| 冻结红砂岩单轴损伤破坏CT实时试验研究 |
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| 引用本文： | 宋勇军,杨慧敏,张磊涛,任建喜.冻结红砂岩单轴损伤破坏CT实时试验研究[J].岩土力学,2019,40(Z1):152-160. |
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| 作者姓名： | 宋勇军 杨慧敏 张磊涛 任建喜 |
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| 作者单位： | 西安科技大学，建筑与土木工程学院，陕西 西安 710054 |
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| 基金项目： | 国家自然科学基金项目（No.11872299，No.11402195）；陕西省自然科学基金项目（No.2017JM1039）；陕西省重点研发计划项目（No.2017GY-156） |
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| 摘 要： | 为探究冻结岩石的宏观力学特性及损伤演化机理，对20、?5、?10 ℃红砂岩进行单轴加载CT实时扫描，获得各扫描层的CT扫描图像。利用Matlab自编程序生成灰度直方图和二值图像，基于CT数H值正比于密度的关系定义岩样扫描层的安全区、损伤区、破坏区，结合温度效应、水的软化作用及冰的冻胀力对岩样的影响，定量地研究冻结岩石的损伤破坏演化规律。试验研究表明，(1) 温度由20 ℃降至?5、?10 ℃时未冻水含量减少而冻结冰含量增加，岩样强度增大、抗变形能力提高、整体稳定性提高，CT图像呈现出岩样裂纹尺寸发展减慢、损坏程度减弱的规律；(2) 不同温度下岩石单轴加载的损伤演化经历了裂隙萌生、闭合、延伸、汇集及形成宏观主裂纹的阶段，岩样变形增大发生破坏；(3) 由于端部效应，中间较两端扫描层的损伤程度高，外侧较内侧扫描层先发生损伤，损伤边缘化并向内部扩展。
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| 关 键 词： | 冻结岩石 CT实时试验 灰度直方图 二值图像 温度效应 冻胀力 损伤演化 |
| 收稿时间： | 2018-12-31 |
CT real-time monitoring on uniaxial damage of frozen red sandstone |
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| SONG Yong-jun,YANG Hui-min,ZHANG Lei-tao,REN Jian-xi.CT real-time monitoring on uniaxial damage of frozen red sandstone[J].Rock and Soil Mechanics,2019,40(Z1):152-160. |
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| Authors: | SONG Yong-jun YANG Hui-min ZHANG Lei-tao REN Jian-xi |
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| Institution: | School of Architecture and Civil Engineering, Xi’an University of Science and Technology, Xi’an, Shaanxi 710054, China |
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| Abstract: | To explore the macro-mechanical characteristics and damage evolution mechanism of frozen rocks, the CT scanning images of each scanning layer of rock samples are obtained by using CT real-time scanning under uniaxial compression at 20 ℃, ?5 ℃ and ?10 ℃. The grayscale histogram and binary images are generated based on self-programming program in Matlab. The safety, damaging and fracture zones in the scanning layers of the rock sample are defined using the relationship between H value and density. Combined with thermal effect, water softening effect and ice frost heaving pressure on rock sample, the damage evolution law of frozen rock is studied quantitatively. The experimental results show that (1) during the process of temperature drops from 20 ℃ to ?5 ℃ and then to ?10 ℃, the unfrozen water content decreases and the frozen ice content increases. Correspondingly, the rock sample strength increases and the resistance to deformation enhances and the overall stability also enhances. The CT scanning images show that the development of cracks slows down and the rock sample damage gradually weakens; (2) the damage evolution of rocks under uniaxial compression generally experiences different stages including crack initiation, closure, propagation, influx and finally the formation of macroscopic main cracks. Thus the deformation of rock samples increases and damage occurs at different temperatures; (3) due to the end effect, the damage degree of the scanning layers at middle is stronger than that of the end. Besides, the damage formation of the external scanning layers is earlier than that of the internal scanning layers. Damage marginalization occurs and it expands to the inside of rocks. |
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| Keywords: | frozen rock CT real-time test grayscale histogram binary image thermal effect frost heaving pressure damage evolution |
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