Mechanical properties and behaviors of macroscopically isotropic mélange

The main purpose of this study was to present a preparation technique and procedure for macroscopically isotropic mélanges.A series of laboratory tests were performed to study the mechanical properties and behaviors of mélanges.The effective compaction stress applied to the materials,which was in the uniaxial bi-directional compaction molds,was more uniform than that in the uniaxial unidirectional molds.The proposed molds could be used to produce the mélanges with various mechanical properties and to recover undisturbed specimen.For theoretical prediction,five micromechanical models were used to predict the Young’s modulus and Poisson’s ratio of isotropic mélanges with different block proportions.Comparing the theoretical predictions with test results,the feasibility of using the micromechanical models to predict the mechanical properties of mélanges was investigated.In respect to observation of failure mode,the rotary scanner designed by the authors was used to catch surface images of failure specimens.The failure modes of mélanges with different block proportions under various confining pressures were also classified and discussed.