An indirect method for measurement of rock dynamic tensile strength and fracture energy using blasting experiments

Abstract

Many parameters in numerical simulation can be directly measured through experiments, yet specific parameters pose challenges for experimental testing. The quantification of dynamic tensile strength and fracture energy in rocks constitutes an indispensable requirement for accurately predicting crack initiation location and propagation velocity. It is imperative to acknowledge that these two parameters exhibit a profound dependence on the strain rate imposed on the rocks. Hence, it is essential to establish a reliable strategy for accurately measuring these parameters. In this paper, a novel blasting experimental measuring system was used to determine crucial dynamic fracture parameters. A single internal crack circular disc (SICCD) configuration was proposed and applied in the sandstone specimens testing. A series of numerical models were developed using a tensile crack softening failure criterion. The mechanical behavior and fracture mechanism of the rock under blasting were analyzed numerically. The relationships between dynamic tensile strength, fracture energy, crack initiation time, and propagation velocity have been thoroughly assessed. Through the utilization of statistical methods and the rapid drawing method, the dynamic tensile strength and fracture energy of rocks can be predicted with high precision by integrating experimental and numerical methods specifically designed. The combined approach enables a comprehensive understanding of the dynamic behavior of rock under extreme loading conditions. Furthermore, the validity of the predicted dynamic tensile strength can be rigorously verified through meticulous testing and evaluation procedures.