The original plan is to use vibro-stone column composite foundation to treat a large oil tank foundation. The result of strengthening is not satisfactory because of some factors, such as difficulty to control quality and long construction period etc. Treated ground can not meet the design requirements. The key in treatment design of tank foundation lies in bearing capacity and deformation of foundation, especially in non-uniform deformation. Through the analysis of site conditions, composite foundation of CFG piles is adopted. It is designed according to strength and deformation of dual contro...