Experimental Study On Concrete Under Biaxial Dynamic Stress

In practical engineering, most concrete structures are in the complex stress state, and the current study on concrete multi-axis experiment are obtained under static loading condition. But the study on concrete under dynamic loading carried out less, now there only Dalian University of Technology have done some work. At present, the date of multi-axis is limited, so it is difficult to analysis comprehensively the dynamic properties of concrete and the establishment of the corresponding dynamic failure criteria and constitutive model, and it is necessary to carry out further milti-axis dynamic tests on concrete. This article as a part of The National Natural Science Foundation of China (90815026), making use of the Dalian University of Technology recently introduced the concrete large-scale triaxial testing machine, carrying out concrete biaxial dynamic compressive tests to study the the dynamic properties of concrete materials within range of strain rates (10-5/s～10-2/s) of earthquake loads. The major research are summarized as follows:(1) Test on uniaxial dynamic compression of concrete is carried out, studying the relationships between the dynamic strength and strain rate.(2) Experiments on concrete with the lateral pressure is carried out, to study the influence to concrete dynamic strength by the lateral pressure and strain rate and establish failure criterion in principal stress space considering the influnce of lateral pressure and strain rate at the same time and failure criterion in octahedral stress space considering the influnce of strain rate.(3) Experiments on concrete with biaxial proportional loading is carried out, to study the influence to concrete dynamic strength by stress ratio and strain rate and establish failure criterion in principal stress space considering the influnce of stress ratio and strain rate at the same time and failure criterion in octahedral stress space considering the influnce of strain rate.(4) Collecting multi-axis dynamic test data have been carried out and combining this test, to establish failure criteria on the deviatoric plane considering the influnce of angle and abtain the dynamic tensile and compression meridians and strength envelope of deviatoric plane according to test data, to confirm surfaces shape of octahedral stress space.