Abstract:The principle of earth pressure and arch action variation with the height of fills and the boundary conditions are studied by model test. The results show that the earth pressures on the top of culvert increase nonlinearly and the arch action occurs as the fills on the culvert is up to a certain height. Because the fills on the culvert are different from the rock,the arch action above the high fill culvert has the characteristics of unstability and the earth pressure can partly transfer to the top of culvert. Based on the principle of earth pressure increase and the characteristics of arch action,a new theory,nonlinear earth pressure theory for the culverts under high fills,is presented. It is demonstrated by an example that compared with the other earth pressure theories,the nonlinear earth pressure theory is a more reasonable earth pressure calculation method for the culverts under high fills.