Noncoaxial Behavior of a Highly Angular Granular Material Subjected to Stress Variations in Simple Vertical Excavation

Abstract

AbstractExperiments were carried out using a dynamic hollow-cylinder apparatus (HCA) to investigate the effects of stress paths and principal stress rotations experienced during a simple vertical excavation on the element-scale deformation and noncoaxial behavior of a highly angular granular material. For this purpose, an improved specimen preparation technique was used to generate homogeneous HCA specimens using a multilayer undercompaction method. The stress paths used in the HCA experiments were extracted from the numerical results obtained in a discrete element simulation of a simple vertical excavation, where complex stress paths and principal stress rotations have been observed. The experimental results show that different stress paths and rotations in excavation significantly affect the element-scale deformation behavior. Noncoaxial behavior (i.e., the deviation of plastic strain increment direction from the principal stress direction) was observed in the HCA tests, which was a result of the combin...