循环气压下原煤微损伤及其破碎特性试验研究

发布时间：2018-02-01 17:41

本文关键词： 原煤试验研究气动疲劳微损伤破碎维度　出处：《中国矿业大学学报》2017年02期 　论文类型：期刊论文

【摘要】：应用岩石力学测试系统TAWD-2000和煤岩气压致裂设备开展了首山矿原煤试件的气压疲劳试验,分析了循环气压及二次气压致裂作用下煤样的微损伤与破碎特性,并利用损伤理论与分形理论进行描述.结果显示:1)基于残余塑性体应变定义微损伤变量,推导损伤演化方程,煤样微损伤随着疲劳次数的增加显著增大.2)含节理面煤样微裂纹发育局部化,产生局域高损伤,气压疲劳导致的整体微损伤效果推迟.3)经历气动疲劳的原煤气压致裂呈现整体破裂特征,破碎程度远大于直接气压致裂所引起的单一对径张拉破坏.4)循环气压下微损伤原煤的破碎特征可利用破碎度的分维数表征,分维数越大,试件破碎度越大,小块度所占比例越大,反之愈小.
[Abstract]:The pneumatic fatigue test of raw coal samples in Shoushan Mine was carried out by using rock mechanics test system TAWD-2000 and coal rock pressure fracturing equipment. The characteristics of micro-damage and breakage of coal samples under cyclic and secondary pressure fracturing are analyzed and described by damage theory and fractal theory. The results show that the micro-damage variables are defined on the basis of residual plastic body strain. According to the damage evolution equation, the micro-damage of coal sample increases significantly with the increase of fatigue times. 2) the local microcracks of coal samples with joints are localized, resulting in local high damage. The whole micro-damage effect caused by air pressure fatigue is delayed. 3) the gas pressure cracking of raw coal subjected to pneumatic fatigue shows the whole fracture characteristics. Breaking degree is much larger than single diameter-tensioning failure caused by direct pressure fracturing. 4) the breakage characteristics of micro-damaged raw coal under cyclic pressure can be characterized by fractal dimension of crushing degree. The bigger the fractal dimension is, the greater the breakage degree of specimen is. The larger the fraction is, the smaller it is.
【作者单位】：中国矿业大学力学与建筑工程学院;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】：国家自然科学基金项目(51404250) 江苏省自然科学基金项目(BK20140189) 江苏省普通高校研究生科研创新计划项目(KYLX15_1409)
【分类号】：TD712.61
【正文快照】： 在我国,半数以上的煤层为高瓦斯煤层,煤层赋存条件复杂多变,瓦斯储存具有“三高三低”的特征[1-2],选择和发展煤层致裂增透技术前景广阔、刻在水钻取样与打磨过程中,尽量减少煤样的浸泡时不容缓.然而,我国煤炭资源与水资源成逆向分布,间,以减小水对原煤性质的影响.试件加工

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