Numerical analysis of buried pipes under field geo-environmental conditions

Abstract

Buried pipes are vital infrastructures and are mostly used to transport energy and other essential commodities. These pipes are generally buried within the top layer of soil deposits, and therefore, are highly affected by different geo-environmental conditions. In this paper, a modeling approach is introduced for the analysis of buried pipelines through real-life scenarios. The model provided reasonable estimates for the elastic deformations of a soil-pipe system under different soil and loading conditions. The model was then used to address the performance of a hypothetical pipeline buried in an unsaturated clay soil. The modeling analysis captured the pipe displacements that occurred due to the change in soil suction associated with changes in the soil moisture content. The soil suction was estimated based on field measurements, and was, then used as an input to the model. The change in volumetric water content in the area studied was found to be as low as 5 %, as high as 20 %, and corresponded well with the seasonal variation in climate conditions. Direct correlations between the change in soil moisture content and the resulting pipe displacements were developed. The results indicated that normalized pipe displacements up to 6 % occurred due to the relative increase in volumetric water content of 20 % representing the change from the field condition to full saturation. The magnitude of pipe displacements increased significantly with the decrease of the pipe depth within the active soil zone.