There are many important problems to be calculated in designing a spanning bridge in mountainous area

one of which is how to calculate the stability of bridge foundation slope. It used to be degenerated into plane problem. In fact

steric effect of bridge foundation slope is obvious. Adopting three-dimensional numerical method

combining traditional theories and empirical formulas

this paper synthetically analyzed the stability of bridge foundation before and after loading; reasonable position of bridge foundation

and the limit stress of piles. Hereby

it indicated reinforced position

and offered corresponding measures. At the same time

this paper jumped a circle that evaluated the stability of slope by a single stability coefficient

offered a new approach

which thought about the reasonable position of bridge foundation and foundation stress

to appraise slope stability of bridge foundation. Aiming at different slopes

different geologic conditions

different types of piles

different lengths of pile

different loads

and different stages of construction

it can analyze stress

strain

and whole stability. The results of analysis can help to confirm the positions and measures of reinforcement.