介绍广州地铁二、八号线桩基主动托换洞内截桩的施工方案。主动托换洞内截桩是桩基托换的一种新做法，吸收了被动桩基托换的部分施工方法，解决了运营中曲线桥梁托换时水平力很难平衡的难题；阐述在动荷载作用下进行桩基托换的施工方法和托换过程中桥梁结构的监控量测；为在复杂结构和地质条件下进行桩基托换积累经验。

The construction scheme for the cutting of the piles inside tunnel in the active pile foundation underpinning on Line 2 and Line 8 of Guangzhou Metro is presented. Cutting the piles inside the tunnel in active underpinning is a new approach of pile foundation underpinning, which absorbs some part of the construction methods of the passive pile foundation underpinning. Due to the new underpinning approach, the problem that it is very difficult to balance the horizontal forces during the underpinning of the operating curvilinear bridge is solved. The construction methods of underpinning under dynamic loading conditions and the monitoring of the bridge structure during underpinning are described. The works practice provides experience for the pile foundation underpinning of complex structures under complex geological conditions in the future.