A New Rock Brittleness Index Based On Energy Dissipation in the Process of Uniaxial or Triaxial Compression Test

Summary The previous rock brittleness evaluation methods based on stress- strain curve generally simplify the complex curve into several lines, and establish the evlauation equation by the characteristics of simplified curve. These methods have such problems as the loss of effective informaion, the difficulty of curve simplification and the multi solution of the calculation results. In order to solve these problems, a new brittleness index based on the conservation of energy transformation of the pre-peak and post-peak stages in compression test is presented in this paper, which has a clear physical implication. The new method does not simplify the stress- strain curve, uses the full information of curve, and then increases the accuracy of the calculation results. In addition, this paper further analyzes the relationship between the new brittleness index and seismic elastic parameters and establishes their correlation expression by using the experimental data, which is of great significance to the practical application of the new index in the oilfield.