循环荷载作用下石膏质岩的疲劳特性试验研究

发布时间：2018-05-14 23:15

本文选题：岩石力学 + 石膏质岩　；参考：《岩石力学与工程学报》2017年04期

【摘要】：利用MTS 815岩石力学测试系统、声发射系统、环境扫描电镜开展石膏质岩循环荷载作用下的疲劳试验,探讨循环荷载条件对其疲劳损伤特性的影响。结果表明:石膏质岩循环荷载作用下的疲劳损伤特征明显,塑性特性显著。其疲劳试验的应力应变全过程曲线具有如下形状特征:加载曲线可分为"近线性"的弹性特征段和"呈压扁状"的塑性特征段,塑性特征段滞后效应明显,卸载曲线呈现近线性特征。循环荷载条件对石膏质岩疲劳损伤特性影响显著,疲劳试验过程的声发射信息演化规律及微观结构变化特征能够较好地揭示其疲劳损伤演化过程及宏观破裂特征:循环应力水平高、上限应力大、加载频率低,疲劳试验的应力应变全过程曲线越饱满疏松、加卸载的滞回环面积越大,声发射信息越强烈而集中、声发射率指标越高,试样的疲劳损伤速率快,每次循环产生的塑性应变量大,微观结构越破碎,试样的疲劳寿命越短。
[Abstract]:The fatigue tests of gypsum rock under cyclic loading were carried out by means of MTS 815 rock mechanics test system, acoustic emission system and environmental scanning electron microscope, and the effects of cyclic load conditions on fatigue damage characteristics of gypsum rock were discussed. The results show that the fatigue damage and plasticity of gypsum rock under cyclic loading are obvious. The stress-strain curve of the fatigue test has the following shape characteristics: the loading curve can be divided into "near-linear" elastic characteristic section and "flat-shaped" plastic characteristic section, the hysteresis effect of the plastic characteristic section is obvious. The unloading curve is nearly linear. The cyclic load condition has a significant effect on the fatigue damage characteristics of gypsum rock. The evolution law of acoustic emission information and the characteristics of microstructure change during fatigue test can better reveal the fatigue damage evolution process and macroscopic fracture characteristics: high cyclic stress level, large upper limit stress, low loading frequency, high cyclic stress level, high upper limit stress and low loading frequency. The curve of the whole process of stress and strain of fatigue test is fuller and looser, the area of hysteresis loop of loading and unloading is larger, the information of acoustic emission is stronger and concentrated, the higher the index of acoustic emission is, the faster the fatigue damage rate of the specimen is. The plastic strain produced by each cycle is large, the microstructure is broken, and the fatigue life of the specimen is shorter.
【作者单位】：长安大学地质工程与测绘学院;
【基金】：国家自然科学基金资助项目(41502278) 中国博士后科学基金资助项目(2015M582588) 中央高校基本科研业务费资助项目(310826172008)~~
【分类号】：TU45

【相似文献】