| 岩石裂纹损伤及围压对剪切破坏影响研究 |
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| 引用本文： | 李晓照,邵珠山,戚承志.岩石裂纹损伤及围压对剪切破坏影响研究[J].岩土力学,2019,40(11):4249-4258. |
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| 作者姓名： | 李晓照 邵珠山 戚承志 |
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| 作者单位： | 1. 北京建筑大学 土木与交通工程学院，北京 100044；2. 北京未来城市设计高精尖创新中心，北京 100044；
3. 西安建筑科技大学 土木工程学院，陕西 西安 710055 |
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| 基金项目： | 国家自然科学基金（No. 51708016）；中国博士后科学基金（No. 2017M610755）；北京市属高校基本科研业务费专项资金资助（No. X18129，No. X18277）。 |
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| 摘 要： | 岩石内部细观裂纹的存在，对压缩作用下岩石剪切断裂的宏观现象有着重要的影响。然而，能够通过解析解阐释细观裂纹几何特性、围压等影响因素对压缩作用下剪切断裂面角度变化趋势的研究很少。基于Ashby模型中提出的裂纹尖端应力强度因子，提出了一种改进的考虑裂纹角度影响的应力强度因子表达式。利用该改进的应力强度因子表达式，推出了一个可以预测岩石峰值强度的裂纹扩展、应变与应力之间的本构关系。结合本构关系的峰值强度与摩尔-库仑失效准则，得到了岩石损伤与内摩擦角、黏聚力、剪切强度及失效断裂面角度之间的理论关系；讨论了围压、裂纹尺寸、角度及摩擦系数对岩石宏观剪切断裂面角度的影响，通过试验结果验证了模型合理性。结果表明：随着损伤增大，内摩擦角、黏聚力及剪切强度不断减小；随着围压增大、摩擦系数增大和初始裂纹尺寸减小，剪切断裂面角度不断增大；随着裂纹角度增大，剪切断裂纹面角度先减小后增大。
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| 关 键 词： | 岩石力学 剪切断裂面角度 裂纹角度 围压 损伤 |
| 收稿时间： | 2018-08-06 |
Study on rock crack damage and confining pressure effects on shear fracture band |
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| LI Xiao-zhao,SHAO Zhu-shan,QI Cheng-zhi.Study on rock crack damage and confining pressure effects on shear fracture band[J].Rock and Soil Mechanics,2019,40(11):4249-4258. |
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| Authors: | LI Xiao-zhao SHAO Zhu-shan QI Cheng-zhi |
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| Institution: | 1. School of Civil and Transportation Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China;
2. Beijing Advanced Innovation Center for Future Urban Design, Beijing 100044, China;
3. School of Civil Engineering, Xi’an University of Architecture & Technology, Xi’an, Shaanxi 710055, China |
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| Abstract: | Existence of rock microcracks has great influence on rock shear fracture under compressive loadings. However, the effects of microcrack geometries and confining pressures on shear fracture angle are rarely studied in rocks. In this study, an improved expression of stress intensity factor containing crack angle effect is derived, which is based on the proposed expression at crack tips in Ashby’s microcrack model. Using this improved stress intensity factor, the constitutive relationship between crack growth, strain and stress is obtained, and it predicts the peak strength in rocks. Coupling this constitutive relationship at state of peak strength and Mohr-Coulomb failure criterion, the correlations of internal friction angle, cohesion, shear strength and damage are obtained. Effects of confining pressure, initial crack size, crack angle and friction coefficient on shear fracture angle are discussed. The rationality of theoretical model is verified with experimental data. The results show that internal friction angle, cohesion and shear strength decrease with increment of damage; shear fracture angle increases with the increment of confining pressure and friction coefficient, or the decrement of initial crack size; shear fracture angle decreases firstly, and then increases with increment of crack angle. |
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| Keywords: | rock mechanics shear fracture angle crack angle confining pressure damage |
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