Study on Dynamic Mechanical Properties and Failure Mode of Shotcrete under Cyclic Impact Loading
Frequent dynamic load disturbances in underground space pose a serious threat to the safety of supporting structures. In order to explore the dynamic mechanical properties and failure modes of shotcrete under high strain rate cyclic impact load, a split Hopkinson pressure bar (SHPB) with a diameter of 50 mm was used to carry out cyclic impact test on concrete specimens based on the Laoyingpan tunnel project. The stress-strain behavior, dynamic mechanical properties, energy conversion law and failure mode were analyzed. The results show that with the increase of impact times, the peak stress of shotcrete decreases gradually, and the ultimate strain and average strain rate increase gradually. The absorption energy of shotcrete is basically unchanged, the reflection energy increases and the transmission energy decreases. During the impact process, the slender micro-cracks in the center of the shotcrete specimen gradually developed and increased, and the cracks extended from the outside to the center. Finally, the cracks ran through the entire concrete structure and abrupt damage occurred.
万方数据
维普
