Abstract: The paper studies in-depth the rheological fracture of jointed rock mass under inducement conditions, summarizes the three different destruction mechanism of rheological fracture, and determines to use the branch crack propagation length as a unified criterion for the three destruction mechanisms in judging jointed rock mass destruction.On this basis, the paper proposes for the first time that the three requirements for a spontaneous caving of jointed rock mass under gravity be destruction conditions, free face conditions and equilibrium conditions, and deduces and establishes the criterion mathematical expression for the rheological fracture and spontaneous caving of jointed rock mass.The study results are then turned into a computer program, providing a new efficient method for the study of spontaneous caving law and the forecast caving speed forecast of rock mass of rheological fracture type.

Key words: Jointed rock mass, Rheological fracture, Spontaneous caving, Criteria