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过程工程学报 ›› 2022, Vol. 22 ›› Issue (2): 258-267.DOI: 10.12034/j.issn.1009-606X.221033

• 研究论文 • 上一篇    下一篇

含裂隙煤体抗压性能的试验研究与模拟计算

史方约,李敏敏*,岳高伟,蔺海晓   

  1. 河南理工大学土木工程学院，河南 焦作，454000
  • 收稿日期:2021-01-29 修回日期:2021-05-11 出版日期:2022-02-28 发布日期:2022-02-28
  • 通讯作者: 李敏敏 zhiyalmm@126.com
  • 作者简介:史方约(1996-)，男，安徽省淮南市人，硕士研究生，主要从事煤岩体损伤破坏及其稳定性的研究工作，E-mail: 2470727287@qq.com；李敏敏，通讯联系人，E-mail: zhiyalmm@126.com.
  • 基金资助:
    国家自然科学基金资助项目

Experimental study and simulation calculation on compressive performance of coal with fracture

Fangyue SHI,  Minmin LI*,  Haixiao LIN,  Gaowei YUE   

  1. School of Civil Engineering, Henan Polytechnic University, Jiaozuo, Henan 454000, China
  • Received:2021-01-29 Revised:2021-05-11 Online:2022-02-28 Published:2022-02-28

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摘要： 煤体内部天然存在的裂隙是瓦斯流动的主要通道和影响煤矿安全的重要因素。为考察不同原生裂隙分布形态的煤体抗压缩强度与裂纹演化规律，对原煤试样进行初始裂隙的提取和室内三轴压缩试验，结合数值模拟方法进一步研究了含裂隙试样在围压分别为1, 3, 5, 7, 9 MPa和加载速率在0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, 0.9, 1.0 m/s下的峰值应力及破坏形态。结果表明，煤样的峰值应力随围压增加呈指数形式增大。垂直方向延伸的原生裂隙对裂纹扩展带的影响较小，当原生裂隙的延伸角度倾向于对角线方向时，裂纹容易在裂隙端部萌生和扩展。试样2的“V”型裂纹带在低围压(1, 3, 5 MPa)时受原生裂隙影响较大，高围压(7和9 MPa)下的破坏特征与试样1相似。随着加载速率逐渐递增，试样的抗压强度变化经历先缓慢上升，后迅速增加，最终趋于平缓的过程。低加载速率下的裂纹多聚集在原生裂隙延伸方向上，较高的加载速率容易造成裂纹集中于试样的角部位置，裂纹数目也迅速增多。

关键词: 裂隙煤体, CT扫描, 三轴压缩, 离散元, 抗压强度, 破坏形态

Abstract: As a heterogeneous brittle material, coal contains many micro pores and randomly distributed cracks, which are difficult to observe. With the help of industrial CT scanning equipment and three-dimensional image reconstruction technology, the location and distribution characteristics of the main primary fractures which are irregular and concentrated in the coal section can be effectively restored. On this basis, the conventional triaxial compression tests with confining pressures of 1 MPa and 3 MPa were carried out. Furthermore, the original fracture data were imported into the discrete element software to obtain the meso scale parameters consistent with the indoor test stress-strain curve, and then the biaxial compression numerical simulation tests with confining pressure of 0, 1, 3, 5, 7, 9 MPa and loading rate of 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, 0.9, 1.0 m/s were carried out for the models with different distribution patterns of original fractures to compare the different confining pressures. The results showed that the compressive strength, elastic modulus, crack growth morphology and other mechanical parameters of the specimen changed with the loading rate. The results showed that the DEM can be used to simulate the mechanical properties of coal under the influence of primary fractures. With the gradual increase of confining pressure, the compressive strength of coal increased exponentially, and the change of elastic modulus was not sensitive. The failure of the specimen was affected by the primary fracture, which was more significant under low confining pressure. With the increase of loading rate, the compressive strength of the sample increased slowly at first, then increased rapidly and tends to be flat. The failure mode of the sample was significantly affected by the primary cracks at low loading rate, and the failure of the sample end was more obvious at high loading rate.

Key words: fractured coal, CT scan, triaxial compression, discrete element, compressive strength, failure mode