考虑摩擦接触特性的钢衬钢筋混凝土管道承载机理研究

采用库伦摩擦接触模型模拟钢衬与外包钢筋混凝土间摩擦接触特征,建立了李家峡水电站坝下游面钢衬钢筋混凝土管道结构模型,系统研究了内水压力作用下外包混凝土起裂荷载、裂缝扩展、管道变形、钢衬与钢筋应力分布特征等承载性能规律。结果表明:考虑钢衬与外包混凝土间的摩擦接触机制时,混凝土裂缝扩展规律与模型试验吻合更好,钢衬应力更为均匀,混凝土裂缝宽度普遍在0.3~0.4 mm,明显大于不考虑摩擦接触特性结果;随着钢衬与外包混凝土间摩擦系数的增加,管顶附近的变形不均匀程度逐渐增加,钢衬应力不均匀程度增加,不利于发挥钢衬的承载性能,但同时上半周裂缝处的钢筋应力峰值明显减小,应变不均匀程度减小,说明摩擦系数的增加有利于裂缝控制。

Bearing mechanism of reinforced concrete penstock with steel liner considering friction-contact behavior

Coulomb friction model is employed to simulate the friction-contact behavior between steel liner and reinforced concrete when a numerical model of reinforced concrete penstock with steel liner located on the downstream surface of concrete dam is built up. The critical pressure of concrete crack initiation, concrete crack propagation law, penstock deformation characteristic and stresses distribution of steel are analyzed upon the friction-contact model (FCM). Some impressive conclusions can be achieved from the results:the concrete crack propagation law of FCM meets the experiments'' results well; the differences of tensile stress of the steel liner between the crown and the bottom are less than the traditional node shared model when FCM model is adopted; the width of the concrete crack of FCM model ranges from 0.3 to 0.4, larger than traditional node shared model; non-uniformities of both the displacement around the penstock crown and the steel liner tensile stresses increase with the friction while tensile stresses values and strain non-uniformities of the cross-crack-reinforcement decrease when the friction are larger. The results indicate that the rebar stresses are less while the non-uniform of liner stresses are greater when the combinations between steel liner and surrounding concrete are enhanced.