预应力高强混凝土管桩抗侧向冲击性能研究

Research on performance of prestressed high-strength concrete pipe piles under lateral impacts

为研究水平荷载作用下预应力高强混凝土管桩的动力响应和破坏模式,采用超高落锤冲击试验装置对4根预应力高强混凝土管桩(PHC管桩)进行冲击试验并使用ABAQUS进行数值模拟,测得不同冲击高度下落锤的冲击速度、冲击力时程曲线及试件冲击区侧面处位移时程曲线,并获取试件的破坏形态。结果表明:该模型能较好地模拟PHC管桩动力响应及破坏形态。基于该模型的可靠性,在PHC管桩内填充C30混凝土并配置钢筋进行冲击模拟。研究表明:PHC管桩在低速冲击作用下具有较好的弹性恢复能力;当PHC管桩局部受到2次大于15km/h的冲击荷载时,将在冲击区发生局部冲切破坏;当PHC管桩受到2次累计冲击荷载时,第2次撞击较首次抗冲击性能减弱;灌芯后的PHC管桩抗冲击性能较PHC管桩增强。

In order to study the dynamic response and failure mode of prestressed high-strength concrete pipe piles under horizontal load, four prestressed high-strength concrete pipe piles(PHC pipe piles) were tested experimentally by a super-high drop hammer impact testing device and simulated numerically by ABAQUS. The impact velocity, impact force-time curve and displacement-time curve at the side of the impact area of the specimen were measured for different impact heights of the falling hammer, and the damage pattern of the specimen was obtained.The results show that the model can simulate the dynamic response and failure mode of PHC pipe piles approximately. Based on the reliability of the model, a PHC pipe pile filled with concrete with a grade of compressive strength of C30 and reinforced with steel bars for impact simulation. The results show that PHC pipe piles can recover to the elastic stage after impacted by a low speed;when PHC pipe piles are locally impacted by a speed more than 15 km/h twice, local punching failure occurs in the impacted area;when PHC pipe piles are subjected to cumulative impact loads twice, the impact capacity of the second impact is lower than that of the first impact;the impact capacity of the PHC pipe pile after grouting is higher than that of the PHC pipe pile.