宿州矿区碎软煤渗透性特征研究

The Permeability Characteristics of Broken Soft Coal in Suzhou Mining Area

摘要: 采集宿州矿区碎软煤与原生结构煤，利用PDP-200渗透率测试仪，结合扫描电子显微镜和孔隙度测试仪(QKX-II)，研究了宿州矿区碎软煤的渗透性特征。研究表明：宿州矿区碎软煤构造裂隙较为发育，渗透率较大，其中碎斑煤的初始渗透率最大；在煤体变形序列中，随着煤体构造变形强度的增大，孔隙度和渗透率大体呈增大趋势；碎软煤的有效应力与渗透率呈负指数关系(R² = 0.92~0.99)，随着有效应力的增大，碎软煤的渗透率呈减小趋势；不同变形程度的碎软煤，其渗透率损害系数和无因次渗透率都随着有效应力的增大而减小，其中碎斑煤的损害系数和碎裂煤的无因次渗透率变化随有效应力的增大，变化最大，表明强脆性变形煤(碎斑煤)压力敏感性大，弱脆性变形煤(碎裂煤)压力敏感性小；煤样降压之后，煤体渗透率呈增长趋势，其中碎斑煤降压前后渗透率变化最大，碎裂煤次之，片状煤最小。

Abstract: The permeability characteristics of broken soft coal (BSC) in Suzhou mining area were studied by using the PDP-200 permeability tester, the scanning electron microscope and the porosity tester (QKX-II). The results show that the fractures of BSC in Suzhou mining area are relatively developed, and the permeability of BSC is large, among which the initial permeability of mortar coal is the largest. The porosity and the permeability of BSC tend to increase with the increase of structural coal deformation strength. There is a negative exponential relationship between the effective stress and the permeability of BSC (R² = 0.92~0.99), and the permeability of BSC decreases with the increase of the effective stress. The damage coefficient and dimensionless permeability of different types BSC decrease with the increase of effective stress, among which the damage coefficient of mortar coal and the dimensionless permeability of cataclastic coal undergo significant changes with the increase of effective stress. These indicate that coal with strong brittle deformation is more sensitive to pressure, while coal with weak brittle deformation is less sensitive to pressure. During depressurization, the permeability of coal shows an increasing trend, of which the change of permeability of mortar coal before and after depressurization is the largest, followed by cataclastic coal, and flaky coal is the smallest.