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.

近几十年来，由于水管破裂，天坑事故迅速增加。尽管最近许多研究人员对天坑现象进行了调查，但大多数研究都与自然天坑的形成、地下空洞检测和坍塌分析有关。尽管媒体频繁出现有关水管爆裂的新闻，但很少有关于在高水管压力下因管道缺陷而导致土壤井喷稳定性的研究表明该问题的相关性。本文旨在利用最新的有限元极限分析技术，研究内部水土流失的三个理想阶段，即水平、半圆形和圆形空腔中损坏的给水干管上方土壤的井喷稳定性。整篇论文都使用无量纲设计参数来提供严格的边界解决方案，设计人员可以直接使用这些解决方案来评估有缺陷管道上方土壤的井喷稳定性。设计图表和表格涵盖了广泛的设计参数，并引入了一个实际示例来说明它们在实践中的使用。