Based on the unequal strain condition between the pile and the pile-surrounding soil

and the new pile-surrounding soil settlement model which considers the characteristics of interaction between the pile and the soil

the vertical and radial displacement of the pile-surrounding soil

the relative sliding between the pile and the soil

and the negative friction of the pile side in the soil-cement composite ground under embankment

the formulas for the pile-surrounding soil settlement in composite ground under embankment were derived.Taking the average settlement of the pile-surrounding soil in pile-soil unit as settlement of composite ground

the formulas for the total settlement and the compressive deformation of the underlying stratum in the soil-cement composite ground were further derived（the difference is just the compressive deformation of stabilized layer）.Theoretical analyses indicate that the compressive deformation of stabilized layer of composite ground is smaller than that of nature ground in same depth

the compressive deformation of the underlying stratum of composite ground is smaller than that of nature ground

and the total compressive deformation of composite ground is smaller than that of nature ground.Meanwhile

theory results conform to that from finite element method and field measurement.