煤层瓦斯渗流非线性运动规律实验研究

EXPERIMENTAL STUDY OF NONLINEAR MOTION LAW FOR GAS SEEPAGE IN COAL SEAMS

以焦作矿区赵固二矿采集加工的原煤煤样为研究对象,利用自主研制的含瓦斯煤热–流–固–力耦合实验装置,在考虑吸附变形量、孔隙气体压缩量和温度膨胀变化量的基础上,对煤样渗透率与有效应力之间的变化关系以及煤样中瓦斯运动规律进行实验研究,建立受载煤体渗透率与有效应力关系方程及描述煤层瓦斯非线性渗流规律的运动方程。研究结果表明:(1)渗透率随有效应力增大而呈非线性递减关系,具有负指数变化规律;(2)在围压和轴压固定情况下,研究不同孔隙压力梯度下瓦斯渗流规律,得到瓦斯渗流速度在煤体变形作用下呈现非线性特征,同时将所建方程与实验数据进行拟合,由相关度可知,实验结果与拟合结果相一致,表明所建立的运动方程与研究方法是合理的。

Taking the raw coal samples of Zhaogu mine in Jiaozuo as a object of study,with a self-developed equipment for thermo-fluid-solid-stress coupling of coal containing methane,experimental studies of the relationship between the coal sample permeability and effective stress as well as the motion law of gas in the coal samples are conducted on the basis of considering the adsorption deformation,pore gas compression volume and temperature expansion. Relationship equation between loaded coal permeability and effective stress and motion equation which describes the nonlinear seepage law of coal seam gas have been established. Results show that:(1) Permeability represents nonlinear decreasing relationship with increasing effective stress,possessing the law of negative exponent;(2) The gas transfusion law under different pore barometric gradients in fixed confining pressure and axial compression is studied,and gas seepage velocity presents nonlinear under the action of coal transformation. Meanwhile,through fitting the experimental data with equation,it can been seen by relevance that test results are consistent with fitting results,which indicates that the established motion equation and method are reasonable.