天峨龙滩特大桥下老岸拱座基坑边坡稳定性分析及加固方案  

Stability Analysis and Reinforcement Scheme of Arch Foundation Pit Slope on Xialao Side of Longtan Tianhu Bridge

作　　者：陈云生 米德才 CHEN Yun-sheng;MI De-cai(Guangxi Communications Design Group Co.Ltd.,Nanning 530029,China;Guangxi Geotechnical Disaster Control Technology Research Center,Nanning 530029,China)

机构地区：[1]广西交通设计集团有限公司,南宁市530029 [2]广西岩土灾害防治工程技术研究中心,南宁市530029

出　　处：《公路》2023年第2期54-60,共7页Highway

基　　金：中国博士后科学基金资助项目,项目编号2019M663874XB;广西科技基地和人才专项,项目编号AD20238069;广西科技基地和人才专项,项目编号AD17129047。

摘　　要：为保障“世界第一拱”的安全,在地调、物探、钻探、钻孔电视及监测的基础上,通过方案比选、赤平投影及FLAC3D数值模拟技术研究了天峨龙滩特大桥下老岸拱座拱背侧边坡的潜在破坏模式、潜在滑动面、稳定性及最优加固方案。研究结果表明:(1)边坡潜在破坏模式为前缘剪出式阶梯状楔形顺层滑动,稳定性主要受强~中风化分界面、层间软弱夹层及陡倾结构面控制;(2)边坡存在3个折线形潜在滑面,从第四级边坡坡脚沿泥页岩软弱夹层剪出的风险最大,强风化与中风化交界面为滑动的第二风险点,第三级边坡坡脚为滑动的第三风险点;(3)边坡开挖后在未防护暴雨工况下处于失稳状态,失稳后水平影响距离为距坡顶开挖线约1倍边坡高度;(4)采用“上短中长、底部适中”的锚固排列方式加固后,经稳定性分析及智能监测验证可知边坡处于稳定状态。In order to ensure the safety of the “world’s first arch”, on the basis of geological survey, geophysical prospecting, drilling, borehole TV and monitoring, the potential failure mode, sliding surface, stability and optimal reinforcement scheme of the slope are studied by comparison of schemes, stereographic projection and FLAC3D numerical simulation. The results show that:(1) the potential failure mode of the slope is the step-shaped wedge sliding with the front edge cut out;(2) there are three broken-line potential sliding surfaces in the slope, and the risk of the slope cutting out from the foot of the fourth slope along the weak interlayer of shale is the greatest, the interface between strong weathering and moderate weathering is the second risk point of sliding, and the foot of the third slope is the third risk point of sliding;(3)after excavation, the slope is in an unstable state under the condition of unprotected rainstorm, and the horizontal influence distance after instability is twice the slope height from the slope top;and(4) it is reasonable to adopt the anchor arrangement mode of “short at upper, long at medium, and moderate at bottom”. After reinforcement, the stability analysis and intelligent monitoring show that the slope is in a stable state.

关 键 词：边坡加固 边坡稳定性 FLAC3D 潜在滑动面 岩质边坡 

分 类 号：U416.1[交通运输工程—道路与铁道工程] P642.22[天文地球—工程地质学]