P-Y analysis of shallow embedded solar farm piles in reactive clay

The number of piles required to construct solar farms can often be in the order of tens to hundreds of thousands and contributes to a significant portion of the capital cost of the project. An important consideration for shallow embedded solar farm piles is the lateral loading imposed by wind. The application of the wind loading in design should also consider the variation of soil moisture conditions over the design life of the pile, for example cracking during the dry cycle at the pile to soil interface and how this can exacerbate the pile deflections and bending moments. To account for this, Australian design practitioners either reduce the shear strength in the crack depth or ignore the soil resistance in the crack depth altogether. In the authors opinion, these approaches have been adopted without considering the implications on pile design or if these assumptions accurately represent the actual soil-pile behaviour. This paper presents an alternative method that uses simplified PY analyses to investigate the behaviour of a pile in a reactive soil with a crack developing at the pile-soil interface during the drying / shrinkage cycle.