| 应力途径对岩石脆性-延性变化的影响 |
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| 引用本文： | 姚孝新,耿乃光,陈顒.应力途径对岩石脆性-延性变化的影响[J].地球物理学报,1980,23(3):313-319. |
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| 作者姓名： | 姚孝新 耿乃光 陈顒 |
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| 作者单位： | 国家地震局地球物理研究所 |
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| 摘 要： | 用两种加载方式对岩石的破裂进行了实验研究。一种方式是在一定的围压下增加轴压使岩石破裂（A型）;另一种方式是在一定围压下增加轴压直到破裂前某一应力状态,然后停止加轴压转而减小围压使岩石破裂（B型）。所用的岩石样品为济南辉长岩和山东掖县白大理岩。着重研究应力途径对岩石脆性-延性变化的影响。辉长岩在1.5千巴以下两种应力途径下的破裂都表现为脆性,但是对于同样的应力状态,B型实验比A型实验显得更脆。随着围压增加到200-250巴之间,大理岩由脆性转变为延性。围压250巴以上,大理岩的A型实验发生延性破裂。样品承受载荷的能力是逐渐丧失的。破裂过程中声发射率极低,听不到破裂声响。最后在样品中形成了剪切断面,但破裂很慢。然而,在大理岩的B型实验中,围压在250巴以上发生了脆性破裂,其表现为轴向应力突然下降,伴随着脆性破裂的声响并有声发射率剧增的前兆。看来,B型应力途径对岩石起了一个脆化的作用。
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| 关 键 词： | 应力途径 延性破裂 B型 大理岩 千巴 A型 声发射率 掖县 应力一应变 岩石破裂 |
| 收稿时间： | 1979-03-26 |
THE EFFECT OF STRESS PATH ON BRITTLENESS AND DUCTILITY OF ROCKS |
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| Yao Xiao-xin,Geng Nai-guang,Chen Yong.THE EFFECT OF STRESS PATH ON BRITTLENESS AND DUCTILITY OF ROCKS[J].Chinese Journal of Geophysics,1980,23(3):313-319. |
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| Authors: | Yao Xiao-xin Geng Nai-guang Chen Yong |
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| Institution: | Institute of Geophysics, State Seismological Bureau |
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| Abstract: | Triaxial compression test of Jinan gabbro and Yexian marble were performed in the following loading cases （stress path）: case A, axial load was increased until the rock sample failed, while the confining pressure was kept constant, case B, starting from a certain stress state, the confining pressure was decreased until rocks failed and axial load was kept constant. Under case A and case B the gabbro exhibited brittle behavior up to 1.5 kb, but in case B the gabbro was more brittle than that in case A of the same stress state. In case A, when the confining pressure was below 200 bars, the marble exhibited brittle behayior, and when confining pressure was about 200-250 bars, a brittle-ductile transition for marble occurred, above 250 bars the marble exhibited ductile behavior, in that time, the ability of sustaining loading in marble gradually vanished, the level of acoustic emission activity was very low, the whole failure process lasted a few minutes and the eventual shear fault appeared. However, it was found that some brittle fracture of marble could appear in case B, even though confining pressure was above 250 bars, in this situation, the ability of sustaining loading vanished abruptly and acoustic emission increased rapidly before rupture. The brittleness of rocks seems to be related to the stress path. |
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