The bearing capacity properties and the influencing factors to building settlement control factors of the composite foundation disposed with deep-mixing pile are both analysed. In allusion to an actual project which is designed with the settlement-control criterion

the load stress distribution characteristic of composite foundation between pile and soil is also studied by the in situ tests with the pressure sensors set on pile top and nearby soil stress and the pile top stress with the settlement-control criterion. The results of the settlement monitoring show that the value of the building settlement is consistent with the predicted one

so as to prove that the settlement control design of the composite foundation is feasible in thick soft clay area or even with the area that existing the soft substratum.