煤体破坏过程中裂纹演化规律试验  

Development of cracks in the process of coal destruction

作　　者：曹树刚[1] 郭平[1] 刘延保[1,2] 张遵国[1] 李勇[1,3] 

机构地区：[1]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044 [2]煤炭科学研究总院重庆研究院,重庆400037 [3]博洛尼亚大学结构力学系,意大利博洛尼亚40136

出　　处：《中国矿业大学学报》2013年第5期725-730,共6页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(51074197);重庆市科委自然科学基金项目(CSTC2010BB6118);中央高校基本科研业务费项目(CDJXS11241181)

摘　　要：利用自行研制的煤岩固-气耦合细观力学试验装置,获得了含瓦斯煤体三轴压缩条件下煤样破坏过程中裂纹变化的实时图像,并利用matlab软件编程提取出细观试验图像中相关的裂纹参数;基于分形理论,研究了煤体裂纹的损伤演化特征.试验结果表明,随着应力、应变的增加,煤体裂纹数呈现出先增多后减少的变化规律,裂纹总长度和裂纹总面积均呈增大趋势;基于＂小岛法＂的相关原理对煤体表面裂纹演化的研究表明,煤体裂纹周长和裂纹面积的双对数具有良好的线性关系,煤体表面图像具有明显的分形特征,分形维数变化范围为1.25~1.48,且煤样表面分形维数与应变之间呈显著二次多项式函数关系.Coupled coal solid-gas meso-mechanics experiments of coal destruction were carried out with a in-house built testing apparatus. The images of crack developed in the process of coal destruction were obtained. The parameters of cracks were extracted using Matlab soft- ware, and the damage evolution law of cracks was studied based on fractal theory. The results demonstrate that the numbers of coal cracks showed a first increases and then decreases, and o- verall length and area of coal cracks increase with the stress and strain increasing. An in-depth study of the damage evolution law of cracks coal was conducted by using ＂slit island method＂. The results show a linear correlation of double logarithmic between cracks＇ length and cracks＇ area. The images of coal surface have obvious fractal characteristics, and the range of fractal dimension changes from 1.25 to 1.48. The relation of fractal dimension of coal surface and coal strain can be described as a quadratic polynomial function.

关 键 词：煤 细观力学 裂纹 分形 

分 类 号：TU458.3[建筑科学—岩土工程]