考虑摩擦接触特性的钢衬钢筋混凝土管道承载机理研究

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

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。

Coulomb friction model is employed to simulate the friction-contact behavior between steel linerand reinforced concrete when a numerical model of reinforced concrete penstock with steel liner located onthe downstream surface of concrete dam is built up. The critical pressure of concrete crack initiation,con-crete crack propagation law, penstock deformation characteristic and stresses distribution of steel are ana-lyzed upon the friction-contact model（FCM）. Some impressive conclusions can be achieved from the re-sults： the concrete crack propagation law of FCM meets the experiments＇ results well; the differences oftensile stress of the steel liner between the crown and the bottom are less than the traditional node sharedmodel when FCM model is adopted; the width of the concrete crack of FCM model ranges from 0.3 to0.4, larger than traditional node shared model; non-uniformities of both the displacement around the pen-stock crown and the steel liner tensile stresses increase with the friction while tensile stresses values andstrain non-uniformities of the cross-crack-reinforcement decrease when the friction are larger. The results in-dicate that the rebar stresses are less while the non-uniform of liner stresses are greater when the combina-tions between steel liner and surrounding concrete are enhanced.