不同加卸载条件下含瓦斯煤力学特性试验研究

EXPERIMENTAL STUDY OF MECHANICAL PROPERTIES OF COAL CONTAINING METHANE UNDER DIFFERENT LOADING-UNLOADING CONDITIONS

利用自行研制的含瓦斯煤热流固耦合三轴伺服渗流实验装置,以平煤十矿原煤样为研究对象,进行不同加卸载条件下(即增加轴压的同时卸载围压)含瓦斯煤力学特性的试验研究。研究结果表明,不同加卸载条件下含瓦斯煤的力学特性表现各异,主要表现为:加卸载煤样的承载强度比常规加载煤样的峰值强度低;加卸载煤样的承载强度随初始轴力的升高呈指数关系降低、随轴力加载速度的增加呈幂函数关系降低、随初始围压的升高呈指数关系降低、随瓦斯压力的升高呈线性关系降低;随着轴向应变的增加,各条件下变形模量呈现先迅速减小然后缓慢减小直至破坏后保持基本稳定的趋势,泊松比表现出先逐渐减小后增加最后基本保持稳定的趋势。该研究对巷道支护和瓦斯抽采具有重要的指导意义。

Based on the self-made triaxial servo-controlled seepage equipment for thermo-hydro-mechanical coupling of coal containing methane,the experimental study of mechanical properties of coal containing methane was performed on raw coal samples in No.10 Mine,Pingdingshan Coal Mining Group Corporation Ltd.,under different loading-unloading conditions i.e.increase axial pressure and unload confining pressure.The results show that mechanical properties of coal containing methane under different loading-unloading conditions are different;bearing strength of coal sample under loading-unloading is lower than peak intensity of coal sample under conventional loading;bearing strength of coal under loading-unloading decreases exponentially with the increasing of initial axial force,bearing strength decreases with increase in axial pressure loading speed which presents the power function relationship;it decreases exponentially with the increase in initial confining pressure,it decreases with increase in gas pressure which presents the linear relationship;with increase in axial strain,deformation modulus under different conditions presents the trend which decreases rapidly first then decreases slowly until to remain approximate stable after failure;the Poisson？s ratio exhibits the tendency that first decreases then increases and maintains stability at last.The research has an important guiding significance on tunnel supporting and gas extraction.