Study on instability criteria of surrounding rock of underground engineering cavern based on catastrophe theory

Surrounding rock system is of high nonlinear and complexity, and there is no unified cognition for its stability criteria. catastrophe theory is used in the study on outside control condition when catastrophe happens to system state, and mainly expatiate on how nonlinear system tend towards system character catastrophe from continuous gradual change state. Catastrophe theory is used in surrounding rock instability criteria to illustrate its catastrophe condition theoretically. Energy catastrophe criterion and entropy catastrophe criterion are applied to analyze system instability based on physics; displacement module catastrophe criterion and yield zone area around cavern catastrophe criterion and generalized viscoplastic shearing strain catastrophe criterion are applied to analyze system instability based on intuitionistic judge condition (key place displacement, yield zone area around cavern and generalized viscoplastic shearing strain). Above five criteria are respectively applied to analyze surrounding rock stability of a underground cavern section, according to the condition of system catastrophe; system instability is judged from different aspects; and it may provide reference for engineering design and construction.