深部下组煤底板软硬岩石阻渗性试验及其耦合特征

为了探讨济北矿区下组煤底板阻水能力,对采动底板下部起主要阻水层位的软硬岩石阻水能力进行了伺服渗透试验研究,系统分析了软硬2种岩样变形破坏过程中应力、渗透率随应变全程变化关系和渗透率与应力耦合特征。试验结果表明:直接底板泥岩及其下部的灰岩在围压和水压作用下的渗透率—应变曲线、应力—应变曲线具有阶段性,峰前和峰后变化存在显著差异性;2种岩石峰前的渗透率与应力耦合结果表明软硬岩石均具有整体相似的变化规律,基本呈3次多项式关系,并得出渗透率随应力变化的1个重要特征拐点,由此可以界定出岩块破坏前后的屈服抗渗强度。

Permeability Test on Soft/hard Floor Strata of Deep Lower Seam and Its Coupling Characteristics

In order to probe into the water-resisting ability of the lower seam floor in Jibei Coal Mining Area,the servo infiltration test study was carried out on the water-resisting ability of the soft/hard floor strata,and systematic analysis was made on the complete variation relation of the stress and infiltration rate with the strain in the breaking and deformation process of two soft/hard rock specimens as well as the coupling characteristics of the infiltration rate and stress.The test results indicated that the infiltration rate-strain curve and the stress-strain curve of the immediate bottom mudstone and its lower limestone were in stage variation under the action of the confining pressure and water pressure,the variation before peak was markedly different from that after peak;the infiltration rate and stress coupling of two kinds of rock before peak showed that both the soft and hard rocks all have an entirely similar variation regularity,basically in a cubic polynomial relation;and an important characteristic inflection point of the variation of the infiltration rate with stress was obtained,and from this the yield anti-infiltration strength of rock before and after failure can be determined.