含瓦斯水合物煤体力学性质离散元建模与试验验证

Discrete element modeling and experimental verification of mechanical properties of gas hydrate bonded coal

为了研究含瓦斯水合物煤体常规三轴压缩试验的宏细观力学性质,对7.72%、9.69%、12.36%不同饱和度含瓦斯水合物煤体进行三维三轴试验的离散元数值模拟,分析含瓦斯水合物煤体在三轴加载过程中应力-应变曲线、颗粒速度场和颗粒位移场的变化规律及破坏状态。结果表明:峰值强度随着饱和度增加而逐渐增高,试验与数值模拟的应力-应变曲线变化趋势相似,故离散元数值模拟方法能较好地模拟试验结果;颗粒速度场出现明显的剪切带,与试验煤样破坏情况相似;含瓦斯水合物煤体的颗粒位移场呈轴对称向外分布,解释了煤样在试验后发生压胀破坏的情况。

This paper aims to study the macro and micro mechanical properties of gas hydrate bound coal in conventional triaxial compression test.The study includes conducting discrete element numerical simulation of three-dimensional triaxial test on gas hydrate bound coal with different saturations(7.72%,9.69%,12.36%);analyzing the variation and collapse state of the stress-strain curve,particle velocity field,particle displacement field behind gas hydrate bound coal under triaxial loading.The results show that the peak strength increases gradually with the increase of saturation,and the variation trend of stress-strain curve is similar by the experimental and numerical simulation,making it better for simulating the test results by using the discrete element numerical simulation method;the particle velocity field appears obvious shear zone,which is similar to the failure of the test coal sample;the particle displacement field of gas hydrate bound coal is symmetrically distributed outwards,which explains the collapse of coal sample after the test.