Model for pipeline extrusion deformation under radial load

Potential hazards from oil leakage can be reduced to the greatest extend or prevented within a short period by means of partial pipeline extrusion technique, according to the characteristics of emergency repair for the leakage of long-distance pipeline. This paper, based on theory of pipeline plastic deformation and principle of the conservation of energy, has formed a model for pipeline extrusion deformation under radial load with the combination of computation model of "Bow-tie" pipeline plastic deformation, and also analyzed and worked out the plastic deformation driven by pipeline extrusion and residual pressure inside pipeline leakage, thus loads required for pipeline extrusion with different sizes as well as distributions of extrusion loads using nonlinear fitting are gained. Results indicate that pipeline extrusion loads increase gradually in S-shape with changing pipe sizes and yield stresses. This model is applicable for determination on loads of pipeline extrusion deformation and also used as the theoretical and practical basis for pipeline extrusion repair.