超高应变率下岩石的破坏机理

通过对大理石的轻气炮试验进行三维数值仿真重现,探索了岩石在超高应变率下的破坏机理.大理石试样中两个高速应力计的实测应力信号被用作数值模拟的匹配目标,结果表明,在高速冲击压缩载荷下,细观静水压破坏是大理石的主要破坏机制,而不是通常认为的细观剪切或拉伸破坏.此外,为再现不同冲击速度下大理石的物理实验观测数据,提出了新的考虑...

Failure mechanism of rock under ultra-high strain rates

We explored the failure mechanism of rock under ultra-high strain rates using 3D numerical modeling of the light gas gun test. Based on numerical results, it concluded that mesoscopic hydro-compressive failure rather than mesoscopic shear or tensile failure is the main mechanism of rock failure under the condition of shock compressive loading. The shock wave, indicated by the stress signals of two stress gauges in the rock specimen, can be well reproduced by numerical simulation with the quasi-static rather than the dynamic elastic parameters. The simulation results indicate that the compressive shock wave involves a compressive failure loading process similar to that shown in the conventional uniaxial compressive failure test rather than the ultrasonic test. A mesoscopic-rate-dependent failure model was developed to take the dynamic effect into account. Our results revealed that larger rock porosity could result in an decrease in dynamic strength and dynamic effect under shock compressive loading.