Construction of South Pylon Foundation of Main Bridge of Jiujiang Changjiang River Highway Bridge

The main bridge of the Jiujiang Changjiang River Highway Bridge is a six-pylon asymmetrical hybrid girder cable-stayed bridge.The foundation of the south pylon at the Jiujiang side is located on the slope way of the upstream surface of the Yongan Embankment in the Changjiang River,consisting of 28 bored piles with a diameter of 2.8 m each and the separated double pile caps upon.Before the foundation construction,the precautions of using riprap to strengthen the bank and building anti-pervading wall were taken to guarantee the safety of the embankment.The percussion type drill machine was used in hole-drilling and several precautionary actions were taken to guarantee the quality of the hole.The method of using supporting piles plus pendulum jet grouting piles was adopted to safeguard the foundation pit excavation of the pile cap ahead of the excavation.Meanwhile,after the foundation pit excavation,the slope of the Changjiang River embankment above the designed low water level was paved by dry-laid precast concrete revetment,and the casting of the concrete was carried out on the platform of the slope ways of the embankment.The results show that the construction quality of the south pylon foundation of the bridge is excellent and the section of the Yongan Changjiang River embankment at the bridge site which withstood the flood season in the year 2010,2011 and 2012 is proved to be sound.