Performance of buried pipes in moving slopes under axial loading – evaluation tools

Abstract

Buried pipeline systems form a key part of effective and safe infrastructures for the transportation of natural resources such as natural gas and liquid. However, they may be constructed in areas prone to landslides where ground movement may exert excessive strains on the pipe sections causing rupture. This paper presents a methodology for estimating strains in a pipe under axial loading induced by ground movement. This methodology quantifies effects of soil displacement rate, total stress and pore pressure changes as well as time-independent (intrinsic) and time-dependent properties on the strains exerted on the pipe. These factors are not explicitly considered in current guidelines for constructing pipelines through areas prone to landslides. The procedure is based on a simplified analytical approach that can be readily implemented in practical design and analysis. A series of design charts are generated for performance evaluation of buried pipeline systems constructed in active slopes. They can be used to assess the frequency of necessary remediation such as in-situ stress relief procedure to protect the environment and maintain pipeline integrity and operation. For illustration, the proposed methodology is used in a case study to evaluate the potential risk of yielding in the pipe with the given soil displacement rates that occurred in the slope.

Keywords

• Buried pipe
• Axial loading
• Moving slope
• Saturated soil
• Rate dependency
• Soil spring model