煤样三轴循环加卸载力学特征颗粒流模拟

发布时间：2018-01-10 17:36

本文关键词：煤样三轴循环加卸载力学特征颗粒流模拟　出处：《煤炭学报》2016年03期 　论文类型：期刊论文

【摘要】：基于煤样常规三轴试验,使用颗粒流程序PFC得到了一组能够较真实反映煤样宏观力学行为的细观参数。在此基础上,对煤样进行不同围压下循环加卸载颗粒流模拟试验,分析了不同围压下煤样的宏观参数、裂纹扩展过程及其之间的关系。通过分析弹性模量和塑性应变随加载轴向应变的变化规律,表明弹性模量随加载轴向应变先增大后减小、塑性应变随加载轴向应变先稳定增加后快速变化,证明了使用颗粒流程序模拟循环加卸载是可行的。其后对循环加卸载过程进行分析,结果表明裂纹数目的非"记忆"行为随加载的进行逐渐加强,峰后微裂纹主要产生于宏观裂纹之间的相互摩擦。结合裂纹在试样内的破裂过程分析,表明剪切带的形成是造成弹性模量和塑性应变出现拐点的主要原因,对试样在循环荷载作用下的破裂过程有了一定的认识。
[Abstract]:Based on the conventional triaxial test of coal samples, a set of meso-parameters which can truly reflect the macroscopic mechanical behavior of coal samples are obtained by using the particle flow program PFC. The particle flow simulation test under different confining pressure was carried out, and the macroscopic parameters of coal sample under different confining pressure were analyzed. By analyzing the variation of elastic modulus and plastic strain with the axial strain, it is shown that the elastic modulus increases first and then decreases with the axial strain. The plastic strain firstly increases steadily and then changes rapidly with the loading axial strain, which proves that it is feasible to simulate cyclic loading and unloading by using particle flow program, and then the cyclic loading and unloading process is analyzed. The results show that the non-memory behavior of the number of cracks increases gradually with the loading, and the micro-cracks after the peak are mainly produced by the mutual friction between the macroscopic cracks, and the fracture process of the cracks in the specimen is analyzed. It is shown that the formation of shear band is the main cause of the inflection point of elastic modulus and plastic strain, and the fracture process of the specimen under cyclic load is well understood.
【作者单位】：中国矿业大学深部岩土力学与地下工程国家重点实验室;
【基金】：国家自然科学基金资助项目(41272344) 江苏省杰出青年基金资助项目(BK20150005)
【分类号】：TD315
【正文快照】： 在自然环境及工程长期的运行条件下,岩石经常受到循环荷载的作用,如地质运动、隧道及硐室的开挖与支护、煤矿的开采,而且岩土工程结构在使用过程中更是经常受到反复加卸载的作用。尤其在煤矿开采时,由于不断地打眼放炮及地应力不断地重新分布,造成岩体工程不断受到循环荷载的

【相似文献】