超细全尾砂充填体动态力学特性研究

充填体作为人工矿柱,为矿房回采创造了条件,但经常受到爆破等冲击荷载作用。充填体的动态力学特性直接关系到充填采矿法的安全高效实施。通过单轴压缩试验和分离式霍布金森压杆(Split Hobkinson Pressure Bar,SHPB)试验技术,进行了不同充填配比参数的超细全尾砂充填体压缩试验,得到其静载和动载下的应力-应变曲线和能量变化曲线,并分析了其破坏模式。研究表明:充填体质量浓度越高,灰砂比越大,峰值应力和峰值应变随之增大,呈现正相关性,其中灰砂比和质量浓度对应力的影响相对一致,但应变受质量浓度影响更大;当冲击荷载由0.3 MPa增大至0.6 MPa时,充填体的破坏形式由保持完整形态变为产生裂纹,直至被压碎,转变为完全失稳破坏状态;充填体能量吸收随着冲击荷载的增加而逐渐递增,但质量浓度和灰砂比增大时,充填体比能量和能量吸收率反而下降,其中灰砂比是影响充填体吸能效率的主要因素,质量浓度次之。

Study on the Dynamic Mechanical Properties of Ultrafine Tailing Backfill

Backfill materials create conditions for mining as an artificial pillar but it is often subjected to impact loadssuch as blasting.The safe and efficient implementation of the backfilling mining method is affected by the dynamic mechanicalproperties of the backfill.Through compression experiment of ultra-fine full tailings backfill which was carried out by uniaxialcompression test and SHPB(Split Hopkinson Pressure Bar)test,the stress-strain curves and energy curves under static anddynamic loads were obtained and the failure mode could be analyzed.The study results show that:the higher the mass concen-tration and cement-sand ratio of backfill was,the larger peak stress and strain would be;the dynamic mechanical properties ofbackfill are positively correlated;the effect of cement-sand ratio and mass concentration on stress was relatively consistent,butthe strain was more affected by mass concentration;when the impact load increases from 0.3 MPa to 0.6 MPa,the failure formof the backfill changes from maintaining a complete shape to producing cracks,until it was crushed,and the backfill changesto a state of complete instability failure;the amount of filling energy absorption increases gradually with the rise of impactload;when the mass concentration and cement-sand ratio increase,the specific energy and energy absorption of the backfill de-crease,the cement-sand ratio was the main factor affecting energy absorption efficiency of the backfill,followed by the massconcentration.