摘要
使用长方形试样的劈裂试验测定岩石抗拉强度时,仍然沿用巴西圆盘抗拉强度计算公式,与实际情况差异较大。基于平面应力状态假设,通过平面应力问题的傅立叶级数解答推导了长方形岩石劈裂应力计算公式,经计算发现,截面最大拉应力出现在试样对称轴上的某一点,且随着试样宽长比b/a的减小,最大拉应力逐渐接近试样中心点的拉应力,通过计算截面形状函数,确定最大拉应力出现的位置,建立了方形岩石劈裂抗拉强度计算公式。经砂岩与大理岩劈裂试验验证,该计算公式计算得到的抗拉强度值一致性较好,能真实反映岩石的力学性能,是测定岩石抗拉强度的一种有效方法,建议采用b/a小于1且2a大于70 mm的试样进行岩石方形劈裂抗拉强度测定。
The Brazilian disc tensile strength formula was still used in splitting test with rectangular specimen of rock, which will cause large error to the results. It was supposed that the rectangular splitting specimen be in the state of plane stress and the tensile stress in the cross section could be determined by Fourier Series Solution. Calculated results indicate that the maximum tensile stress occurs at a certain point in the specimen ＇ s symmetry axis. When the width to length ratio, b/a, of the specimen is relatively small, the maximum tensile stress is close to the tensile stress of the center point. The exact location of the maximum tensile stress and the corresponding shape function can be calculated by Fourier Series Solution. And the splitting tensile strength formula of rock with rectangular specimen can be established. According to the results of the sandstone and marble splitting test, the tensile strength values obtained by the formula have a good agreement and the mechanical properties of the rock can be reflected truly. The formula can be a potential method for determining tensile strength of rock and good experimental results can be obtained when b/a 〈1 and 2a〉70mm.
出处
《地下空间与工程学报》
CSCD
北大核心
2015年第2期370-374,403,共6页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金资助项目(51404212)
河南省教育厅科学技术研究重点项目(12B130005)
河南省高等学校青年骨干教师资助计划项目
