砂岩Ⅰ型断裂的尺寸效应试验研究

发布时间：2018-07-07 10:33

本文选题：岩石力学 + 尺寸效应　；参考：《工程科学学报》2017年10期

【摘要】：通过对尺寸成等比例的砂岩试样进行三点弯曲试验,研究了Ⅰ型断裂问题中试样尺寸对砂岩断裂参数的影响.结果表明:随着试样尺寸的增大,名义张拉强度减小,名义断裂韧度和破裂过程区长度增大,三者均为试样尺寸的函数.基于试验结果,引入有效破裂过程区长度cf,建立等效线弹性断裂力学尺寸效应模型,通过理论分析,发现其尺寸效应曲线介于理想脆性和理想塑性材料之间,体现出准脆性材料的尺寸效应特点,并计算得到了不同尺寸试样的破裂过程区长度等断裂参数.为验证该尺寸效应模型在砂岩中的正确性,采用数字图像匹配技术(DIC)测定相应尺寸砂岩试样的破裂过程区长度,测定结果和理论模型计算值相符.
[Abstract]:The effect of specimen size on sandstone fracture parameters in mode I fracture problem was studied by means of three-point bending test of sandstone specimen with equal size. The results show that the nominal tensile strength decreases and the nominal fracture toughness and fracture process zone length increase with the increase of specimen size. Based on the experimental results, an equivalent linear elastic fracture mechanics size effect model is established by introducing the effective fracture zone length cf. through theoretical analysis, it is found that the dimension effect curve is between ideal brittle and ideal plastic material. The size effect of quasi brittle materials is reflected and fracture parameters such as the length of fracture process zone are calculated. In order to verify the validity of the size effect model in sandstone, digital image matching technique (DIC) was used to determine the fracture process zone length of sandstone samples of corresponding size. The measured results were in agreement with the calculated values of the theoretical model.
【作者单位】：北京科技大学金属矿山高效开采与安全教育部重点实验室;
【基金】：国家基础研究发展计划资助项目(973计划)(2015CB060200)
【分类号】：TU45

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