A New Stress–Energy Criterion for Interfacial Crack Initiation in Brittle Rock–Concrete Bi-materials
摘要
Interfacial crack initiation criterion is of great significance for the safety assessment and anti-cracking design of the multi-layered rock engineering (e.g., compressed air energy storage caverns). However, current stress, energy and stress–energy initiation criteria have limitations in predicting the interfacial crack penetration either along the original crack plane or without distinguishment of Mode I and Mode II mechanism. In this study, the generalized energy release rates (G) for the inclined interfacial crack with arbitrary singularity (0 < λ < 1) are proposed based on Mode I/II characteristic lengths (calculated by critical tensile/shear stresses) to establish the new stress–energy criterion of the interfacial crack initiation. Prediction results show that for the bi-material Brazilian disk specimens of arbitrary interfacial cracks (0 < λ < 1), the interfacial crack is more prone to penetrate through the interface in Mode I when the relative crack length (a/r) is increased or the loading angle (β) is decreased. Otherwise, the interfacial crack is more prone to penetrate through the interface in Mode II or to deflect into the interface. With the increasing of K2max/K1max, the interfacial crack is more easily to penetrate through the interface in Mode II under E2/E1 > 1 or to deflect into the interface under E2/E1 < 1. Decreasing of the interfacial crack length by adding lining reinforcement and increasing of the sealing-layer elastic modulus to meet E2/E1 < 1 would avoid the penetration of interfacial crack through the interface into the sealing layer as much as possible. The new stress–energy initiation criterion of arbitrary interfacial crack is verified by our bi-material Brazilian disk test results and can provide a theoretical basis for the safety assessment and anti-cracking optimal design of the multi-layered CAES cavern.