Pipeline burst-related ground stability in blowout condition

Abstract

Sinkhole incidents have increased rapidly in recent decades due to water main breaks. Although numerous researchers have recently conducted investigations in sinkhole phenomenon, most of the studies are related to natural sinkhole formation, underground cavity detection, and collapse analysis. Very few studies can be found in relation to the blowout stability of soils due to defective pipeline under high water main pressures, in spite the frequent media news about the water main bursts which enlighten the relevance of the problem. The present paper aims to study the soil's blowout stability above a damaged water main pipeline in three idealized stages of internal soil erosion, i.e. horizontal, semi-circular, and circular cavities using the latest finite element limit analysis technique. Dimensionless design parameters are used throughout the paper to present rigorous bounding solutions that can be used directly by designers to evaluate blowout stability of soils above defective pipelines. Design charts and tables are presented to cover a wide range of design parameters, and a practical example is introduced to illustrate their use in practice.