不排水黏土地层沉井基础刃脚极限承载性状研究  

Ultimate Bearing Capacity of Caisson Foundation Foot Blade in Undrained Clay

作　　者：王安辉 张艳芳 罗如平 Wang Anhui;Zhang Yanfang;Luo Ruping(China Construction Industrial&Energy Engineering Group Co.,Ltd.,Nanjing 210023,China;School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang 330013,China;Engineering Research&Development Centre for Underground Technology of Jiangxi Province,Nanchang 330013,China)

机构地区：[1]中建安装集团有限公司,江苏南京210023 [2]华东交通大学土木建筑学院,江西南昌330013 [3]江西省地下空间技术开发工程研究中心,江西南昌330013

出　　处：《市政技术》2023年第3期45-51,114,共8页Journal of Municipal Technology

基　　金：国家自然科学基金项目(41972291);江苏省自然科学基金项目(BK20210051)。

摘　　要：沉井广泛用于取水管线、港口设施等市政工程的基础结构中,其极限承载力是工程设计重点关注的问题之一。由于沉井底部为带刃脚结构,且沉井内侧土体不断被开挖,沉井基础端部极限承载性状较传统基础存在较大差异。基于有限单元极限分析方法,建立了考虑刃脚形状及土体盆式开挖的沉井基础极限承载性状的分析模型,对不同刃脚高度、踏面宽度、倾斜角大小及土体开挖参数下沉井基础刃脚处土体破坏特性和极限承载性状进行了研究。研究结果表明:刃脚踏面宽度能显著减小沉井端部极限承载力,踏面宽度为0.1倍沉井壁厚时,其极限承载力约为非刃脚情况下极限承载力的0.4~0.6倍;井内土体开挖能进一步降低刃脚极限承载力值,且降低幅度与预留土宽度、土体开挖倾角有关。Being widely used in water tower,harbor facilities and other engineering structures,ultimate bearing capacity of open caisson is one of the important issues in engineering design.The ultimate bearing capacity of the caisson is quite different from that of the traditional foundation because the bottom of the open caisson is a structure with foot blade and the inside is constantly excavated.Considering the shape of cutting face and soil basin excavation,an analytical model is established by finite element limit analysis method to study the failure characteristics and ultimate bearing capacity of caisson foundation under different cutting face height,cutting face width,cutting face inclination angle and soil excavation parameters.The results show that the ultimate bearing capacity can be significantly reduced by width of the cutting face.When the width of the cutting face is 0.1 times of the wall thickness,the ultimate bearing capacity is about 0.4~0.6 times of that without cutting face.The soil excavation in the open caisson can further reduce the ultimate bearing capacity and the reduction portions is related to the reserved soil width and the excavation inclination angle.

关 键 词：沉井 刃脚 极限承载力 极限分析 盆式开挖 

分 类 号：TU473.2[建筑科学—结构工程]