Experimental Study on Constitutive Models of Rocks Under Loading With Active Confining Pressure

Constitutive model of rock-like brittle material, which is necessary for studying blasting mechanism, stress wave propagation, destruction effect analysis of underground structure, is always one of the most important aspects in the study of rock mechanics. On the basis of damage mechanics and statistical theory, through combining visco-elastic model and statistic damage model, considering the influence of confining pressure and strain rate to rock mechanical properties, a new statistical damage constitutive model of rock based on weibull distribution under dynamic loading is developed. Then, in order to simulate real stress state of underground rock by hydraulic pressure, the traditional SHPB apparatus was improved. The impact test of amphibolites with different confining pressure and strain rate was carried out by using improved 100mm diameter SHPB. Thus parameters of constitutive model were obtained, and the influences of parameters to constitutive model were analyzed. In order to improve the precision, the statistical damage constitutive model of rock was modified reasonably, so as to set up dynamic damage constitutive model of rock which corresponding to reality better. At last, comparing the curve gotten by constructing constitutive model to the one from SHPB experiment, the rationality of constitutive model has been tested and verified.