临近新建隧道边墙的桥梁桩基加固方案

针对广州地铁11号线穿越既有桥梁桩基础工程,提出对临近隧道边墙的桥梁基桩进行加固处理的技术方案。参考相关隧道穿越工程设计经验和规范,提出采用围岩位移和基桩位移双指标来控制隧道施工对既有桩基的影响,并采用有限差分数值分析软件MIDAS/GTS进行了验算。结果表明,对侵入隧道边墙的基桩进行托换处理,对距离隧道边墙1.5倍桩径范围的基桩进行加固处理,可将穿越施工时基桩沉降控制在5 mm以内,拱顶沉降控制在50 mm以内。该方案实施后,实际监测值与数值模拟计算值接近,托换基桩的最大竖向位移始终在控制值以内。

Reinforcement Scheme of Bridge Pile Foundation near the Side Wall of New Tunnel

Aiming at the project of Guangzhou Metro Line 11 passing through the existing bridge pile foundation,thetechnical scheme of reinforcing the bridge foundation pile near the tunnel side wall was proposed.Referring to therelevant design experience and specifications of tunnel crossing engineering,the double indexes of surrounding rockdisplacement and foundation pile displacement were proposed to control the influence of tunnel construction on existingpile foundation,and the finite difference numerical analysis software MIDAS/GTS was used for checking calculation.The results show that underpinning treatment can be carried out for the foundation piles that intrude into the side wall ofthe tunnel,and the foundation piles which are 1.5 times the pile diameter from the side wall of the tunnel can bereinforced.The settlement of the foundation pile and the vault settlement can be controlled respectively within 5 mm and50 mm during the crossing construction.After the implementation of the reinforcement scheme,the actual monitoringvalue is close to the numerical simulation value,and the maximum vertical displacement of underpinning pile is alwayswithin the control value.