摘要
针对圆形锚板及螺旋锚基础承载力问题,基于欧拉–拉格朗日单元耦合分析方法,采用可考虑应变软化的改进Mohr–Coulomb弹塑性本构模型,对砂土中圆锚拉拔过程进行数值模拟。在与单盘螺旋锚离心机试验结果对比验证数值模型有效性的基础上,探讨不同密实度砂土中锚板的拉拔破坏机理,并分析浅埋圆锚的破坏滑裂面形式,以及滑裂面上土体强度参数及侧压力分布规律等。数值结果表明,滑裂面上土压力系数及内摩擦角非常值,土压力系数从锚盘边缘开始直线上升,至0.2D(盘径)高度时达到峰值,而后呈指数衰减至某一稳定值;对于松及中密砂土,滑裂面上等效内摩擦角可采用Davis折减公式确定,对于密砂,Davis折减公式会高估等效内摩擦角(约3°)。基于分析结果,提出了浅埋圆形及螺旋形锚板的上拔承载力理论计算方法,并建议现有理论计算公式的适用条件,相关成果为工程应用提供一定参考。
A numerical study combining coupled Eulerian–Lagrangian method to large deformation analysis and modified Mohr–Coulomb elasticplastic constitutive model that can describe the soil behavior of strain softening has been performed to investigate the pullout mechanism of circular or helical anchor plates in sand. The validity of the numerical model has been established through the comparison against the centrifugal tests of single-helix anchors. The uplift failure mechanism of circular anchors in sand with different compactnesses was then investigated. The failure modes, distributions of normal stress and changes of soil strength along failure surfaces in loose, medium and dense sands have been analyzed. It was demonstrated that the coefficients of lateral earth pressures and the friction angles along the failure surface were not constant. The coefficient of lateral earth pressure rose linearly from the edge of the plate, up to the peak value at approximately 0.2D(plate diameter), and then decreased exponentially to a stable value. The equivalent friction angle along the failure surfaces in loose and medium sand could be determined by the reduction formula proposed by Davis, and it would be overestimated approximately 3° in the dense sand. Furthermore, a theoretical calculation method for the uplift capacity of shallow circular or helical anchor plates was proposed based on the above analyses. Meanwhile, the comparison among several existing theoretical formulas has been made, and the applicability for each formula has been proposed, which can provide references for the engineering design.
作者
郝冬雪
袁驰
陈榕
张新
史旦达
孔纲强
HAO Dongxue;YUAN Chi;CHEN Rong;ZHANG Xin;SHI Danda;KONG Gangqiang(School of Civil Eng.and Architecture,Northeast Electric Power Univ.,Jilin 132012,China;College of Architecture and Civil Eng.,Beijing Univ.of Technol.,Beijing 100124,China;Northeast Electric Power Design Institute Co.,Ltd.of China Power Eng.Consulting,Changchun 130021,China;College of Ocean and Eng.,Shanghai Maritime Univ.,Shanghai 201306,China;Key Lab.of Geomechanics and Embankment Eng.(Hohai Univ.),Ministry of Edu.,Nanjing 210098,China)
出处
《工程科学与技术》
EI
CSCD
北大核心
2022年第2期101-112,共12页
Advanced Engineering Sciences
基金
国家自然科学基金项目(52078108)
吉林省科技厅中青年科技创新创业卓越人才(团队)项目(20210509058RQ)
吉林省教育厅科学研究项目(JJKH20210103KJ)。
关键词
圆或螺旋形锚板
上拔承载力
应变软化
破坏机理
circular/helical anchor plate
uplift capacity
strain softening
failure mechanism
