冲击钻孔施工对临近框架桥影响的数值模拟研究  

Numerical Simulation of Influence of Pile Driving Construction on Nearby Frame Bridge

作　　者：谢春明 李明国 黄华江 任艳 XIE Chun-ming;LI Ming-guo;HUANG Hua-jiang;REN Yan(Research and Development Center on Road Transport Safety and Emergency Support Technology&Equipment,Guangzhou 510420,China;Guangdong Hualu Traffic Technology Co.,Ltd.,Guangzhou 510420,China;School of Civil Engineering,Guangdong Communication Polytechnic,Guangzhou 510800,China)

机构地区：[1]公路交通安全与应急保障技术及装备交通运输行业研发中心,广东广州510420 [2]广东华路交通科技有限公司,广东广州510420 [3]广东交通职业技术学院土木工程学院,广东广州510800

出　　处：《世界桥梁》2021年第3期97-102,共6页World Bridges

摘　　要：某高速互通立交主线桥第15~44跨为30×15 m钢筋混凝土结构框架桥,经多次加固后仍存在多处破损、露筋和开裂等病害,需在该桥两侧修建新桥后再进行拆除。新桥桩基础距旧桥最近净距约1.4 m,拟采用冲击钻孔施工工艺,冲击钻采用的冲锤重量为5 t,冲击时间为5 ms。为了解冲击钻孔施工对该桥结构的影响,分析其适用性,采用有限元软件建立部分框架桥分离式共节点模型,考虑首次冲击和孔底冲击2种工况,对冲击钻孔施工影响下临近框架桥的力学响应进行数值模拟。结果表明:首次冲击工况、孔底冲击工况框架桥墩柱最大竖向位移分别为1.75 mm、3.3 mm,桥面外侧横向水平位移分别为3.2 mm、1.7 mm;采用冲击钻孔工艺施工,考虑到冲击钻孔过程中需要多次冲击,引起的临近框架桥沉降值以及桥面横向水平位移较大,导致结构承受较大的安全风险,建议改用回旋钻成孔工艺施工。The part of mainline bridge of a highway interchange between the 15th span and 44th span is a 30×15 m reinforced concrete frame structure.Although subjected to several times of retrofit,damages,exposed reinforcement and cracks still existed in many locations.It was determined to build new bridges on both sides of the existing bridge and demolish the existing bridge once the new bridges came into service.The pile foundations of the new bridge stand not far from the existing bridge,with a minimum net distance of about 1.4 m.The piles were designed to be driven by the impact drill that had a 5 t hammer working at time steps of 5 ms.To investigate the influence of pile driving construction on the nearby existing bridge and the feasibility of the construction method,the finite element model of part of the frame bridge was built up,featuring the node-to-segment and node-to-surface interface.In the numerical simulation,the initial driving and hole-base driving were considered to analyze the influence of pile driving construction on the nearby frame bridge.The results show that in the contexts of initial driving and hole-base driving,the maximum vertical displacements of the pier columns of the frame bridge were 1.75 mm and 3.3 mm,respectively,and the lateral displacements measured at the edges of the deck were 3.2 mm and 1.7 mm,respectively.Considering that the consecutive driving during the pile driving construction would induce oversized settlement of the nearby frame bridge and the lateral displacement of the deck,the rotary drilling technique was proposed to reduce the safety risk of the structure.

关 键 词：框架桥 钢筋混凝土结构 冲击钻孔 共节点分离式模型 位移 应力 数值模拟 

分 类 号：U448.15[建筑科学—桥梁与隧道工程] U445.551[交通运输工程—道路与铁道工程]