EXPERIMENTAL STUDY ON DYNAMIC TRIAXIAL MECHANICAL PROPERTIES OF SAND AND MUDSTONE IN BREEZY RED BED

Red beds are widely distributed in Sichuan Basin and its surrounding areas. Affected by earthquakes and engineering construction disturbances in this area, the rock dynamic characteristics are the most concerned factors in engineering construction. In this paper, a series of dynamic triaxial compression tests have been carried out on three typical breezy red bed rocks, namely silty mudstone, argillaceous siltstone and fine sandstone, under the medium strain rate conditions. The confining pressure effect and strain rate effect of their dynamic characteristics were revealed. The dynamic strength, dynamic elastic modulus and dynamic Poisson's ratio of the three kinds of rocks are obviously sensitive to both the confining pressure and strain rate. The dynamic strength and dynamic elastic modulus increase with the increase of strain rate and confining pressure, while the dynamic Poisson's ratio decreases with the increase of strain rate and increases with the increase of confining pressure. Based on binary nonlinear regression analysis, the dynamic strength prediction models of three kinds of rocks in the range of test conditions were proposed, in order to provide reference for engineering applications.