加卸荷条件下胶结充填体声发射b值特征研究  

Experimental study on b-value characteristics of acoustic emission of cemented filling body under loading and unloading test

作　　者：龚囱[1] 李长洪[1] 赵奎[2] 

机构地区：[1]北京科技大学金属矿山高效开采与安全教育部重点实验室,土木与环境工程学院,北京100083 [2]江西理工大学工程研究院,江西赣州341000

出　　处：《采矿与安全工程学报》2014年第5期788-794,共7页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(51064010;50364012);国家重点基础研究发展计划(973)项目(2010CB731500)

摘　　要：为认识胶结充填体在外界扰动下的响应特征,进行了单轴循环加卸载试验,研究了胶结充填体在加-卸载过程中声发射b值特征。试验结果表明:在胶结充填体压密阶段,声发射b值先减小后增大;在弹性阶段,声发射b值随应力的增大而有序下降;经多次加卸载后,当加载应力不断接近峰值应力时,声发射b值持续大幅度减小。在卸载阶段,胶结充填体具有明显的声发射事件。当卸载始于压密阶段时,声发射b值是逐渐增大的;当卸载始于弹性阶段时,声发射b值在小范围内波动;当卸载始于胶结充填体临界状态时,声发射b值呈现"台阶"状上升。声发射b值数值表现出的不同特征,说明在加卸载过程中微破裂处于动态演化之中。In order to study the response characteristics of cemented filling body under external dis-turbance, the studies have been carried out by virtue of uniaxial cyclic loading and unloading tests on cemented filling body, and the b-value characteristics of acoustic emission （AE） of cemented filling body is examined. The results show that, during the compression phase, the b-value decreases firstly and then increases. By contrast, the b-value declines orderly as stress increases in elastic stage. After undergoing repeated loading and unloading, the b-value reduces greatly as loading stress approaches to the peak stress. Similarly, The AE events are obvious in unloading process. The b-value increases grad-ually when unloading is started from compressing phase. And when unloading is started from elastic phase, the b-value fluctuates in a small range respectively. Finally, the b-value appears step-increasing trend when unloading is started at critical state of cemented filling body. The different b-value charac-teristics indicates that the occurrence of micro crack is in dynamic evolution during loading and un-loading process.

关 键 词：胶结充填体 加载 卸载 声发射b值 

分 类 号：TU45[建筑科学—岩土工程]