动静组合加载下冲击倾向性煤声发射特性试验研究

    Experimental study on acoustic emission characteristics of impact tendency coal under combined dynamic and static loading

    • 摘要: 采用DTAW-8000型岩石高压动力学试验系统及声发射技术,通过施加不同动载扰动频率的单轴压缩试验,研究了冲击倾向性煤在动静组合加载下的破裂特征与声发射特性参数的关系、分析了冲击倾向性煤受压损伤全过程并建立了损伤演化模型。研究表明:动载扰动频率增强,冲击倾向性煤岩主破裂角呈现先减小后增大的变化趋势,且应力、应变均呈降幅现象;冲击倾向性煤岩内部裂缝的发育、扩展过程与声发射信号紧密相关,煤岩受压全过程的声发射振铃累计数变化趋势可大致分为稳定阶段、突增阶段和缓慢增长直至破坏阶段;煤岩损伤演化模型趋势与试验数据趋势一致;动载扰动频率是煤岩损伤的缓增-急速增长阶段影响煤岩破裂时程的主要因素。

       

      Abstract: Using DTAW-8000 rock high-pressure dynamic test system and acoustic emission technology, through uniaxial compression tests with different dynamic load disturbance frequencies, the relationship between fracture characteristics and acoustic emission characteristic parameters of impact tendency coal under dynamic and static combined loading is studied, the whole process of impact tendency coal compression damage is analyzed, and the damage evolution model is established. The results show that with the increase of dynamic load disturbance frequency, the main fracture angle of coal rock with impact tendency decreases first and then increases, and the stress and strain both decrease; the development and expansion process of internal fractures in coal rock with impact tendency are closely related to acoustic emission signal, the cumulative number of acoustic emission ringing changes in the whole process of coal rock compression can be roughly divided into stable stage, sudden increase stage and slow increase until failure stage; the trend of coal and rock damage evolution model is consistent with the test data; the frequency of dynamic load disturbance is the main factor that affects the time history of coal rock fracture in the stage of slow-rapid growth of coal rock damage.

       

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