A New Formulation for Establishing the Lateral Interaction Between Buried Steel Pipeline and Sandy Soil Subjected to Strike-Slip Faulting

Buried pipelines are faced with and vulnerable to extreme hazards such as earthquakes, different types of faulting, and landslides. Generally, a buried pipeline is modeled as a beam on a series of springs, which represent the surrounding soil. To determine the specifications of these springs, the equations proposed by ASCE Guideline are usually used. Its accuracy was doubted by some recent studies. In this study, two full-scale tests simulating the effect of strike-slip faulting were initially carried out on 4 and 8-in. diameter steel pipes buried in compacted sandy soil. The displacement of the pipe was recorded directly at any moment, along its length. Then through optimization-based simulations, the specifications of the equivalent springs of the soil were calculated so that the deformation of the pipe along its length would be consistent with the experimental results. Then, based upon verified finite element models, a database of different parameters of buried pipes subjected to strike-slip faulting including the diameters and different burial depths was created. The results showed that the ASCE equations need modification at the condition of strike-slip faulting and so, based on the created database, a new form of the equations of lateral interaction between dense sandy soil and steel pipe in the presence of strike-slip fault was proposed.