## 4 Conclusions  
In this paper, concrete specimens were treated with different temperatures, and a dynamic splitting test and dynamic compression test were carried out. The progressive failure process of the concrete specimens was studied, the splitting and compression failure modes of the specimens were determined, and the influence mechanism of temperature on the dynamic stress-strain curves and impact resistance of the concrete was revealed. The main conclusions are as follows:  
1. In the impact splitting test, the specimen was first slightly damaged at the loading point, and gradually extended to the core area of the specimen to form a triangular crushing zone. Finally, a penetrating crack was formed in the loading direction, and the specimen was split into two parts. In the impact compression test, the specimen was damaged from the edge and cracks appeared on the surface. The direction of the cracks was consistent with the direction of the loading. With an increase in the load, micro-cracks developed and merged, resulting in the surface block of the specimen falling off, the main crack developing in the core concrete, and the specimen presenting axial splitting failure. After the high-temperature treatment, the specimen showed brittle failure and was finally crushed into fine blocks.
2. In the impact splitting and impact compression tests, the specimen was in the elastic stage at the initial stage of loading, and quickly reached the peak of the dynamic strength. With an increase in the load, the strength of the specimen decreased sharply, the crack broke through quickly, and the specimen was crushed. After the action of high temperature, the free water and partially bound water inside the concrete produced water vapor pressure, which caused the concrete to be strained and produced micro-cracks and material deterioration, resulting in concrete damage. The dynamic impact resistance of the concrete decreased gradually with the temperature, the toughness of the concrete decreased significantly, and the specimens showed brittle failure in the failure stage. The next steps are to optimize the mix ratio and improve the strength of the sealing wall.
3. Under impact load, the concrete specimens consumed a lot of energy in the processes of crack initiation, development, penetration, and failure. At a high temperature, the cohesion and viscoelasticity of the specimens decreased due to various thermal damage changes caused by the temperature. The energy of the specimen for crack initiation development increased and the energy dissipation increased. However, the  
Figure 11: Variation curves of dissipated energy of specimens at different temperatures.  
strength of the specimen decreased continuously with the increase in temperature, the absorbed energy was less under the same impact load, and the absorbed energy required for the specimen to achieve failure decreased. Finally, with the increase in the temperature, the dissipated energy generally showed a decreasing trend.  
Writing--original draft preparation, Q.W.; supervision, Z.L. All authors have read and agreed to the published version of the manuscript.  
The research is supported by the Shaanxi Province Innovative Talent Promotion Plan-Science and Technology Innovation Team (Grant No. 2020 TD-021).  
Not applicable.  
We would like to express our sincere gratitude to editor and scholars who diligently reviewed our paper. Their valuable feedback and insightful suggestions have significantly contributed to its substantial improvement.  
The authors declare no conflict of interest.