含雁行裂纹砂岩静态加载速率效应实验研究

发布时间：2018-10-25 20:07

【摘要】：为研究裂隙岩体的静态加载速率效应,以含预制雁行裂纹砂岩为实验对象,测试了不同加载速率下试样的力学性质、破裂模式、能量耗散及声发射响应特征,综合声发射定位和裂纹扩展演化录像,分析了裂纹扩展演化过程及加载速率效应机制。结果表明:(1)裂隙砂岩受载过程存在着明显的静态加载速率效应。随着加载速率的升高,试样峰值强度、峰值应变、起裂应力、峰值处积累的弹性能和声发射计数峰值均逐渐增大但增幅放缓,弹性模量呈现出先增大后减小趋势,累计声发射总计数则逐渐减小。(2)试样新裂纹的起裂萌生均对应着应力的局部下降、耗散能的突升及声发射的高值响应。(3)加载速率较小时,试样沿一条预制裂纹扩展、滑移而形成剪切型破坏;当加载速率较大时,试样最终破坏模式为裂纹岩桥贯通,并由裂纹外端沿与加载方向平行扩展而成的拉破坏。研究结果为深入认识煤岩动力灾害的力学响应机制及揭示其演化过程提供了有益的参考。
[Abstract]:In order to study the static loading rate effect of fractured rock mass, the mechanical properties, fracture mode, energy dissipation and acoustic emission response characteristics of specimens with prefabricated geese walk crack sandstone were tested under different loading rates. The evolution process of crack propagation and the mechanism of loading rate effect are analyzed by synthesizing acoustic emission localization and crack propagation evolution video. The results show that: (1) there is obvious static loading rate effect in the loading process of fractured sandstone. With the increase of loading rate, the peak strength, strain, crack stress, elastic energy accumulated at the peak and the peak value of acoustic emission increased gradually, but the increase slowed down, and the modulus of elasticity increased first and then decreased. The accumulative total number of acoustic emission gradually decreased. (2) the initiation and initiation of the new crack in the specimen correspond to the local decrease of stress, the sudden rise of dissipative energy and the high value response of acoustic emission. (3) the loading rate is small. The specimen propagates along a precast crack and slips to form shear failure. When the loading rate is high, the ultimate failure mode of the specimen is the crack rock bridge through, and the tensile failure caused by the outer end of the crack propagating parallel to the loading direction. The results provide a useful reference for further understanding the mechanical response mechanism of coal and rock dynamic disasters and revealing the evolution process of coal and rock dynamic disasters.
【作者单位】：中国矿业大学煤矿瓦斯与火灾防治教育部重点实验室;中国矿业大学安全工程学院;重庆大学煤矿灾害动力学与控制国家重点实验室;
【基金】：国家重点研发计划资助项目(2016YFC0801401) 国家自然科学基金资助项目(51574231) 江苏省普通高校学术学位研究生科研创新计划资助项目(KYLX16_0572)
【分类号】：TD315

【相似文献】