analyzed. The results have shown that the strengthening roles of filling walls mainly show as the lateral rein- forcement action at strip coal pillar and share of its beating loads. The strength of filling wall and lateral reinforcement action should meet the controlled conditions to ensure the performance improvement ef- fects of strip coal pillar. The key action of filling falls in plastic zone of strip coal pillar for improving is restricting the lateral deformation of coal body its beating capacity and decreasing the width of plastic zone. Besides, the filling walls share parts of bearing loads of strip coal pillar so that the whole abutment pressure reduces. The filling walls with high-strength gangue concrete act better in im- proving the properties of coal pillar than the filling walls with low-strength paste： they can share more bearing loads of strip coal pillar more effectively restrict its lateral deformation, and provide enough lateral restraint to ensure the stability of strip coal pillar under the same conditions. The most reasonable width of filling wall with high-strength gangue concrete is 3 m under the simulated geological and min- ing conditions, which can significantly improve the performances of strip coal pillar and does not in- crease the costs too much. The stress distribution of strip coal pillar flattens out, and the lateral deforma- tion is small. The 3-m-wide filling wall with high-strength gangue concrete has equivalent effect to 7.93-m-wide strip coal pillar, the size of strip coal pillar can reduce by 15.86 m, and coal recovery rate can increase by 17.62%.