| 单轴压缩条件下不同含水率黑云母二长花岗岩破坏特征与机制 |
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| 引用本文： | 曹洋兵,陈玉华,张朋,黄真萍,张向向,陈杨涛.单轴压缩条件下不同含水率黑云母二长花岗岩破坏特征与机制[J].地质科技通报,2021,40(3):163-172. |
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| 作者姓名： | 曹洋兵 陈玉华 张朋 黄真萍 张向向 陈杨涛 |
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| 基金项目： | 福建省自然科学基金项目2019J05036岩土钻掘与防护教育部工程研究中心开放基金项目201702贵州省地质矿产勘查开发局地质科研项目黔地矿科合[2020]1号 |
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| 摘 要： | 花岗岩在不同含水率条件下的变形破坏特征和机制对此类工程岩体稳定性评价具有重要的意义。开展不同含水率黑云母二长花岗岩单轴压缩试验，分析破坏特征和应力-应变曲线特征，开展断口扫描电镜试验，分析微观形貌特征，研究破坏机制。试验结果表明:黑云母二长花岗岩具有明显的应变软化特征；随含水率增大，曲线上微裂隙压密阶段长度逐渐增加，稳定破裂阶段及非稳定破裂阶段长度均逐渐缩短，但所占比例增大，曲线上峰前阶段涨落交替现象加剧；饱和时单轴抗压强度和弹性模量相比干燥时分别降低了40.68%，20.3%；变形破坏过程可大致分为以下5个阶段:平静期、裂纹萌生期、裂纹扩展伴随颗粒弹射期、片状碎片剥落伴随颗粒弹射期及崩落式破坏期；随含水率增大，花岗岩破坏时的剧烈程度、发出的声响及脆性程度均逐渐降低；花岗岩破坏机制为拉-剪复合破坏，低含水率时以压致拉张破坏为主，随含水率增大呈现拉张破坏减少而剪切破坏增多的趋势，饱和时以剪破坏为主。研究结果可为黑云二长花岗岩与水之间的耦合模型构建提供理论支撑，对水-岩耦合环境下工程岩体稳定性分析具有重要科学意义。
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| 关 键 词： | 黑云母二长花岗岩 含水率 力学特性 破坏特征 破坏机制 |
| 收稿时间： | 2020-08-01 |
Failure characteristics and mechanism of biotite monzogranite with different water content under uniaxial compression |
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| Abstract: | The deformation and failure characteristics and mechanism of granite under different water content are of great significance to the stability evaluation of this kind of engineering rock mass. The uniaxial compression tests of biotite monzogranite under different water content were carried out to analyze the failure characteristics and stress-strain curve characteristics. The fracture scanning electron microscope test was carried out to analyze the micro morphology characteristics, and study the failure mechanism of granite. The test results show that: biotite monzogranite has obvious strain softening characteristics. With the increase of water content, the length of the microfracture compaction stage increases, while the length of the stable fracture stage and the unstable fracture stage gradually shortens, but the proportion increases, and the fluctuation alternation in the pre-peak stage of the curve intensifies. Compared with dry samples, the uniaxial compressive strength and elasticity modulus of saturated sample decreased by 40.68% and 20.3% respectively. The deformation and failure process can be roughly divided into five stages: quiescent stage, crack initiation stage, crack growth with particle ejection stage, flaky debris peeling with particle ejection stage and caving failure stage. With the increase of water content, the intensity, sound and brittleness of granite failure gradually decrease. In general, the failure mechanism of granite is tension-shear composite failure. When the granite with low water content, the dominant failure mechanism is tensile failure induced by compression; with the increase of water content, the tensile failure decreases and the shear failure increases; and while the granite is in saturation, the dominant failure mechanism is shear failure. The research results can provide theoretical support for the construction of coupling model between biotite monzogranite and water, and have important scientific significance for the stability analysis of engineering rock mass under water-rock coupling environment. |
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