Failure criteria for structurally heterogeneous materials

Purpose. To analyze the current research regarding rock failure criteria and justify the analytical failure criterion for structurally heterogeneous materials in three dimensional stress-strain state. Methods. The study is based on an integrated approach with the use of analysis and synthesis of literature on the issues related to failure of the rock with heterogeneous structure, and application of analytical and empirical failure criteria to assess the strength of rocks. Findings. The analytical failure criterion is compared with the results of testing rocks in three dimensional stress-strain state. It is proposed to assess the degree of danger of the rock media failure for any point of homogeneous rock mass in the vicinity of mine working through the safety factor , by comparing the value of equivalent stress with tensile strength in uniaxial compression . Application of structural attenuation coefficient allows to pass from assessment of the rock sample strength to the evaluation of strength of the real structurally inhomogeneous rock mass. Originality. Failure criterion for structurally heterogeneous bodies with defects in the form of joint system which allows to adequately assess stability of the rock mass is proposed. Practical implications. Comparison of the analytical criterion with the results of laboratory testing of structurally heterogeneous materials in three dimensional stress state allows to predict rock failure in the massif with the accuracy of 94%.