冻融循环作用下岩石疲劳损伤计算中关键问题的讨论

发布时间：2018-03-16 16:30

本文选题：岩石力学　切入点：冻融循环作用　出处：《岩石力学与工程学报》2017年02期 　论文类型：期刊论文

【摘要】：利用疲劳损伤理论来研究冻融循环条件下岩石的损伤累积在理论上是可行的。主要分析冻融疲劳损伤模型在计算自然条件下岩石冻融损伤时面临的主要问题,包括复杂多变的自然条件下如何简化、近似冻融循环作用,如何选取合适的物理量来计算损伤变量,及如何计算多种机制作用下岩石的冻融损伤。经过分析认为:研究自然条件下的昼夜循环和年度循环对人类工程活动意义最大,根据岩石中饱和度的高低和岩石中未冻水迁移速率的快慢,可分别将昼夜循环和年度循环划分并等效为高周或低周疲劳荷载;冻融循环条件下岩石孔隙率的变化可直接反映冻融损伤的特征,利用缺陷面积和残余应变定义的损伤变量其本质是相同的,均可用孔隙率计算得来;建立冻融循环作用下砂岩的高周疲劳损伤模型和低周疲劳损伤模型,利用模型进行分析表明,在计算自然条件下岩石的冻融损伤时高周疲劳荷载的作用是不可忽略的,并且低周疲劳和高周疲劳荷载的作用顺序具有显著的影响。
[Abstract]:It is feasible to use the fatigue damage theory to study the damage accumulation of rock under freeze-thaw cycle. The main problems in calculating the freeze-thaw damage of rock under natural condition are analyzed. Including how to simplify and approximate freeze-thaw cycle under complex and changeable natural conditions, how to select appropriate physical quantities to calculate damage variables, And how to calculate the freezing and thawing damage of rock under the action of many mechanisms. It is considered that the study of circadian cycle and annual cycle under natural conditions is of great significance to human engineering activities. According to the degree of saturation in rock and the speed of unfrozen water migration in rock, the circadian cycle and annual cycle can be divided into high cycle and low cycle fatigue load respectively. The change of rock porosity under freeze-thaw cycle can directly reflect the characteristics of freeze-thaw damage. The damage variable defined by defect area and residual strain is essentially the same and can be calculated by porosity. The high cycle fatigue damage model and low cycle fatigue damage model of sandstone under freeze-thaw cycle are established. The analysis shows that the effect of high cycle fatigue load can not be ignored in the calculation of freeze-thaw damage of rock under natural conditions. And the sequence of low cycle fatigue and high cycle fatigue load has a significant effect.
【作者单位】：西安科技大学建筑与土木工程学院;中国地质大学工程学院;
【基金】：国家自然科学基金资助项目(41302228) 中国博士后科学基金资助项目(2013M532070,2014T70931)~~
【分类号】：TU45

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