神东侏罗纪泥岩微观组构对其力学性质的影响

Influence of Micro-fabric of Jurassic Mudstone on Its Mechanical Properties in Shendong Mining Area

泥岩的矿物组成和微观结构对其力学性质起决定作用。利用XRD、SEM以及岩石力学试验系统对神东侏罗纪含煤地层的泥岩进行研究,同步测定泥岩声波传播速度,从而建立了泥岩的力学特性与其矿物组成以及微观结构之间的关系。结果表明,神东侏罗纪泥岩的矿物组成以石英和黏土矿物为主,平均含量分别为55.22%和26.67%,而华北石炭-二叠纪泥岩中石英和黏土矿物的平均含量分别为31.90%和63.24%,二者相差分别为23.32%和36.57%,导致神东侏罗纪泥岩的力学性质明显高于石炭-二叠纪泥岩。随着石英含量的增高,泥岩的单轴抗压强度和弹性模量均呈增大趋势;随着黏土矿物含量的增加,其规律相反。同时,随着泥岩致密程度增加,声波速度、单轴抗压强度和弹性模量均增大。

The mineral composition and the microstructure of mudstone play a decisive role in its mechanical properties. The mudstone in Jurassic coal measures was studied using XRD, SEM and rock mechanics test system, and simultaneously acoustic velocity of the mudstone was tested. The correlations between mechanical properties and mineral composition as well as microstructure of mudstones have been established. The results show that the mudstone of Jurassic coal measures in Shendong Mining Area is mainly composed of quartz and clay minerals with mean contents of 55.22% and 26.67% respectively. Whereas,mean contents of quartz and clay minerals of mudstones in Carboniferous Permian coal-bearing strata are 31.90% and 63.24%with difference of 23.32% and 36.57% respectively, which resulted in lower mechanical properties than that of Jurassic mudstones.With the increase of quartz content, the uniaxial compressive strength and elastic modulus show an increasing trend, while, with the increase of clay minerals content, the trend is opposite. Meanwhile, the acoustic velocity, uniaxial compressive strength and elastic modulus increase with the increase of mudstone density.