基于颗粒真实几何形状的含瓦斯水合物煤体三轴试验离散元模拟
Simulation of triaxial discrete element of MHBC based on real geometry of particles
高霞 1要远1
作者信息
- 1. 黑龙江科技大学 建筑工程学院,哈尔滨 150022
- 折叠
摘要
为了更加真实地模拟含瓦斯水合物煤体的力学特性,采用电镜扫描及二维离散元程序,提出了一种基于球度和扁平度的随机几何模型生成技术,建立基于室内三轴试验结果的二维离散元模型.通过构建不同瓦斯水合物饱和度的数值试样,模拟三轴压缩下含瓦斯水合物煤体的力学特性及变形破坏规律,从细观角度探究饱和度对其力学性质的影响机理.结果表明:随着饱和度增大,试样峰值强度和弹性模量呈线性增加,剪缩量略微减小,剪胀量明显增大;所有试样均呈先剪缩后剪胀,饱和度越大,进入剪胀阶段越快;当饱和度从20%提升至60%,试样内部的强力链数量明显增多,颗粒间的最大接触力提升了约50%,说明水合物越多,颗粒间粘结作用越强,从而提升了试样的峰值强度.
Abstract
This paper intends to simulate the mechanical characteristics behind methane hydrate-bearing coal(MHBC)more realistically and proposes a random geometric model generation technique based on sphericity and flatness with electron microscopy scanning and DEM,and establishes the two-di-mensional DEM model according to the indoor triaxial test results.The study is accomplished by establis-hing the numerical samples with different gas hydrate saturation;simulating the mechanical properties and deformation failure laws behind MHBC under triaxial compression;and exploring the influence mecha-nism of saturation on the mechanical properties of MHBC from the meso-perspectives.The results show that with the increase of the saturation,the peak strength and elastic modulus of the sample increase line-arly,the shear shrinkage decreases slightly,and the shear expansion increases significantly.All samples show the deformation characteristics of first shear contraction and then dilatancy;and the greater the satu-ration,the faster the sample enters the shear dilatancy stage.When the saturation increases from 20%to 60%,the number of strong chains inside the sample increases significantly,and the maximum contact force between particles increases by about 50%,indicating that the more the saturation of hydrate,the stronger the inter-particle bonding,which further increases the peak strength of the MHBC.
关键词
含瓦斯水合物煤/不规则颗粒/宏细观力学特性Key words
methane hydrate-bearing coal/irregular particles/macro-and meso-mechanical proper-ties引用本文复制引用
基金项目
国家自然科学基金联合基金项目(U21A20111)
国家自然科学基金面上项目(51974112)
出版年
2024
国家科技期刊平台
NSTL
万方数据