绿汁江大桥非对称隧道式锚碇结构稳定性分析  

Stability Analysis of Asymmetric Tunnel Anchorage of Lvzhijiang Bridge

作　　者：胡靖[1] 陈应高[1] 邓平 饶克夏 HU Jing;CHEN Yinggao;DENG Ping;RAO Kexia(Guizhou Transportation Planning Survey&Design Academe Co.,Ltd.,Guiyang 550081,China;China Railway Development Investment Group Co.,Ltd.,Kunming 650200,China)

机构地区：[1]贵州省交通规划勘察设计研究院股份有限公司,贵州贵阳550081 [2]中铁开发投资集团有限公司,云南昆明650200

出　　处：《世界桥梁》2023年第5期82-88,共7页World Bridges

基　　金：贵州省交通运输厅重大科技攻关项目(2023-122-025);国家自然科学基金项目(52268022)。

摘　　要：绿汁江大桥为主跨780 m单塔单跨钢箱梁悬索桥,玉溪岸隧道锚处围岩条件较差且左、右幅锚地质条件存在差异,因此将左、右幅锚设计优化为非对称方案,将右幅锚前锚室与部分锚塞体底面改为弧形,右幅锚塞体长度增加5 m,锚碇中部截面突变处理。为研究优化后隧道锚及围岩的稳定性,采用简化力学模型和数值模拟软件FLAC3D分析优化后隧道锚拉拔稳定系数和围岩稳定系数,以及隧道施工对隧道锚和围岩的影响。结果表明:优化设计后,2种方法计算的隧道锚拉拔稳定系数均大于2.0,围岩稳定系数大于4.0,均满足规范要求;隧道施工对右幅锚各剖面计算点位移影响很小,右幅锚围岩未出现拉应力,围岩塑性区主要集中在边坡开挖的工作面和锚碇后锚室后方,隧道施工对隧道锚的安全影响很小。The Lvzhijiang Bridge is a mono-tower steel box girder suspension bridge,the main span length reaches 780 m and the hanger cables are only arranged in the main span.The Yuxi-side tunnel anchorages are located where the rock condition is not well,the geological conditions at the sites of left and right tunnel anchorages are different,as a result,the two anchorages do not adopt similar structures.For the right anchorage,the bottom of the front anchor chamber and partial anchor body are curved,and the anchor body is lengthened by 5 m,and the cross-section shows abrupt variation in the central part of the anchorage.To study the stability of the modified tunnel anchorage and surrounding rock,a simplified mechanical model accompanied with numerical simulation in FLAC3D were taken to analyze the pullout stability coefficient and rock stability coefficient as well as the influence of tunnel construction on the anchorage and surrounding rock.It is shown that the pullout stability coefficients of the tunnel anchorage and the stability coefficient of surrounding rock calculated by the two methods are over 2.0 and 4.0,respectively,meeting the code requirements.The construction of anchorage exerted minimal influence on the displacements of calculation points on the cross-sections of right anchorage,and no tensile stress occurred in the surrounding rock of right anchorage.The plastic zones in the surrounding rock mainly concentrated in the slope excavation area and rocks behind the rear anchor chamber,and tunnel construction had minor threat to the safety of tunnel anchorage.

关 键 词：悬索桥 隧道式锚碇 非对称结构 稳定性 位移 应力 塑性区 数值模拟 

分 类 号：U448.25[建筑科学—桥梁与隧道工程] U443.24[交通运输工程—道路与铁道工程] U441