冲击破坏条件下煤的强度型统计损伤本构模型与分析

为研究冲击作用下煤体破坏特征,利用分离式霍普金森压杆(SHPB)试验系统对取自苇町矿的煤样进行了不同冲击载荷条件下的动态冲击试验,分析了煤在冲击载荷条件下的动态力学特性。试验结果表明煤是一种典型的率相关材料,弹性模量和抗压强度均随应变率的增大而增大。根据岩石力学的强度理论和统计损伤理论,建立了煤的强度型统计损伤本构模型,给出了模型参数的确定方法,验证了模型的正确性。对比分析了元件型统计损伤本构模型和强度型统计损伤本构模型的优劣,分析确定了强度型统计损伤本构模型的准确性与合理性。研究结果表明:强度型统计损伤本构模型结构简单,引入参数少,物理意义清晰,能够有效地描述煤体冲击破坏过程中的动态力学性质;相较于元件型统计损伤本构模型,利用强度型统计损伤本构模型拟合的相关性系数更高,与试验结果保持了很好的一致性,具有更好的普适性。

Analysis and strength statistical damage constitutive model of coal under impacting failure

Using Split Hopkinson Pressure Bar (SHPB) experimental system,the experiments on the failure characteristics of coal samples taken from Weiding coal mine under impact loading were carried out.Then the coal dynamic mechanical properties were analyzed in detail.According to the experimental data,it is clear that coal is a typical rate-depended material.Moreover,both the coal elastic modulus and compressive strength increase with the strain rate increases.Besides,a strength statistical damage constitutive model of coal was built based on the strength theory and statistical damage theory,a method to determine the model parameters was proposed,and the model correctness was verified by the testing data.The model is proved to be accurate and reasonable compared with the component statistical damage constitutive model.The research results show that the strength statistical damage constitutive model not only can effectively describe the coal dynamic mechanical properties,but also has several advantages,such as simple construction,few parameters and clear physics meaning.Therefore,the model with high relevance is more suitable and universal to describe the coal dynamic mechanical properties than the component statistical damage constitutive model.