The uplift resistance of submarine pipelines buried in medium dense sand

Buried submarine pipelines need to be operated under high temperature and high pressure, and ensuring sufficient buried depth is a necessary factor for safe operation. Based on the plane strain assumption, the purpose of this study is to study the evolutionary mechanism of pipe-soil interaction under the monotonic uplift of buried submarine pipelines through model tests and the Discrete Element Method (DEM) numerical simulation. The results show that the uplift resistance is affected by the embedment ratio and the pipe diameter; during the pipeline uplift process, the development of the uplift resistance is divided into three stages: the development stage, the softening stage, and the residual stabilization stage. The displacement at the peak uplift resistance increases with the increase of the embedment ratio, and the value is about 0.5–1.5%H, and the sand particle size has a great influence on the displacement of the peak uplift resistance and the post-peak softening behavior. According to the comparison of the test results, the prediction model of the load-displacement response of pipe-soil interaction is proposed.