煤系岩石单轴压缩损伤破坏演化规律与表征

Evolution and characterization of uniaxial compression damage and destruction of coal measures rocks

为了研究煤系岩石单轴压缩损伤破坏演化规律及其表征方法,以煤系岩层中普遍存在的3种不同岩性岩石为研究对象,重点讨论不同矿物组成以及不同微观结构等对其自身岩石力学性质的贡献关系,对比分析了声发射多维度特征参数的特殊表征意义,借助于计数与能量参数表征破坏尺度大小的关系,以及借助于声发射高灵敏定位效果来表征破坏位置的演化,通过两者的结合可进一步表征出承载体损伤演化全过程的可行性,基于理论分析,推导了响应的本构方程。结果表明:不同岩性煤系岩石微观形貌特征及矿物组成成分的差异直接影响其物理力学性质与受载损伤破坏特征;声发射特征振铃计数及声发射能量能有效表示岩石受载过程中损伤演化过程,声发射空间定位点分形维数D能在一定程度上反映岩石的损伤破坏过程,但受岩石孔隙率及致密程度的影响较大。基于岩石孔隙率特征及受载过程中的声发射累计振铃计数,建立了考虑初始损伤和累计损伤的本构模型,并分析了孔隙率对损伤张量Dn的影响规律。

In order to study the damage evolution law of coal measures rocks under uniaxial compression and its characterization method,three kinds of rocks with different lithology conditions and commonly existing in coal measures rocks are taken as the research object,and different mineral compositions and different microstructures are emphatically discussed,based on the contribution of rock mechanical properties,the special characterization of multi-dimensional acoustic emission parameters is analyzed,and the relationship between damage scale and count and energy parameters is described,based on the theory analysis,the constitutive equation of the response is derived,and the damage evolution process of the bearing body can be further characterized by the combination of the two methods.The results show that the differences of rock micro-morphology and mineral composition of different lithological coal measures directly affect their physical and mechanical properties and damage characteristics under loading.The acoustic emission characteristic ringing counts and acoustic emission energy can effectively represent the damage evolution process during rock loading.The fractal dimension D of acoustic emission space locating point can reflect the damage and destruction process of rock to a certain extent,but it is greatly influenced by the porosity and density of rock.Based on rock porosity characteristics and acoustic emission cumulative ringing counts during loading,a constitutive model considering initial damage and cumulative damage is established and the influence rule of porosity on damage tensor Dn is analyzed.