岩石在冲击载荷下的过应力本构模型研究

 采用分离式霍布金森压杆(SHPB)试验系统对深井软岩材料进行动态力学性能测试，测试的应力–应变曲线表现出显著的塑性变形特性。基于修正的过应力模型本构方程，根据 的变化量与应变率和应变之间的函数关系，采用量纲一化分析法对修正的过应力模型本构方程进行简化，得到简化的过应力模型本构方程；考虑动载作用下损伤对岩石动载强度的影响，将连续损伤理论和统计强度理论引入到简化的过应力模型本构方程，建立简化的损伤型过应力模型本构方程，使得本构模型方程适用于动态全程应力–应变曲线。采用简化的损伤型过应力模型本构方程对实测曲线进行曲线拟合，实测曲线和拟合曲线两者具有很好的一致性。

RESEARCH ON EXCESS STRESS CONSTITUTIVE MODEL OF ROCK UNDER IMPACT LOAD

Mechanical properties of soft rock materials in deep shaft are tested with experimental system of split Hopkinson pressure bar(SHPB). The experimental results indicate that the dynamic stress-strain curves of soft rock materials are of distinct plastic yield characteristics. Based on modified excess stress constitutive model，according to the function relationships of strain，strain rate and  ，to simplify constitutive equation of modified excess stress model with dimensionless analysis，the simplified constitutive equation of modified excess stress model is obtained. And then，continuum damage theory and statistical damage theory are incorporated into the simplified constitutive equation of modified excess stress model account for the influence of damage on dynamic strength of rock，so the simplified constitutive equation of damage excess stress model is established. The simplified constitutive functions are fitted out respectively on the basis of experimental data. There is a good coherence between the stress-strain curves fitted by the simplified damage excess stress constitutive model and the experimental stress-strain curves.