Abstract: In an attempt to identifying the influence of buried depth of culvert on the bearing capacity of foundation, a formula for the bearing capacity of buried culvert is deduced based on Terzaghi’s theory and Gu Anquan’s formula. Moreover, the allowable value of foundation’s bearing capacity is determined by analyzing the change of load-settlement curve against soil fill height using finite element approach. The allowable bearing capacity of foundation obtained by finite element method is compared with those by different calculation methods. In addition, the influence of shear strength of foundation soil on bearing capacity of foundation in different calculation methods is discussed. Finally, the rationality of the formula is verified by an engineering example. The research findings are as follows: (1) The side soil fill reinforces the shear strength of foundation soil and improves the bearing capacity of the culvert foundation. Such improvement is influenced by the additional soil pressure on the soil fill. (2)With the increase of internal friction angle, the bearing capacity of foundation increases nonlinearly, while with the increase of cohesion,bearing capacity increases in an approximately linear trend, and the impact of internal friction angle is much larger than that of cohesion. The influence of the internal friction angle on the bearing capacity of the foundation is significantly greater than that of the cohesive force.(3)The bearing capacity calculated by the formula proposed in this paper is in good agreement with the calculated value by finite element method, and also is much larger than the earth pressure at culvert base, which accords with the actual situation of the culvert foundationin a safe state.

Key words: buried culvert, burial depth effect, bearing capacity of foundation, finite element analysis, field test