| 冻融循环作用下砂岩单轴压缩破坏断口特征分形研究 |
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| 引用本文： | 周盛涛,方文,蒋楠,胡萌,罗学东.冻融循环作用下砂岩单轴压缩破坏断口特征分形研究[J].地质科技通报,2020,39(5):61-68. |
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| 作者姓名： | 周盛涛 方文 蒋楠 胡萌 罗学东 |
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| 基金项目： | 国家自然科学基金项目41572281 |
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| 摘 要： | 寒区岩石的力学特征往往受到冻融循环和荷载的共同影响，冻融岩石单轴压缩破坏断口蕴含着与冻融循环和荷载有关的损伤演化信息，冻融岩石单轴压缩破坏断口研究对冻融岩石断裂破坏机理分析有重要价值。为研究冻融岩石单轴压缩破坏断口形貌特征及其与宏观力学参数之间的关联性，通过摄影观测经历不同次数冻融循环的砂岩单轴压缩破坏断口形貌，采用像素点覆盖法计算断口分维值，探究了断口分维值与宏观力学参数之间的关系。结果表明:随着冻融次数的增加，冻融砂岩的力学性能劣化，单轴抗压强度、弹性模量、断口分维值、耗散能密度逐渐减小，峰值应变增大；单轴抗压强度、弹性模量、耗散能密度均与断口分维值之间存在指数关系，断口分维值越大，对应的单轴抗压强度、弹性模量、耗散能密度越大。冻融岩石单轴压缩破坏断口分维值可作为寒区岩体断裂破坏机理分析的有效参数。
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| 关 键 词： | 冻融循环 单轴压缩 破坏断口 分形几何 |
| 收稿时间： | 2019-10-18 |
Fractal geometry study on uniaxial compression fracture characteristics of sandstone subjected to freeze-thaw cycles |
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| Abstract: | The mechanical properties of rocks in cold regions are often affected by freeze-thaw cycles and loads. The uniaxial compression fractures of rocks subjected to freeze-thaw cycles contain damage evolution information related to freeze-thaw cycles and loads. It is of great value to study the uniaxial compression fracture of freeze-thaw rocks for the rock fracture failure mechanism after freeze-thaw degradation. To study the uniaxial compression fracture morphology of freeze-thaw rock and its correlation with the macro mechanical parameters, in this paper, fractures of sandstone under the uniaxial compression and different freeze-thaw cycles are observed by photography. The fracture fractal dimension is calculated by the pixel covering method, and the relationship between the fractal dimension and the macro-mechanical parameters is discussed. The results indicate that as the number of freeze-thaw cycles increases, the uniaxial compressive strength, elastic modulus, fracture fractal dimension, and energy dissipation density decrease gradually, and the peak strain increases. There are exponential relationships between the three parameters (uniaxial compressive strength, elastic modulus and dissipated energy density) and the fracture fractal dimension. The larger the fracture fractal dimension is, the greater the three parameters are. The fractal dimension of the freeze-thaw rock fracture under the uniaxial compression can be used as an effective parameter for the mechanism analysis of rock failure in cold regions. |
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