摘要
为提升充填体的抗拉性能、抗裂性能和韧性,通过抗压、巴西劈裂和落锤冲击试验研究了聚丙烯纤维对充填体强度特征、变形特征、抗冲击性能和能量演变的影响.结果表明:随着纤维掺量增加,充填体强度先增大后减小,弹性模量逐渐降低;掺入纤维后,充填体总耗能增加,达到峰值后释放动能减小,摩擦内能增加,可促进弹性应变能转变为耗散应变能;随着纤维掺量增加,充填体冲击耗能、延性比和韧性系数先增大后减小,终裂形态由"开裂即碎"演变为"裂而不碎";掺入0.10%纤维的充填体抗拉强度、韧性和抗冲击等性能最优.强化机制主要是充填体内纤维"筋网结构"延缓裂纹产生、抑制裂纹扩展和提升能量吸收上限.研究成果有助于提升采场充填体顶板的稳定性,保障矿山生产作业安全.
Abstract
In order to enhance the tensile strength,crack resistance,and toughness of the backfill,the influences of polypropylene fibers on the strength characteristics,deformation characteristics,impact resistance,and energy evolution of the backfill were investigated through uniaxial compression,Brazilian splitting,and drop-weight impact tests.The results indicate that with an increase in fiber content,the strength of the backfill first increases and then decreases,while the elastic modulus gradually decline.The fiber content increases the total energy consumption of the backfill,reduces the kinetic energy release after the peak,increases internal friction energy,and promotes the transformation of elastic strain energy into dissipation strain energy.As the fiber content increases,the impact energy consumption,ductility ratio and toughness coefficient show a tendency to increase and then decrease,and the crack transitions change from"cracking is broken"to"cracking but not broken".The tensile strength,toughness and impact resistance of the backfill with 0.10%fiber content are optimal ones.The reinforcement mechanism involves the"fibrous network structure"within the backfill,which delays the generation of cracks,inhibits crack expansion,and enhances the upper limit of energy absorption.The research contributes to improving the stability of the backfill roof in mining stopes,ensuring the safety of mining operations.
基金项目
国家自然科学基金资助项目(52274126)
中国博士后基金资助项目(2021M693837)
湖南省自然科学基金资助项目(2019JJ50516)
国家重点实验室开放基金资助项目(GZSYS-KY-2020-013)
湖南省教育厅优秀基金资助项目(19B486)
湖南省研究生研究与创新资助项目(CX20220969)
NETL
NSTL
万方数据