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该文首先建立了钢丝从混凝土基材中拔出的试验方法,并试验测定了不同锚固长度的钢丝拉拔行为,获得了拉拔荷载与拔出端位移之间的定量关系。在此基础上,建立了基于细观力学分析的钢丝拔出模型。通过模型计算,获得了钢丝与混凝土之间的界面粘结参数,并计算分析了锚固长度、倾斜角度等因素对钢丝拔出行为、最大承载力的影响。试验与模型计算结果表明,钢丝在混凝土中的拔出行为可分为脱粘和拔出两个阶段。在脱粘阶段,钢丝与混凝土之间的粘结强度可视为常数;在拔出阶段,钢丝与混凝土之间的粘结强度随拔出位移首先快速减小,之后减小速率逐渐降低,并趋于恒定值。对相同养护龄期,钢丝锚固长度越长,钢丝极限拔出荷载越大,同时与最大拔出力相对应的拔出位移也逐渐增大。钢丝埋置深度和角度相同时,养护龄期越长,钢丝抗拔能力增强。钢丝拔出方向与锚固方向不一致时,钢丝拔出荷载将增大,钢丝拔出方向与埋入方向夹角越大,抗拔极限承载力越大。模型与实验结果对比表明,所建模型及其所获得的粘结参数可良好地预测不同锚固长度的钢丝从混凝土中的拔出行为。
In this paper, the test method of pulling out the steel wire from the concrete base is established first, and the drawing behavior of the wire with different anchorage length is tested. The quantitative relationship between the pulling load and the displacement of the pull-out end is obtained. Based on this, a model of wire drawing based on micromechanics analysis was established. Through the model calculation, the interfacial bonding parameters between steel wire and concrete were obtained, and the influence of anchor length and inclination angle on the pull-out behavior and the maximum bearing capacity of steel wire was calculated. Experimental and model calculations show that the pulling behavior of steel wire in concrete can be divided into two stages of de-bonding and drawing. In the de-bonding stage, the bond strength between the steel wire and the concrete can be regarded as a constant. At the pulling-out stage, the bond strength between the steel wire and the concrete firstly decreases rapidly with the pulling-out displacement and then decreases gradually, and Tends to constant value. For the same maintenance age, the longer the wire anchorage length, the larger the wire pull-out load and the larger the pull-out displacement corresponding to the maximum pull-out force. Steel buried depth and angle of the same, the longer curing age, enhanced anti-pull wire. When the pulling direction of the steel wire is different from the anchoring direction, the pulling-out load of the steel wire will increase. The larger the included angle between the drawing direction of the steel wire and the embedding direction is, the larger the ultimate bearing capacity of the pulling-up will be. The comparison between the model and experimental results shows that the model and the obtained bonding parameters can predict the pull-out behavior of steel wires with different anchorage lengths from concrete.