| 开挖卸荷对既有群桩竖向承载性状的影响分析 |
| |
| 引用本文： | 伍程杰,俞 峰,龚晓南,林存刚,梁荣柱.开挖卸荷对既有群桩竖向承载性状的影响分析[J].岩土力学,2014,35(9):2602-2608. |
| |
| 作者姓名： | 伍程杰 俞 峰 龚晓南 林存刚 梁荣柱 |
| |
| 作者单位： | 1.浙江大学 滨海和城市岩土工程研究中心，杭州 310058；2.浙江大学 软弱土与环境土工教育部重点实验室，杭州 310058； 3.浙江理工大学 建筑工程学院，杭州 310018 |
| |
| 基金项目： | 国家自然科学基金项目（No. 41102179）；浙江省科技厅公益技术研究项目（No. 2012C23029）。 |
| |
| 摘 要： | 既有建筑下增层开挖对已有桩基础的影响不同于基坑开挖对坑内桩基的影响。基于工程实例验证的有限元参数，用硬化土弹塑性模型模拟土体，用接触面单元模拟桩土相互作用，建立了桩筏基础-地基-增层开挖三维有限元模型，对增层开挖后群桩基础的竖向承载性状进行研究。分析了桩顶刚度、桩身轴力、桩侧摩阻力、桩端阻比以及土体回弹的变化规律，并研究了不同桩端土体刚度和增层开挖深度对这些参数的影响。结果表明，增层开挖后群桩中不同基桩表现出不同的承载性状，增大桩端土体刚度可明显提高单桩承载力和端阻比临界值；随着增层开挖深度的增加，侧阻和端阻的发挥程度也随之提高。研究结果有望为地下室增层开挖施工中的结构托换变形控制和补桩设计提供依据。
|
| 关 键 词： | 既有建筑 开挖 群桩基础 三维有限元法 |
| 收稿时间： | 2013-06-13 |
Influence of excavation unloading on vertical bearing behavior of existing pile groups |
| |
| WU Cheng-jie,YU Feng,GONG Xiao-nan,LIN Cun-gang,LIANG Rong-zhu.Influence of excavation unloading on vertical bearing behavior of existing pile groups[J].Rock and Soil Mechanics,2014,35(9):2602-2608. |
| |
| Authors: | WU Cheng-jie YU Feng GONG Xiao-nan LIN Cun-gang LIANG Rong-zhu |
| |
| Institution: | 1. Research Center of Coastal and Urban Geotechnical Engineering, Zhejiang University, Hangzhou 310058, China; 2. MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058, China; 3. School of Civil Engineering and Architecture, Zhejiang Sci-Tech University, Hangzhou 310018, China |
| |
| Abstract: | The effect of further downward excavation beneath an existing building on the pile foundation is different from the one encountered in a newly-created excavation case. Based on the finite-element parameters derived from a case history, a hardening-soil model and a contact-surface model are adopted to simulate the characteristics of soil and the pile-soil interaction, respectively. The three-dimensional finite element framework takes into account the interaction of piled raft foundation, ground and excavation, and is able to investigate the vertical bearing behavior of the existing pile groups after the excavation. The investigation accounts for the effects of end-bearing soil stiffness and excavation depth on the variation trends of pile-head rigidity, pile force, pile shaft resistance, ratio of pile base resistance and soil rebound. The results show that individual piles in an existing pile group subjected to further excavation behaved differently. Increasing the stiffness of the end-bearing soil is crucial to enhancing pile capacity and the critical ratio of pile base resistance. The excavation depth is a key factor that positively influences the mobilization degree of the shaft and base resistances of existing piles. The present results are possible to assist the deformation control of structure underpinning and the design of supplemented pile for further excavation under existing basement. |
| |
| Keywords: | existing building excavation group-pile foundation three-dimensional finite element method |
|
| 点击此处可从《岩土力学》浏览原始摘要信息 |
| 点击此处可从《岩土力学》下载免费的PDF全文 |
|
