Soil-pile interaction during pile installation . Observations from x-ray tomography and 3 D-DIC
Soil-pile interaction during pile installation . Observations from x-ray tomography and 3 D-DIC
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发表时间：
2015
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通讯作者：
M. Silvaa;Gaël COMBEa
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作者：
M. Silvaa;Gaël COMBEa
摘要。在砂土中安装打孔桩的机理是复杂的，很难从现场试验中确定。诸如颗粒破碎、砂密度局部变化、桩磨损和拱效应等现象通常通过间接方法或使用小型实验室模型进行研究。本文介绍了一项实验实验室研究的结果，该研究致力于分析在硅质砂样品中安装无仪器封闭模型桩期间的土壤运动学。研究的重点是通过关注桩尖周围的砂桩相互作用来了解安装过程的微观力学方面。结合x射线层析成像和三维数字图像相关得到三维位移场。结果显示了位移和应变集中的两个明确的区域。这些区域的相互作用为控制桩身摩擦的机制提供了新的思路，当桩嵌入砂土时，这些区域由连续的砂土收缩和伸展阶段联系在一起。
Abstract. The mechanisms behind the installation of a driven pile in sands are complex and difficult to identify from field tests. Phenomenon such as grain breakage, local variations in sand density, pile abrasion and arching effects, are commonly studied through indirect methods or by using small laboratory models. This article presents the results of an experimental laboratory research devoted to the analysis of the soil kinematics during the installation of an uninstrumented close-ended model pile in a specimen of siliceous sand. The research has focused on understanding the micromechanical aspects of the installation process by focusing on sand-pile interaction around the pile’s tip. A three dimensional displacement field was obtained with the combined use of x-ray tomography and three dimensional digital image correlations. The results show two well-identified zones where the displacement and therefore strains concentrate. The interaction of these zones, which are linked by consecutive phases of sand contraction and extension as the pile embeds into the sand, gives new ideas about the mechanisms controlling the pile shaft friction.