Abstract: In this paper, the layer of gravel soil with soft lens is treated using the cement deep mixing piles (CDMP). The field observation is also carried out to investigate the settlement and deformation of the apartment. Results show that, after CDMP treatment, the bearing capacity of the gravel layer with soft lens increases 63% with the replacement rate of 23%, and increases 15%―31% with the replacement rate of 11.6%. In the case of concrete-cored cement deep mixing pile composite foundation, the bearing capacity of composite foundation can increase roughly 105% if the replacement rate is 23%, and the settlement and deformation is reduced significantly.