实时温度下花岗岩动态压缩破坏特性试验与数值研究

Experimental and numerical studies on dynamic compression failure characteristics of granite under real-time temperatures

为了研究黑云母花岗岩热动力学性能,对不同实时温度(20℃,100℃,200℃)下的花岗岩试样力学响应和破坏过程进行了室内试验和数值模拟分析。结果表明:在所研究的温度范围内,20℃时岩样的抗压强度和弹性模量值最大,100℃时最小,且100℃下岩样的破碎程度比20℃和200℃的明显偏大;随着加载速率的提高,应力–应变曲线上的峰值应力和峰值应变增加,岩样内部裂纹演化及破坏程度也随之增大;低加载率时试样周边易萌生裂纹,高加载率下试样内部裂纹在加载初期甚至也可被激活;所提出的Holmquist-Johnson-Cook(HJC)模型参数确定方法是可行的,数值模拟能较好地描述热处理岩样在冲击荷载作用下力学特性;HJC模型与相关失效准则相结合,能逼真地展现岩样动态压缩破裂过程及其形破坏态变化。

To investigate the thermodynamic properties of biotite granite,the mechanical response and failure process of the rock samples under different real-time temperatures(20℃,100℃and 200℃)are analyzed based on the laboratory tests and numerical simulations.The results show that the compression strength and elastic modulus of the granite sample are the largest at the temperature of 20°C and the lowest at 100°C.The fracturing degree of the sample at 100°C is more obvious than that at20°C and 200°C.As the loading rate rises,the peak strength and peak strain of the stress-strain curve increase along with the crack evolution and failure degree.At a low loading rate,the microcracks in the peripheral area of the sample are firstly initiated.The internal microcracks of the sample can be activated even at the initial stage of loading with the increase of loading rate.In addition,the proposed method for determining the Holmquist-Johnson-Cook(HJC)model parameters is proved to be feasible and accurate.The numerical simulation can well reflect the mechanical characteristics of the rock sample under the coupling action of impact loading and real-time temperatures,and the failure mode and rupture process of the sample during dynamic compression can be also illustrated realistically using the coupled HJC model and related failure criterion.