1.School of Aeronautical Engineering, Air Force Engineering University;2.Air Force Support Department of Southern Theater Command
The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan)
Due to the high technicality of the multi-axial test equipment, the dynamic research of concrete under complex stress condition is relatively less. In order to study the dynamic compressive properties of concrete under biaxial compression, the impact compression tests of concrete cube specimens under five types of biaxial compression conditions were carried out by using the true triaxial static and dynamic comprehensive loading test system. The effects of biaxial compression on the dynamic response of concrete are analyzed from the aspects of stress-strain curve characteristics, strength characteristics and deformation characteristics. The results show that: under biaxial compression, the concrete exhibits typical brittle failure when subjected to impact load, and there is no obvious compaction stage in the initial stage of the stress-strain curve; when the spindle pressure ratio is fixed, with the increase of the unilateral pressure ratio, the dynamic compressive strength of concrete shows a trend of first increasing and then decreasing, and the peak strain and average strain rate show a trend of first decreasing and then increasing; biaxial compression has the effect of reinforcement and restraint on concrete, which improves its dynamic compressive strength and deformation resistance. When the ratio of spindle pressure ratio to unilateral pressure ratio is 0.4: 0.4, the effect is the best.