A new true triaxial cell for testing mechanical properties of rock, and its use to determine rock strength and deformability of Westerly granite
A new true triaxial cell for testing mechanical properties of rock, and its use to determine rock strength and deformability of Westerly granite
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DOI：
10.1016/s1365-1609(99)00106-9
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发表时间：
2000-01-01
影响因子：
7.2
通讯作者：
Chang, C
中科院分区：
文献类型：
--
作者：
Haimson, B;Chang, C
一个新的真三轴细胞已经设计，制造，校准，并成功地测试。它的主要特点是在所有三个正交方向上都有很高的加载能力，使测试能够对受到大的最小和中间主应力的坚硬结晶岩石进行破坏。施加到矩形棱柱试样（尺寸为19 x 19 x 38 mm）的所有三个主应力均由伺服控制。该单元被用来在西风花岗岩中进行一系列广泛的测试。考虑中间主应力的影响，得到了一个新的真三轴强度准则。事实证明，这是如此重要，以至于它对以莫尔、库仑、格里菲斯和其他人的名字命名的标准的适用性提出了严重的问题。在所有三个主方向上的应变测量结果表明，相对于主要的主应力在故障的发病率大幅上升，作为中间主应力的增加。真三轴试验还表明，在相同的最小水平应力下，西风花岗岩的主裂隙倾角随中间主应力的增大而增大，表现出强化效应。有限的薄片和扫描电镜研究表明，微裂纹扩展，裂纹局部化和主要断裂特征基本上类似于在普通三轴试验中观察到的。(C)2000爱思唯尔科技有限公司版权所有。
A new true triaxial cell has been designed, fabricated, calibrated, and successfully tested. Its main feature is very high loading capability in all three orthogonal directions, enabling the testing to failure of hard crystalline rocks subjected to large least and intermediate principal stresses. All three principal stresses applied to rectangular prismatic specimens, 19 x 19 x 38 mm in size, are servo controlled. The cell was used to conduct an extensive series of tests in Westerly granite. A new true triaxial strength criterion for the ruck was obtained that takes into account the effect of the intermediate principal stress. This turns out to be so significant that it raises serious questions about the suitability of criteria such as those named after Mohr, Coulomb, Griffith, and others. Measurements of strain in all three principal directions revealed that the onset of dilatancy relative to the major principal stress at failure rises substantially as the intermediate principal stress increases. The true triaxial tests also demonstrate that for the same least horizontal stress the main fracture dip angle in Westerly granite increases as a function of the intermediate principal stress, suggesting a strengthening effect. Limited thin section and SEM study shows that microcrack propagation, crack localization, and main fracture characteristics are basically similar to those observed in common triaxial tests. (C) 2000 Elsevier Science Ltd. All rights reserved.