基于水下钢球法的水工混凝土磨损影响因素研究

Influencing factors of abrasion of hydraulic concrete based on underwater method

为了预测水工泄水建筑物抗冲磨混凝土在含推移质水流作用下的使用寿命,需了解磨损介质粒径和水流速度对混凝土破坏程度的影响。为此,分别采用12.6mm、19.0mm、25.4mm、30.0mm四种直径的钢球作为磨损介质,并在近底水流速度约1.8m/s和1.5m/s两种水流速度下,进行两种强度等级抗冲磨混凝土的水下钢球法试验。结果表明,钢球粒径为19.0mm时,混凝土磨损率最高;随着水流速度的提高,钢球粒径越大,混凝土磨损率增加越多。采用泥沙运动力学分析,钢球的动量和钢球直径的关系与混凝土磨损率和钢球直径的关系较为一致,且钢球动量和混凝土磨损率有较好的指数函数关系。

Influences of abrasive particle size on abrasion charge and flow velocity on hydraulic concrete abrasion are crucial to prediction of service life of the concrete of discharge structures under bed load.In this work,underwater method was used to experimentally test the abrasion rate of concrete of two strength grades,with steel balls as abrasive particle of 12.6mm,19.0mm,25.4mm and 30.0mm in diameters under two flow velocities of 1.8m /s and 1.5m /s.The results show that abrasion rate is the highest with 19.0mm balls and that it increases with ball size and flow velocity.An analysis based on sediment transport mechanics indicates that the relationship of steel ball diameter versus vertical composition force on the ball is consistent with that of abrasion rate versus ball diameter,and that relationship of composition force versus abrasion rate follows an exponential law fairly well.