摘要
目的 研究密砂中单盘螺旋锚安装过程中锚周土体变形特性及其对抗拔能力的影响,为螺旋锚基础精细化设计提供技术支撑.方法 利用MatDEM软件建立密砂中螺旋锚安装及拉拔过程的数值计算模型,通过与室内模型试验结果对比标定颗粒微观力学参数,进而分析钻入和预埋两种安装方式下不同埋深和盘径的螺旋锚安装效应及上拔承载力.结果 当H/dw≤10时,钻入安装的极限上拔力较预埋低,当H/dw＞10后,安装方式带来承载力差别不再随埋深增加而增加;随着盘径增大,两种安装方式下螺旋锚的承载能力均表现出增大的趋势,钻入方式下的Qut比预埋下的Qup降低量从33％增至53％,预埋方式螺旋锚的承载能力高于钻入.结论 钻入安装螺旋锚的上拔承载力低于预埋方式的承载力,但当埋深比超过10后,安装扰动对承载力的影响随着深度变化很小;随着盘径增加,安装扰动对极限上拔承载力的影响增大,相较于埋深变化带来的安装扰动差异,盘径变化带来的影响更明显.
Abstract
The purpose of this study is to investigate the deformation characteristics of the soil around the anchor during the installation process of a single helix anchor in dense sand and its impact on the uplift capacity,in order to provide technical support for the refined design of helix anchor foundations.A numerical calculation model for the installation and pull-out process of helix anchor in dense sand was established using MatDEM software.The micro mechanical parameters of particles were calibrated by comparing with indoor model test results.The installation effect and uplift capacity of helix anchors with different embedment depths and diameters under drilling and pre embedding installation methods were analyzed.When H/dw≤ 10,the ultimate uplift capacity of drilling installation is lower than that of pre embedded.When H/dw＞10,the difference in uplift capacity caused by the installation method no longer increases with the increase of embedment depth;As the diameter of the disc increases,the uplift capacity of the helix anchor under both installation methods shows an increasing trend.The decrease in Qut under the drilling method compared to the pre embedded Qup increased from 33％to 53％.The uplift capacity of the helix anchor under the pre embedded method is higher than that under the drilling installation method.The conclusion is that the uplift capacity of drilling and installing helix anchors is lower than that of pre embedded methods,but when the embedment depth ratio exceeds 10,the impact of installation disturbance on the uplift capacity changes little with depth;As the diameter of the disc increases,the impact of installation disturbance on the ultimate uplift capacity increases.Compared to the difference in installation disturbance caused by changes in embedment depth,the impact of diameter changes is more significant.
基金项目
国家自然科学基金项目(52078108)
吉林省科技厅科研项目(20210509058RQ)
吉林省教育厅科学研究项目(JJKH20210103KJ)
NETL
NSTL
万方数据