In this paper

through analyzing the action of ground overloading on supporting structure

a method to define the influential extent of ground overloading was proposed according to the methodology of stress diffusion

and a calculating model was set up to derive the formula of soil pressure on supporting structure

which can explain why the active soil pressure is bigger while the passive soil pressure is smaller in the classic theory of soil pressure.The model has been successfully applied in engineering practice to reduce significantly the cost of the pit support

which shows the efficiency of the model in terms of both applicability and economy.So

it is useful in both the theoretical study and the engineering practice of pit support and slope support.