In order to obtain the key wind characteristic parameters for wind resistance design of Bridg-es in typical V-shaped terrain in mountain canyons,an model was established by the method of"nu-merical wind tunnel test",a three-dimensional terrain grid was constructed with real bridges as the en-gineering object,and the wind field characteristics of bridge sites were analyzed based on three typical turbulence models and fluid wall roughness.The optimal turbulence model and fluid wall roughness were selected to explore the wind field characteristics at the bridge site.From these two topographic pa-rameters,mountain height and angle,which affect the wind characteristics of the bridge site,the varia-tion law of the downwind characteristic parameters of the V-shaped canyon terrain is summarized,and the design reference wind speed of the bridge deck is calculated by comparing with the current norms.The results show that the optimal turbulence model and fluid wall roughness of the V-shaped canyon terrain are RNG and 20m respectively.With the change of mountain height and mountain angle,the in-crease of wind speed is 2.37％～12.56％and 1.24％～6.98％,respectively.Under the two variable parameters of mountain height and mountain angle,the gradient wind height is about 700 m and 800 m respectively.The actual turbulence intensity is greater than the standard values of the four types of sur-face in the specification,and the turbulence intensity is closer to the D type surface in the range of 40 m above the ground.The actual V-shaped canyon bridge site can not be classified as C or D terrain simply according to the code.The code and empirical formula must be considered comprehensively when designing the wind parameter calculation,and the accuracy could be improved by means of simulation.
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