太洪长江大桥隧道式锚碇设计

太洪长江大桥主桥为跨径808 m单跨简支钢箱梁悬索桥,南川岸采用隧道式锚碇,锚碇位于极软岩中,岩石天然饱和抗压强度为4.49 M Pa,围岩级别为Ⅴ级,地质条件差.针对锚碇工程地形、地质条件,通过在主索鞍处向外旋转边跨主缆及隧道式锚碇轴线角度2°,解决了隧道式锚碇浅埋以及2个锚塞体间距过小的问题;进行多参数比选,隧道式...

Design of Tunnel Anchorage of Taihong Changjiang River Bridge

The main bridge of Taihong Changjiang River Bridge is a simply-supported steel box girder suspension bridge with a single span of 808 m.The Nanchuan-side anchorage is a tunnel anchorage that is located in poor geological environment,where the compressive strength of fully-saturated rock is 4.49 MPa and the stability of the surrounding rock is graded V.The shallow burying depth of the tunnel anchorage and small spacing between the two anchor plugs posed great challenges to the construction of main cables and the anchorage itself.To address this issue,the side-span main cables and the axis of the tunnel anchorage were rotated outwardly by 2°at the saddles to facilitate the construction.As per parametric comparison,the tunnel anchorage obtains a circular arc roof,with the front and rear anchor surfaces of 13 m(width)×13 m(height)and 18 m(width)×19 m(height),respectively.The anchor plugs are 58 m long,and the front and back anchor chambers are 35 m and 3.8 m long,respectively.Based on the code,the calculated safety factor of uplift resistance is 4.3(greater than the value of 2.0 given in code).The stability safety factor of surrounding rock gained from special geotechnical test and numerical simulation is 6.0(greater than the value of 4.0 given in code).During the tunnel excavation,measures were taken to control the damage of surrounding rock,and smooth blasting was also applied for the same purpose.To strengthen the integral load bearing performance of the anchor plugs and surrounding rock,the strong grid steel frame was used for shoring and protection.