Jet grouting Soild-cement-Pile Strengthened Pile（JPP） is a new type of pile and has the advantages of high bearing capacity and low costs.The loads in many static tests of engineering single pile can be applied up to only double of the design load but not the ultimate or failure load.It is of pratical significance for civil engineers to accurately predict the ultimate bearing capacity of JPP with the limited measurement data available.Based on the gray theory

a non-uniform step GM（1

1） model was introduced to predict the capacity of JPP.Three different methods of predicting the ultimate bearing capacity and the loadsettlement relation are discussed in detail.The analytical results of the engineering cases before and beyond failure have proved that the three grey models are all reliable with enough precision to meet the engineering requirement

and the model of iso-dimension and new information grey has the highest accuracy.