岩土力学 ›› 2019, Vol. 40 ›› Issue (S1): 152-160.doi: 10.16285/j.rsm.2018.2371

• 基础理论与实验研究 • 上一篇    下一篇

冻结红砂岩单轴损伤破坏CT实时试验研究

宋勇军,杨慧敏,张磊涛,任建喜   

  1. 西安科技大学,建筑与土木工程学院,陕西 西安 710054
  • 收稿日期:2018-12-31 出版日期:2019-08-01 发布日期:2019-08-16
  • 通讯作者: 杨慧敏,女,1994年生,硕士研究生,主要从事岩石力学与地下工程方面的研究工作。E-mail:yanghm94@163.com E-mail:songyj79@xust.edu.cn
  • 作者简介:宋勇军,男,1979年生,博士,副教授,硕士生导师,主要从事岩石力学与地下工程方面的教学与研究工作
  • 基金资助:
    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)

CT real-time monitoring on uniaxial damage of frozen red sandstone

SONG Yong-jun, YANG Hui-min, ZHANG Lei-tao, REN Jian-xi   

  1. School of Architecture and Civil Engineering, Xi’an University of Science and Technology, Xi’an, Shaanxi 710054, China
  • Received:2018-12-31 Online:2019-08-01 Published:2019-08-16
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (11872299, 11402195), the Natural Science Foundation of Shaanxi Province (2017JM1039), and the State Key Research Development Program of Shaanxi Province (2017GY-156).

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。

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

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.

Key words: frozen rock, CT real-time test, grayscale histogram, binary image, thermal effect, frost heaving pressure, damage evolution

中图分类号: 

  • TU452
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