摘要
随着开采深度的增大,采场地压显现日趋严峻.胶结充填体作为充填采矿法中采场的重要结构单元,对维护采场稳定具有重要作用,因此了解认识胶结充填体在外界荷载作用下的响应特征具有重要意义.通过进行单轴循环加卸载试验,研究胶结充填体在加载阶段的声发射特征,以及声发射"平静期"的分形特征.结果表明:胶结充填体存在明显的压密阶段.在压密阶段初期,声发射能率较大.而后随着应力的增大,声发射能率又逐步降低,并最终维持在较低的水平;在弹性阶段,声发射事件率和能率随应力的增大而增大,并且声发射事件率普遍大于其余加载阶段;在加载应力达到胶结充填体峰值应力前,声发射会出现"平静期".在此时期,声发射能率出现剧烈波动,且声发射分形维数是不断减小的;试验中,下级加载声发射能率大于上级加载,并且声发射能率对充填体损伤程度的敏感性大于声发射事件率.
With the increase of mining depth, the ground pressure of stope is becoming more and more serious.As one of the important structural units in filling mining method, consolidated filling body plays an important role in maintaining the stability of stope, and there fore understanding the response characteristics of consolidated filling body has important significance. The studies on acoustic emission（AE） characteristics and fractal characteristics of AE quiet period were carried out by the uniaxial cyclic loading and unloading test on consolidated filling body. The results show that there is obvious compaction stage for consolidated filling body,which the AE energy value is high in the beginning. After that the AE energy will reduce gradually with increasing of the stress, finally maintains at a low level. In the elastic stage, the AE rate value and energy will increase with the stress growing. Moreover, the AE rate is greater than other loading stages.Before the loading stress getting to the peak, the AE will take on a quiet period in which the AE energy will fluctuate dramatically and the AE fractal will drop continuously. According to the test, the AE energy in subsequent loading is higher than previous loading, and also AE energy is more sensitive to the damage of consolidated filling body, compared with the AE rate.
出处
《有色金属科学与工程》
CAS
2017年第4期91-97,共7页
Nonferrous Metals Science and Engineering
基金
江西省科技计划项目(20143ACG70010)
关键词
循环加载
胶结充填体
声发射
关联分形维数
cyclic loading
consolidated filling body
acoustic emission
fractal dimension
