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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第31卷    第9期    总第270期    2021年9月

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文章编号:1004-0609(2021)-09-2583-13
SHPB冲击荷载下碱化水稻秸秆基尾砂胶结充填体动态力学性能响应
宋学朋1,王 石1,魏美亮1,刘 武1,王晓军1,陶铁军2,王 婕3

(1. 江西理工大学 资源与环境工程学院,赣州 341000;
2. 贵州大学 土木工程学院,贵阳 550025;
3. 江西理工大学 建筑与测绘工程学院,赣州 341000
)

摘 要: 充填采矿过程中,充填体不可避免地经历开挖和爆破等动态扰动,降低了充填体的稳定性。为此,将成本低、来源广的农业废弃物水稻秸秆掺加到尾砂胶结充填体中,采用分离式霍普金森压杆(SHPB)研究了掺不同含量碱化水稻秸秆(经NaOH溶液碱化处理)的充填体在单次与循环冲击荷载下的动态力学特征。结果表明:单次冲击荷载下,所有充填体均具有明显的应变率增强效应,而碱化水稻秸秆的掺入显著提高了充填体的动态抗压强度;随着碱化水稻秸秆含量由0%增加至0.4%,充填体的动态抗压强度先增加再减小,充填体的动态抗压强度增幅14.06%~26.81%,碱化水稻秸秆最佳掺量为0.3%。掺碱化水稻秸秆的充填体应变更大;随着平均应变率增加,充填体的破坏程度逐渐加剧,但是碱化水稻秸秆的掺入更能维持充填体的稳定性,最终发生破坏时块体更大。相同冲击次数的循环冲击荷载下,掺碱化水稻秸秆的充填体动态抗压强度更大,且碱化水稻秸秆最佳掺量仍为0.3%。碱化水稻秸秆表面被水泥水化产物覆盖,提高了其与充填体基体的黏结强度,使碱化水稻秸秆在充填体基体内部起到桥连作用,抑制了裂纹的扩展,为预脱落的块体提供拉力,进而改善了充填体的动态力学特征。碱化水稻秸秆显著提高了充填体的稳定性和抗冲击性能,更有利于提高井下作业的安全性。

 

关键字: 碱化水稻秸秆;冲击荷载;尾砂胶结充填体;动态抗压强度;SHPB

Response of dynamic mechanical properties of alkali rice straw based cemented tailings backfill under SHPB impact load
SONG Xue-peng1, WANG Shi1, WEI Mei-liang1, LIU Wu1, WANG Xiao-jun1, TAO Tie-jun2, WANG Jie3

1. School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China;
2. College of Civil Engineering, Guizhou University, Guiyang 550025, China;
3. School of Architectural and Surveying and Mapping Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China

Abstract:In the process of backfill mining, the backfill inevitably experiences dynamic disturbance, such as excavation and blasting, which reduces the stability of the backfill. Therefore, the low-cost and widely-sourced agricultural waste rice straw was added to the cemented tailings backfill, and the dynamic mechanical characteristics of the backfill with different contents of alkalized rice straw (alkalized by NaOH solution) under uniaxial single and cyclic impact loads were studied by using split Hopkinson pressure bar (SHPB). The results show that, under single impact load, the strain rate enhancement effect of all the backfill is obvious, and the dynamic compressive strength of the backfill is significantly improved due to the addition of alkalized rice straw. With alkalized rice straw content increases from 0 to 0.4%, the dynamic compressive strength of the backfill first increases and then decreases. The dynamic compressive strength of backfill increases by 14.06%-26.81%, and the optimal addition amount of alkalized rice straw is 0.3%. The strain of the backfill with alkalized rice straw is greater. With the average strain rate increases, the damage degree of the backfill gradually intensifies, but the addition of alkalized rice straw can maintain the stability of the backfill, and the block is larger when the final fragmentation failure occurs. Under the cyclic impact load of the same number of impacts, the dynamic compressive strength of the backfill with alkalized rice straw is greater, and the optimal addition amount of alkalized rice straw is still 0.3%. The surface of the alkalized rice straw is covered by cement hydration products, which improves the adhesive strength between the alkalized rice straw and the backfill matrix. The alkalized rice straw plays a bridging role in the backfill, which inhibits the expansion of cracks, and provides tension for the pre detached block, thus, the dynamic mechanical characteristics of the backfill is improved. The stability and impact resistance of the backfill are significantly improved by alkalized rice straw, which is more conducive to improving the safety of underground operation.

 

Key words: alkalized rice straw; impact load; cemented tailings backfill; dynamic compressive strength; SHPB

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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