Specimen shape and cross-section effects on the mechanical properties of rocks under uniaxial compressive stress
Specimen shape and cross-section effects on the mechanical properties of rocks under uniaxial compressive stress
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单轴压应力下试样形状和截面对岩石力学性能的影响
DOI：
10.1007/s10064-019-01518-x
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发表时间：
2019-04
影响因子：
4.2
通讯作者：
Tao M
中科院分区：
文献类型：
--
作者：
Du K;Su R;Tao M
岩石的单轴压缩特性对于工程设计和建设非常重要。根据确定这些性能的现有标准，需要具有适当几何形状的高质量芯样。在许多情况下，标准试样，特别是在粘土，破碎，风化岩石，总是无法制备。另一方面，在某些自然条件下，具有不同尺寸、形状和横截面的岩石承受单轴压缩载荷。因此，为了评价岩石的单轴抗压强度与试件形状和横截面的相关性，制备了一些具有圆形、方形和矩形三种不同横截面以及四种不同形状比（高径比）的大理石试件并进行了测试。宽比）为0.5、1、2和3。轴向和横向应变，声发射（AE），并在测试过程中记录相机照片。岩石的强度特性是基于几个应力阈值，包括裂纹闭合应力（σcc），裂纹萌生应力（σci），损伤应力（σcd），和峰值应力（σucs）。结果表明，σ cc与试件的截面形状无关。随着形状比的增大，σ cc逐渐增大，σ cd和σ ucs大幅度减小，而σ ci基本保持不变。当r ≤ 1时，截面形状效应开始起作用。此外，棱柱体和方柱体的σ cd和σ ucs值均低于圆柱体，表明棱柱体的裂纹失稳扩展发生较早。不同截面形状试样间的σ cd和σ ucs差值随形状比的增大而显著减小。声发射和摄像记录的数据表明，当形状比从3减小到0.5时，矩形和正方形棱柱体试样的断裂模式更容易从剪切断裂转变为板状断裂。当矩形棱柱体试件的形状比从3变为1和0.5时，主裂纹扩展面由宽面变为窄面。研究结果对地下硬岩矿山矿柱设计具有参考意义。
Uniaxial compressive properties of rocks are very important for designing and constructing engineering projects. Based on the available standards for determining these properties, high quality core specimens with proper geometry are needed. In many cases, the standard specimens, especially in clay-bearing, fractured, and weathered rocks, are always not able to be prepared. On the other hand, in some natural conditions, rocks with different size, shape, and cross-section are undergoing uniaxial compressive loading. Therefore, in order to evaluate the uniaxial compressive strength dependency behaviors of rocks on the shape and cross-section of tested specimens, some marble specimens with three different cross-sections, including circular, square, and rectangular, as well as four different shape ratios (height to diameter/width ratio) of 0.5, 1, 2, and 3 were prepared and tested. Axial and lateral strains, acoustic emission (AE), and camera photographs were recorded during the tests. Rock strength behavior was evaluated based on several stress thresholds, including crack closure stress (σcc), crack initiation stress (σci), damage stress (σcd), and peak stress (σucs). The results indicated thatσccwas not dependent on the cross-sectional shape of specimens. With increasing shape ratio,σccgradually increased, whileσcdandσucsgreatly decreased, andσciremained at a constant value. The cross-sectional shape effect became operative whenrwas less than or equal to 1. Moreover, the values ofσcdandσucsof rectangular prism specimens and square prism specimens are lower than those of cylindrical specimens, indicating that the unstable crack propagation of prism specimens occurs earlier. The difference gap ofσcdandσucsbetween specimens with different cross-sectional shapes was dramatically decreased with increasing shape ratio. The AE and camera recorded data indicated that the fracture modes of rectangular and square prism specimens are more likely to change from shearing to slabbing fracture when the shape ratio decreased from 3 to 0.5. The main crack developed surface turned from wide surface to narrow surface with the shape ratio of rectangular prism specimens changing from 3 to 1 and 0.5. The research results are of referential meaning to the design of pillars in underground hard rock mines.
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DOI：
--
发表时间：
1968
期刊：
--
影响因子：
--
作者：
S. J. Green;R. Perkins
通讯作者：
S. J. Green;R. Perkins
试件高宽比对单轴压缩硬岩矩形棱柱试件破坏模式的影响
影响因子：
6.2
作者：
Li, Diyuan;Li, Charlie C.;Li, Xibing
通讯作者：
Li, Xibing
影响因子：
7.4
作者：
W. Judd
通讯作者：
W. Judd
DOI：
10.1016/s1003-6326(15)63639-1
发表时间：
2015-02
影响因子：
4.5
作者：
K. Du;Xibing Li;Di-yuan Li;Lei Weng
通讯作者：
K. Du;Xibing Li;Di-yuan Li;Lei Weng
DOI：
10.1016/0148-9062(71)90031-3
发表时间：
1971-11
期刊：
International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts
影响因子：
--
作者：
S. Bordia
通讯作者：
S. Bordia