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THREE DIMENSIONAL FINITE ELEMENT ANALYSES OF PARTIALLY SUPPORTED WATER MAINS
Session: Transportation and Linear Infrastructure III / Transports et infrastructures linéaires III
Kasuni Liyanage, Graduate Research Student (Canada)
Ashutosh Dhar, Assistant Professor, Memorial University of Newfoundland (Canada)
Buried water mains used in water distribution systems are subjected to aggressive environmental conditions and undesirable soil conditions, causing deterioration of the pipelines. As a result, a number of water main break occur every year across the municipalities. Circumferential cracking is a predominant failure mode for water mains that results from excessive longitudinal stresses. The longitudinal stress in pipe wall may be due to non-uniform soil support condition caused through erosion of surrounding soil by the water from any leakages. Localized concentrated supports are also expected on the pipe wall within the erosion voids due to the presence of large rock pieces when the fine soil particles are eroded away. In the current research, three dimensional finite element analyses are used to investigate the effects of erosion voids and localized support on pipe wall stresses. A cast iron water main buried in elastoplastic soil, subjected to soil load and surcharge, is considered. FE results are compared with analytical solutions available in the literature for evaluation. A parametric study is followed up in order to investigate the influence of the void size, geometry and void location around the pipe circumference on the stress development in the pipe wall.
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