Over And Under The Stability Of Surrounding Rock Of Underground Caverns Dug State Numerical Analysis

Overbreaking and underbreaking problem are frequently met in underground engineering construction. It directly influences the stability, construntion cost, construction safty of tunnel engineering.The past works mostly concentrated on the forecasting and evaluation of overbreaking or underbreaking in underground engineerings. Most existed analysis adopted elastic plane strain theory, the results are obvious defective. Based on the theory of Non-linear finite element and through a three-dimension non-linear analysis model, utilized the numerical simulation method, this text studied the stability of rock mass caused by opening in the underground cavity. Following works are finished:1) An analying under no overbreaking and underbreaking, it can be a comparision standard for other analysis in this text.2) The influence of overbreaking positi ons to the stability of tunnel is disscused, find that the sidewall, arching Conner are the most disandvantageous positions.3) The effects of overbreaking depth are also analysed. With the increasing of overbreaking depth, the stress concentration becomes more distinct.4) With the increasing of overbreaking quanitities, the plastic zone is also increasing.5) With the upgrading of rock intergrality and strength parameter values, the stress concentration become more intensive.