不同卸围压速度对含瓦斯煤岩力学和瓦斯渗流特性影响试验研究

 利用自行研制的“含瓦斯煤热流固耦合三轴伺服渗流试验装置”，进行不同初始围压和不同瓦斯压力组合条件下，不同卸围压速度对含瓦斯煤岩力学和瓦斯渗流特性影响试验研究。研究结果表明：从力学的角度来看，卸围压开始后煤岩会经历一个应力平台阶段，然后发生失稳破坏。卸围压速度越大，煤岩维持在应力平台阶段的时间越短，煤岩越容易发生失稳破坏。卸围压开始后煤岩应力平台阶段的时间与卸围压速度呈幂函数关系。从瓦斯渗流的角度来看，煤岩的渗透率的变化与煤岩的变形损伤密切相关，煤岩体积应变的变化趋势能很好地体现煤岩渗透率的变化趋势。卸围压开始后煤岩渗透率的变化经历4个阶段，且渗透率一直在增大。卸围压速度越大，煤岩的渗透率增大的越快。卸围压开始后煤岩在应力平台阶段的渗透率与卸围压时间呈指数函数关系。

EXPERIMENTAL STUDY OF INFLUENCE OF CONFINING PRESSURE UNLOADING SPEED ON MECHANICAL PROPERTIES AND GAS PERMEABILITY OF CONTAINING-GAS COAL ROCK

Using self-made “triaxial stress thermal-hydro-mechanical coal containing gas permeameter”，an experimental study was carried out to investigate how the unloading speed of confining pressure influences the mechanical properties and gas permeability of containing-gas coal rock，under cooperation of different initial confining pressures and various gas pressures. The research result showed that from an aspect of mechanics，the coal would first undergo a stage of stress flat roof，after the unloading process began，and then a break would happen due to destabilization. When the confining pressure was unloaded at a higher speed，the destabilizing breakage was easier to happen on the coal which also represented shorter time to maintain at the stage of stress flat roof. During the unloading process of confining pressures，the time of coal being in the stage of stress flat roof showed a power function with the unloading speed of confining pressures. From an aspect of gas permeation，the permeability of coal was tightly relevant with its deformation and the changing trend of its volume strain could well reflect the changing trend of its permeability. When the confining stress was being unloaded，the permeability of coal varied in an experience of four stages and it kept increasing. The permeability of coal increased at a faster rate when the unloading speed was larger. During the unloading process of confining pressures，the permeability of coal being in the stage of stress flat roof showed an exponential function with the corresponding time.