Mechanical behavior of buried composite pipelines subjected to strike-slip fault movement

Buried composite pipelines crossing active faults can be deformed significantly due to strike-slip fault movement. Because of the problem complexity arising from material mechanical behavior and imposed large deformation, a numerical analysis was conducted using a nonlinear finite element approach. The lateral displacement incrementally was imposed normal to the pipe axis until one of the pipe layers failed based on the Hashin failure criteria. The effective factors on the buried composite pipeline performance, such as the pipe dimensions, composite lay-up, and soil stiffness, were studied parametrically. The results showed that the winding angle of the composite pipe has significant effects on the response of the pipe subjected to the fault movement, therefore determining an optimum winding angle is very important for practical engineering designs. In addition, the results show that the effect of changing the pipe diameter cannot be predicted easily, and also it is depended on the winding angle. However, changing the soil stiffness did not change the optimum winding angle. Furthermore, the comparison conducted for the studied composite and steel pipes at the similar simulation conditions showed that the composite pipe has a better response until the onset of the failure, and the composite pipe could be considered as a suitable replacement for the conventional buried steel pipeline.