【摘要】 利用建立的煤岩体分级加载扰动试验系统,进行了煤系岩石典型单轴压缩实验、无扰动分级加载试验,以及分别施加不同速率及幅度的扰动载荷的分级加载试验,同步采集声发射(AE)信号,并利用加卸载响应比理论对AE信号进行分析.结果表明,扰动载荷能够使岩石的抗压强度显著降低,施加扰动载荷条件下9个岩样单轴抗压强度降低了20~60 kN(约为单轴极限抗压强度的10%~25%);扰动速率的变化(由650 N/s增至1 kN/s)较载荷大小的变化(由2.5 kN增至5 kN)对岩样强度影响明显;AE能量与加载路径对应良好,其加卸载响应比随载荷水平的增加存在先减小后增大的趋势.更多还原

【Abstract】 An existing coal and rock step-load perturbation test system was used to carry out typical uniaxial compression tests,non-perturbation step-load tests,and step-load tests with different perturbation rates and ranges on coal rocks.During the tests,AE signals were collected and analyzed using loading-unloading response ratio(LURR) theory.The results show that the compressive strength of the rock decreased dramatically under the conditions of perturbed loads.Nine samples exhibited a decrease in compressive strength of 20-60 kN(about 10% to 25% of the ultimate compression strength).Compared to the load change(from 2.5 kN up to 5 kN),the increase in perturbation rate(from 650 N/s up to 1 kN/s) has a much more obvious influence on the measured rock strength.The AE energy corresponds well with the load route;the loading-unloading response ratio first decreased and then increased with an increase in load level.更多还原