Application of strain-based theory in failure analysis of pipeline subjected to mining collapse areas

Key words:  mining collapse  pipeline  strain-based theoiy  limit strain  failure analysis

Abstract:

The interaction of long-dislance oil and gas transportation pipeline and underlying mined-out area is a kind of complicated pipe-soil coupling mechanical problem, and it is difficult to give a safety evaluation of pipeline subjected to ground moveraenl and surface subsidence due to mining collapse. Based on the Ramberg-Osgood constitutive equation, the deformation regu ations of pipeline subjected to mining collapse were analyzed using finite element numerical simulation by taking intot the change of spatial position of mined bed and different mining ways. The effects of strain-based theory and ment numei effects of si based theory on failure criteria of pipeline were compared. The results indicate that the pipe strain has a negative correlation with the mining depth H, and a positive correlation with the mining thickness M. The mining deplh has a more important influence on pipe strain than the mining thickness when H/M is constant. The multiple repeated mining is more likely to cause larger defomiation of pipeline than single mining. The ability to resislance to ^real deformation of pipeline can be utilized sufficiently taking the strain-based theory as failure criteria of pipeline subjected to mining collapse.