Experimental Research And Numerical Analysis On Dynamic Mechanical Properties Of Concrete

Recently, concrete has been widely applied in the civil engineering throughout the buildings, bridges, municipal, transportation, hydraulic and other fields. Compared to the background of prosperity of engineering application of concrete, research on material properties, for example, strength criterion and constitutive relation, under multi-axis dynamic loads such as earthquakes, do not keep up with what's the developmental need. To reveal correctly the concrete failure mechanism under dynamic load has became the key for further development of concrete mechanical properties research. It is necessary to carry on through going and do an intensive studying on the concrete failure characteristics in the dynamic compression.Consequently, in this paper, base on the comparative analysis on various concrete dynamic performance test methods, supported by the National Natural Science Foundation of China (Grant No. 90410012 and No. 50908026), dynamic compressive experiments of ordinary concrete and roller compacted concrete specimens under uniaxial loading, constant confining pressure loading and biaxial equal proportion loading are performed. The influence of the strain rates on compressive ultimate strength and deformation characteristics of concrete and RCC are studied systematicly. The variation of mechanical characteristics such as strength, elastic modulus and peak strain are analyzed, expressions of compression strength considering the influence of strain rates are proposed.In this paper, combined with the characteristics of large concrete structure under seismic load, the dynamic compression test of uniaxial stress state under cyclic reversed loading is carried out. Considered the stress characteristics of actual concrete structures, the influence of loading history on dynamic compressive capability and deformation property such as concrete compressive strength, elastic modulus and critical strain is studied; the effect of cyclic loading history on the dynamic damage evolution law after cyclic loading history is analyzed.The finite element numerical simulation of gravity dam under the action of seismic response spectrum with the data of compressive test under biaxial equal proportion loading of stress ratio 1:1 in strain rate of 10-3/s and compressive test under constant confining pressure of 10MPa in strain rate of 10-3/s are performed. The stress-strain distributions of concrete gravity dam with various constitutive relationships under earthquake are obtained. The similarities and differences between two constitutive relationships of biaxial equal proportion loading and constant lateral pressure loading are discussed, which are reflected in the actual simulation of stress-strain distribution in the dam. This paper lays a good foundation for a reasonable multi-axis dynamic constitutive model of concrete.