Dynamic multiaxial strength and failure criterion of dam concrete

Dynamic multiaxial strength experiments on both dam and wet-screened concretes were carried out by using a large static and dynamic triaxial electro-hydraulic servo testing machine. The dynamic strength under uniaxial compression (C), uniaxial tension (T), biaxial compression–compression (C–C), biaxial compression–tension (C–T), triaxial compression–compression–tension (C–C–T) and triaxial compression–compression–compression (C–C–C) are presented in the paper. The influence of strain rate (ranging from 10−5/s to 10−2/s) and stress ratio on the failure modes and dynamic strength of dam and wet-screened concretes is analyzed. It is found that the failure modes of both dam and wet-screened concretes were mainly dependent on the stress ratio, but independent of the strain rate. The ultimate strengths of dam and wet-screened concretes are found to increase with the increase of strain rate. Particularly, the dynamic increasing factor (DIF) increases obviously when the tensile stress is included. It is noted that the maximum DIF existed in the triaxial C–C–T stress state and the minimum DIF corresponded to the triaxial C–C–C state. The octahedral normal and shear stresses are increased but the similar angle is kept constant with the increase of strain rate in the octahedral stress space. The dynamic failure criterion is developed after analyzing the effect of octahedral normal stress and similar angle on the dynamic strength.