Based on Mindlin displacement solution subjected to centralized load，the settlement coefficient subjected to uniform load is proposed. Simplifying the interaction between foundation with free boundary and ground soil

the formula of interaction taking into account interaction between foundation and subsoil is obtained. Considering the condition of rigidity or flexibility foundation plate

a comparison between Mindlin solution and Boussinesq solution results is made with the load condition of centralized load or uniform load. The results indicate that the depth ratio has an important influence

the results of foundation settlement

groundsill counterforce and the bending moment of foundation plate. The settlement coefficient considering depth ratio is presented; it can be referenced in practice.