Analysis Of Pressure And Research Of Mechanism Of Abrasion Of Windward Of Bridge By Wind-borne Sand

The dissertation is the extension of the National Natural Science Foundation of China (51178033) named "The research on the effect of highway construction on regional airflow field". The construction of the New Silk Road economic belt requires strictly the high-quality service of the transportation system, especially bridges playing an important role in it. As a result of the fact that the bridges generally pass through varieties of landscape with complex and varying atmospherical conditions, these constructions must bear the comprehensive fruit from tough geography and atmosphere in respects of safety and durability. Given that the characteristic of the geography and atmosphere in western China are severely sandy and windy, there is no doubt that the phenomenon of the wind-borne sand erosion is obvious, which asks taking action against the threat of abrasion for bridges. Based on this goal, the study of the stress distribution along the windward of bridge and the erosive mechanism are the start line and the focal point.Having perused masses of corresponding literatures about erosion from wind-borne, abrasion of material, Contact Mechanics, Impact Dynamics, Fracture Mechanics and Continuum Damage Mechanics, the research is undergone as follows:(1) According to the test of erosive wear to cement mortar conducted by Yanping Wang, which provides the parameters and useful conclusion the paper needs, the text is numerical stimulated and the erosive critical pressure was defined by the paper.(2) Establish the bridge model via Gambit, reasonable mesh theme and boundary types. And set the sizefunction in Gambit to mesh the fluid zone. Then, determine the velocity of wind-borne sand, the sand content in it and the model of wind-sand two-phrase flow, numerical stimulation by CFD following after that.(3) Compare the pressure distribution under the condition of net wind with under the condition of wind-borne sand, and analyze the feature of wind-borne sand flow in peripheral bridge, the pressure distribution along the windward of the bridge with height and angle of attack.(4) Deduce the wind-borne sand impact pressure formula, define and deduce the wind erosion initial pressure, analyze the mechanism of wind erosion, define and deduce attenuation equation of elastic modulus, define and calculate the minimum value of elastic modulus when wind erosion happens, deduce the formula of how many times sands impact when wind erosion happens under the condition of initial elastic modulus known, and analyze the distribution properties of erosion along the windward of bridge with the height, angle of attack and sand content.The academic achievement of the dissertation is a start of the research for the durability of bridge under wind-borne sand condition, which provides reference of protection of bridge windward under wind-borne sand and subsequent study.