为探讨粒径组成对三点弯曲受拉破坏材料的声发射(AE)特性的影响规律,制备了4种粒径的类岩石材料试件,分别进行三点弯曲声发射试验,分析了各试件加载过程中的力学特性和声发射特性。研究表明:类岩石材料的三点弯曲荷载-位移曲线经历非线性和近似线性2个阶段;随着粒径的减小,峰值荷载和到达峰值荷载时的声发射累计事件数均呈增大趋势,声发射累计撞击数与声发射累计能量的比值r的最大值也呈减小趋势,说明粒径越小产生相对高能量的声发射事件越多,振铃计数的关联维数D值变化幅度呈减小趋势,同时,到达最低点时的相对荷载水平越高。r值升高后再次降低到持续的低值阶段为孕育主破裂阶段,可将D值的最低值作为主破裂前兆点。

In order to obtain the characteristics of acoustic emission (AE) of materials with different particle sizes,the laboratory experiments on the characteristics of AE of rock-like materials with four different particle sizes under three-point bending are carried out. Then the characteristics of AE and mechanical properties of specimens are analyzed. The results indicate that there are two stages in the rock-like materials under three-point bending. With the decrease of par-ticle size,the peak load and the cumulative number of acoustic emission events at peak load are increasing,and the maximum of r values (the ratio of cumulative hits and cumulative energy) are decreasing. It also shows that the smal-ler the particle size is,the more AE events are generated with relatively high energy,and the variation law of D value of ringing count is decreasing. At the same time,the relative load level at the lowest point is higher. The main rupture stage is the sustained low value stage following the increase and decrease of b value. Then the lowest D value is taken as the main rupture precursor.