成都地铁河中桥梁桩基托换施工技术

成都地铁2号线春熙路站-东门大桥站区间盾构隧道左线自东门大桥桩基中穿过，为保证盾构顺利通过并确保桥梁安全，采用托台换桩法对侵入隧道桩基进行托换处理。施工中采用河中围堰、帷幕注浆、降水、人工挖孔和静态爆破等辅助方法有效控制了地下水的影响和桥台沉降，确保了桥梁、管线安全及整个托换施工的顺利实施。

Construction Technology of Underpinning of Pile Foundations in Water: a Case in Construction of Chengdu Metro

The left tube of the shield-bored running tunnel from Chunxi Road Station to Dongmen Bridge Station on the second line of Chengdu Metro crosses the pile foundations of Dongmen Bridge.In order to ensure the successful boring of the shield,underpinning method is adopted.Countermeasures,such as building cofferdam in water,curtain grouting,dewatering,manual-cut holes and static blasting,are taken during construction,which brings the settlement of the bridge abutments under effective control and ensures the safety of the bridge,the utility lines and the pile foundation underpinning construction.