多相介质煤岩体力学实验研究

Study on Mechanics Experiments of Multiphase Medium Coal Rocks

基于自然煤样、水饱和煤样和气、水饱和煤样的三轴对比力学实验得出 :自然煤样的弹性模量、抗压强度和体积压缩系数大于饱和水煤样的 ,饱和水煤样的又大于气、水饱和煤样的 ,而泊松比则正好相反 ;平行层理方向的应变大于垂直层理方向的应变 ;煤吸附气、水介质后 ,体积发生膨胀 ,煤体强度和机械能降低。指出了在地面开发煤层气过程中 ,随着气、水介质的排出 ,煤基质发生收缩 ,煤体强度提高 ,泊松比减少 ,上覆重力在煤储层水平方向的分量降低 ,煤储层渗透率得到改善。

Experiments were conducted on natural, water saturated and water gas saturated coal samples to compare their mechanics. The results indica that elasticity modulus, compression strength and volume compress coefficient of natural coal samples are larger than those of water saturated coal samples and the latter are larger than those of water gas saturated coal samples. However, their poisson's ratios are opposite, and strains of parallel layer direction are larger than that of vertical layer orientation. The swelling experiments demonstrated that coal volume swells when it adsorbs gas and/or water medium, and the coal rock strength and mechanical energy decreases. It was pointed that coal matrixes will shrink continuously, the coal reservoir mechanical intensity will gradually increase, and the poisson's ratio and the plane stress ponderance of the covering stratum gravity will decrease, and the coal reservoir permeability may be improved with the discharging of water and gas medium during the coal bed methane recovery in ground wells.