PVC Soil and Traffic Loads
Loads are exerted on buried pipe due to:
- Soil pressures
- Traffic loads
- Superimposed loads
For normal water supply systems, laid in accordance with Vinidex installation guidelines and AS/NZS 2032, the minimum depths of burial (cover) stipulated in AS/NZS 2032 should be observed. Under these conditions and up to a maximum of 6 metres cover, soil and traffic loadings are of little significance and design calculations are not warranted. This applies to all classes of pipe.
For depths shallower than those recommended, traffic loading may be of significance.
At greater depths, soil loadings may control selection of pipe class. In these instances, lighter pipe classes may not be suitable and specific design calculations and/or special construction techniques may be required. Wet trench conditions may also require further investigation.
For design purposes, AS/NZS 2566.1 sets out procedures to be adopted.
Special construction techniques can involve backfill stabilisation, load bearing overlay or slab protection.
It should be noted that cover of less than 1.5 diameters may result in flotation of empty pipes under wet conditions. Low covers may also result in pipe “jacking” (lifting at vertically deflected joints) when pressurised.