Study On Soil Resistance During Pipeline Upheaval Buckling

With the rapid development of ocean engineering, more and more submarine pipelines have been installed. Buckling of submarine pipelines occur due to the introduction of axial compressive forces caused by the constrained expansions set up by thermal and internal pressure actions. When a pipeline is operated under the condition of high temperature difference and pressure difference between the interior and the exterior of the pipeline, it can not transform freely due to the constraint action of foundation soil, which leads to produce an additional stress. The potential resistant effect of foundation soil is an important subject of researching the intense variation problem caused by pipeline buckling. In this thesis, the subject carried out the following studies.1. Systematic literature research and preparation works, a comprehensive summary of the domestic and international research in this area.2. Model test were carried out, which selected as a pilot with sand and clay soil and the use of 30cm, 50cm and 80cm diameter stainless steel tube simulation pipeline, design of buried pipeline rate (H/D) were 1-9, a total of conducted 161 group test, the system and analyzing the experimental results.3. Based on model tests data, an experimental formula was derived to definite the maximum resistance when a buried pipeline moved upward movement. A nonlinear spring model was established to describe the behavior of soil resistance during pipe moving.4. Simulation of pipe-soil interaction. The process of model tests was simulated by software named PLAXIS. Soil failure mode when pipe moved upward and the peak value of soil resistance relate to the pipe diameter and burial depth was analyzed by this software. The analyzing results were compared with experimental results.The results of tests, theoretical and numerical analysis explained the process and rules of soil resistances acting on the pipelines in different directions. Results of this paper provide supports for the intense variation caused by pipeline buckling, and theory basis for project measures preventing pipelines from buckling destruction.