加卸载条件下原煤渗透率与有效应力的规律

为研究采动过程中有效应力的变化对渗透率的动态演化的影响,基于自行研制的"含瓦斯煤热流固耦合三轴伺服渗流实验装置",进行了单调加载和不同初始应力状态加卸载条件下原煤渗流特性的试验研究。考虑瓦斯力学作用和瓦斯吸附作用两个方面对有效应力系数的影响,得到了加卸载条件下原煤的有效应力计算公式及渗透率与有效应力关系的公式,根据初始孔隙率、吸附常数等试验数据和不同条件下渗流试验数据对建立的渗透率与有效应力表达式进行验证。研究结果表明,理论计算值和试验结果吻合度比较高,单调加载与加卸载条件下原煤的渗透率随着有效应力的增加呈负指数关系下降。

Permeability properties and effective stress of raw coal under loading-unloading conditions

To study the change of effective stress impact on permeability dynamic evolution during mining，based on domestic-developed triaxial servo-controlled seepage equipment for thermal-hydrological-mechanical coupling of coal containing methane，the experimental study of permeability properties was performed on raw coal samples under monotonic loading and loading-unloading conditions of different initial stress states.Combined effects of gas mechanism and gas adsorption on the effective stress coefficient，the effective stress calculation and the permeability with effective stress equation under loading-unloading conditions were established，and then according to the initial porosity and the adsorption constants and experimental permeability data under different conditions，the permeability model was verified.The results show that theoretical permeability calculation values and experimental results under loading and loading-unloading conditions are quite high.With the increase of effective stress，permeability of coal samples under different conditions decreases as negative exponential relationship.