摘要
大直径霍普金生压杆试验表明：云驾岭煤矿无烟煤的动态本构曲线具有显著的塑性屈服特征,初始弹性模量E_b、屈服强度σ_s与极限强度σ_b都随着应变率的增加而提高,但屈服强度最为显著。根据试验曲线的特征,在对既有岩石动态本构模型进行分析和初步的拟合后,引入一个新的损伤型黏弹性本构模型,以1根线性弹簧和2个不同松弛时间的Maxwell体并联的黏弹性模型表达无烟煤显著的塑性流动,2个Maxwell体分别表示无烟煤的低应变率响应和高应变率响应,以动态应力-应变曲线任一点与原点连线的斜率E(ε_i)相对于初始模量E_b的降低来度量损伤D。模型的数值拟合曲线与实测动态本构曲线具有较好的一致性。拟合参数表明,无烟煤对低应变率的响应与混凝土相同,对高应变率的敏感性远远高于混凝土。
Experiments performed on split Hopkinson pressure bar（SHPB） with a large diameter of 75 mm show that the dynamic stress-strain curve of anthracite of Yunjialing coal mine is of distinct plastic yield characteristics： and the initial elastic modulus, yield strength, as well as the ultimate strength go up with strain rate; but there is the best correlation between yield strength and the strain rate. Based on the characteristics of measured dynamic stress-strain curves and analysis of existing dynamic constitutive models of rock, as well as preparatory simulation, a new viscoelastic damage model has been introduced. A linear spring is put to parallel to two Maxwell units with different relaxing time to express distinct plastic flow, and the damage D is equal to the ratio of Eb-E（εi） to Eb, where Eb is the initial elastic modulus and E（εi） is the slope of the line between the origin point and any other point on the tested dynamic stress-strain curve. In the new constitutive model, one Maxwell unit with low relaxing time φ1 is used to describe the low strain rate response of anthracite; and the other one with high relaxing time φ2 to describe high strain rate response of anthracite. Simulated stress-strain curves using the new model is of good consistency with measured curves; and the simulated parameters indicate that the response of the low strain rate of anthracite is just as same as that of concrete; but the response of the high strain rate of anthracite is much more violent than that of concrete.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2006年第11期2258-2263,共6页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金(50374070)
关键词
采矿工程
岩石动力学
无烟煤
动力特性
本构模型
分离式霍普金森压杆
mining engineering
rock dynamics
anthracite
dynamic properties
constitutive model
split Hopkinson pressure bar（SHPB）
