(1. 江西理工大學(xué) 資源與環(huán)境工程學(xué)院，贛州 341000；
2. 貴州大學(xué) 土木工程學(xué)院，貴陽(yáng) 550025；
3. 江西理工大學(xué) 建筑與測(cè)繪工程學(xué)院，贛州 341000)
摘 要: 充填采礦過(guò)程中，充填體不可避免地經(jīng)歷開(kāi)挖和爆破等動(dòng)態(tài)擾動(dòng)，降低了充填體的穩(wěn)定性。為此，將成本低、來(lái)源廣的農(nóng)業(yè)廢棄物水稻秸稈摻加到尾砂膠結(jié)充填體中，采用分離式霍普金森壓桿(SHPB)研究了摻不同含量堿化水稻秸稈(經(jīng)NaOH溶液堿化處理)的充填體在單次與循環(huán)沖擊荷載下的動(dòng)態(tài)力學(xué)特征。結(jié)果表明：?jiǎn)未螞_擊荷載下，所有充填體均具有明顯的應(yīng)變率增強(qiáng)效應(yīng)，而堿化水稻秸稈的摻入顯著提高了充填體的動(dòng)態(tài)抗壓強(qiáng)度；隨著堿化水稻秸稈含量由0%增加至0.4%，充填體的動(dòng)態(tài)抗壓強(qiáng)度先增加再減小，充填體的動(dòng)態(tài)抗壓強(qiáng)度增幅14.06%~26.81%，堿化水稻秸稈最佳摻量為0.3%。摻堿化水稻秸稈的充填體應(yīng)變更大；隨著平均應(yīng)變率增加，充填體的破壞程度逐漸加劇，但是堿化水稻秸稈的摻入更能維持充填體的穩(wěn)定性，最終發(fā)生破壞時(shí)塊體更大。相同沖擊次數(shù)的循環(huán)沖擊荷載下，摻堿化水稻秸稈的充填體動(dòng)態(tài)抗壓強(qiáng)度更大，且堿化水稻秸稈最佳摻量仍為0.3%。堿化水稻秸稈表面被水泥水化產(chǎn)物覆蓋，提高了其與充填體基體的黏結(jié)強(qiáng)度，使堿化水稻秸稈在充填體基體內(nèi)部起到橋連作用，抑制了裂紋的擴(kuò)展，為預(yù)脫落的塊體提供拉力，進(jìn)而改善了充填體的動(dòng)態(tài)力學(xué)特征。堿化水稻秸稈顯著提高了充填體的穩(wěn)定性和抗沖擊性能，更有利于提高井下作業(yè)的安全性。
關(guān)鍵字: 堿化水稻秸稈；沖擊荷載；尾砂膠結(jié)充填體；動(dòng)態(tài)抗壓強(qiáng)度；SHPB
（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
