含瓦斯煤全应力–应变过程中力学及渗流特性试验研究

Experiment Study on Mechanics and Permeability of Coal Containing Gas under the Total Stress-Strain Tests

摘要: 利用自行研制的含瓦斯煤热流固耦合伺服渗流试验装置，以原煤试样为研究对象，进行含瓦斯煤全应力–应变渗流试验。研究表明：在连续加载过程中，含瓦斯煤的应力–应变关系可以分为四个阶段：初始压实阶段、弹性阶段、屈服破坏阶段、破坏后阶段，这四个阶段煤样的应力–应变关系有较大差异；含瓦斯煤的弹性模量先下降后稳定，在破坏后快速下降；泊松比先下降后缓慢上升，在破坏后快速上升；含瓦斯煤的轴向应力与渗透率随轴向应变的变化规律基本呈相反的趋势；含瓦斯煤渗透率与体积应变密切相关，但分析发现，煤样体积最小时，其渗透率不是最低。

Abstract: A self-developed device called the coal-containing heat solid coupling servo seepage device is used to do the total stress-strain tests of coal samples. The result shows: In the process of continuous load, the stress-strain relationship of coal containing gas can be divided into four stages: the initial com-paction phase, the elastic phase, the yield and damage phase, the post-failure phase. The stress- strain relationship of these four phases makes a big difference; elastic modulus of coal containing gas first decreases and then keeps constant; it declines rapidly after destruction; the Poisson's ratio firstly dropped after a slow rise, and it raised rapidly after destruction. With the change of axial stress, the axial stress of the coal containing gas and its permeability is opposite. Permeability of the coal containing gas is closely related with its volumetric strain. But we have analyzed and found that, the permeability of the coal is not the lowest when its volume is the smallest.