Experimental Investigation of Leakage Flow Rate and Fluidisation beneath Polyethylene Pipes in Non-Uniform Soils

Abstract

Soil fluidisation around buried pipes is one of the water leakage effects that has a direct influence on the ultimate failure of pipelines. In this research, using a laboratory model, the fluidisation caused by water leakage from three cracks with three lengths (14, 17, and 20 mm) and a 3 mm diameter hole for five pressures (1.5–5.5 bar) in non-uniform soils has been evaluated. The experiments were carried out both for pipes buried in soil, as well as exposed pipes. In the buried pipe tests, leakage flow rate, fluidisation, and mobile bed zone dimensions were investigated. The results showed that the increase in leakage flow rate due to an increase in pressure and crack length in exposed pipes is higher than in buried pipes. The exponent of the leakage–pressure relationship was obtained between 0.40 and 0.47 for the hole and between 0.8 and 1.9 in the crack. Observing different development patterns for fluidisation and mobile bed zones in cracks and holes, new relationships are presented for the height, width, and cross-sectional area of the leakage zones.

Leakages in Water Distribution Networks: Estimation Methods, Influential Factors, and Mitigation Strategies—A Comprehensive Review

“…Asbestoscement pipes (A/C), which are no longer utilized in the construction of new water supply networks, exhibit greater rates of failure mostly due to their aging. Following steel pipes and PVC pipes, HDPE pipes exhibit the lowest failure rate, as evidenced by Kettler and Goutler [74], Sharafodin et al, [80], Goutler and Kazemi [81], and Kanakoudis and Tolikas [76].…”

“…Surface erosion of soil poses a significant risk to pipelines by exposing them to various environmental factors capable of altering construction materials and compromising their strength [80]. Examples include PVC and HDPE pipelines affected by sun radiation and steel exposed to moisture and atmospheric air and/or corrosive salts found near the trench.…”