单轴压缩条件下尾砂胶结充填体的损伤变量与比能演化

为探究充填体单轴压缩过程中损伤变量D、比能演化及二者间的关系, 以大冶铁矿灰砂比1∶6的充填体为研究对象, 开展了单轴压缩及声发射监测试验, 计算损伤变量D、总比能U、弹性比能Ue及耗散比能Ud。结果表明, 充填体的损伤过程可划分为初始损伤(OA')、损伤稳定发展(A'B')、损伤快速发展(B'C')和损伤破坏(C'点以后段)4个阶段, 分别对应压密(OA)、弹性(AB)、屈服(BC)和破坏后(C点以后段)等阶段。损伤变量D在OA段、AB段、BC段和C点以后段分别呈快速增长、缓慢增长、急剧增长、缓慢增长;总比能U和弹性比能U_d不断增大, 且增长速率逐渐加快, 耗散比能U_e先增大后减小。OA'段, U、U_e和U_d均缓慢增长;A'B'段, U、U_e增长较快, U_d增长较慢;B'C'段, U、U_d快速增长, 而U_e增长速率逐渐下降;C'点以后段, U、U_d先快速增长后急剧增长, 且U_d增长速率更高, 而U_e先缓慢下降后急剧下降。试验充填体U_d随D呈指数增长。

Analysis of Damage Variables and Specific Energy Evolution for Cemented Tailings Backfill under Uniaxial Compression Condition

In order to explore damage variable D and specific energy evolution, as well as their relationship for the cemented tailings backfill (CTB) under uniaxial compression, tests of the uniaxial compression of CTB and its acoustic emission (AE) monitoring were conducted for the CTB of Daye Iron Mine with cement-tailings ratio at 1∶6. The variable D, the total specific energy U, the elastic specific energy Ue and the specific energy dissipation Ud of the CTB were all calculated. The obtained stress curve map shows that the damage process of backfill is divided into four stages: an initial damage stage (OA'), a stable damage development stage (A'B'), a rapid damage development stage (B'C') and a failure stage (after C' point), which correspond to a compaction stage (OA), an elastic stage (AB), a yield stage (BC) and a post-failure stage (after C point), respectively. The variable D increases rapidly at OA stage, slowly at AB stage, sharply at BC stage and slowly at the stage after C point. The total specific energy U and elastic energy U_d increase continuously at an increasing rate, while the energy dissipation U_e decreases after an initial increase. At OA' stage, the U, U_e and U_d all increase slowly. At A'B' stage, U and U_e increase faster while U_d increase slower. At B'C' stage, U and U_d increase rapidly, while U_e increases at a gradual decreasing rate. After C' point, U and Ud increase rapidly first and then sharply, in which U_d increases at a faster rate, while U_e decrease sharply after an initial slow decrease. Furthermore, U_d increases exponentially with valuable D in the CTB test.