都汶公路彻底关大桥桥墩抗滚石冲击防护研究

RESEARCH ON ROCKFALL IMPACT PREVENTION OF CHEDIGUAN BRIDGE PIER,DUWHEN ROAD

都(江堰)—汶(川)公路是进出5·12汶川地震极重灾区的生命通道,横跨岷江两岸的彻底关大桥桥墩在5·12汶川地震中被左岸崩落的滚石击中而倒塌,经过恢复重建,新建彻底关大桥于2009年5月12日建成通车。2009年7月25日凌晨4:40左右,岷江右岸高位危岩发生大面积崩塌,巨石再次将彻底关大桥砸毁。经调查,岷江两岸山体存在多处危岩,极有可能再次发生滚石砸毁大桥的灾难性事件。为此,研发一种新型桥墩抗滚石冲击垫层结构,采用非线性有限元对桥墩受滚石撞击过程进行数值模拟研究,考虑滚石撞击过程中材料非线性、几何非线性和接触非线性以及桥墩中的横向箍筋和纵向钢筋的影响,结果表明所采用的垫层防护装置能够有效地缓冲滚石的冲击,大幅度提高桥墩抗滚石冲击的能力,按此思路设计的桥墩防护结构已经竣工3a,运行效果良好。

Dujiangyan-Whenchuan road is the life line engineering of disaster areas hit by the 5?12 Whenchuan earthquake. Chediguan bridge on the road which stretches across the both sides of Mingjiang River collapsed due to rockfalls during the earthquake. After reconstruction,the new Chediguan bridge was open to traffic on May 12, 2009. July 25,2009,at 4:40 or so,a large area collapse on the Mingjiang River bank high unstable rock occurred, rockfalls smashed the Chediguan bridge again. After investigation, there are many rocks existing in the mountains of both sides of Minjiang River,which will likely trigger the catastrophic events of rockfalls smashed the bridge. On this basis,the development of a new cushion structure of rockfalls impact piers is executed,using nonlinear finite elemnet method,considering the effects of nonlinear material properties,nonlinear geometry,nonlinear contacts and rebars during the processes. The results show that,the cushion structures could effectively buffer the impact of the rockfalls,the ability of rockfalls impact piers could be improved,and up to now,the consequences are very well.