Innovative testing technique of rock stress wave propagation

Abstract

Inadequacy of rock mechanics chamber test devices and test systems that cannot accurately simulate gradient static stresses on specimens, this paper presented an innovative testing technique, which relates to the stress wave propagation of rock subjected gradient static stress. The method involves modification of a split Hopkinson pressure bar, such that the test specimen is subjected to gradient static stress and axial impact loading. The device has the features of simple loading and multiple static stress gradients, which verifies the feasibility of stress wave propagation test of red sandstone specimens under linear gradient static stress and conducts stress wave propagation test of red sandstone specimens under linear gradient static stress. Tests on red sandstone specimens with different static stress gradients show that the stress wave propagation of the specimens under gradient static stress is different with their corresponding homogeneous static stress state. The attenuation coefficients of stress waves are different under different conditions, and loading gradient static stress can accelerate the attenuation process. The results of this study will be useful for the analysis of stress wave propagation in deep engineering blasting and the stability analysis of adjacent structures.