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采用实地调查及CFD数值分析方法,研究水沙冲刷作用对山区桥梁墩柱磨蚀损伤的影响。调查了岷江上游13座跨江桥梁的墩柱磨蚀情况,测得了磨蚀深度、磨蚀分布模式以及材料表面硬度。根据调查,基于临界速度和弹性模量的线性相关假定,对Finnie冲蚀磨损模型进行修正,并构建了水沙两相流模型,以桥墩表面混凝土的磨蚀厚度和磨蚀面积作为评价指标,考察了桥墩形状与尺寸、河流水深、流速、含砂率、沙粒粒径等因素对桥墩磨蚀损伤的影响及其变化规律。结果表明:圆形墩柱抗磨蚀能力最好;桥梁墩柱的磨蚀损伤程度与河水含砂率基本呈线性关系但受水深的影响较小;水速对最大磨蚀厚度影响非常明显,却对平均磨蚀厚度影响较小;含沙量相同,粒径越大,对桥梁墩柱的磨蚀作用越大;岷江上游混凝土圆形墩柱的平均磨蚀厚度可按3~5mm/a进行预测。
Field investigation and CFD numerical analysis were used to study the effect of water and sediment erosion on the abrasion damage of bridge pier columns in mountainous areas. The pier abrasion of 13 cross-river bridges in the upper reaches of the Minjiang River was investigated. The depth of erosion, the mode of erosion distribution and the surface hardness of the bridge were measured. According to the investigation, Finnie erosion model is modified based on the linear correlation assumption of critical velocity and elastic modulus, and a two-phase model of water and sediment is constructed. Taking the erosion thickness and erosion area of concrete on the pier surface as evaluation indexes, Influence of pier pier shape and size, river depth, flow velocity, sand content, grain size and other factors on the abrasion damage of bridge pier and its variation. The results show that the circular column has the best anti-abrasion ability. The abrasion damage of the bridge pier column is basically linear with the sand content of the river, but it is less affected by the water depth. The effect of water velocity on the maximum erosion thickness is obvious, The erosion thickness of the bridge pier is larger; the average abrasion thickness of the concrete circular pier in the upper reaches of Minjiang River can be predicted by 3 ~ 5mm / a.