Dynamic Characteristics and Numerical Simulation of Granite Rock-Filled Subgrade Based on Energy Damage

With the continuous development and improvement of China's highway traffic network, rock-filled subgrade has been paid more and more attention in highway engineering. In order to analyze the impact dynamic characteristics, failure characteristics and engineering application performance of granite rock-filled subgrade, based on the energy damage theory and basic physical and mechanical properties, this paper adopted split Hopkinson pressure bar test to carry out impact compression test on Hubei granite, and analyzed the stress, strain and failure of granite through finite element numerical simulation of ANSYS/LS-DYNA. The results of numerical simulation were compared with laboratory tests. The results show that the impact failure of Hubei granite has a certain directivity, from axial split failure to shear failure. The impact crushing failure of granite gradually extends from the edge to the interior, which reflects the effect of impact stress wave. The impact pressure has an enhancement effect on granite strength, and the enhancement effect becomes more obvious with the increase of impact pressure. The stress–strain curve of granite can be divided into four conventional curves. The greater the impact pressure, the longer the time to reach the peak stress, and the stress value drops sharply after reaching the peak stress. The failure morphology and stress–strain results of granite impact load test are basically consistent with the simulation results, which reflects the engineering feasibility and reference value of granite rock-filled subgrade.