摘要
Pipes,especially buried pipes,in cold regions generally experience a rash of failures during cold weather snaps.However,the existing heuristic models are unable to explain the basic processes involving frost actions.This is because the frost action is not a direct load but one that causes variations in pipe-soil interactions resulting from the coupled thermo-hydro-mechanical process in soils.This paper developed and implemented a holistic multiphysics simulation model for freezing soils and extended it to the analysis of pipe-soil systems.The theoretical framework was implemented to analyze both static and dynamic responses of buried pipes subjected to frost actions.The multiphysics simulations reproduced phenomena commonly observed during frost actions,e.g.,ice fringe advancement and an increase in the internal stress of pipes.The influences of important design factors,i.e.,buried depth and overburden pressure,on pipe responses were simulated.A fatigue cracking criterion was utilized to predict the crack initialization under the joint effects of frost and dynamic traffic loads.The frost effects were found to have detrimental effects for accelerating fatigue crack initialization in pipes.
Pipes,especially buried pipes,in cold regions generally experience a rash of failures during cold weather snaps.However,the existing heuristic models are unable to explain the basic processes involving frost actions.This is because the frost action is not a direct load but one that causes variations in pipe-soil interactions resulting from the coupled thermo-hydro-mechanical process in soils.This paper developed and implemented a holistic multiphysics simulation model for freezing soils and extended it to the analysis of pipe-soil systems.The theoretical framework was implemented to analyze both static and dynamic responses of buried pipes subjected to frost actions.The multiphysics simulations reproduced phenomena commonly observed during frost actions,e.g.,ice fringe advancement and an increase in the internal stress of pipes.The influences of important design factors,i.e.,buried depth and overburden pressure,on pipe responses were simulated.A fatigue cracking criterion was utilized to predict the crack initialization under the joint effects of frost and dynamic traffic loads.The frost effects were found to have detrimental effects for accelerating fatigue crack initialization in pipes.
